Ketamine, a dissociative anesthetic, is metabolized primarily in the liver by cytochrome P450 enzymes, especially 3A4 and 2B6, into the active metabolite norketamine and other minor compounds. Recent metabolomics studies show ketamine alters glycolysis, the tricarboxylic acid cycle, amino acid metabolism, and mitochondrial fatty acid oxidation. Understanding these metabolic pathways may improve clinical and forensic characterization of ketamine.
Dextromethorphan (DXM), a common cough suppressant in over-the-counter medications, can produce psychoactive effects at high doses, leading to abuse. This review describes DXM's metabolism, including sequential O-demethylation and N-demethylation by enzymes to produce dextrorphan (the major active metabolite) and other compounds, as well as glucuronide conjugation. Genetic variations in metabolizing enzymes and drug interactions cause large differences between individuals in DXM's effects and toxicity. Understanding this metabolism helps explain variable responses and avoid adverse effects.