Research Report Eur Addict Res 2004;10:35–40 DOI: 10.1159/000073724 Relationship between Prescribing and Risk of Opiate Overdose among Drug Users in and out of Maintenance Treatment Lan-Ho Man David Best Michael Gossop Garry Stillwell John Strang National Addiction Centre, London, UK Lan-Ho Man National Addiction Centre, Addiction Sciences Building 4 Windsor Walk, Denmark Hill London, SE5 8AF (UK) Tel. +44 20 784 80835, Fax +44 20 784 80967, E-Mail LMan@iop.kcl.ac.uk ABC Fax + 41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2004 S. Karger AG, Basel 1022–6877/04/0101–0035$21.00/0 Accessible online at: www.karger.com/ear Key Words Risk factors W Poly-drug use W Personal overdose W Prescribed medication W Methadone maintenance Abstract 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 pu- rity, 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. Copyright © 2004 S. Karger AG, Basel Introduction Overdose is extremely prevalent among injecting drug users [1–4]. In a third of a mixed clinical and non-clinical sample of heroin users, over a third had previously over- dosed [5]. In clinical samples, rates may be even higher. Just over half of the methadone maintenance clients inter- viewed in Edinburgh and London had overdosed [6] and, in a separate cohort of London drug users in treatment, nearly half had taken an opiate overdose [7]. Among heroin users in Sydney, Australia, over two-thirds had overdosed at some point [3]. There are several risk factors for overdose including route of drug administration [8, 9], reduced tolerance [10, 11] and suicidal intention [6, 10]. However, the most commonly identified risk factors for overdose are concur- rent alcohol and poly-drug use. Over half of a sample of injecting drug users in London, who had overdosed, reported having drunk alcohol prior to the overdose [2]. Among a sample of overdose fatalities, mean blood mor- phine concentrations were lower in cases positive for alco- hol [12, 13]. Many overdoses are due to the combined effects of opiates with other drugs, especially alcohol and benzodiazepines [14] and the combination of opiate and non-opiate drugs (particularly benzodiazepines) is a com- mon cause of overdose deaths among drug users [2]. This has also been shown in a longitudinal study of deaths among drug users in which causes of death were con- Downloaded by: Kings's College London 159.92.174.159 - 11/11/2013 11:49:39 AM