Nitrous Oxide: Appearance, Uses, Mechanism Of Action, Indications, Side Effects, Treatment

Nitrous Oxide:

Similar Names:

  1. Dinitrogen monoxide;
  2. laughing gas;
  3. Hyponitrous acid anhydride;
  4. factitious air.

How Does It Appear?

  1. It is a colourless gas with a slightly sweet taste as well as odour.
  2. It exists in the form of crystals and also liquid form.
  3. It is found abundant in the atmosphere.
  4. It produces from the decomposition of organic nitrogen compounds in soil.

What Are The Uses Of Nitrous Oxide

  1. It is used as an analgesic in dental and obstetric surgery.
  2. It can also be used as an anaesthetic in combination with other agents.
  3. Nitrous oxide is used as the foaming agent in whipped cream, as an oxidant in organic compounds, to make nitrates in alkali metals.
  4. It is also used in some rocket fuel combinations.
  5. Whipped cream found in the can have been reported to release up to 1.5L of nitrous oxide.
    Nitrous Oxide

    Nitrous Oxide

Mechanism Of Action

  1. This gas acts as a central nervous system depressant.
  2. It can cause asphyxiation by oxygen displacement.
  3. It inactivates the biological activity of vitamin B12 and oxidizes cobalt which results in deprivation of vitamin B12.
  4. Naloxone has been found to partially reverse the activity of nitrous oxide-induced analgesia.


  • Uses as General Anaesthesia:- It is used in combination with other anaesthetics
    1. Nitrous oxide is used as a weak inhalational anaesthetic. It has a very low amount of alveolar concentration, that is the reason it can’t be used alone in general anaesthesia. So, it is combined with other potential inhalational anaesthetics for general anaesthesia.
    2. Nitrous oxide is most commonly used in mask induction of general anaesthesia in children. It is combined with oxygen and potent inhalational anaesthetic like sevoflurane which is delivered via mask inhalation.
  • In Dentistry
    1. Nitrous oxide helps to decrease the pain and anxiety associated with dental procedures. It is delivered in combination with oxygen by nasal passage or mask. These nasal masks are specially designed to fully cover the nose which allows the mixture to flow while allowing the dental procedures through the mouth of the patient.
    2. It is commonly used by paediatric dentists to assist in procedures like amnesia, analgesia, as well as relaxation and cooperation in younger patients.
    3. Nitrous oxide uses in adult dental patients include lower pain tolerance, anxiety, mental retardation or any underlying psychiatric disorder.
  • Other Indications include:
    1. Additional uses include colonoscopy, sigmoidoscopy, ophthalmic procedures, laser procedures, obstetrical labour pain, ambulance transport and medical procedures including joint injections.
    2. Nitrous oxide is less commonly self-administered in case of chronic pain because of terminal illness and in case of pain associated with cancer treatment.
    3. In the case of paediatric patients, it’s used is indicated in lumbar puncture, venous cannulation, or dressing changes has helped in a significant reduction in pain levels which allows shorter recovery time.
    4. A study has shown that nitrous oxide in combination with oxygen. When administered to the patients for three minutes displayed less anxiety and distress and it was effective in reducing pain in children.
    5. Nitrous oxide also used successfully in minor surgeries of children such as cyst surgery and abscess drainage

What Are The Side Effects Of The Gas?

  1. The solubility of nitrous oxide increases by 35 times in blood than nitrogen.
  2. When we inhale it, it increases the air-containing spaces such as bowel in size, while non-air containing spaces such as eustachian tube increases in pressure. This increase in pressure and size leads to bowel distention and rupture of the tympanic membrane.
  3. It has been reported that Nitrous oxide may cause mild hypertension when given as anaesthetic.
  4. It can also cause cardiac arrhythmias which may also result from hypoxia.
  5. Nausea and vomiting may also occur
  6. It causes intoxication which results in acute neuralgia due to asphyxia.
  7. Side effects of inhalations also include a headache, dizziness, and excitation that results in CNS depression, seizures, and death.
  8. The respiratory disturbance may also occur.
  9. It may also cause interstitial emphysema and pneumomediastinum because of inhalation of gas from whipped cream cans.
  10. Based on the research it has been evaluated that it is a potential carcinogen.


It Causes:

  1. Increased muscle tone
  2. Respiratory depression
  3. hypertension
  4. cardiovascular failure
  5. Mydriasis
  6. Prolonged usage can lead to bone marrow depression, polyneuropathy, megaloblastic changes, and death can also occur.
  7. Impotence also occurs due to nitrous oxide-induced myeloneuropathy.
  8. Neurological and hematopoietic effects are also reported and it may result in selective inactivation of vitamin B12.

Fatal Dose

  1. When a person is exposed to 50-70% of nitrous oxide for 3 hrs it can cause aplastic anaemia and sometimes death.
  2. If 40% of nitrous oxide is inhaled in the air can cause confusion and sedation while 80% level can lead to unconsciousness in most people.


  1. The way to treat a cough or difficulty in breathing, respiratory tract irritation, hypoxia, bronchitis or pneumonitis is to remove from the source of exposure.
  2. If cerebral oedema and ICP (elevated intracranial pressure)  administer mannitol and elevate the head of the individual.
  3. Hyperventilation is recommended if the impending herniation occurs.
  4. Usage of folinic acid, IV is recommended for bone marrow abnormalities.
  5. For neurologic damage, methionine supplements are recommended.

Supportive Measures Include:

  1. Control the relapse of seizures
  2. Treatment of hypoxia
  3. Continuous monitoring of arrhythmias
  4. Treatment of respiratory irritation.