Zopiclone – Sleep Aid: Effects, Dosage, Side Effects

What is Zopiclone?

Zopiclone is a medication belonging to the class of drugs known as Z-drugs (non-benzodiazepine hypnotics) and is prescribed for the short-term treatment of insomnia (sleep disorders). It is available by prescription only and is among the most commonly prescribed sleep aids in many countries.

Mechanism of Action

Zopiclone acts on the central nervous system by binding to the GABA-A receptor complex. GABA (gamma-aminobutyric acid) is the main inhibitory neurotransmitter in the brain. By enhancing GABA activity, zopiclone reduces neuronal excitability, producing sedative, anxiolytic, and sleep-inducing effects. Although it is chemically distinct from benzodiazepines, its mechanism of action is very similar.

Indications

Zopiclone is used to treat:

• Difficulty falling asleep (sleep onset insomnia)
• Difficulty staying asleep (sleep maintenance insomnia)
• Sleep disturbances associated with anxiety or stress
• Transient sleep problems (e.g., caused by shift work or jet lag)

Treatment should be limited to a maximum of 2 to 4 weeks, as prolonged use increases the risk of physical and psychological dependence.

Dosage

The standard adult dose is 3.75 mg to 7.5 mg taken shortly before bedtime. For elderly patients or those with impaired liver function, a lower starting dose of 3.75 mg is typically recommended to minimize the risk of side effects. Dosage should always be determined individually by a healthcare professional.

Side Effects

Like all medications, zopiclone can cause side effects. The most common include:

• Bitter or metallic taste in the mouth (very common)
• Dry mouth
• Daytime drowsiness or grogginess (hangover effect)
• Impaired concentration and memory
• Dizziness and coordination problems
• Development of dependence with prolonged use
• Rebound insomnia (temporary worsening of sleep problems after stopping the medication)

Less common but more serious side effects include confusion, depression, and sleep-related behaviors such as sleepwalking (parasomnias).

Contraindications

Zopiclone should not be taken by individuals with:

• Known hypersensitivity to the active substance
• Severe respiratory insufficiency or sleep apnea syndrome
• Severe hepatic impairment
• Myasthenia gravis (a neuromuscular disorder)
• During pregnancy or breastfeeding
• Children and adolescents under 18 years of age

Drug Interactions

Zopiclone may interact with other substances. Caution is particularly warranted when combined with:

• Other sedatives or sleep medications
• Alcohol (significantly enhances sedative effects)
• Opioid pain relievers
• Certain antibiotics and antifungal agents that affect how zopiclone is metabolized in the liver

Dependence and Discontinuation

An important consideration with zopiclone use is its potential for dependence. Physical tolerance can develop within just a few weeks. Abrupt discontinuation may lead to withdrawal symptoms such as anxiety, tremors, rebound insomnia, and in rare cases, seizures. Zopiclone should therefore always be tapered gradually and under medical supervision.

References

1. Benkert, O. & Hippius, H. - Compendium of Psychiatric Pharmacotherapy, 14th Edition, Springer Verlag (2023)
2. National Institute for Health and Care Excellence (NICE) - Hypnotics and anxiolytics: guidance on prescribing, available at: www.nice.org.uk
3. European Medicines Agency (EMA) - Product Information for Zopiclone, available at: www.ema.europa.eu