Australia - Zolpidem (Stilnox®) was marketed in Australia in late 2000 for the short-term treatment of insomnia. It is structurally unrelated to the benzodiazepines, but has a similar pharmacological action. In 2001, the Australian Drug Reactions Advisory Committee (ADRAC) received 72 reports describing 170 reactions in association with zolpidem.

Of these 72 reports, 56 described one or more neurological or psychiatric reactions, especially visual hallucinations, confusion, depression and amnesia. Most reactions occurred with a daily dose of 10 mg and 70% occurred after the first dose. Most of the 15 reports of hallucinations occurred within a few hours, often soon after the drug was taken. Half of the reports of amnesia described a total loss of memory for events immediately after the drug was taken, although two described poor memory on subsequent days. The onset of confusion and depression was sometimes apparent within hours of taking the drug but in most cases occurred the following day.

Prescribers should be alerted to the fact that zolpidem may be associated with distressing neurological or psychiatric reactions, including visual hallucinations, nausea, confusion, depression, amnesia, dizziness, headache, somnolence, depersonalisation, agitation, anxiety, somnambulism, or vomiting.

Reference: Australian Adverse Drug Reactions Bulletin, 21: (2) February 2002.