Hydrocodone is the methyl ether of hydromorphone, but is much weaker an analgesic than hydromorphone. The analgesic potency of oral hydrocodone is approximately that of morphine. Hydrocodone is often combined with acetaminophen or ibuprofen to treat moderate-to-severe pain. It is also used as an antitussive. Hydrocodone is metabolized in the liver to several metabolites, one of which is hydromorphone via the actions of CYP450 2D6, which can be affected by drug-drug interactions.