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Tricyclic Antidepressant / Neuropathic Pain Agent Pregnancy: Caution — neonatal withdrawal symptoms reported; use lowest effective dose

Amitriptyline (Neuropathic Pain / Migraine)

Brand names: Tryptizol

Adult dose

Dose: Neuropathic pain/migraine prophylaxis: 10–25 mg OD at night, increase by 10–25 mg weekly. Target: 25–75 mg OD. Antidepressant: 75–150 mg/day (much higher doses).
Route: Oral
Frequency: Once daily at night (analgesic/prophylaxis doses)
Max: 75 mg OD (neuropathic pain); 150 mg/day (depression)
At low doses (10–75 mg), used for neuropathic pain and migraine prophylaxis — NOT same dose range as depression. Significant anticholinergic and sedative side effects — less so at low doses. Take at night.

Paediatric dose

Route: Oral
Frequency: OD at night
Max: Not recommended in children <16 for depression; off-label use for neuropathic pain/nocturnal enuresis under specialist guidance
Concentration: 25 mg/5 mL liquid mg/ml
Nocturnal enuresis: 6–10 years: 10–20 mg at night; 11–16 years: 25–50 mg at night (specialist). Neuropathic pain in adolescents: 10–25 mg OD at night under specialist guidance.

Dose adjustments

Renal

No dose adjustment required; caution in severe renal impairment

Hepatic

Avoid in severe hepatic impairment

Clinical pearls

  • Low-dose at night: sedation is a therapeutic benefit (improved sleep, reduced pain perception)
  • NICE NG193: amitriptyline first-line for neuropathic pain (evidence for diabetic neuropathy, post-herpetic neuralgia)
  • Overdose: TCA overdose is dangerous — ECG changes (widened QRS), arrhythmias; treat with sodium bicarbonate IV for QRS widening
  • Dental cavities: significant dry mouth — advise regular dental checkups and good oral hygiene

Contraindications

  • Recent MI
  • Cardiac arrhythmias (QT prolongation)
  • Mania
  • MAOIs (within 14 days)
  • Severe hepatic impairment
  • Closed-angle glaucoma

Side effects

  • Sedation (use to advantage — take at night)
  • Dry mouth
  • Constipation
  • Urinary retention
  • Blurred vision
  • Orthostatic hypotension
  • Weight gain
  • QT prolongation
  • Tachycardia

Interactions

  • MAOIs — serotonin syndrome (absolute contraindication — 14-day washout)
  • SSRIs — serotonin syndrome risk
  • QT-prolonging drugs — additive QT risk
  • Antihistamines — additive anticholinergic effects
  • Tramadol — serotonin syndrome risk

Monitoring

  • ECG (QTc) before starting in cardiac patients
  • Anticholinergic effects (constipation, urinary retention)
  • Weight
  • Mood assessment (antidepressant doses)

Reference: BNFc; BNF; NICE NG193 Neuropathic Pain; NICE NG150 Migraine. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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