Temazepam

Temazepam is an intermediate-acting benzodiazepine hypnotic used only for short-term insomnia. It is conjugated by the liver to inactive metabolites. Next-day sedation, dependence and misuse are the main concerns. In some regions it is a controlled drug and the gel capsules have been misused by injection.

Classification. Benzodiazepine hypnotic, intermediate-acting.

Mechanism. Positive allosteric modulation of GABA-A receptors, which increases chloride channel opening and neuronal inhibition.

Pharmacokinetics. Well absorbed orally, peak in 30 to 90 minutes (slower with the gel capsule). Glucuronidated to inactive metabolites. Half-life 8 to 20 hours. Approximate equivalence for switching: temazepam 20 mg is about diazepam 10 mg.

All regimens are oral with no loading dose.

Insomnia, adults (short term).

• 10 to 20 mg at night, 30 to 60 minutes before bed; 15 to 30 mg in some labels.
• Maximum 40 mg at night in resistant cases under specialist advice.
• Duration: no longer than 2 to 4 weeks, including the taper.

Older adults. 5 to 10 mg (7.5 mg in some labels) at night.

Dose limits. Liver impairment and respiratory disease: lower doses; avoid in severe disease. Kidney impairment: start low.

Contraindications. Respiratory depression, severe sleep apnoea, acute pulmonary insufficiency, myasthenia gravis, severe liver impairment, pregnancy in some labels, hypersensitivity. Major warning of profound sedation and death with opioids; abuse and misuse; dependence and withdrawal.

Serious adverse effects. Respiratory depression, complex sleep behaviours (sleep-walking, sleep-driving), dependence and withdrawal seizures, paradoxical agitation, anterograde amnesia, falls and fractures, delirium in older adults.

Common adverse effects. Next-day drowsiness, dizziness, ataxia, headache, confusion, memory impairment.

Interactions. Opioids, alcohol, gabapentinoids and other sedatives add respiratory depression. Few cytochrome interactions. Probenecid raises levels. Clozapine with temazepam can cause collapse.

Common prescribing errors. Prescribing for longer than 4 weeks; giving to patients who drive early; combining with opioids or alcohol; abrupt stopping.

Special groups.

• Pregnancy: avoid; floppy infant syndrome and neonatal withdrawal with late exposure.
• Breastfeeding: avoid repeated dosing; infant sedation reported.
• Children: not advised.
• Older adults: 5 to 10 mg; high risk of falls and delirium.
• Kidney impairment: start low.
• Liver impairment: use lower doses; avoid in severe disease.

Formulations. Tablets 10 mg and 20 mg; capsules 10 mg, 15 mg, 20 mg and 30 mg; oral solution 10 mg/5 mL in some regions. Take at bedtime when able to sleep for 7 to 8 hours.

Baseline. Sleep history and sleep hygiene, alcohol and sedative use, respiratory status, driving requirements, history of dependence, pregnancy status.

Monitoring. Review at 1 to 2 weeks and at the end of the planned course. Ask about next-day impairment, sleep behaviours and escalating use.

Stopping. After more than 2 weeks of nightly use, reduce the dose by 5 to 10% every 1 to 2 weeks or reduce frequency to every second night; abrupt stopping can cause rebound insomnia and withdrawal.

Referral and escalation. Refer to addiction or psychiatric services for dependence. Complex sleep behaviours or respiratory depression needs the drug stopped and urgent review.