The prescription-only sleeping tablet zopiclone, which can become addictive if used for more than a few weeks, is easily available online, warn experts in The BMJ.

Paul Dargan and colleagues from the clinical toxicology unit at Guy’s and St Thomas’ NHS Foundation Trust in London, say regulatory authorities “must take measures to ensure that these websites comply with medicines and other regulations for the supply of this prescription-only drug.”

“Z drugs” can be prescribed by a doctor for short periods to ease symptoms of insomnia. They can work well in the short term, but are not normally prescribed for more than two to four weeks because of concerns about dependence and addiction.

The use of Z drugs has recently increased. In 2013-14, zopiclone was the sixth most common drug among enquiries to the UK National Poisons Information Service’s online database, TOXBASE.

The authors describe how they recently managed a patient whose overdose of 100 tablets of 7.5mg zopiclone, reportedly purchased from an Internet site without prescription, highlights these problems.

To investigate the availability of zopiclone, they identified 37 websites selling zopiclone tablets in quantities of up to 2,000. Thirty five also sold similar drugs and 15 offered bulk purchase discounts.

Most (24) provided information and/or warnings about dosage, but 22 clearly stated that no prescription was necessary for purchase, while 14 made no mention of this at all.

Only one website stated that a prescription was needed.

In 2014, zopiclone was controlled in the UK as Class C, schedule IV part 1 drug, owing to concerns about dependence and potential for misuse. Yet despite this, zopiclone is available from internet sites without prescription, write the authors.

“Not only do these websites bypass necessary oversight required for supply, they provide access for vulnerable people who may buy it for self poisoning, suicide, or misuse,” they argue.

“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,” they conclude.