Nitrous oxide, often called “laughing gas,” is a colorless gas with a slightly sweet odor. It is used in medical and dental fields for its anesthetic and pain-reducing properties. The World Health Organization includes it on its List of Essential Medicines due to its role in surgery and dentistry.
How Nitrous Oxide Affects the Body
Upon inhalation, nitrous oxide rapidly affects the central nervous system. Effects appear within 10 to 30 seconds and last about 60 seconds after administration stops. Its rapid removal from the lungs causes this quick onset and short duration. It works by inhibiting N-methyl-D-aspartate (NMDA) receptors in the brain, reducing excitatory actions of glutamate, a major neurotransmitter.
This interaction leads to decreased neural activity, resulting in sedation and pain relief. Users may experience euphoria, light-headedness, giggling, a sense of detachment, and altered perceptions of time and sound. It also enhances the release of endogenous opioids, contributing to its pain-relieving effects.
Potential Health Complications
Excessive nitrous oxide use can lead to negative health impacts. An immediate danger is hypoxia (lack of oxygen), which occurs because nitrous oxide displaces oxygen in the lungs. This can cause dizziness, nausea, confusion, fainting, seizures, or brain damage if oxygen deprivation is prolonged.
Direct contact with the cold gas from canisters can cause frostbite injuries to the mouth, throat, lips, or inner thighs if held between the legs. The gas reaches -40°C when released, causing rapid tissue freezing. Injuries range from superficial frostnip to full-thickness damage, potentially requiring surgical intervention and resulting in lifelong harm.
Chronic or heavy use can lead to a functional vitamin B12 deficiency. Nitrous oxide oxidizes the cobalt ion in vitamin B12, rendering it inactive even if overall B12 levels appear normal. This disrupts the body’s ability to convert homocysteine to methionine, essential for maintaining the myelin sheath that insulates nerve fibers.
Neurological complications may develop, such as peripheral neuropathy (numbness, tingling, weakness in hands and feet). More severe damage includes myelopathy, affecting the spinal cord, leading to spasticity, muscle weakness, and sensory loss. Anemia and bone marrow suppression are also reported with prolonged use.
Recognizing Misuse and Dependence
Problematic use involves escalating amounts and frequency of inhalation. Users may become preoccupied with obtaining the substance, continuing use despite negative consequences like health issues or social problems. While physical dependence is less common than with other substances, psychological dependence can develop due to euphoric effects and social context.
When use is stopped, physical withdrawal symptoms are not as pronounced as with other drugs. However, psychological distress may occur, including unease, anxiety, irritability, insomnia, headaches, and difficulty concentrating. These symptoms are similar to those experienced when stopping chronic cannabis or nicotine use. Signs of misuse include numerous used nitrous oxide cartridges or large canisters, often marketed as whipped cream dispensers.