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Tricyclic Antidepressant (TCA) — Active Metabolite of Amitriptyline Pregnancy: Avoid if possible — use sertraline in preference. Neonatal withdrawal reported.

Nortriptyline

Brand names: Allegron

Adult dose

Dose: Depression: 75–100mg daily (start 25mg TDS or 75mg OD at night); maximum 150mg daily. Neuropathic pain: 10–25mg ON initially; titrate to 50–75mg ON.
Route: Oral
Frequency: Once daily at night or in divided doses (TDS)
Max: 150mg daily (depression); 75mg ON (neuropathic pain)
Nortriptyline is the active metabolite of amitriptyline — less sedating and less anticholinergic than amitriptyline. Preferred TCA in elderly due to slightly better tolerability profile. Plasma level monitoring available and clinically useful (therapeutic range 50–150 nanograms/mL). Less weight gain than amitriptyline.

Paediatric dose

Route: Oral
Frequency: Once daily at night
Max: Individualised
BNFc: Nocturnal enuresis (7–17 years): 10–35mg ON, adjusted up to 35–70mg ON. Not licensed for depression under 18 years. Seek specialist paediatric opinion.

Dose adjustments

Renal

Use with caution — limited data; potential accumulation in severe impairment.

Hepatic

Avoid in severe hepatic impairment — reduced metabolism, accumulation risk.

Clinical pearls

  • Therapeutic drug monitoring (TDM) is clinically useful for nortriptyline — target plasma level 50–150 nanograms/mL. Helps guide dose titration and assess adherence
  • Preferred TCA in elderly for neuropathic pain — less sedating and anticholinergic than amitriptyline; still Beers Criteria caution but relatively better tolerated
  • Overdose antidote (cardiac toxicity): IV sodium bicarbonate — same as amitriptyline
  • Less sedating than amitriptyline — may be preferred when daytime sedation is problematic

Contraindications

  • Recent MI
  • Arrhythmias, heart block
  • Mania
  • Closed-angle glaucoma
  • MAOIs within 14 days
  • Hypersensitivity to nortriptyline or TCAs

Side effects

  • Orthostatic hypotension
  • Dry mouth, constipation (anticholinergic — less than amitriptyline)
  • Sedation (less than amitriptyline)
  • QTc prolongation
  • Weight gain (less than amitriptyline)
  • Urinary hesitancy

Interactions

  • MAOIs — contraindicated
  • CYP2D6 inhibitors (paroxetine, fluoxetine) — significantly increase nortriptyline levels; monitor plasma levels
  • QT-prolonging drugs — additive
  • Adrenaline — interaction as per amitriptyline

Monitoring

  • Plasma level (nortriptyline TDM — target 50–150 ng/mL)
  • ECG (QTc)
  • Orthostatic blood pressure
  • Anticholinergic symptom review

Reference: BNFc; BNF 90; NICE NG59 (Neuropathic Pain). Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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