Also known as diacetyl morphine or diamorphine, this Class A controlled drug is an opiate – a group which includes morphine, codeine, pethidine and methadone. It is a powerful analgesic and cough suppressant, but its capacity to produce euphoria rapidly induces dependence. The need to inject the drug, with associated risks of HIV or hepatitis virus infection, is relevant to its use by addicts (see DEPENDENCE). Withdrawal symptoms include restlessness, insomnia, muscle cramps, vomiting and diarrhoea; signs include dilated pupils, raised pulse rate, and disturbed temperature control. Although rarely life-threatening, the effects of withdrawal may cause great distress, and for this reason methadone, which has a slower and less severe withdrawal syndrome, is commonly used when weaning addicts off heroin. Legally still available to doctors in the UK, heroin is normally only used in patients with severe pain, for example from MYOCARDIAL INFARCTION, or in palliative care for the dying.