Overview
Nitrous oxide is an inhalational anesthetic and analgesic gas used for procedural sedation, dental procedures, and labor pain management. It produces rapid-onset sedation and analgesia with quick recovery, though it has low anesthetic potency requiring supplementation for surgical anesthesia.
Mechanism of Action
Acts as an NMDA receptor antagonist, inhibiting excitatory neurotransmission in the CNS. Also enhances GABAergic inhibition and activates opioid receptors, producing dissociative anesthesia, analgesia, and anxiolysis.
Indications
- Procedural sedation and analgesia
- Dental procedures
- Labor pain management
- Supplement to general anesthesia
- Emergency analgesia
Dosage
Typically administered as 30-70% nitrous oxide with oxygen via inhalation mask. Titrate to effect: Start with 30% nitrous oxide/70% oxygen, increase gradually to maximum 70% nitrous oxide. Continuous monitoring required. Maximum exposure limits apply for occupational safety.
Contraindications
- Pneumothorax or air embolism
- Bowel obstruction or ileus
- Middle ear occlusion
- Severe COPD or respiratory depression
- Increased intracranial pressure
- Vitamin B12 deficiency
- First trimester pregnancy (relative)
Side Effects
- Nausea and vomiting
- Dizziness and lightheadedness
- Headache
- Sweating
- Euphoria or dysphoria
- Diffusion hypoxia during recovery
- Megaloblastic anemia with chronic use
- Neuropathy with prolonged exposure
Interactions
- Potentiates effects of other CNS depressants
- Increased risk of myocardial depression with volatile anesthetics
- May enhance effects of opioids and benzodiazepines
- Concurrent use with MAOIs may cause hypertension