26 November 2008

It is difficult to know the extent of the use and adverse effects of zolpidem and other z-drugs (zopiclone and zaleplon) because they have never been listed on the Australian Pharmaceutical Benefits Scheme, senior Sleep Disorders Physician Dr Les Olson writes in the latest edition of Australian Prescriber.

Following the media attention given to side effects in patients taking zolpidem, Dr Olson reviews the known adverse reactions of the z-drugs.

“Although the media have been impressed with the outlandish adverse events reported with zolpidem, these events are not unprecedented. Amnesia, hallucinations and bizarre behaviour were also seen frequently in patients taking the short-acting benzodiazepine, triazolam, for insomnia,” Dr Olson writes.

"All of the bizarre behaviours reported, such as sleep eating, sleep sex and sleep driving, are more likely to represent 'wakeful behaviour with amnesia' than behaviour while asleep."

“Z-drugs have few advantages over benzodiazepines, and there is no good reason for their use in insomnia. It is possible to manage insomnia without ever using hypnotic drugs and this approach should be the rule rather than the exception.”

“If patients are prescribed z-drugs they should be made aware that sedation, confusion and disinhibition may occur. They should be advised to avoid alcohol, and the hypnotic should always be taken once the patient is in bed, not on the way to bed.”

“Evidence that z-drugs, especially zolpidem, commonly cause adverse effects not predictable from their pharmacology is weak. Zolpidem may cause hallucinations relatively frequently (as triazolam did), but reports of 'abnormal behaviour with amnesia' probably reflect predictable effects.”

Dr Olson says these adverse effects are not unique to z-drugs and could be limited by reduced prescribing.

“If there were fewer prescriptions for zolpidem and other z-drugs there would be fewer adverse events,” Dr Olson writes.

Non-medicine strategies for managing insomnia and guidance for counselling patients are available from the National Prescribing Service Limited (NPS) website www.nps.org.au.

For all hypnotics, NPS advises that doctors use the lowest dose for the shortest time possible (ideally for less than two weeks and no longer than four weeks) and re-evaluate within seven to 14 days of starting therapy.

The complete article will be available on the Australian Prescriber website www.australianprescriber.com on 1 December.

ENDS

For further advice health professionals can also call the NPS Therapeutic Advice and Information Service (TAIS) – a medicines information service staffed by specialist drug information pharmacists – on 1300 138 677 Monday to Friday 9am-7pm Eastern Standard Time for the cost of a local call (mobiles may cost more).

Australian Prescriber is an independent peer-reviewed journal providing critical commentary on therapeutic topics for health professionals, particularly doctors in general practice. It is published by the National Prescribing Service Limited (NPS), an independent, non-profit organisation for Quality Use of Medicines funded by the Australian Government Department of Health and Ageing. Australian Prescriber is distributed every two months in hard copy to health professionals, free of charge, and online in full text at www.australianprescriber.com.