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Nitrous oxide: the hidden addiction

Written by Dr. Graeme Cunningham, RCDSO Wellness Program Consultant

Dentistry is a stressful profession and those who practise may have an increased risk of divorce, depression, alcoholism, drug addiction and suicide.1

Many factors influence these risks: dentistry’s inherent stress, the isolation of the practitioner, physical and emotional demands, prescription writing privileges, and the availability of drugs.2

Isolation is a critical factor. It provides a fertile climate for addictive and self-destructive behaviour. The office often becomes a safe haven for the dentist that drinks and uses other drugs. These factors play a part in what can be seen as dentistry’s own specialized addiction – the abuse of and dependency on nitrous oxide.3

A dentist that abuses nitrous oxide is basically confined to their dental office due to the constraints of the equipment needed to administer the substance.4

History of nitrous oxide

Nitrous oxide was first discovered in 1772 by Joseph Priestley. By 1800, it was used as a purifying gas by practitioners of pneumatic medicine, a practice that used inhalation of specific gases to clear the body of ailments.

One of these practitioners was English physician Thomas Beddoes. It was Beddoes’ assistant, Humphrey Davy, who wrote extensively on the effects of nitrous oxide inhalation. He also held public demonstrations of the subjective effects of nitrous oxide by providing it to random subjects where they would act intoxicated after inhalation of the gas.

The American dentist Horace Wells attended one of these demonstrations in 1844. He observed one subject accidently injure himself while he was under the influence of the gas, yet appearing totally unaware of the injury or the pain that most surely accompanied it. Dr. Wells recognized the potential of the gas as an anesthetic and proceeded to experiment in its possible use in dentistry and surgery.

As a result, nitrous oxide has become one of the most widely used inhalation anesthetic gases in medicine and dentistry and has become the almost exclusive inhalation analgesic used for the reduction of anxiety.5

Analgesic effects

At lower to moderate concentrations, nitrous oxide produces analgesic and emotional effects similar to the narcotic analgesics. Studies have indicated that nitrous oxide may exhibit its analgesic effects by influence in the body’s own endogenous opioid system or directly at the opioid receptor sites of neural synapses.3 By acting like an opioid, the inhalation of nitrous oxide produces similar euphoric effects that drive the addictive properties of other narcotic analgesics such as morphine and hydrocodone.

Health risks of abusing nitrous oxide

Chronic nitrous oxide abuse exhibits certain physical health risks. Most notable is a peripheral neuropathy that manifests itself as a loss of sensory perception, initially beginning in the hands and feet of the abuser. This neuropathy has been shown to be the result of demyelination as a result of a disruption of vitamin B12 metabolism.

The symptoms of the chronic abuser of nitrous oxide is the same as the symptoms of an individual afflicted with pernicious anemia (vitamin B12 deficiency).This anemia is a severe medical condition caused by the absence of intrinsic factor, the protein necessary for the absorption of vitamin B12 (cobalamin) by the intestine.

Along with the neural toxic effects already mentioned, nitrous oxide abuse can also result in severe, megaloblastic anemia.

In summary, chronic nitrous oxide abuse can produce abnormalities in bone marrow activity as a result of the interference with enzymes containing cobalamin.

Signs of abuse/dependency

Many times nitrous oxide abuse/ dependence is a silent addiction within the dental profession. Individuals afflicted with this addictive disease can go undetected until significant physical and personal damage has occurred.

An increase in the number of nitrous oxide cylinders used in the office in a month, an increase in the amount of time spent at the dental office alone after hours and on weekends, loss of coordination while handling dental instruments or a stumbling gait may all be signs that someone is abusing this anesthetic agent.


  1. Mandel, I.D. (1993). Occupational risks in dentistry: comforts and concerns. Journal of the American Dental Association, 124, 41-49.
  2. Gropper, J.M. & Porter,T.L. (2000) Addiction and progressive self-destructive behaviour in dentistry, Clark’s Clinical dentistry, Philadelphia,PA: Harper&Row.
  3. Eger II, E.I. (1985). Nitrous Oxide N2O. New York, NY: Elsevier.
  4. Jasak, J.T.(1991). Nitrous Oxide and its abuse. Journal of the American Dental Association,122(2),48-52.
  5. Gillman, M.A. & Lightfield, F.J. (1994). Opioid properties of psychotropic analgesic nitrous oxide (Laughing gas). Perspectives in Biology and Medicine, 38(1), 125-138.