Zolpidem (e.g. STILNOX) has been available since 1991 for short-term treatment of sleep disorders and is now prescribed more often than the market leader benzodiazepine hypnotic lormetazepam (e.g. NOCTAMID). Zolpidem has no structural resemblance to benzodiazepines but has almost identical pharmacological effects. Side effects in the neurological or psychiatric area such as visual hallucinations (a-t 2002; 33: 31-2), depression, confusion, memory disorder (a-t 1998; no. 10: 94), nightmares (a-t 1992; no. 3: 32) and sleepwalking (a-t 1998; no. 5: 52) are reported remarkably often (1).

Uncontrolled eating while asleep ("sleep-eating") was described in five patients taking zolpidem in 2002. In the morning they cannot remember eating during the night (2). There are now reports from Australia about 16 sleepwalkers who showed bizarre behaviour after taking zolpidem, also with subsequent loss of memory (1). One woman who had gained 23 kg within seven months was discovered asleep in front of an open refrigerator. Another patient also fetched food from the kitchen while asleep. One woman awoke with a paintbrush in her hand. She had painted the front door in her sleep (1).

One of our readers reported "marked sleepwalking with considerable self-endangerment" in a 40-year old woman taking zolpidem plus perazine to our NETWORK OF MUTUAL INFORMATION (TAXILAN etc.; NETWORK report No. 9.479). A 60-year old woman suffered from a nocturnal autoaggressive phase after only one tablet - she scraped both feet with a callous parer - with amnesia next morning (NETWORK report No. 5.995).

In the USA the consequences of driving a car under the influence of zolpidem ("sleep-driving") are legally pending. One woman only learned from the police that she had rammed a parking car with her car in the night. She had woken up in bed without any memory of the event (3). In view of zolpidem's short half-life of two to three hours, it is astonishing that the hypnotic is often named in the files of traffic offences. In Wisconsin (USA) within five years zolpidem was found in the blood of 187 drivers who had attracted attention of the police (3). Taking it at the wrong time, at excessive dose and with alcohol may have contributed to incorrect reactions.

Nocturnal eating with anterograde amnesia is also known with the short-acting benzodiazepines midazolam (e.g. DORMICUM) and triazolam (HALCION) (2). Patients and their relatives must know that sleepwalking is possible when short-acting benzodiazepine receptor agonists such as zolpidem are used and activities may include endangerment of self and others. In the officially approved German prescribing information, for example that of STILNOX (4), specific warnings about this dangerous side effect complex are lacking.

1

Austr. Adv. Drug React. Bull. 2007; 26: 2-3

2

MORGENTHALER, T.I., SILBER, M.H.: Sleep Medicine 2002; 3: 323-7

3

Scrip 2006; Nr. 3140: 14

4

Sanofi-Synthelabo: Prescibing information STILNOX, Jan. 2003