Doxepin

TCA·Psychiatry - Antidepressants

Major Depressive Disorder

PBSTCASinequan, Deptran50 mgS4+1

Max Dose

300 mg/day

Half-life

17 h

H1 Blockade

EXTREME

Insomnia

OFF-LABEL

Rapid Summary

Overview

Tricyclic Antidepressant. Possesses the absolute strongest H1-antihistamine receptor binding affinity of any drug in psychiatry. Used in micro-doses as a powerful sleeping pill and anti-itch medication.

Maximum Dose

Max 300 mg/day (Depression). Max 10-50 mg/day (Insomnia/Pruritus).

Clinical Focus

Highly sedating. Must be taken exactly at bedtime.

Bottom Line

Doxepin is a TCA used at low dose for insomnia and at high dose for depression, but has potent antihistaminic sedation and is dangerous in overdose.

Formulation & Access

Brand Names

Sinequan, Deptran

Oral Routes

Capsules (10, 25, 50 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Off-Label

OFF

Refractory insomnia, chronic idiopathic urticaria, severe neuropathic itch.

Clinical Place

Obsolete for depression. First-line rescue agent for dermatologists treating ungodly, whole-body chronic itching that fails standard antihistamines.

Quick reference

Class & Role

TCA — Tricyclic Antidepressant.

Route / Formulation

Capsules (10, 25, 50 mg). (Sinequan, Deptran)

Usual Dose & Max

Start PO 50-75 mg NOCTE. Titrate up to 300 mg/day. Max 300 mg/day (Depression).

Key Indication Doses

Depression: Start PO 50-75 mg NOCTE. Titrate up to 300 mg/day. Insomnia / Severe Pruritus (Off-Label): PO 10-25 mg NOCTE. Elderly: Max 10-25 mg/day (High risk of morning hangover and falls).

Best Uses

Doxepin is a TCA used at low dose for insomnia and at high dose for depression, but has potent antihistaminic sedation and is dangerous in overdose.

Avoid / Cautions

Recent MI, heart block, severe BPH/urinary retention, concurrent MAOIs. Pregnancy Category C.

Key Risks

Neurological: Profound next-day hangover, lethargy, delirium, cognitive blunting. Lowers seizure threshold. Gastrointestinal: Dry mouth, severe constipation. Cardiovascular: Fatal in overdose (arrhythmias). Orthostatic hypotension.

Key Interactions

Additive severe CNS depression with Opioids, Benzos, and Alcohol. CYP2D6 inhibitors (Paroxetine) drastically spike Doxepin levels.

Monitoring

Baseline ECG before treating depression (High doses). Warn the patient not to drive the morning after their first dose due to the massive hangover effect.

Clinical Pearl

When a patient has end-stage renal failure or severe liver disease, they often develop a relentless, maddening whole-body itch (uremic/hepatic pruritus). Standard antihistamines do nothing. A tiny 10mg dose of Doxepin at night often cures the itch entirely and lets them sleep.

Access

Sinequan, Deptran50 mg

Brand: Sinequan, Deptran
Formulation: Capsules (10, 25, 50 mg)

Doxepin

TCA·Psychiatry - Antidepressants

Major Depressive Disorder

PBSTCASinequan, Deptran50 mgS4+1

Max Dose

300 mg/day

Half-life

17 h

H1 Blockade

EXTREME

Insomnia

OFF-LABEL

Rapid Summary

Overview

Maximum Dose

Max 300 mg/day (Depression). Max 10-50 mg/day (Insomnia/Pruritus).

Clinical Focus

Highly sedating. Must be taken exactly at bedtime.

Bottom Line

Doxepin is a TCA used at low dose for insomnia and at high dose for depression, but has potent antihistaminic sedation and is dangerous in overdose.

Formulation & Access

Brand Names

Sinequan, Deptran

Oral Routes

Capsules (10, 25, 50 mg).

Prescribing & PBS

Unrestricted General Benefit (S4).

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Off-Label

OFF

Refractory insomnia, chronic idiopathic urticaria, severe neuropathic itch.

Clinical Place

Obsolete for depression. First-line rescue agent for dermatologists treating ungodly, whole-body chronic itching that fails standard antihistamines.

Quick reference

Class & Role

TCA — Tricyclic Antidepressant.

Route / Formulation

Capsules (10, 25, 50 mg). (Sinequan, Deptran)

Usual Dose & Max

Start PO 50-75 mg NOCTE. Titrate up to 300 mg/day. Max 300 mg/day (Depression).

Key Indication Doses

Depression: Start PO 50-75 mg NOCTE. Titrate up to 300 mg/day. Insomnia / Severe Pruritus (Off-Label): PO 10-25 mg NOCTE. Elderly: Max 10-25 mg/day (High risk of morning hangover and falls).

Best Uses

Doxepin is a TCA used at low dose for insomnia and at high dose for depression, but has potent antihistaminic sedation and is dangerous in overdose.

Avoid / Cautions

Recent MI, heart block, severe BPH/urinary retention, concurrent MAOIs. Pregnancy Category C.

Key Risks

Key Interactions

Additive severe CNS depression with Opioids, Benzos, and Alcohol. CYP2D6 inhibitors (Paroxetine) drastically spike Doxepin levels.

Monitoring

Baseline ECG before treating depression (High doses). Warn the patient not to drive the morning after their first dose due to the massive hangover effect.

Clinical Pearl

Access

Sinequan, Deptran50 mg

Brand: Sinequan, Deptran
Formulation: Capsules (10, 25, 50 mg)