Hydrocodone, sold under brand names such as Vicodin and Norco among many others, is a semisynthetic opioid derived from codeine, one of the opioid alkaloids found in the opium poppy. It is a narcotic analgesic used orally for relief of moderate to severe pain, but also commonly taken in liquid form as an antitussive/cough suppressant.As with members of all categories of semi-synthetic opioids derived from morphine (and codeine is one of these, in fact) with the exception of the simple esters of morphine like heroin, nicomorphine, acetyldipropanoylmorphine &c, hydrocodone made commercially is manufactured in a much more efficient synthesis from thebaine, a close chemical relative of codeine found in fairly high concentrations in opium. Hydrocodone is two steps from codeine and therefore three from morphine, and in fact a number of syntheses were found, with others being from dihydrocodeine, dihydromorphine, tetrahydrothebaine and a large number of total syntheses from coal tar or petroleum through morphine, codeine, and thebaine. Hydrocodone's closest structural relatives are fellow 14-hydroxycodeineones such as oxycodone, oxymorphone, hydromorphinol, oxymorphol, and hydromorphone. Much of hydrocodone's activity is from the last of these produced in the liver from the hydrocodone, in the one step which activates similar drugs by turning them into stronger derivatives in the same fashion in which the liver turns codeine to morphine. However, hydrocodone is also turned into other active products by other metabolic pathways and hydrocodone does, like oxycodone, have intrinsic activity of its own to a greater extent than is the case for codeine.
Hydrocodone is an opioid, and acts as a selective agonist of the μ-opioid receptor, the main biological target of the endogenous neuropeptide β-endorphin.Hydrocodone is prescribed predominantly within the United States, with the International Narcotics Control Board reporting that 99% of the worldwide supply in 2007 was consumed in the United States. Several common imprints for hydrocodone are M365, M366, M367.