Australian Dental Council (ADC) Practice Test 2025 - Free ADC Practice Questions and Study Guide.

Nitrous oxide, commonly known as laughing gas, is primarily excreted from the body through the lungs. When inhaled, nitrous oxide is rapidly absorbed into the bloodstream, where it exerts its anesthetic effects. After this effect wears off, the gas is not metabolized significantly by the body; instead, it is redistributed back to the lungs, from where it is exhaled.

This mode of excretion is efficient and accounts for most of the elimination of the gas from the body. The low solubility of nitrous oxide in blood means that it does not linger for long periods, allowing it to leave the body quickly after administration. Other routes such as urine, sweat, or saliva play a negligible role in the elimination of nitrous oxide, making the lungs the primary pathway for its excretion. This characteristic is important for both patient safety and recovery, as it enables rapid cessation of the drug's effects.