Benzodiazepines
💡 Zopiclone and Zolpidem are not benzodiazepines but are “Z-drugs.”
They act on the same GABAA receptor complex and produce similar hypnotic and anxiolytic effects.
📖 About
- 💊 Widely used for anxiety, insomnia, periprocedural amnesia, and sedation.
- 🦴 Also relax skeletal muscles (used in movement disorders, spasticity).
- 😴 Induce sleep - hence their key role in hypnotic therapy.
🧠 Mode of Action
- Bind to the benzodiazepine receptor site on the GABAA receptor–Cl⁻ channel complex.
- Enhance the effect of GABA (they do not mimic GABA itself).
- Increase the frequency (not duration) of Cl⁻ channel opening → hyperpolarisation → CNS inhibition.
- Contrast: Barbiturates increase duration of Cl⁻ channel opening.
💊 Indications
- 🧩 Anxiolytic (e.g., lorazepam for acute anxiety).
- 😴 Hypnotic (temazepam, Z-drugs for insomnia).
- 🧪 Premedication before procedures (sedation + amnesia).
- ⚡ Anticonvulsant (clonazepam, diazepam in status epilepticus).
- 💪 Muscle relaxant (spasticity, myoclonus).
- 🍷 Alcohol withdrawal (e.g., chlordiazepoxide, diazepam).
⚠️ Contraindications / Cautions
- 🚗 Driving or operating machinery - causes sedation, impaired reflexes.
- 💊 Concurrent use with opioids/other CNS depressants → ↑ risk of respiratory depression.
- ⚠️ Caution in depression (may worsen suicidal risk).
- 📉 Avoid prolonged use (>4–6 weeks) → high risk of tolerance and dependence.
🧪 Common Benzodiazepines
- Short-acting: Temazepam, Lorazepam
- Long-acting: Diazepam, Chlordiazepoxide
- Special uses: Clonazepam (anticonvulsant)
❗ Side Effects
- 😴 Sedation, drowsiness, poor concentration.
- 🌀 Ataxia, impaired psychomotor performance, falls (elderly).
- 🫁 Respiratory depression (esp. with opioids/alcohol).
- 🧠 Amnesia, tolerance, withdrawal symptoms (agitation, seizures).
- 🔄 Rebound insomnia when stopped abruptly.
- ⚡ Dependence can develop after 4–6 weeks of regular use.
- ⏳ Long-acting BZDs (e.g., diazepam) → “hangover” effect.
🔀 Interactions
- 💊 Potentiated by alcohol, opioids, antihistamines, antipsychotics.
- Diazepam and chlordiazepoxide: few major drug–drug interactions, but cumulative sedation with other CNS depressants.
- ⛑️ Flumazenil = competitive antagonist at benzodiazepine receptor, reverses sedation but short-acting (risk of seizures in chronic BZD users).
