Hydrocodone is a semi-synthetic opioid derived from codeine. Hydrocodone is used orally as a narcotic analgesic and antitussive, often in combination with paracetamol or ibuprofen. Hydrocodone is biotransformed by the liver into several metabolites, and has a serum half-life that averages 3.8 hours. The hepatic cytochrome P450 enzyme CYP2D6 converts it into hydromorphone, a more potent opioid. However, extensive and poor cytochrome 450 CYP2D6 metabolizers had similar physiological and subjective responses to hydrocodone, and CYP2D6 inhibitor quinidine did not change the responses of extensive metabolizers, suggesting that inhibition of CYP2D6 metabolism of hydrocodone has no practical importance. Ultrarapid CYP2D6 metabolizers may have an increased response to hydrocodone; however, hydrocodone metabolism in this population has not been studied.
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