Nitrous oxide

What is nitrous oxide?

The English chemist, Joseph Priestley, discorvered nitrous oxide in the 18th century and since the 19th century, it has been used in anesthesia. Laughing gas”, as it is also known, is still commonly used by dentists, in obstetrics or in emergency medicine, in non anesthising doses, for its analgesic, sedative and anxiolytic properties.

Outside the medical field, nitrous oxide has also attracted media attention due to the risk of abuse and intoxication when inhaled for its euphoric effects.

Nitrous oxide acts on targets similar to those of ketamine (NMDA receptor antagonist and partial opioid receptor agonist).

Numerous studies are investigating its use at low doses in the treatment of depressive symptoms and other psychiatric indications (withdrawal from alcohol or other substances), but also in the treatment of certain acute or chronic neuropathic pains, with particularly promising results.

As with ketamine, the antidepressant action is much faster than that of conventional antidepressants, with effects observed within a few hours. Likewise, this treatment does not “cure” depression, but complements other treatments whose efficacy is insufficient.

Who should use nitrous oxide?

Nitrous oxide inhalation may be indicated in patients with a severe depressive episode (unipolar or bipolar) without psychotic symptoms. Like ketamine, it has a strong anti-suicidal action.

Other indications include resistant anxiety disorders such as generalized anxiety, and post-traumatic stress disorder (PTSD). It can also be used in the context of withdrawal from alcohol or other substances.

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Is nitrous oxide effective?

Nitrous oxide has been shown to reduce or eliminate depressive symptoms, suicidal ideation and anxiety.

While data are still limited, the treatment looks particularly promising. A recent study showed an improvement in 85% of patients, a response in 55% and remission in 40%, comparable to what can be observed with ketamine. The antidepressant effect of nitrous oxide can be felt within 2 hours of treatment, and lasts up to 4 weeks in some patients after a single session.

How is the treatment given?

Two 60-minute sessions will be scheduled per week for 4 weeks, followed by possible booster sessions with progressive spacing depending on response to treatment.

At each session, the patient lies comfortably on a couch. They are accompanied by a nurse anesthetist throughout the session, under the supervision of a physician anesthetist. A multiparametric monitor is used, tracking cardiac activity, blood pressure and pulse oximetry.

For inhalation, we use a specific system that enables precise control of the quantities of oxygen and nitrous oxide administered, and collect and remove the gas to avoid exposure of medical staff.

During treatment, there are few psychoactive effects, unlike with ketamine infusion. Most patients report a feeling of relaxation, calm and well-being. In all cases, a professional is present at all times and can intervene if necessary.

At the end of each session, nitrous oxide is rapidly eliminated from the body, and the patient recovers very quickly with no residual sedation. Inhalation lasts about an hour, and the whole procedure takes approximately 1.5 to 2 hours.

Before each inhalation, the patient must fast for 4 hours for solids and 2 hours for liquids. A treatment to prevent nausea should be taken one hour before the session, and a vitamin supplement will be prescribed.

Risks and adverse effects

When used pure without oxygen and unsupervised, nitrous oxide can be extremely toxic, as it replaces oxygen in the lungs, leading to hypoxia, asphyxia, brain damage and death. Repeated use can cause vitamin B12 deficiency, anaemia and neurological damage. Although its use can be abused, it does not, strictly speaking, cause addiction.

Nitrous oxide has been in use for medical purposes for a very long time, and benefits from a considerable hindsight. In our procedure, nitrous oxide is always administered with oxygen, the proportion of nitrous oxide never exceeding 50%.

Nitrous oxide administered for antidepressant purposes has few side effects, but can sometimes cause dizziness, nausea, vomiting and headaches. If this should occur during inhalation, the treatment can be temporarily suspended. These effects are transient and disappear rapidly. Before the start of treatment, medication to prevent nausea and vitamin B12 supplements are prescribed.


  • Limited nasal breathing (rhinitis, sinusitis)
  • Middle ear occlusion or eardrum surgery
  • Chronic obstructive pulmonary disease
  • Intestinal obstruction
  • Pneumothorax
  • After specific ophthalmological procedures (intraocular gas injection)
  • Gas embolism
  • Vitamin B12 or folate deficiency
  • Pregnancy 1st and 2nd trimester

Is nitrous oxide covered by insurance?

Nitrous oxide inhalations are not reimbursed by either basic or complementary insurance schemes in Switzerland.

The patient has to meet the entire cost of treatment as well as of the monitoring by specialists in psychiatry and anaesthesia.

More information on costs and payment terms is available upon request.

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