Effect of anxiolytic and hypnotic drug prescriptions on mortality hazards: retrospective cohort study

In recent years, use of Z-drugs has increased significantly; in 2013/14, zopiclone was the sixth most common drug amongst enquiries to the UK National Poisons Information Service’s online database, TOXBASE (1). Weich et al. noted increased mortality risk with hypnotic drugs (2) amidst increasing concern about non-medical misuse (3,4). Further, people’s changing expectations of healthcare provision (5) towards a consumerist approach provides new regulatory challenges.

We recently managed a patient whose overdose of 100 tablets of 7.5mg zopiclone – reportedly purchased from an Internet site without prescription – highlights these issues.

To investigate zopiclone availability, we undertook an Internet snapshot survey using EMCDDA methodology (6). We identified 37 websites selling zopiclone tablets in quantities of up to 2,000. Thirty-five (94.6%) also sold other benzodiazepines/Z-drugs and 15 (40.5%) offered bulk-purchase discounts. Most (24; 64.9%) provided information/warning about dosage, however 22 (59.4%) clearly stated that no prescription was necessary for purchase, while 14 (37.8%) made no mention of this at all. Only one (2.7%) stated that a prescription was required.

In 2014, zopiclone was controlled in the UK as Class C, Schedule IV Part 1, due to concerns about dependence and misuse potential (7). We are concerned that, despite this, zopiclone is easily available from Internet sites without prescription. Not only do these websites bypass necessary oversight required for supply, they provide access for vulnerable populations who may purchase it for self-poisoning, suicide, and/or misuse. Regulatory authorities need to ensure that appropriate measures are taken so that these websites comply with medicines and other regulations for the supply of this prescription only medicine.

James H Ho
specialist registrar in clinical toxicology

David M Wood
consultant clinical toxicologist

John R H Archer
consultant clinical toxicologist

Paul I Dargan
professor and reader in clinical toxicology

Clinical Toxicology, Guy’s and St Thomas’ NHS Foundation Trust, London, UK

Competing interests: PID is a member of the EMCDDA Scientific Committee and the UK Advisory Council on the Misuse of Drugs; DMW is an expert advisor to the EMCDDA and a co-opted member of the UK Advisory Council on the Misuse of Drugs.

1. National Poisons Information Service: Report 2013/14. [15 June 2015]. Available from: http://www.npis.org/NPISAnnualReport2013-14.pdf.
2. Weich S, Pearce HL, Croft P, Singh S, Crome I, Bashford J, Frisher M. Effect of anxiolytic and hypnotic drug prescriptions on mortality hazards: retrospective cohort study. BMJ. 2014;348:g1996.
3. Advisory Council on the Misuse of Drugs (ACMD). Z-drugs: a review of the evidence of misuse and harm. [15 June 2015]. Available from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/fil....
4. Kapil V, Green JL, Le Lait C, Wood DM, Dargan PI. Misuse of benzodiazepines and Z-drugs in the UK. Br J Psychiatry. 2014;205(5):407-8.
5. Anderson C. Changing the way pharmacy only drugs are supplied would be unwise. BMJ. 2015;351:h3951.
6. Hillebrand J, Olszewski D, Sedefov R. Legal highs on the Internet. Subst Use Misuse. 2010;45(3):330-40.
7. Home Office. A Change to the Misuse of Drugs Act 1971. [15 June 2015]. Available from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/fil...