Ketamine is metabolized by the hepatic microsomal system.
Major pathway:
N-demethylation ->
ketamine
norketamine (metabolite I)
Norketamine, with 20-30% of the activity of ketamine, is hydroxlyated to hydoxynorketamine, conjugated with glucuronate and excreted in the urine. Norketamine, with t1/2(elimination) = 6 hours, probably contributes significantly to analgesia.