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Typical dose range: Major depressive disorder: start 25–50 mg at bedtime; increase by 25–50 mg every 3–7 days toward 100–150 mg/day in divided doses or as a single nightly dose. Maximum 300 mg/day under specialist supervision with ECG monitoring.
Therapeutic drug monitoring recommended; reference range 80–250 ng/mL.
Last reviewed: 2026-02-22
Dosing & forms
Forms/strengths: Oral tablets: 10 mg (scored), 25 mg, 50 mg, 75 mg, 100 mg, 150 mg.; Tablets may be split or crushed; pharmacies can compound 10 mg/mL oral solutions for patients with swallowing difficulty.; No extended-release, parenteral, or long-acting injectable formulations are available.
Frequency: Major depressive disorder: start 25–50 mg at bedtime; increase by 25–50 mg every 3–7 days toward 100–150 mg/day in divided doses or as a single nightly dose. Maximum 300 mg/day under specialist supervision with ECG monitoring.
Typical range: Major depressive disorder: start 25–50 mg at bedtime; increase by 25–50 mg every 3–7 days toward 100–150 mg/day in divided doses or as a single nightly dose. Maximum 300 mg/day under specialist supervision with ECG monitoring.
Therapeutic range: 80–250 ng/mL
Mechanism (brief)
Tertiary-amine tricyclic antidepressant that inhibits serotonin and norepinephrine reuptake while strongly antagonising histamine H1, muscarinic, and α1-adrenergic receptors; sodium-channel blockade contributes to analgesia.
Metabolism & Half‑life
Metabolism: CYP2D6, CYP2C19, CYP3A4, CYP1A2
Half‑life: Single-dose mean 21 h; Steady-state mean 24 h
Therapeutic Drug Monitoring (TDM)
Recommended: Yes
Reference range: 80–250 ng/mL
Sampling: Trough at steady state (≈12 h post-dose or immediately pre-dose).