Nitrous Oxide

What Kind of Drug Is It?

Nitrous oxide is a type of anesthetic, a substance used to deaden pain. It can alleviate pain without causing a loss of consciousness. Best known by the nickname "laughing gas," nitrous oxide is used primarily by dentists to keep patients comfortable during painful procedures. It can also be used in combination with other drugs as a general anesthetic. When administered by trained medical professionals, the gas is considered a safe and effective form of anesthesia.

As a recreational drug—a drug used solely to get high, not to treat a medical condition—nitrous oxide is classified as an inhalant. (An entry on inhalants is available in this encyclopedia.) Inhalants contain dangerous vapors, which are gases or fumes that can be irritating or physically harmful when breathed in. Vapors from inhalants produce psychoactive, or mind-altering, effects when breathed in through the mouth or nose.

More than 1,000 different household and industrial products—all readily accessible to consumers of any age—are sniffed or huffed for their intoxicating effects. Glues, paints, markers, nail polish, correction fluid, and shoe polish are among the most commonly abused inhalants.

Among young teens, nitrous oxide is typically obtained from canned whipped cream available at grocery stores. Nitrous oxide gas is used to propel, or to drive out, the whipped cream from the can. Sales of nitrous oxide to older teens and adults usually occur at dance clubs and all-night dance parties called raves or through Internet transactions.

Official Drug Name: Nitrous oxide, dinitrogen oxide, nitrogen oxide

Also Known As: Balloons, buzz bombs, cartridges, hippie crack, laughing gas, nitrous, whip-its, whippets, whippits

Drug Classifications: Not scheduled

Overview

In the 1700s and the 1800s, chemists, doctors, and dentists in Europe and the United States experimented with three different anesthetic gases: nitrous oxide, ether (EETH-uhr), and chloroform (KLOR-uh-form). These compounds revolutionized surgical and dental procedures. While under the influence of an anesthetic gas, a patient's perception of pain is altered. Nitrous oxide, ether, and chloroform all dull or block painful sensations. They also produce a rather intense high.

The intoxicating side effects of the gases, however, led to their use and abuse as recreational drugs. A research report titled "Inhalant Abuse," prepared by the National Institute on Drug Abuse (NIDA) and updated in 2005, noted that "nitrous oxide is the most abused of these [three] gases."

Nitrous oxide is a gas with both anesthetic and analgesic (pain relieving) properties. It was first discovered in 1772 by British scientist, theologian, and philosopher Joseph Priestley (1733–1804). Earlier, Priestley had identified oxygen, which he termed "phlogisticated (floh-JISS-tih-kay-ted) air." The term "phlo-gis-tic" comes from a Greek word meaning "flammable."

Nitrous Demonstrations: An Unusual Form of Entertainment

Although Priestley is credited with discovering nitrous oxide, another scientist recognized the potential value of its numbing and intoxicating effects. This man was Sir Humphry Davy (1778–1829), a British chemist who experimented with the gas on himself and his friends. In a book Davy wrote on the subject in 1800, he suggested that nitrous oxide's ability to dull pain might make it a useful anesthetic in surgeries. But, as Julie M. Fenster noted in Ether Day: The Strange Tale of America's Greatest Medical Discovery and the Haunted Men Who Made It, "no one took his suggestion."

And so, despite Davy's writings on the subject, nitrous oxide was not put to use in the medical field for another four decades. Apparently, according to historical sources, pain was such an accepted part of medical intervention during the early nineteenth century that neither scientists nor doctors seriously considered trying to ease it. Instead, nitrous oxide, which had earned the nickname "laughing gas," enjoyed popularity as a way for the British upper classes to entertain themselves at social gatherings. "The gas was soon offered at dinner parties instead of wine," wrote Fenster. It was even demonstrated in theaters and at festivals. In 1824, crowds in London were amazed by a show called "M. Henry's Mechanical and Chemical Demonstrations." The highly successful performances showed the uninhibiting effects of nitrous oxide on audience volunteers eager to try the gas.

"A New Era in Tooth-Pulling!"

Meanwhile in the United States, laughing gas was featured in traveling medicine shows and carnivals. Gardner Q. Colton (1814–1898), a former medical student, made a good living by giving public demonstrations of nitrous oxide. In New York City in 1844, he organized the "Grand Exhibition of Nitrous Oxide" on Broadway, charging the then-outrageous price of twenty-five cents per ticket. Colton moved his act to Hartford, Connecticut, later that year. Dr. Horace Wells (1815–1848), a dentist in Hartford, attended the nitrous exhibition with his wife. The evening's entertainment changed Wells' life forever.

Both Wells and his wife were among the volunteers from the audience who tried the laughing gas. The couple apparently engaged in some silly antics after sampling the nitrous oxide, but Wells was actually more interested in the effects of the gas on another member of the audience. A local man named Sam Cooley had seriously gashed his legs on a piece of furniture while stumbling around the stage on his nitrous high. His knees were bleeding badly, but he felt no pain. In fact, he didn't even realize he had been hurt. Wells was stunned by the effect of the gas and concluded that nitrous oxide might be useful as a medical anesthetic. In Wells' own often-quoted words, it was the beginning of "a new era in tooth-pulling!"

In keeping with the tradition of scientific experimentation in the nineteenth century, Wells used himself as a test subject. He devised a test case involving his dental colleague and friend Dr. John Riggs, who agreed to extract a tooth from Wells' mouth. The experiment took place on December 11, 1844. Wells asked Colton to set up his nitrous oxide equipment at the office Wells shared with Riggs. Wells administered the gas himself and soon nodded off from its effects. Riggs immediately pulled a sore wisdom tooth from Wells' mouth. The nitrous oxide had worked. Wells woke up shortly after the procedure and reported feeling no pain.

Considering his test a success, Wells began using nitrous oxide—quite successfully—as an anesthetic in his dental practice. When people heard about the new dental procedure, Wells' business increased. He was confident that painful dentistry would soon become a thing of the past.

A Demonstration Gone Bad

In January of 1845, before an audience of experts from the Harvard Medical School and Massachusetts General Hospital, Wells attempted to demonstrate the anesthetizing effects of nitrous oxide. He used a bag of the gas to sedate a patient before removing a tooth. However, the bag was withdrawn too soon, and the patient awoke before the procedure was complete. The experiment was considered a failure, and Wells was devastated. He never fully recovered from the disastrous demonstration and committed suicide in 1848. More than a decade later, in the early 1860s, the medical community came to understand and accept nitrous oxide as a valuable tool. It was finally being used not as a prop in a traveling sideshow, but as the anesthetic that Wells had suggested.

Modern Uses

By 1871, companies in both the United States and Great Britain were producing compressed nitrous oxide in cylinders. As of 2003, according to the Compressed Gas Association (CGA), nearly 90 percent of the nitrous oxide manufactured in the United States is intended for medical and dental applications. Another 5 to 8 percent is used in the food industry. Other legitimate uses for nitrous oxide include the manufacture of airbags, semiconductors, and fuels that boost horsepower in race car engines.

About Those Other Gases …

Ether is a flammable liquid with the chemical formula C₄H₁₀O. (Flammable means that the substance is capable of catching fire and burning quickly.) The intoxicating effects of ether have been known since the thirteenth century. It was first used as an anesthetic beginning in the mid-1800s, but its high flammability made it dangerous for medical use. The word ether comes from the Greek term meaning "to ignite" or "blaze."

Because ether is a liquid at room temperature, it can be swallowed, or the fumes from the liquid can be inhaled. In the 1760s, it was often dispensed by doctors by the drop onto a lump of sugar or mixed with water and used as a tonic. The use of ether as a recreational drug increased when users realized that it produced intoxication without a hangover. For a time, ether was actually consumed in place of alcohol, but many accidental fires occurred when drinkers sipped on their ether cocktails with a cigarette in hand.

It was not until the nineteenth century that ether caught on as an inhalant. So-called "ether frolics," or parties, became quite popular in the 1820s. The ether high was often compared to a spiritual experience. In fact, the term ethereal refers to the heavens or regions beyond the bounds of Earth.

Dr. William T. G. Morton first administered ether as a general anesthetic on October 16, 1846, at Massachusetts General Hospital. That day has since become known as "Ether Day."

Chloroform is a toxic (poisonous) liquid with a chemical formula of CHCl₃. This colorless anesthetic, discovered in 1833, is volatile, meaning it easily converts to a vapor. It is no longer used as a general anesthetic because of its dangerous side effects, which include serious damage to the liver.

Chloroform is an age-old tool of the trade among villains in films and television shows. In typical "bad-guy" style, a villain douses a cloth with chloroform and then approaches an unsuspecting victim from behind, placing the chloroform-soaked cloth over the person's nose and mouth. When inhaled, the fumes from the cloth quickly knock out the victim, leaving him or her defenseless.

However, the laughing gas parties and public demonstrations of the early 1800s evolved into a serious problem of abuse that has persisted into the twenty-first century. The gas is often sold at dance clubs and raves in balloons. Whipped cream cartridges, nicknamed "whippets," also contain nitrous oxide. These cartridges are sold through restaurant supply companies but are frequently purchased for illegal use.

What Is It Made Of?

Nitrous oxide is a compound made from nitrogen and oxygen. Its chemical formula is N₂o The gas itself is clear and colorless, with a slightly sweet odor and taste. Nitrous oxide should not be confused with the potentially toxic gas known as nitric oxide (NO). Nitric oxide is found in the atmosphere as an air pollutant. It is also found in very small amounts in the human body, where it helps to move oxygen to the tissues and transmit nerve impulses.

Nitrous oxide is best described as a liquefied gas. It is synthesized from a compound found in fertilizers and explosives. This compound, ammonium nitrate (NH₄NO₃), forms steam and nitrous oxide when heated. The nitrous oxide is then processed and turned into a liquid form for storage in tanks, cylinders, or cartridges.

Pure nitrous oxide is deadly. The gas must be mixed with oxygen to be used safely as an anesthetic.

How Is It Taken?

N₂O is used as an aerosol propellant in cans of whipped cream and some other food and beverage products. These products are a primary source of nitrous oxide for some abusers.

Depending on its intended use, nitrous oxide can be purchased in varying "grades," or degrees of purity. A food-grade version of the gas is sold to restaurants and caterers in small, bullet-shaped, metal cartridges. These cartridges are perfectly legal for use in the food preparation industry. Nitrous abusers refer to them as "whippets." One whippet delivers enough nitrous oxide to produce a three- to five-minute high. To release the nitrous oxide from a whippet, the high-pressure seal on the canister is pierced with a device called a "cracker." The resulting hole then emits a stream of nitrous oxide gas, which users inhale directly or use to inflate a balloon. Mishandling the cracker or piercing the wrong part of the canister can result in explosions and serious injuries.

Dealers often sell nitrous oxide to users at concerts, clubs, and raves. Instead of using small food-grade canisters, however, they use huge medical-grade nitrous tanks to dispense the gas into balloons. (Medical grade nitrous oxide is considered a prescription drug. These tanks can only be purchased legally by qualified medical personnel.) Nitrous-filled balloons sell for $3 to $5 apiece. One large cylinder of nitrous oxide can fill enough balloons to generate $20,000 to $30,000 in sales.

Sometimes, users fill plastic bags with nitrous oxide gas and then place the bags over their mouths or heads. This method of use carries a particularly high risk for serious injury and possible death. The user can easily lose consciousness and suffocate on the bag. Suffocation can also occur when nitrous oxide is consumed in large quantities in poorly ventilated spaces, such as closed-up cars or closets.

Are There Any Medical Reasons for Taking This Substance?

As an anesthetic, nitrous oxide has many legitimate uses. Its ability to reduce anxiety, restlessness, and fear makes it especially useful in the field of dentistry. Adults and children over the age of six have been shown to experience less discomfort and mental distress when given nitrous oxide during short but painful medical or dental procedures.

Scooby and Shaggy Rile Viewers

Nitrous oxide abuse became a hot topic in 2004, when recreational use of the gas showed up in a kids' film. In a one-minute-long scene from the PGrated Warner Bros. movie Scooby-Doo 2: Monsters Unleashed, one of the main characters, Shaggy, sniffs nitrous oxide from a whipped cream can and jokes about it. Seeing Shaggy do whippets is "supposed to make kids laugh," wrote Sue Marquette Poremba on the Preteenagers Today Web site. "It's supposed to be harmless fun. … That's the problem."

The scene in question begins with Shaggy and Scooby going to the kitchen. Shaggy opens the refrigerator and takes out a can of whipped cream. He shakes it up, sprays some cream into Scooby's mouth, and smiles broadly while Scooby's mouth fills up with the cream. Shaggy then takes a "hit" off the whipped cream canister. He breathes in the nitrous oxide without dispensing any cream, then hiccups. Shaggy then acts drunk and silly, saying that he needs to go outside to get some fresh air.

Concerned parents contacted the National Inhalation Prevention Coalition (NIPC) about the Scooby-Doo whippet spoof. Many were upset and believed that the film company was being insensitive to people who had lost loved ones due to inhalant abuse. One parent was especially concerned that the joke might go right over some adults' heads, yet lead children to copy the behavior. Harvey Weiss, the NIPC's executive director, brought attention to the issue in an "NIPC Inhalant Update Alert." Weiss urged Americans to view the scene from the film as a wakeup call, stating: "Our efforts should be to advance people's understanding about the dangers of inhalant use so they are recognized as a broad public health issue."

American obstetricians—physicians specializing in the birthing process—used nitrous oxide as a common pain management tool for women in labor until the early 1970s. By the early twenty-first century, however, the anesthetic had been replaced by newer drugs in the United States. However, a half-and-half mixture of nitrous oxide and oxygen was still being used in the United Kingdom to ease the pain of childbirth.

In a 2005 article for The Age, Julie Robotham reported on a group of Australian doctors who believed that nitrous oxide should no longer be used as a base for general anesthetics. According to an international study involving more than 2,000 patients, the use of nitrous oxide "doubles the rate of serious vomiting and pneumonia after surgery," explained Robotham. Both of these side effects can result in a patient's death.

Usage Trends

Nitrous oxide is among the substances of abuse categorized as inhalants. It gained popularity on the dance club circuit because of its supposed aphrodisiac effects. It is also preferred over other inhalants such as spray paints, shoe polish, markers, and glue because it does not leave stains on skin and clothes.

Food-grade nitrous oxide chargers, better known as "whippets," are available by the box or the case and are sold on the Internet. David Holthouse commented in a Phoenix New Times article, "The cardboard boxes [of whipped cream chargers] are decorated with images of fancy desserts and fresh berries, next to warnings not to … directly inhale the contents." Whippets were blamed for the death of a twenty-year-old Virginia Polytechnic Institute student in 1999. The student suffocated after inhaling nitrous oxide from whipped cream cartridges he had purchased through an online merchant.

Patterns of Inhalant Abuse

The Office of National Drug Control Policy (ONDCP) Web site notes in its "Inhalants: Drug Facts" publication that "typically, first use of inhalants occurs between late childhood and early adolescence." According to the "2003 National Survey on Drug Use and Health (NSDUH)"—the latest survey data available in 2005—more youths age twelve and thirteen used inhalants than marijuana between 2002 and 2003. (An entry on marijuana is available in this encyclopedia.)

But general statistics on the broad category of inhalant abuse do not necessarily reflect the rate of nitrous oxide abuse. The 2003 NSDUH reports that less than one third of 1 percent of U.S. twelve and thirteen year olds reported using nitrous oxide as a recreational drug in their lifetimes. However, the rate of glue and/or shoe polish inhalation among youths in the same age group was nearly fifteen times higher than that, at about 4.3 percent.

Heavy nitrous abusers tend to be eighteen years of age or older. This may be due to N₂O's growing status as a club drug. According to NIDA, nitrous oxide use occurs frequently at raves, where it is often mixed with other club drugs such as ketamine, ecstasy (MDMA), GHB, and LSD (lysergic acid diethylamide). (Separate entries on each of these drugs are available in this encyclopedia.) By the early 2000s, nitrous oxide had gained popularity as a drug that enhanced sexual pleasure. It was even featured in a 2004 episode of the television series CSI: Miami as the cause of death in an otherwise healthy young woman.

Abuse in the Medical and Dental Fields

There have also been cases of nitrous oxide abuse among healthcare professionals. Dentists and anesthesiologists with easy access to the drug seem to be at a higher risk than the general public of developing nitrous-related dependence problems. Dependence is the belief that a person needs to take a certain substance in order to function.

Substance abuse is also especially high among healthcare professionals who administer anesthesia in a hospital setting. According to the American Association of Nurse Anesthetists (AANA), about 15 percent of anesthesia providers are substance abusers. "Nurse anesthetists are dying … from accidental overdose or from suicide," reported Carlos "Rusty" Ratliff in "Anesthetists in Recovery: Chemical Dependency in the Profession." Like dentists, certified registered nurse anesthetists have large supplies of nitrous oxide readily available to them. Consequently, nitrous oxide is one of the drugs these professionals may end up abusing.

Dental Highs

In an article posted on the American Dental Association (ADA) Web site titled "Escaping Addiction: The Door to Freedom," Dr. Thomas L. Haynes discusses the topic of addiction among dentists. "The access to large amounts of nitrous oxide," noted Haynes, along with the stress and isolation of the profession, increases the risk of abuse. "Many a dentist has been found lifeless in the office," he continued, "the N₂O mask still strapped to the face."

"Chemical Dependence in Anesthesiologists," a document developed by the ASA TaskForce on Chemical Dependence, addresses the problem of drug abuse among anesthesiologists. Although addicted medical doctors typically become hooked onopioids such as fentanyl, nitrous oxide was mentioned by the ASA as another potential drug of abuse. (An entry on fentanyl is available in this encyclopedia.)

Calling Attention to a Serious Problem

NIDA began an intensive campaign against inhalant abuse in 2005. This action was prompted by the results of the 2004 Monitoring the Future (MTF) study, an annual survey of drug use among young people in the United States. The MTF survey is conducted by the University of Michigan with funding from NIDA. Findings for 2002 through 2004 indicate that inhalant abuse among eighth-grade students was on the rise during that period. As of 2004, approximately 17.3 percent of eighth graders in the United States had abused an inhalant at some time in their lives. That represents an increase over the 2003 figure of 15.8 percent. This "upward trend in use," according to the MTF report, was accompanied by a "decline among eighth graders in the perceived risk of using inhalants."

Effects on the Body

Nitrous oxide acts as a depressant on the human body. Once inhaled, the gas enters the bloodstream through the lungs. The blood then carries it throughout the rest of the body. It reaches the brain quickly, affecting vital functions such as breathing and heart rate. It also alters other mechanisms of the nervous system, such as the activity of neurotransmitters that regulate thought processes, behavior, and emotions.

A single balloon filled with nitrous oxide can bring on a shortlived but intense high. The overall effects of the gas depend largely on the user's frame of mind. It can further stimulate an already excited user, or it can sedate a more relaxed user. Symptoms of a nitrous oxide high include giddiness, a loss of balance, slurred speech, twitching, mental confusion, and an inability to feel pain. After the effects of the gas wear off, users may experience side effects such as nausea (upset stomach), restlessness, tiredness, difficulty concentrating, and the appearance of spots before their eyes.

How Nitrous Oxide Works

Nitrous oxide alters the user's perception of time. Because the effects of a single "hit" last only three minutes or so, some abusers inhale the gas many times over the course of a few hours. Such attempts to maintain a nitrous high can be fatal, since continued

breathing of the gas causes respiratory depression. In addition, the possibility of brain damage increases when the brain does not receive sufficient amounts of oxygen.

Abusers also run the risk of vomiting and losing consciousness while intoxicated by nitrous oxide. Unconscious individuals are not able to clear their own airways of vomit. This increases the possibility of death by choking. Even if vomiting does not occur, an individual who loses consciousness from an overdose of nitrous oxide is likely to stop breathing. In addition, pure nitrous oxide takes the place of oxygen in the lungs. This process could result in asphyxiation—death or unconsciousness caused by the inability to breathe—unless the unconscious person is quickly moved to an area with fresh air. According to the CGA, death frequently occurs when abusers of the gas "attempt to achieve a higher state of euphoria [happiness and well-being]" by breathing "pure N₂O in a confined space—in a small room, inside an automobile or other vehicle cab, or by placing their head inside a plastic bag."

Death by overdose of nitrous oxide is very difficult to recognize. It leaves no telltale signs for a coroner or medical examiner to identify. Under normal circumstances, blood carries oxygen to the tissues and organs of the body. But nitrous oxide pushes oxygen out of the blood. Without a sufficient supply of oxygen in the bloodstream, the tissues and organs of the body cannot function properly. Damage to the brain and other organs may result. Long-term abuse of nitrous oxide can also interfere with the production of blood cells in the bone marrow.

Additional Dangers

As nitrous oxide takes the place of oxygen in the lungs, a deficiency in vitamin B₁₂ may result. This sparks a series of negative effects within the body. The user's red blood cell count decreases, leading to anemia (uh-NEE-mee-uh), a condition in which the blood is lacking in oxygen-carrying red blood cells. Nerve damage may also occur, leading to difficulty walking as well as tingling, numbness, or pain in the arms and legs. These side effects are usually reversible if nitrous use is stopped.

People who have a genetic disorder called phenylketonuria (fenn-uhl-kee-tuh-NORR-ee-yuh) should be particularly careful about nitrous oxide use. Phenylketonuria (PKU) is an inherited disorder that interferes with the breakdown of a certain protein called phenylalanine (fenn-uhl-AL-uh-neen). The protein is found in milk, eggs, and other foods. Individuals with PKU require a special diet that can cause a vitamin B₁₂ deficiency. Because nitrous oxide can remove even more B₁₂ from the bloodstream, the possibility of nerve and brain damage is especially high under these circumstances.

Nitrous users who inhale the gas while standing risk falling down and possibly breaking a limb or suffering a head injury. In addition, injury to the face, mouth, throat, and hands may occur because of the extremely low temperature of nitrous oxide. In an article for the Phoenix New Times, David Holthouse warned, "When N₂0 is released from a whippit, it's cold enough to flash-freeze spittle." Sometimes, users who get hurt while high on nitrous oxide are completely unaware of their injuries because of the numbing effect of the gas.

Improper handling of any compressed gas tank or cylinder can also cause injuries. Attempting to inhale a gas like nitrous oxide directly from a large gas cylinder can damage the lungs beyond repair. The force of the gas entering the lungs is so powerful that the air sacs in the lungs actually burst. Victims die in a matter of seconds due to internal bleeding. Inhaling any compressed gas is especially risky for people with ear problems, as the pressure of the gas may damage the inner ear.

N₂O Plus Pre-Existing Conditions Can Equal Death

Individuals with certain medical conditions may also suffer severe and potentially fatal side effects from the use of nitrous oxide. For example, anyone with a history of pulmonary hypertension, asthma, airway obstruction, head injury, or chest infection should not take nitrous oxide under any circumstances.

Nitrous oxide should not be given to pregnant women in the early or middle stages of pregnancy. The gas can interfere with the baby's development and may cause the mother to lose the baby before it is born. Heavy, ongoing nitrous oxide exposure during pregnancy has been shown to cause birth defects in animals.

Reactions with Other Drugs or Substances

Nitrous oxide produces effects on the body similar to those of alcohol, which is a depressant. When used along with other depressants, nitrous oxide can slow the user's breathing rate to a dangerously low—and sometimes even deadly—level.

The increasing use of nitrous oxide in combination with other club drugs poses serious risks to users. In the event of a multiple-drug overdose, emergency medical personnel may not be able to identify the mix of drugs the patient has consumed. This further complicates emergency treatment and could delay lifesaving measures.

Treatment for Habitual Users

Abuse of nitrous oxide alone has not been shown to cause withdrawal symptoms—the physiological effects of terminating use of an addicting drug. Because of this, it is not considered an addictive or habit-forming substance. At the very least, however, the gas does appear to cause psychological dependency. "Supposedly, nitrous is nonaddictive," wrote Holthouse, but "habitual users have a [tendency] to sit around doing whippit after whippit until all the whippits are gone, then go buy more whippits."

Nitrous oxide is eliminated from the body rapidly. However, if the patient has been abusing other drugs as well, the detoxification period, in which one rids the body of the drugs' toxins, could take up to forty days, depending on the chemicals involved. After detox, the primary goal of treatment is avoiding future drug use.

Substance abusers need to identify the underlying causes of their drug use. To curb drug abuse, they may need to alter their lifestyles substantially. This may include not going to the same clubs or hanging out with the same circle of friends if they are continuing to use drugs illegally. It may mean finding a new supportive, drugfree network of friends. Nitrous oxide abusers, like other substance abusers, typically benefit from individual therapy that focuses on changing unhealthy patterns of behavior and developing better coping skills. Group therapy and self-help organizations can also assist in the recovery process. Discussing addiction in a group setting can help drug abusers gain insight into their own thoughts and behaviors through the eyes and experiences of others.

Consequences

There are few studies that focus specifically on the illicit use of nitrous oxide. Rather, the abuse of this gas is usually lumped into the general category of inhalant use. According to the 2003 NSDUH report, young adolescents who use inhalants tend to have more academic, social, and behavioral problems than those who do not. High school dropout rates and involvement in serious fights, thefts, and illicit drug use were especially high among inhalant abusers. These statistics reflect patterns seen among users of all inhalants, not just nitrous oxide.

Specifically, nitrous oxide abuse may cause mood swings and personality changes in heavy users. Users report that the gas decreases their inhibitions. People with lowered inhibitions tend to take more chances and engage in riskier behavior than they would if they were not high. Nitrous oxide is also viewed as an aphrodisiac (sex enhancer) in some social circles. Some users might engage in unsafe sex, thereby increasing their risk for contracting sexually transmitted diseases, including HIV (the human immunodeficiency virus), which can lead to AIDS (acquired immunodeficiency syndrome).

The Law

Nitrous oxide is regulated by the U.S. Food and Drug Administration (FDA) as a food-grade propellant, medical-grade gas, and prescription drug. In 1971, the state of Maryland began controlling its sale and distribution. In the 1990s, in an attempt to curb the growing abuse of the gas, a number of other states followed suit. Connecticut, Arizona, Texas, Michigan, and Wisconsin were among the states that passed laws placing strong safeguards and stricter penalties on the illicit use of nitrous oxide.

Selling nitrous oxide for use as a drug carries stiff penalties. Distributors face up to 15 years in prison and fines of up to $1.5 million. In 2001, an Arizona man was sentenced to a 15-month jail term and fined $40,000 for a nitrous oxide sale that resulted in the death of a Virginia college student.

Until federal legislation is passed to prohibit the possession, inhalation, and distribution of nitrous oxide for purposes of intoxication, the CGA has proposed a list of recommendations regarding its use. The main goal of these recommendations is to keep the gas from falling into the wrong hands. Among the guidelines proposed by the CGA are:

• restricting the sale of nitrous oxide to those who can prove they have a "legitimate use" for it
• encouraging legitimate users to store containers of the gas and other equipment in a secured area
• requiring medical and restaurant personnel to keep a careful count of used and unused cylinders
• reporting any thefts to the police immediately.

For More Information

Books

Brecher, Edward M., and others. The Consumers Union Report on Licit and Illicit Drugs. Boston: Little Brown & Co., 1972.

Fenster, Julie M. Ether Day: The Strange Tale of America's Greatest Medical Discovery and the Haunted Men Who Made It. New York: HarperCollins, 2001.

Lobo, Ingrid A. Inhalants. Philadelphia: Chelsea House Publishers, 2004.

Menhard, Francha Roffe. The Facts about Inhalants. Tarrytown, NY: Benchmark Books, 2005.

Periodicals

Holthouse, David. "Softly into That Good Nitrous." Phoenix New Times (September 29, 1999).

Robotham, Julie. "Laughing Gas Unsafe, Say Doctors." The Age (May 5, 2005).

White, Josh. "Virginia Student's Death Leads to Drug Conviction." Washington Post (October 21, 2000).

Web Sites

"2003 National Survey on Drug Use and Health (NSDUH)." U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration.http://www.oas.samhsa.gov/nhsda.htm (accessed July 31, 2005).

"About Inhalants." National Inhalant Prevention Coalition.http://www.inhalants.com/about.htm (accessed July 31, 2005).

ASA Taskforce on Chemical Dependence. "Chemical Dependence in Anesthesiologists." American Society of Anesthesiologists. 1999. http://www.asahq.org/publicationsAndServices/chemical.html (accessed July 31, 2005).

"CGA/NWSA Nitrous Oxide Fact Sheet" (November 3, 2003). Compressed Gas Association. http://www.cganet.com/N2O/factsht.asp (accessed July 31, 2005).

"Drugs of Abuse: 2005 Edition." U.S. Department of Justice, Drug Enforcement Administration.http://www.usdoj.gov/dea/pubs/abuse/index.htm (accessed July 31, 2005).

"Drugs of Abuse: Uses and Effects Chart" (June, 2004). U.S. Department of Justice, Drug Enforcement Administration.http://www.usdoj.gov/dea/pubs/abuse/chart.htm (accessed July 31, 2005).

Haynes, Thomas L. "Escaping Addiction: The Door to Freedom" (November, 2004). American Dental Association.http://www.ada.org/prof/resources/topics/topics_wellbeing_drcares_addiction02.pdf (accessed July 31, 2005).

"Inhalant Abuse: NIDA Research Report Series" (2005). National Institutes of Health, National Institute on Drug Abuse.http://www.nida.nih.gov/researchreports/inhalants (accessed July 31, 2005).

"Inhalant Use Is Associated with Other Substance Use and Delinquency" (March 17, 2005). U.S. Department of Health and Human Services, Substance Abuse and Mental Health Services Administration.http://www.samhsa.gov/news/newsreleases/050317nr_inhalants.htm (accessed July 31, 2005).

"Inhalants: Drug Facts" (February, 2003). Office of National Drug Control Policy. http://www.whitehousedrugpolicy.gov/publications/factsht/inhalants/index.htm (accessed July 31, 2005).

"INHALANTS.DRUGABUSE.GOV." National Institutes of Health, National Institute on Drug Abuse.http://www.inhalants.drugabuse.gov/ (accessed July 31, 2005).

Johnston, Lloyd, et. al. "Overall Teen Drug Use Continues Gradual Decline, but Use of Inhalants Rises" (December 21, 2004). Monitoring the Future.http://www.monitoringthefuture.org/ and http://www.nida.nih.gov/Newsroom/04/2004MTFDrug.pdf (both accessed July 31, 2005).

"NIPC Inhalant Update Alert." National Inhalant Prevention Coalition.http://www.inhalants.com/alert_update.pdf (accessed July 31, 2005).

"Nitrous Oxide Issues and Incidence of Abuse" (November 3, 2003). Compressed Gas Association.http://www.cganet.com/N2O/issues.asp (accessed July 31, 2005).

"Nitrous Oxide (Laughing Gas)." MedicineNet.com, December 13, 1998. http://www.medterms.com/script/main/art.asp?articlekey=7793 (accessed July 31, 2005).

"The NSDUH Report: Inhalant Use and Delinquent Behaviors among Young Adolescents" (March 17, 2005). Office of Applied Studies, Substance Abuse and Mental Health Services Administration.http://www.oas.samhsa.gov/2k5/inhale/inhale.htm (accessed July 31, 2005).

Poremba, Sue Marquette. "Sucking the Life from Your Child: The Danger of Inhalants." Preteenagers Today.http://preteenagerstoday.com/resources/articles/inhalents.htm (accessed July 31, 2005).

Ratliff, Carlos "Rusty." "Anesthetists in Recovery: Chemical Dependency in the Profession" (January, 1996). American Association of Nurse Anesthetists.http://www.aana.com/peer/recovery.asp (accessed July 31, 2005).

"Spring 2005 NIPC Inhalant Prevention Update." National Inhalant Prevention Coalition. http://www.inhalants.com/SPRING_UPDATEMAY_2005.pdf (accessed July 31, 2005).

Other

"After the Fall." CSI: Miami (television series), CBS, November 29, 2004.

See also: Amyl Nitrite; Inhalants

NITROUS OXIDE

OFFICIAL NAMES: Nitrous oxide

STREET NAMES: N2O, nitrous, laughing gas, whippets, whip-its, hippie crack

DRUG CLASSIFICATIONS: Not scheduled

OVERVIEW

Nitrous oxide is a gas with anesthetic (numbness-causing) and (painkilling) analgesic properties. It was first discovered in 1772 by English scientist, theologian, and philosopher Joseph Priestly. Priestly was also the man who co-discovered oxygen (which he termed "phlogisticated air"). In 1776, he wrote about the discovery of N₂O, which he called "nitrous air."

The first scientist to discover the unique anesthetic and intoxicant effects of nitrous oxide was Sir Humphry Davy, an English physiologist whose self-experimentations with the gas became legendary. In Davy's book Researches, Chemical and Philosophical: Chiefly concerning nitrous oxide, or dephiogisticated nitrous air, and its respiration (1800) he suggests that nitrous may be a useful anesthetic in surgical situations, and "appears capable of destroying physical pain."

However, despite Davy's writings on the subject, nitrous oxide had no serious medical use for another four decades. Instead, nitrous, now nicknamed "laughing gas," enjoyed popularity as a way for the English upper classes to entertain themselves at social gatherings. Among those who regularly inhaled the gas for its pleasurable and uninhibiting properties were the poets Robert Southey and Samuel Taylor Coleridge, and the author Peter Roget (of Roget's Thesaurus). Laughing gas was also demonstrated in theaters and at festivals; in 1824, a run of performances at London's West End Aldelphi Theatre entitled "M. Henry's Mechanical and Chemical Demonstrations" showed the effects of nitrous oxide on audience volunteers to a disbelieving crowd.

Meanwhile in America, laughing gas was appearing in traveling medicine shows and carnivals. Gardner Quincy Colton, a former medical student, presided over one of these nitrous oxide demonstrations in Hartford, Connecticut, in December of 1844. One of the audience volunteers who had just inhaled the gas injured his leg without feeling any pain. In the audience was dentist Horace Wells, who took note of this and immediately seized on the idea that nitrous oxide might be a powerful anesthetic in the operating room.

Enlisting Colton to bring his nitrous oxide equipment to the dentist's office, Wells used himself as the test subject. Colton administered the gas while a dentist colleague and friend of Wells' pulled a tooth from his mouth. The experiment was successful; Wells woke up shortly after and reported feeling no pain from the procedure. Buoyed by this success, Wells began using nitrous oxide as an anesthetic in his dental practice.

In January 1845, at the Harvard Medical School and the Massachusetts General Hospital, Wells made a presentation in which he used a bag of nitrous oxide to sedate the patient before removing a tooth. Unfortunately, the bag was withdrawn too soon, and the patient complained of pain after the procedure, so the experiment was considered a failure. Nitrous would remain an entertaining oddity until Gardner Colton, the medical school dropout and traveling showman who first introduced the gas to Wells, returned it to medicine in the early 1860s. Starting his own business, Colton provided anesthetic services for dentists using 100% pure nitrous oxide gas. His business proved successful.

In 1868, Chicago dentist Dr. Edmund Andrews published a paper reporting his use of an 80%/20% mix of nitrous and oxygen on patients undergoing dental surgery. The mixture allowed for a longer period of unconsciousness for lengthy procedures. Later that same year, a UK company, Coxeter and Sons, developed a gas mask and tank system for the administration of nitrous oxide and other gases during surgery. Also that year, another English firm, Barth, compressed N₂O into cylinders. By 1871, companies in both America and the UK had succeeded in producing compressed and liquid nitrous oxide in cylinders.

By the end of the century, nitrous oxide had also gained popularity as a anesthesia for women in labor, remaining a standard anesthetic choice for that purpose in the United Kingdom.

Unfortunately, the laughing gas parties and parlor tricks of the early 1800s have evolved into abuse, and nitrous oxide is one of many commonly abused inhalants in the United States. The National Inhalant Prevention Coalition reports that one in five American children have used an inhalant by eighth grade.

CHEMICAL/ORGANIC COMPOSITION

The chemical symbol for nitrous oxide is N₂O (shorthand for two atoms of nitrogen joined with one atom of oxygen). The gas itself is clear and colorless, with a slightly sweet odor and taste.

Nitrous oxide is synthesized, or produced, by heating ammonium nitrate (NH₄NO₃) and then condensing out the water and filtering impurities. The gas is then compressed and turned into liquid for storage in tanks, cylinders, or cartridges.

Commercial grade nitrous oxide—such as that used in food and beverage dispensing, fuel injection, and chemical and semiconductor manufacturing—may contain a number of impurities, including the toxic chemicals sulphuric acid, ammonia, and nitric oxide.

Nitrous oxide should not be confused with nitric oxide, or NO, another gas that dilates the blood vessels (but is an air pollutant).

Ingestion methods

Depending on its intended use, nitrous oxide may be purchased in varying "grades," or degrees of purity.

Medical grade nitrous oxide is a prescription drug sold as a compressed liquid in cylinder tanks. Its buyer requires appropriate credentials to obtain it (which are governed by state law). Nitrous oxide used for other legitimate applications, such as manufacturing and auto racing, is often sold in a "denatured" form. Denatured nitrous contains chemicals that render it unfit for human consumption.

N₂O is used as an aerosol propellant in cans of whipped cream and some other food and beverage products. These products are also a source of N₂O for some nitrous abusers.

A food-grade version of the gas is also sold in small metal cartridges as a propellant for whipped cream cans and dispensers (hence the name slang name "whippets"). These small, bullet-shaped charging cartridges are legal. Because of their accessibility, portability, and low-cost, whippets are the most common means of taking the drug among nitrous oxide abusers.

Sometimes, masks or plastic bags are filled with laughing gas and then placed over the mouth and/or head. This practice carries a particularly high risk for serious injury and possible death, because the user can lose consciousness and suffocate on the mask or bag. Suffocation can also occur when nitrous oxide is consumed in large quantities in a poorly ventilated space, such as a car or closet, or when the user doesn't breathe in a sufficient amount of oxygen during prolonged use.

THERAPEUTIC USES

As an anesthetic, nitrous oxide has many legitimate uses. In dentistry it is used to calm patients and lower their anxiety (a process known as conscious sedation).

American obstetricians used nitrous oxide as a common pain management tool for women in labor through the early 1970s. Today, the anesthetic has been largely replaced in the United States, but a 50/50 mix of nitrous oxide and oxygen is still the anesthetic of choice for women in labor in the UK—over 60% use the gas for pain relief.

Nitrous oxide's ability to reduce anxiety is useful for uncomfortable or painful medical procedures. Some studies have also shown that children over the age of six experience less discomfort and mental distress when given nitrous oxide during short but painful medical procedures.

And somewhat ironically, nitrous oxide appears to have some use as an treatment for withdrawal symptoms. Several South African studies have demonstrated the usefulness of nitrous oxide in treating withdrawal symptoms and reducing cravings during alcohol, marijuana, and nicotine detoxification. And in early 2002, a small study published in Clinical Psychiatry found that the gas may also be helpful in helping smokers kick the habit. Researchers found that 92% of patients who inhaled a 50%/50% mixture of nitrous oxide and oxygen for 20 minutes on the day they quit smoking experienced decreased cravings for cigarettes over the following three days. Further studies are needed to determine the role that nitrous oxide may have in smoking cessation and substance abuse treatment.

USAGE TRENDS

Nitrous oxide is difficult to categorize. Technically, it is an inhalant, yet there are several characteristics that set the drug apart from the typical volatile substances that inhalant abusers favor. First, N₂O is not as readily accessible as hair spray, glue, household cleaners, and other off-the-shelf huffing chemicals of choice. Secondly, since nitrous oxide is an actual prescription anesthetic, it may have more perceived prestige among users who would look down at most volatile substance abuse as "kid's stuff."

According to the National Institute on Drug Abuse (NIDA), nitrous oxide is showing up more frequently at raves, mixed-and-matched with other club drugs like ketamine, ectasy/MDMA, GHB, and LSD. There have also been cases of nitrous oxide abuse in healthcare professionals. Nurses, anesthesiologists, and other medical personnel with easy access to the drug may be at risk of developing dependence problems. According to the American Association of Nurse Anesthetists (AANA), over 15% of anesthesia providers (including anesthesiologists and certified registered nurse anesthetists, or CRNAs) are substance abusers.

This abuse is not unique to the United States, either. In late 2001, an investigation was launched into the birthing unit staff at Australia's Wollongong Hospital. Ten Australian midwives and a physician allegedly took part in a series of "laughing gas parties," illicitly indulging in the hospital's supply of nitrous oxide and the sedative temazipan.

Dentists are also at risk. The Talbott Recovery Center, a nationally recognized drug treatment facility that specializes in the rehabilitation of healthcare professionals, suggests that addiction may develop due to the nature of a dentist's work (i.e., long and sometimes tedious procedures, relative isolation, and the stress of dealing with anxious patients), combined with open access to anesthetic drugs. The Journal of the California Dental Association reports that the most commonly abused drugs among dentists are alcohol, hydrocodone, and nitrous oxide.

Scope and severity

An annual survey conducted by the Substance Abuse and Mental Health Services Administration (SAMHSA) reports that 8.27 million Americans have used nitrous oxide illicitly (not for medical purposes) at least once in their lifetime.

Inhalant abuse as a whole is a growing crisis worldwide. An international study funded and published by NIDA in 1995 ("Epidemiology of Inhalant Abuse: An International Prospective"), reports increasing inhalant abuse in Mexico, Latin America, Nigeria, Asia, the United Kingdom, and Australia. In Latin America alone, over half of the estimated 40 million street children abuse inhalants (primarily glues and solvents).

Age, ethnic, and gender trends

Inhalant abuse starts early. As of 2000, approximately 2.1 million, or 8.9%, of American youths aged 12 to 17 had used some form of inhalant at some time in their lives. "Monitoring the Future," an annual survey of drug use among youth and young adults conducted by the NIDA and the University of Michigan, reports that one in five eighth graders surveyed in 2000 had used inhalants at least once in their lives, and one in 20 reported use in the prior month. Inhalants are the second most popular class of drugs for eighth graders (marijuana is first) and the third most popular (after marijuana and amphetamines) for tenth graders.

One-third of all inhalant abusers admitted to treatment programs in 1999 had first used inhalants by the age of 12, with an additional 24% reporting first use by age 14. Overall, the general use of inhalants decreases with age, with 9% of eighth graders reporting inhalant use in the past year compared to just 2% of young adults (in the "National Household Drug Use Survey 2000").

Nitrous oxide use, however, follows the opposite trend. In 2000, 456,000 children ages 12–17 reported use in the prior 12 months, in comparison to over 2.6 million between the ages of 18 and 25, and 5.1 million adults age 26 or older. This may be due to N₂O's growing status as a club drug.

MENTAL EFFECTS

Nitrous oxide depresses the central nervous system (CNS). It also affects the activity of neurotransmitters—the CNS chemicals that enable nerve impulses, or signals, to travel from neuron to neuron and regulate thought processes, behavior, and emotion. Once inhaled, it enters the lungs and is carried through the body via the bloodstream. Users experience an immediate feeling of giddiness (not unlike alcohol intoxication), a "floating" and disconnected sensation, dizziness, mental confusion, and slurred speech. In strong enough concentrations, N₂O can cause also short-term memory loss (dissociative amnesia).

Psychological dependence on nitrous oxide can lead users to try riskier and often fatal methods of increasing their intake of the drug, such as filling garbage bags with the gas and putting them over their heads. Memory loss, difficulties with work or school, learning problems, and preoccupation with obtaining the drug are all common features of psychological dependence.

PHYSIOLOGICAL EFFECTS

In addition to the mental effects described above, nitrous oxide impairs motor control and causes a partial insensitivity to pain. Users may lose consciousness at high doses. The intoxication from nitrous is typically short-lived—sometimes lasting under a minute.

Harmful side effects

The biggest risk of nitrous oxide use and abuse is hypoxia, or insufficient oxygen intake. Most abusers take the gas at high concentrations without an oxygen mix. High levels of nitrous oxide in the body can make a person unconscious or even stop breathing. Nitrous oxide displaces oxygen (pushes it out), so there is less of it in the bloodstream. Because the blood carries oxygen throughout the body to "feed" tissues and organs, diminished oxygen capacity can result in brain damage. Lack of oxygen can also cause a loss of consciousness and death by suffocation.

It is this oxygen deprivation that sometimes causes a bluish tinge on the lips of chronic nitrous abusers. After the initial high of nitrous wears off, chronic users may also experience such varied side effects as nausea, visual disturbances (seeing spots), feelings of claustrophobia, fatigue, and difficulty concentrating.

In cases of severe abuse, published studies have described chronic symptoms such as impairment of the nervous system, tingling and/or numbness of the hands and feet, and uncontrolled muscle twitching and movement. These side effects may be related to the depletion of vitamin B₁₂ and folate caused by nitrous oxide abuse. They are usually reversible if nitrous use is stopped.

Because of the extreme cold temperature of nitrous oxide, frostbite of the face, mouth, throat, and hands may occur. In many cases, the injury is made worse by the anesthetic affect of the drug; the nitrous user may do further damage to the skin because he or she does not initially feel the frostbite.

Anyone inhaling gas directly from a nitrous tank valve is vulnerable to frostbite and possible lung damage, in addition to the various side effects already mentioned.

Also, if nitrous users inhale the gas standing up, they will more likely than not fall down—hard—possibly breaking a limb or suffering a head injury.

Also, working with any compressed gas may be dangerous. Although nitrous oxide itself is not flammable, the pressurized contents can explode and cause serious injury if a gas tank or cylinder is improperly stored, or is dropped, knocked over, or punctured.

Long-term health effects

Chronic nitrous oxide abuse can remove a lot of vitamin B₁₂ from the bloodstream. B₁₂ (cobalamin) is necessary for the creation of blood cells and neurotransmitters, as well as the protective layers that cover nerves. This results in nerve damage and pain; balancing, walking, and concentration difficulties; mental impairment; mood disturbances (such as depression); and other physical problems. Chronic nitrous oxide use may also interfere with the production in bone marrow of white blood cells and red blood cells. Treatment with intramuscular injections of B₁₂ may reverse these symptoms.

As a consequence of B₁₂ depletion, levels of folic acid may also be reduced in chronic N₂O abusers. Again, supplements may help.

Nitrous oxide abuse may also lead to spontaneous abortion in pregnant women. It also interferes with DNA synthesis. For these reasons, it is not given to pregnant women, particularly in the first two trimesters. Heavy, ongoing nitrous oxide exposure during pregnancy has caused birth defects in animal studies, as well.

It is important to note that there have been no harmful physiological effects observed in infants born to mothers who are administered nitrous oxide and oxygen during labor itself, as the gas is quickly metabolized. However, a few long-term studies have shown a possible link between heavy nitrous oxide use during labor and the later development of opiate and methamphetamine addiction of offspring in adulthood.

Long-term nitrous oxide exposure may also cause infertility. Several studies of dental workers and midwives who had been exposed to low levels of the gas in the workplace found that their fertility was reduced in direct relation to the level and length of exposure. Equipment to limit nitrous oxide levels can be installed in a doctor's office to reduce this risk.

Individuals with certain chronic illnesses and medical conditions may also suffer severe and potentially fatal side effects from the use of nitrous oxide. For example, anyone with a history of pulmonary hypertension, asthma, airway obstruction, head injury, or chest infection should not take nitrous under any circumstances.

REACTIONS WITH OTHER DRUGS OR SUBSTANCES

When used along with other CNS depressants (such as alcohol) nitrous oxide can stop the user's breathing, which can be fatal.

Anyone with the condition phenylketonuria (PKU), a metabolic disorder, should be particularly careful about nitrous oxide use. Individuals with PKU require a diet that is high in protein in low in animal fats, which frequently results in a vitamin B₁₂ deficiency. Nitrous oxide can remove even more B₁₂ from these individuals' bloodstreams, possibly causing mental impairments, as well as severe nerve and brain damage.

TREATMENT AND REHABILITATION

In 1999, 7.8 million Americans reported the illicit use of nitrous oxide at least once in the prior 12 months. Yet according to SAMHSA, substance abuse treatment admissions for all inhalants accounted for only slightly over 1,300 of the almost 1.6 million substance abuse treatment admissions that same year.

Inhalant treatment numbers are low because inhalants are accessible and legal. They are easy to hide, use, and abuse in secrecy. And because they are legal, users often don't consider them a "real drug." Adults sometimes consider inhalant use a phase that adolescents will "grow out of" in time. Interestingly enough, the majority of inhalant users who reported illicit use of nitrous oxide are 18 and older—with most of them over the age of 25 (according to data in the "National Household Survey on Drug Abuse 2000").

Specialized treatment programs targeted at inhalant abusers are still rare in the United States, although many general drug treatment programs can

and do successfully treat these patients. Unfortunately, inhalant abusers suffer a higher rate of "relapse" (a return to drug use) than abusers of other drugs, in part because legal inhalants are widely available in just about any store.

As of early 2002, there were only a handful of specialized inhalant abuse treatment centers in the United States, including programs in Texas, Wisconsin, South Dakota, and New Mexico.

Several treatment programs in the United States have been designed for healthcare professionals with substance abuse problems. Facilities like the Talbott Recovery Center in Atlanta, Georgia have customized rehab programs for physicians, pharmacists, dentists, and nurses. These programs focus on long-term recovery, as well as on returning the patient to their healthcare career or a suitable alternative.

Drug rehabilitation programs may be either "inpatient" or "outpatient." Inpatient, or residential, drug programs require a patient to live at the hospital or rehab facility for a period of several weeks to several months. Outpatient programs allow patients to spend part of their day at the treatment facility, and return home at night. Nitrous oxide is rapidly eliminated from the body, and abuse of N₂O alone is not associated with withdrawal. This means that a lengthy detoxification period (removal of the drug from the body) is typically not required.

However, if the patient has also been abusing other inhalants, the detoxification period could conceivably take up to 40 days, depending on the chemicals involved. Withdrawal symptoms in inhalant abusers may include nausea, vomiting, muscle pain and cramping, chills and sweats, irritability, tremors, headaches, and hallucinations. Depending on the severity of the symptoms and the patient's physical condition, the controlled environment of a residential setting may be preferred for the detox period.

After detox, the primary goals of treatment are abstinence (i.e., quitting the drug) and long-term recovery. Recovery is the life-long process of avoiding not just drug use, but the unhealthy behaviors and thought patterns that trigger it as well. An effective drug rehabilitation program focuses on changing these patterns of behavior and teaching recovering patients coping skills. Drug education on the long-term physical and mental effects of substance abuse is also part of a rehab program.

"Relapse"—using a drug again after a period of sobriety or abstinence—may occur if the emotional and behavioral issues surrounding drug use aren't under-stood. Some of the methods used to understand them include individual psychotherapy, behavioral therapy, cognitive-behavioral therapy, group therapy, and family counseling.

Individual psychotherapy

One-on-one counseling that explores the emotional issues underlying a patient's drug dependence and abuse. Individual psychotherapy is particularly when there is also some type of mental disorder, such as depression or an anxiety disorder along with the drug abuse.

Behavioral therapy

Behavioral therapy focuses on replacing unhealthy behaviors with healthier ones. It uses tools such as rewards (positive reinforcement for healthy behavior) and rehearsal (practicing the new behavior) to achieve a drug-free life.

Cognitive-behavioral therapy

Like behavioral therapy, cognitive-behavioral therapy (CBT) also tries teaching new behavioral patterns. However, the primary difference is CBT assumes that thinking is behind behavior and emotions. Therefore, CBT also focuses on—and tries to change—the thoughts that led to the drug abuse.

Family therapy

Family members often develop habits and ways of coping (called "enabling") that unintentionally help the addict continue their substance abuse. Group counseling sessions with a licensed counselor or therapist can help family members build healthy relationships and relearn old behaviors. This is particularly important for adolescents in drug treatment, who should be able to rely on the support of family.

Group therapy

Group therapy offers recovering drug abusers a safe and comfortable place to work out problems with peers and a group leader (typically a therapist or counselor). It also provides drug abusers insight into their thoughts and behaviors through the eyes and experiences of others. Substance abusers who have difficulty building healthy relationships can benefit from the interactions in group therapy. Offering suggestions and emotional support to other members of the group can help improve their self-esteem and social skills.

Self-help and twelve-step groups

Self-help organizations offer recovering drug abusers and addicts important support groups to replace their former drug-using social circle. They also help create an important sense of identity and belonging to a new, recovery-focused group.

Twelve-step groups, one of the most popular types of self-help organizations, have been active in the United States since the founding of Alcoholics Anonymous (AA) in 1935. Narcotics Anonymous (NA), a group that serves recovering drug addicts, was founded in 1953. Like AA and other 12-step programs, NA is based on the spiritual philosophy that turning one's will and life over to "a higher power" (i.e., God, another spiritual entity, or the group itself) for guidance and self-evaluation is the key to lasting recovery.

The accessibility of self-help groups is one of their most attractive features. No dues or fees are required for AA and NA, so they are a good option for the uninsured and underinsured. Meetings are held in public places like local hospitals, healthcare centers, churches, and other community organizations, and frequent and regular attendance is encouraged.

In addition, 12-step groups work to empower members and promote self-esteem and self-reliance. NA meetings are not run by a counselor or therapist, but by the group or a member of the group. The organization encourages sponsorship (mentoring another member), speaking at meetings, and other positive peer-to-peer interactions that can help reinforce healthy social behaviors. Today, the internet and on-line support communities have added a further degree of accessibility to those who live in rural or remote areas.

PERSONAL AND SOCIAL CONSEQUENCES

Substance abusers become preoccupied with when and where they will be able to get their next dose. As drug use takes center stage in an abuse's life, relationships with family and friends frequently deteriorate. Although nitrous oxide and other inhalants are known for their relatively low cost, an N₂O abuser may suffer financial hardships as a result of unemployment, automobile accidents, or poor performance at school.

Chronic inhalant use is related to poor academic performance. According to the "National Household Survey on Drug Abuse 2000," kids with a D average in school were three times more likely to have used inhalants in the prior 12 months than the A-average students surveyed.

Substance abuse in general is a far-reaching societal problem, impacting not only personal relationships and health but also contributing to crime, domestic violence, sexual assault, drop-out rates, unemployment, and home-lessness. It is also a factor in public health problems, like the spread of sexually transmitted diseases (STDs) and unwanted pregnancy. Chronic inhalant abuse can lead to serious birth defects.

Inhalant abuse is a financial drain on society as well. Indian Health Services estimates a cost of $1.6 million to treat a young adult with a history of inhalant abuse and all its associated physical, mental, legal, occupational, and social problems. The Office of National Drug Control Policy (ONDCP) estimates that illegal drugs cost the U.S. economy $160 billion in the year 2000, an annual increase of 5.8% between 1998 and2000. That estimate includes $14.8 billion in healthcare costs and $110.4 billion in lost productivity from drug-related illness, incarceration, and death.

The perception of inhalants as dangerous, harmful substances has risen among young people. In 2001,76.4% of tenth graders said they thought regular inhalant abuse a "great risk" to the user. And socially, inhalants are becoming risky as well, with 91.3% of tenth graders strongly disapproving of regular inhalant use among their peers. This may be due in part an to anti-inhalant advertising campaign launched in the mid-1990s by the Partnership for a Drug-Free America.

LEGAL CONSEQUENCES

Most states have laws regarding inhalant (or volatile substance) use and abuse on the books. In recent years, laws that are specific to nitrous oxide use and distribution have been written in many states. For example, in Connecticut, Arizona, Texas, and Michigan, it is illegal for anyone under the age of 18 to purchase nitrous oxide, even in food grade cartridges. In Arizona, anyone caught selling N₂O to minors faces up to 18 months in jail and a $150,000 fine.

In Wisconsin, the minimum age for purchasing nitrous oxide is 21. However, state legislation passed in 1998 makes it illegal for anyone to inhale or even intend to inhale nitrous outside of medical or dental settings. Anyone who distributes or delivers nitrous to someone with the knowledge that they are using it for illicit purposes can also be charged under Wisconsin law. A number of states, including Texas, California, Ohio, and Iowa, have variations on this law.

Illicit use, or possession with intent to use, is typically a misdemeanor in most states, and may be punishable by a small fine. Knowingly selling nitrous for illicit use carries a heftier price tag; it is a felony in many states and can involve significant jail time and cash fines.

Legal history

Nitrous oxide is not a U.S. Drug Enforcement Administration controlled substance. Nitrous oxide is regulated at the federal level by the United States Food and Drug Administration (FDA), as a food-grade propellant, medical grade gas, and prescription drug. In the 1990s, in an attempt to curb growing abuse of nitrous oxide, a number of states passed laws placing strong safeguards and stricter penalties on its illicit use.

Federal guidelines, regulations, and penalties

Use of the medical grade gas is by prescription only, and regulated by the FDA. Compressed medical gas suppliers must register with FDA, and are subjected to facility inspections from FDA at least once every two years. Licenses required to purchase and administer nitrous oxide in the healthcare setting is regulated on a state level.

Theft of nitrous oxide tanks from medical and other facilities is not uncommon. Some industry trade groups are working with state legislatures to pass stricter regulations on nitrous sales and theft-prevention guidelines in an effort to deter abuse.

See also Inhalants

RESOURCES

Books

Fenster, Julie M. Ether Day: The Strange Tale of America's Greatest Medical Discovery and the Haunted Men Who Made It. New York: HarperCollins, 2001.

Periodicals

Johnston, Lloyd D., et al. Monitoring the Future: National Survey Results on Drug Use, 1975-2000. Vols. I and II. Bethesda, MD: National Institute on Drug Abuse, 2001.

Organizations

National Inhalant Prevention Coalition, 2904 Kerbey Lane, Austin, TX, USA, 78703, (512) 480-8953, (512) 477-3932, (800) 269-4237, [email protected], <http://www.inhalants.org/>.

National Institute on Drug Abuse (NIDA), National Institutes of Health, 6001 Executive Boulevard, Room 5213, Bethesda, MD, USA, 20892-9561, (301) 443-1124, (888) 644-6432, [email protected], <http://www.nida.nih.gov>.

Paula Anne Ford-Martin

Nitrous Oxide

OVERVIEW

Nitrous oxide (NYE-truss OX-side) is also known as dinitrogen oxide, dinitrogen monoxide, nitrogen monoxide, and laughing gas. It is a colorless, nonflammable gas with a sweet odor. Its common name of laughing gas is derived from the fact that it produces a sense of light-headedness when inhaled. The gas is widely used as an anesthetic, a substance that reduces sensitivity to pain and discomfort.

KEY FACTS

OTHER NAMES:

See Overview.

FORMULA:

N₂O

ELEMENTS:

Nitrogen; oxygen

COMPOUND TYPE:

Nonmetallic oxide (inorganic)

STATE:

Gas

MOLECULAR WEIGHT:

44.01 g/mol

MELTING POINT:

−90.8°C (−131°F)

BOILING POINT:

−88.48°C (−127.3°F)

SOLUBILITY:

Slightly soluble in water; soluble in ethyl alcohol and ether

Nitrous oxide was probably first produced by the English chemist and physicist Robert Boyle (1627–1691), although he did not recognize the new compound he had found. Credit for the discovery of nitrous oxide is, therefore, usually given to the English chemist Joseph Priestley (1733–1804), who produced the gas in 1772 and named it "nitrous air." Other early names used for the gas include "gaseous of azote" (nitrogen) and "oxide of speton." The most complete experiments on the gas were conducted by the English chemist and physicist Sir Humphry Davy (1778–1829), who tested nitrous oxide on himself and his friends. He found that the gas could lessen pain and discomfort and provided a sense of relaxation and well-being. Before long, doctors were making use of Davy's discovery by using nitrous oxide as an anesthetic.

The public found other uses for the gas as well. During the Victorian period in England, members of the upper class often held laughing gas parties at which people gathered to inhale nitrous oxide as a recreational drug, rather than for any therapeutic purpose. In the United States, the showman P. T. Barnum (1810–1891) created a sideshow exhibit in which people were invited to test the effects of inhaling nitrous oxide. After seeing a demonstration of this kind, the American dentist Horace Wells (1815–1848) first used nitrous oxide as an anesthetic on his patients.

In 1868, the American surgeon Edmund Andrews (1824–1904) extended the use of nitrous oxide as an anesthetic for his surgical patients. He mixed the gas with oxygen to ensure that patients received enough oxygen while receiving the anesthetic. The gas is still widely used by dentists as a safe and relatively pleasant way of helping patients endure the discomfort of drilling and other dental procedures.

HOW IT IS MADE

The most common commercial method of producing nitrous oxide involves the controlled heating of ammonium nitrate (NH₄NO₃). The compound decomposes to form nitrous oxide and water. The reaction is essentially the same one originally used by Priestley in 1772. Although an efficient means of producing the gas, the reaction must be carried out with extreme care as ammonium nitrate has a tendency to decompose explosively when heated. Nitrous oxide can also be produced by the decomposition of nitrates (compounds containing the NO₃ radical), nitrites (compounds containing the NO₂) radical, or nitriles (compounds containing the CH⁻ radical).

COMMON USES AND POTENTIAL HAZARDS

Nitrous oxide is best known and most widely used as an anesthetic. Its use is limited primarily to dental procedures and minor surgeries. Dentists favor nitrous oxide as an anesthetic because the gas does not make patients completely unconscious and does not require an anesthesiologist to administer it. Nitrous oxide works as an anesthetic by blocking neurotransmitter receptors in the brain, preventing pain messages from being transmitted.

Interesting Facts

• Humphry Davy proposed the name laughing gas for nitrous oxide.
• In the United Kingdom, nitrous oxide is often used as an anesthetic for women about to give birth.
• In the 1830s, Samuel Colt (1814–1862), inventor of the Colt 45 revolver, toured North America, giving laughing gas demonstrations.

Nitrous oxide is also used as a fuel additive in racing cars, in which case it is often referred to as nitro. The gas is injected into the intake manifold where it mixes with air and fuel vapors. Since it breaks down at the high temperatures in the car's engine, it provides additional oxygen to increase the efficiency with which the fuel burns. During World War II, pilots used nitrous oxide for a similar purpose in their airplanes.

Some additional uses of nitrous oxide include:

• As a propellant in food aerosols;
• For the detection of leaks;
• As a packaging gas for potato chips and other snack foods, preventing moisture from making the product become stale;
• In the preparation of other nitrogen compounds; and
• As an oxidizing agent for various industrial processes.

Nitrous oxide is safe to use in moderate amounts under controlled conditions. Some people use the compound as a recreational drug, however, hoping to get a "high" from inhaling it. One risk of this practice is that the inhalation of nitrous oxide may reduce the amount of oxygen a person receives. Also, some long-term health effects, such as anemia (low red blood cell count) and neuropathy (damage to the nerves), have been associated with excessive use of the compound. The use of nitrous oxide for recreational purposes is a crime in some states.

Words to Know

ANESTHETIC

A substance that reduces sensitivity to pain and discomfort.

NITRATE

A compound that includes the radical consisting of one nitrogen atom and three oxygen atoms (NO₃).

NITRITE

A compound that includes the radical consisting of one nitrogen atom and two oxygen atoms (NO₂).

RADICAL

A group of atoms bonded together that act like a single entity in chemical reactions.

FOR FURTHER INFORMATION

"Gas Data: Nitrous Oxide." Air Liquide. http://www.airliquide.com/en/business/products/gases/gasdata/index.asp?GasID=55 (accessed on October 20, 2005).

Neff, Natalie. "No Laughing Matter." Auto Week (May 19, 2003): 30.

"Nitrogen Oxide." Center for Advanced Microstructures and Devices, Louisiana State University. http://www.camd.lsu.edu/msds/n/nitrous_oxide.htm#Synonyms (accessed on October 20, 2005).

"Occupational Safety and Health Guideline for Nitrous Oxide." Occupational Safety and Health Administration. http://www.osha.gov/SLTC/healthguidelines/nitrousoxide/recognition.html (accessed on October 20, 2005).

Pae, Peter. "Sobering Side of Laughing Gas." Washington Post (September 16, 1994): B1.

See AlsoAmmonium Nitrate

Nitrous Oxide

Definition

Nitrous oxide is a colorless, sweet-smelling gas used as an anesthetic, most commonly during dental procedures.

Purpose

Nitrous oxide, also called laughing gas, is the weakest form of sedation to aid in the relaxation of the anxious dental patient. When inhaled, nitrous is absorbed by the body and has a quick-acting calming effect on the patient.

Description

The nitrous gas used in dental offices is actually a blend of two gases: oxygen and nitrous oxide. Mixed together it has a sweet-smelling aroma that gives a sense of well-being and aids in relaxation of the entire body. It causes light, conscious sedation, while the patient still retains the ability to respond to verbal commands.

Nitrous oxide has three kinds of sedative characteristics, including:

• Conscious sedation: Being awake and able to interact vocally with the dental staff, but feeling completely relaxed.
• Inhalation sedation: Becoming sedated through inhalation with the nose or mouth with a sedative agent such as nitrous oxide.
• Psychosedation: Nitrous oxide acts on the psyche or the central nervous system in such a way that pain impulses are not relayed to the cerebral cortex or their interpretation is altered.

According to the American Academy of Pediatric Dentistry, nitrous oxide/oxygen is the safest sedative in dentistry. It is non-addictive, mild, and easily administered to the patient. It is a safe, effective technique for calming patient fears of the dental office and procedures to be performed.

Operation

The concentration of nitrous oxide in the oxygen mixture varies, allowing for a range from light to deep sedation, depending on the apprehension, anxiety, fear, and pain the patient is experiencing. Consideration of the patient risks due to health issues or age may determine the amount of gas used during the dental procedure. Commonly used first in the dental office as a calming agent before an injection of a local anesthetic, nitrous oxide is inhaled through a nosepiece attached to the patient's face. From two separate tanks, two tubes carry the oxygen and the nitrous oxide gases to the nosepiece, where they are combined into one gas. Each tank has separate controls that indicate how much oxygen and nitrous are being used at any one given time. The minimum number of people involved in the administration of the gas should be two, the dentist or other licensed professional and an assistant trained to monitor the patient during the procedure to make certain the amount of gas flowing through both tubes is correct. The effectiveness of all procedures using nitrous oxide is greatly enhanced by a quiet environment. Near the end of the dental procedure the flow of nitrous oxide is shut off and the patient is allowed to inhale 100% oxygen. The body quickly dissipates the nitrous oxide, and the patient begins to come out of the conscious sedated state.

Pregnant women should not use or handle nitrous oxide, because studies of pregnant mice and rats exposed to nitrous oxide have linked the use of the gas with birth defects.

Maintenance

Monitoring the control panels from each tank of oxygen and nitrous oxide at the beginning of each day is essential for safe practice. Daily checking of the tubes and nosepiece is vital to make certain they are free of blockages and small tears.

The tanks of oxygen and nitrous oxide should have an oxygen fail-safe system that is calibrated weekly. All emergency equipment should be functional and within reach.

Health care team roles

The dental office staff, including the dentist, dental hygienist, and dental assistant all working as team, help create a calm environment. To ensure an adequate supply, the supervising dental assistant should monitor the amount of gas in each tank of oxygen and nitrous oxide, and schedule tank replacements as necessary. At least one back-up tank of each gas should be on hand, in addition to the ones being actively used with patients.

The front office staff maintains a current health history on each patient seen in the office. This health history has all known allergies or medical problems kept up to date for the dentist to refer to when deciding if nitrous oxide is safe for a particular patient.

The dental assistant in charge of the patient during the conscious sedation needs to document the heart rate, blood pressure, respiratory rate, and responsiveness of the patient periodically during the procedure, including the few minutes of recovery period when the patient is inhaling 100% oxygen.

Training

Many state laws require dental offices to have a license for housing a nitrous oxide unit and administering the gas. Dentists and dental hygienists receive training for using the gas in their degree courses. Continuing education courses on how to administer nitrous oxide are offered for the dental assistant. However, the dental assistant can only monitor the patient under the guidance of a licensed general dentist or licensed dental hygienist. A separate test is required to become fully licensed for use without supervision.

KEY TERMS

Anesthesia— A complete or partial loss of sensation.

Conscious sedation— Being awake during a procedure, able to respond to questioning, but completely relaxed.

General sedation— Being completely asleep during the procedure.

Inhaled sedation— Reaching a sedated state through inhalation of the nose or mouth with a sedating agent, such as nitrous oxide.

Sedative— An agent having a calming, relaxing effect.

Resources

PERIODICALS

Nitrous Oxide. American Academy of Pediatric Dentistry (AAPD). Brochure. 2001. 〈http://aapd.org/publications/brochures/nitrous.html〉.

ORGANIZATIONS

Academy of General Dentistry (AGD). 211 East Chicago Ave., Chicago, IL 60611. (312) 440-4300. 〈http://www.agd.org〉.

American Academy of Pediatric Dentistry. 211 East Chicago Avenue, Suite 700, Chicago, IL 60611-2663. 〈http://aapd.org〉.

OTHER

Anesthesia. Academy of General Dentistry. 〈http://www.agd.org/consumer/factsheets/anesthesia.html〉.

Nitrous oxide

Nitrous oxide (N₂O), also called di-nitrogen monoxide, is one of several gaseous oxides of nitrogen . It is sometimes referred to as laughing gas, because when inhaled it causes a feeling of intoxication, mild hysteria, and sometimes laughter. The gas is colorless and has a faint odor and slightly sweet taste. It can lessen the sensation of pain and is used as an anesthetic in dentistry and in minor surgery of short duration. For more complex surgery, it is combined with other anesthetics to produce a deeper and longer-lasting state of anesthesia. Nitrous oxide also is commonly used as a propellant for pressurized food products, and sometimes is used in race cars to boost the power of high performance engines. It is one of the few gases capable of supporting combustion . In this process, it transfers its oxygen to the material being combusted and is converted to molecular nitrogen (N₂).

Nitrous oxide is an important component of the Earth's upper atmosphere at heights above 30 mi (45 km). It is one of the greenhouse gases , together with carbon dioxide , methane , and ozone , that allow radiation from the Sun to reach the Earth's surface but prevent the infrared or heat component of sunlight from re-irradiating into space. This leads to the so-called greenhouse effect , and results in warmer temperatures at the earth's surface. Greenhouse warming is important in creating surface temperatures suitable for life, but recent studies have shown that the levels of some greenhouse gases are increasing at rates that are a cause for concern. Human-made gases, such as chlorofluorocarbons , are also contributing to the greenhouse effect. An increase in the Earth's ability to trap infrared radiation can be expected to result in global climate change with wide-ranging consequences.

Concern over greenhouse gases has centered on reports of increasing concentrations of atmospheric carbon dioxide (CO₂). Two factors thought to be responsible are the widespread use of fossil fuels (which add CO₂ to the atmosphere) and the rapid destruction of tropical rain forests which remove CO₂). The levels of other greenhouse gases may also be changing. Studies indicate that atmospheric levels of nitrous oxide may also be increasing as a result of human activity. Nitrous oxide is produced in nature by microorganisms acting on nitrogen-containing compounds in the soil . Increased use of nitrogen fertilizer in lawns, gardens, and agricultural fields may stimulate microbial production of nitrous oxide. Manure and municipal sludge , applied as soil enhancers and fertilizers, and burning fossil fuels also may contribute to an increase.

Nitrous oxide production in soils is greatly influenced by soil temperature, moisture level, organic content, soil type, pH , and oxygen availability. In agricultural soil, rates of fertilizer application, fertilizer type, tillage practices, crop type, and irrigation all influence nitrous oxide production. High soil temperature, moisture, and organic content tend to enhance production, whereas tilling of the soil tends to lower it. The relative importance of each of these factors has not been determined, and further study is needed to develop recommendations to limit harmful nitrous oxide emissions from soils.

[Douglas C. Pratt Ph.D. ]

RESOURCES

BOOKS

Minnesota Pollution Control Agency, Air Quality Division. Minnesota Greenhouse Gas Inventory 1990. St. Paul, MN: Minnesota Pollution Control Agency, 1995.

Umarov, M. "Biotic Sources of Nitrous Oxide (N₂O) in the Context of Global Budgets of Nitrous Oxide," Soils and the Greenhouse Effect, A. Bowman, ed. Chicester, U.K.: John Wiley and Sons, 1990.

PERIODICALS

Smith, S.C. "N₂O Laughing Gas: Has the NHRA Been Looking the Other Way after Allegations That Pro Stock Champions Got There with the Help of Nitrous Oxide?" Car and Driver 41, no. B (February 1996): 105.

OTHER

U.S. Department of Energy. Emissions of Greenhouse Gases in the United States, 1985–1990. DOE/EIA-0573. Washington, D.C.: GPO, 1993.

U.S. Environmental Protection Agency. State Workbook: Methodologies for Estimating Greenhouse Gas Emissions. EPA-230-B-92-002, Washington, D.C.: GPO, 1992.