Relationship between prescribing and risk of opiate overdose among drug users in and out of maintenance treatment.

Opiate users (n = 135) from southern England, Glasgow and Edinburgh were interviewed about opiate overdose (lifetime). Fifty-six percent had overdosed. The majority (66%) reported mixing opiates with at least one other drug (mainly alcohol and/or benzodiazepines) at their last overdose. Patients identified misjudgements of purity, mixing drugs and misjudgements of tolerance as causes of overdose. The sample was divided into groups: (1) 'no prescription', (2) prescribed 'diazepam only', (3) prescribed 'methadone only' and (4) prescribed 'methadone + diazepam'. The 'methadone + diazepam' group reported more lifetime and deliberate overdoses, the 'methadone only' group were more likely to have used several drugs at the time of their last overdose and the 'no prescription' group to have used only heroin. Drug users' overdose risk may vary as a result of their prescribed and non-prescribed drug use. Interventions should be developed and tailored according to clients' needs and current use patterns.