Imovane (Zopiclone)

Zopiclone is a cyclopyrrolone used to treat sleep disorders, primarily insomnia, by enhancing GABA‑mediated inhibition to promote sedation.

• Insomnia: helps adults achieve faster sleep onset and improve overall sleep duration.
• Sleep‑onset insomnia: reduces the time required to fall asleep.
• Sleep‑maintenance insomnia: decreases nighttime awakenings and promotes continuous sleep.
• Short‑term insomnia: provides temporary relief for acute sleep disturbances lasting up to four weeks.
• Insomnia related to shift work: assists individuals with irregular sleep schedules to obtain restorative sleep.

• Zopiclone acts as a positive allosteric modulator at the benzodiazepine binding site of the GABA‑A receptor complex. By enhancing the affinity of GABA for its receptor, it increases chloride ion influx, leading to hyperpolarisation of neuronal membranes and reduced neuronal excitability. This potentiation of inhibitory neurotransmission produces a sedative‑hypnotic effect that facilitates sleep onset and maintenance. The effect is dose‑dependent and reversible upon discontinuation.

Zopiclone may cause a range of adverse reactions, which are classified by frequency.

Common Side Effects

• Drowsiness: feeling of sleepiness during daytime.
• Bitter taste: unpleasant metallic taste in the mouth.
• Dry mouth: reduced salivary secretion.
• Headache: mild to moderate head pain.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Nausea: mild stomach upset or queasiness.

Serious or Rare Side Effects

• Complex sleep behaviours: sleepwalking, sleep‑driving, or performing other activities while not fully awake.
• Allergic reactions: rash, itching, swelling, or difficulty breathing.
• Dependence or withdrawal: signs of physical or psychological dependence with abrupt cessation.
• Mood changes: depression, anxiety, or suicidal thoughts in rare cases.

When prescribing Zopiclone, clinicians should consider several precautionary measures to ensure safe use.

• Assess patient history: evaluate for prior substance abuse, depression, or respiratory disorders.
• Limit duration: use the lowest effective dose for the shortest period, typically ≤4 weeks.
• Avoid alcohol: concurrent intake can enhance sedative effects and respiratory depression.
• Caution in the elderly: increased sensitivity may raise risk of falls and cognitive impairment.
• Pregnancy and lactation: weigh benefits against potential risks; use only if clearly needed.
• Store at ambient temperature: keep tablets in the original container, protect from moisture and light.

Zopiclone can interact with other medicines, altering its sedative effect or safety profile.

Major Interactions (Avoid)

• Central nervous system depressants: concurrent use with opioids, barbiturates, or antihistamines may cause profound sedation or respiratory depression.
• CYP3A4 inhibitors: strong inhibitors such as ketoconazole or itraconazole can increase Zopiclone plasma levels, raising toxicity risk.
• Alcohol: combined use markedly enhances sedation and impairs psychomotor performance.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers: agents like rifampicin may reduce Zopiclone effectiveness.
• Other hypnotics: co‑administration with benzodiazepines may increase cumulative sedative burden.
• Antidepressants: certain SSRIs can modestly affect Zopiclone metabolism, requiring observation.