Amitriptyline 💊
⚠️ Amitriptyline has a high incidence of anticholinergic and cardiac side-effects, and is very toxic in overdose (narrow therapeutic index). Careful prescribing and monitoring are essential. 🚨
ℹ️ About
Always check the BNF link here 📖 for detailed prescribing advice.
- Tricyclic antidepressant (TCA) with sedating properties 😴.
- Used in depression and commonly in neuropathic pain and migraine prophylaxis (low-dose use).
⚙️ Mode of Action
- Blocks neuronal reuptake of noradrenaline (NA) and serotonin (5-HT) → enhanced synaptic levels.
- Also exhibits antimuscarinic, antihistaminic, and alpha-adrenergic blockade → explains sedation, weight gain, and cardiovascular side effects.
💊 Indications & Dose
- Can be given as a single bedtime dose, especially useful if insomnia is present.
- Neuropathic pain / Migraine prophylaxis: 10–75 mg ON, titrated slowly under specialist supervision.
- Depression (specialist use): 30–75 mg ON, higher doses titrated cautiously.
📏 Dose Range (BNF)
| Name | Dose | Frequency | Route |
| Amitriptyline | 10–75 mg | ON (night) | PO |
🔑 Always confirm with BNF or datasheet - dosing varies with indication and patient tolerability.
⚠️ Interactions
- See BNF. Major concerns: ↑ toxicity with MAOIs (avoid within 2 weeks), ↑ sedation with alcohol, benzodiazepines, opioids, ↑ arrhythmia risk with other QT-prolonging drugs.
🔎 Cautions
- Elderly patients (↑ sensitivity to anticholinergic effects, falls risk).
- Liver impairment (metabolised hepatically).
- Suicidal patients - high lethality in overdose ⚠️.
🚫 Contraindications
- Cardiac disease (conduction abnormalities, recent MI, long QT).
- History of epilepsy (lowers seizure threshold).
- Glaucoma (anticholinergic effect can ↑ intraocular pressure).
- Phaeochromocytoma.
❗ Side Effects
- Common: sedation 😴, dry mouth, constipation, urinary retention, blurred vision, weight gain.
- Cardiac: arrhythmias, conduction abnormalities, QT prolongation ❤️.
- Neuro: confusion, tremor, lowered seizure threshold.
- Serious: neuroleptic malignant syndrome (rare), sudden death in overdose.
- Withdrawal effects - taper slowly when discontinuing.
📚 References
