Codeine

Codeine is an opiate drug, primarily used in the management of mild-to-moderate pain. It occurs naturally in the sap of the opium poppy. The most common route of administration is oral via a pill, in which case the drug normally begins working within 30 minutes, although injection of codeine into a vein provides the quickest effects.

Codeine is a Class B drug in the UK, although it may be purchased in pharmacies in low doses.

Codeine is a prodrug of morphine (which also occurs naturally in opium) meaning it metabolises into morphine after administration. Recreational users of illegal opiates, such as heroin, may use codeine to ward off opiate withdrawals (among other opiates such as methadone, and other drugs including vallium and alcohol) when the user's preferred drug can't be obtained.