Unintentional rapid opioid detoxification.

Naltrexone is a long acting opioid antagonist that is used in rehabilitation programmes to maintain heroin abstinence. It is a relatively new drug prescribed by specialists in substance misuse. Its actions and effects may not be familiar to many accident and emergency doctors or even to the people who take it. A case report is described where accidental ingestion of naltrexone results in a medical emergency by precipitating acute withdrawal in a heroin addict.