# What is the fate of nitrous oxide when administered for relative analgesia?
A. Excreted by kidney
B. Detoxified in liver
C. Exhaled by lungs
D. Exhaled by sweat glands
The correct answer is C. Exhaled by lungs.
As the sole agent, N2O (50%) has been used with O2 for dental and obstetric analgesia. It is
nontoxic to liver, kidney and brain. However, prolonged N2O anaesthesia has the potential to
depress bone marrow and cause peripheral neuropathy. Metabolism of N2O does not occur;
it is quickly removed from the body by lungs. It is cheap and commonly used.
Reference: Essentials of Medical Pharmacology, KD Tripathi, Seventh edition page no 378
