ClinCalc Pro
Menu
Calculators Drugs Pathways AI Dx Donate Get the App
Tricyclic Antidepressant (TCA) Pregnancy: Avoid in pregnancy if possible; neonatal withdrawal reported

Amitriptyline

Brand names: Tryptizol

Adult dose

Dose: 10-75 mg for neuropathic pain; 75-150 mg for depression
Route: Oral
Frequency: Once daily at night (sedating)
Max: 150 mg/day (outpatient); 300 mg/day inpatient under specialist supervision
Low doses (10-25 mg nocte) used for neuropathic pain, migraine prophylaxis, and fibromyalgia

Paediatric dose

Dose: Seek specialist opinion N/A/kg
Route: Oral
Frequency: Seek specialist opinion
Max: Seek specialist opinion
Seek specialist opinion

Dose adjustments

Renal

Use with caution — accumulation of active metabolite

Hepatic

Avoid in severe hepatic impairment

Paediatric weight-based calculator

Seek specialist opinion

Clinical pearls

  • Beers Criteria 2023 and STOPP v3: Amitriptyline is potentially inappropriate in elderly — high anticholinergic burden increases risk of delirium, falls, urinary retention, constipation, and cognitive impairment
  • If TCA required in elderly for neuropathic pain, nortriptyline is preferred — less anticholinergic, less sedating
  • For depression in elderly, SSRIs (sertraline, citalopram) are preferred first-line — safer cardiac and anticholinergic profile
  • Anticholinergic Cognitive Burden (ACB) score: amitriptyline scores 3 (highest risk) — contributes to cumulative anticholinergic load in polypharmacy
  • Overdose risk: cardiotoxic in overdose (QRS prolongation, VT) — NaHCO3 IV for QRS widening; limit dispensing quantity in depression

Contraindications

  • Recent myocardial infarction
  • Arrhythmias (especially heart block)
  • Mania
  • Acute porphyria
  • Concurrent MAOI use

Side effects

  • Anticholinergic effects: dry mouth, urinary retention, constipation, blurred vision
  • Sedation
  • Postural hypotension (falls risk)
  • Cardiac arrhythmias (QT prolongation)
  • Confusion and delirium (elderly)
  • Weight gain

Interactions

  • MAOIs (severe; avoid)
  • Tramadol / SSRIs (serotonin syndrome)
  • Antiarrhythmics (additive QT prolongation)
  • Anticholinergics (additive)
  • Alcohol (increased sedation)

Monitoring

  • ECG (QTc) before starting in patients with cardiac risk factors
  • Postural blood pressure
  • Cognitive function
  • Urinary symptoms

Reference: BNFc; BNF 90; NICE CG173 (Neuropathic Pain); AGS Beers Criteria 2023; STOPP/START v3; ACB scale. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

Calculators
Drugs
Pathways