Some of the views expressed in the following notes on newly approved products should be regarded as tentative, as there may have been limited published data and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. As a result of fuller experience, initial comments may need to be modified. The Committee is prepared to do this. Before new drugs are prescribed, the Committee believes it is important that full information is obtained either from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Imovane (Rhone-Poulenc Rorer)
7.5 mg film-coated tablets
Indication: insomnia
Drugs are not the first-line treatment of insomnia.1 If a hypnotic is prescribed, it is usually a benzodiazepine. Zopiclone now offers an alternative as it is a non-benzodiazepine hypnotic.
Zopiclone is a cyclopyrrolone which binds to benzodiazepine receptors in the brain. It is rapidly absorbed reaching a peak plasma concentration within two hours. The drug is also rapidly eliminated by metabolism with a half-life of approximately 5 hours. The metabolites have little pharmacological activity.
Few adverse effects have been reported, but lighter sleep and anxiety can occur when the drug is withdrawn. Common adverse effects are bitter taste, dry mouth, drowsiness, headaches and fatigue.
Zopiclone is as effective as the benzodiazepine hypnotics, but the risk of dependence is unknown. As the lack of data on dependence has been a cause for concern2, the drug is approved for short-term use (2-4 weeks)only.
References
1. M ant A, Bearpark H. Management of insomnia. Aust Prescr1990;13:51-4.
2. Z opiclone: another carriage on the tranquilliser train[editorial]. Lancet 1990;335:507-8.
