TCA — Interstitial Cystitis / Chronic Pelvic Pain Pregnancy: Avoid in pregnancy if possible

Amitriptyline

Brand names: Tryptizol

Adult dose

Dose: 25 mg at bedtime initially, increasing to 50-75 mg

Route: Oral

Frequency: Once daily at night

Max: 75 mg/day (IC/BPS indication; higher doses used for depression)

Used at low doses for interstitial cystitis / bladder pain syndrome. Sedating — take at night. Titrate slowly over weeks. Anticholinergic effect also helps OAB symptoms

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

Patient weight (kg)

Seek specialist opinion

Clinical pearls

ESSIC and EAU IC/BPS Guidelines: amitriptyline is the most studied oral agent for IC/BPS — reduces pain, urgency, and frequency; anticholinergic properties and central pain modulation both contribute to benefit
IC/BPS is a diagnosis of exclusion — ensure bladder cancer, radiation cystitis, UTI, and endometriosis excluded before initiating
Analgesic mechanism at low doses: inhibits neuronal reuptake of serotonin and noradrenaline, reduces central sensitisation, sodium channel blockade — pain modulation distinct from antidepressant mechanism
Sedation at night actually beneficial — promotes sleep in patients whose symptoms disrupt sleep
High anticholinergic burden (ACB score 3) — avoid in elderly patients with cognitive impairment; use cautiously in patients with glaucoma or BPH

Contraindications

Recent myocardial infarction
Arrhythmias
Mania
Concurrent MAOI use

Side effects

Dry mouth
Constipation
Urinary retention (paradoxically may worsen some IC symptoms)
Sedation
Postural hypotension
Weight gain
QT prolongation

Interactions

MAOIs (severe — avoid)
Tramadol / SSRIs (serotonin syndrome)
Anticholinergics (additive effects)
Antiarrhythmics (QT prolongation)

Monitoring

IC symptom scores (ICSI/ICPI, pain VAS)
ECG (QTc in patients with cardiac risk factors)
Urinary retention
Cognitive function (elderly)

Reference: BNFc; BNF 90; EAU IC/BPS Guidelines 2024; ESSIC Guidelines; Sant et al. (2003) IC/BPS amitriptyline RCT. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways