Zopiclone is a member of cyclopyrrolones, and is a new-generation sedative-hypnotic with anticonvulsant and muscle relaxant properties. Zopiclone and related drugs such as eszopiclone and suriclone are non-benzodiazepine hypnotic/ anxiolytic agents. Even though these drugs are chemically unrelated to benzodiazepines, they nevertheless potentiate gamma-aminobutyric acid (A)-mediated neuronal inhibition.
Overdose leads to rapid loss of consciousness. Chronic use is associated with metallic or bitter taste, dry mouth or sialor-rhoea, GI distress, drowsiness, rebound insomnia, and confu-sion. Other common adverse effects include asthenia, dizziness, memory impairment, feeling of drunkenness, euphoria, anxiety, depression, impaired co-ordination, hypotonia, and speech disorder. Severe overdoses may result in hypoxia, pulmonary oedema, and respiratory failure. The potential for physical dependence has been reported; psychiatric reactions, including hallucinations, have also been described. Abrupt withdrawal of zopiclone, particularly following higher dosages and longer usage, may result in convulsions, tremor, abdominal and muscle cramps, vomiting, sweating, dysphoria, perceptual disturbances, and insomnia.
Treatment of overdose is on general lines. Provide general supportive therapy as indicated, including adminis-tering intravenous fluids and maintaining adequate airway. Monitor respiratory, cardiac, and haemodynamic status of all patients following significant overdose. Flumazenil may be beneficial.