imipramine

Adjunctive therapy • Brands: Tofranil

Last reviewed: 2025-12-29

General information

Class: Adjunctive therapy
Common US brands: Tofranil
Typical dose range: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.
Therapeutic drug monitoring recommended; reference range 150–300 ng/mL.
Last reviewed: 2025-12-29

Dosing & forms

Forms/strengths: Tablets: 10 mg, 25 mg, 50 mg; capsules (pamoate) 75 mg, 100 mg, 125 mg, 150 mg.
Frequency: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.
Typical range: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.
Therapeutic range: 150–300 ng/mL

Mechanism (brief)

Tricyclic antidepressant; blocks serotonin and norepinephrine reuptake with anticholinergic effects.

Metabolism & Half‑life

Metabolism: CYP2D6, CYP1A2
Half‑life: Single-dose mean 19 h; Steady-state mean 24 h

Therapeutic Drug Monitoring (TDM)

Recommended: Yes

Reference range: 150–300 ng/mL

View labelExact

Monitoring highlights

Baseline ECG and electrolytes when cardiac risk is present or when higher doses are used; recheck ECG when symptoms (palpitations, syncope) occur or when QT-active drugs are added.
Anticholinergic adverse effects (constipation, urinary retention, delirium), especially in older adults; dose reduction is often safer than adding more anticholinergics.
TDM for suspected toxicity, nonadherence, or poor response, particularly when CYP2D6 inhibitors are co-prescribed.

Sources

Imipramine prescribing information — DailyMed (2025)
Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology: Update 2017 — Pharmacopsychiatry (2018)
APA Clinical Practice Guideline for the Treatment of Depression — American Psychiatric Association (2023)
CANMAT 2024 Clinical Guidelines for the Management of Major Depressive Disorder — Canadian Journal of Psychiatry (2024)

General information

Class: Adjunctive therapy

Common US brands: Tofranil

Typical dose range: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.

Therapeutic drug monitoring recommended; reference range 150–300 ng/mL.

Last reviewed: 2025-12-29

Dosing & forms

Forms/strengths: Tablets: 10 mg, 25 mg, 50 mg; capsules (pamoate) 75 mg, 100 mg, 125 mg, 150 mg.

Frequency: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.

Typical range: Depression (adult): typical starting doses are 25–50 mg at bedtime, with increases of 25–50 mg every 3–7 days to 150–200 mg/day (single bedtime dose or divided). Maximum 300 mg/day is typically reserved for inpatient settings with monitoring.

Therapeutic range: 150–300 ng/mL

Monitoring highlights

Baseline ECG and electrolytes when cardiac risk is present or when higher doses are used; recheck ECG when symptoms (palpitations, syncope) occur or when QT-active drugs are added.

Anticholinergic adverse effects (constipation, urinary retention, delirium), especially in older adults; dose reduction is often safer than adding more anticholinergics.

TDM for suspected toxicity, nonadherence, or poor response, particularly when CYP2D6 inhibitors are co-prescribed.