Dosulepin

TCA·Psychiatry - Antidepressants

Major Depressive Disorder

Authority requiredPBSTCAProthiaden, Dothep25 mg tablet+2

Max Dose

225 mg/day

Half-life

11-24 h

Toxicity in OD

FATAL

Anticholinergic

HIGH

Rapid Summary

Overview

Tricyclic Antidepressant (also known as Dothiepin). Historically popular but now considered the most dangerous TCA in overdose due to profound cardiac toxicity.

Maximum Dose

Max 225 mg/day (Usually 75-150 mg NOCTE).

Clinical Focus

Do not initiate. TGA guidelines actively discourage prescribing Dosulepin due to the unacceptably narrow margin between therapeutic dose and fatal overdose.

Bottom Line

Dosulepin is a TCA with no advantages over other antidepressants but the highest lethality in overdose of all TCAs, and should generally be avoided in new prescriptions.

Formulation & Access

Brand Names

Prothiaden, Dothep

Oral Routes

Capsules/Tablets (25 mg, 75 mg).

Prescribing & PBS

Authority Required (PBS). Actively restricted.

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Clinical Place

Obsolete. Only used in patients who have been stabilized on it for decades and refuse to cross-taper to safer agents.

Quick reference

Class & Role

TCA — Tricyclic Antidepressant (also known as Dothiepin).

Route / Formulation

Capsules/Tablets (25 mg, 75 mg). (Prothiaden, Dothep)

Usual Dose & Max

PO 75-150 mg NOCTE. Max 225 mg/day.

Key Indication Doses

Depression: PO 75-150 mg NOCTE. Max 225 mg/day. Elderly / Frail: Avoid. High risk of falls, delirium, and sudden cardiac death.

Best Uses

Dosulepin is a TCA with no advantages over other antidepressants but the highest lethality in overdose of all TCAs, and should generally be avoided in new prescriptions.

Avoid / Cautions

Recent myocardial infarction, heart block, concurrent MAOIs, narrow-angle glaucoma, history of epilepsy.

Key Risks

Cardiovascular: Massive QRS widening, ventricular fibrillation, and heart block in overdose. Extreme orthostatic hypotension. Neurological: Lowers seizure threshold significantly more than other TCAs. HIGH — Sedation, delirium. Gastrointestinal: Severe dry mouth, constipation, urinary retention.

Key Interactions

MAOIs, Tramadol (Serotonin Syndrome). Additive CNS depression with alcohol. CYP2D6 inhibitors (Fluoxetine, Paroxetine) spike levels into the lethal range.

Monitoring

Baseline and routine ECG (monitoring QTc and QRS width) is absolutely essential. Actively attempt to cross-taper the patient to an SSRI or Nortriptyline if they are admitted to the ward.

Clinical Pearl

Of all the TCAs (which are already dangerous), Dosulepin has the highest toxicity index. The gap between a dose that fixes depression and a dose that stops the heart is frighteningly small.

Access

Authority requiredProthiaden, Dothep25 mg tablet

Brand: Prothiaden, Dothep
PBS status: Authority required
Formulation: Capsules/Tablets (25 mg, 75 mg)

Dosulepin

TCA·Psychiatry - Antidepressants

Major Depressive Disorder

Authority requiredPBSTCAProthiaden, Dothep25 mg tablet+2

Max Dose

225 mg/day

Half-life

11-24 h

Toxicity in OD

FATAL

Anticholinergic

HIGH

Rapid Summary

Overview

Tricyclic Antidepressant (also known as Dothiepin). Historically popular but now considered the most dangerous TCA in overdose due to profound cardiac toxicity.

Maximum Dose

Max 225 mg/day (Usually 75-150 mg NOCTE).

Clinical Focus

Do not initiate. TGA guidelines actively discourage prescribing Dosulepin due to the unacceptably narrow margin between therapeutic dose and fatal overdose.

Bottom Line

Dosulepin is a TCA with no advantages over other antidepressants but the highest lethality in overdose of all TCAs, and should generally be avoided in new prescriptions.

Formulation & Access

Brand Names

Prothiaden, Dothep

Oral Routes

Capsules/Tablets (25 mg, 75 mg).

Prescribing & PBS

Authority Required (PBS). Actively restricted.

Indications & Use

Primary

PBSTGA

Major Depressive Disorder.

Clinical Place

Obsolete. Only used in patients who have been stabilized on it for decades and refuse to cross-taper to safer agents.

Quick reference

Class & Role

TCA — Tricyclic Antidepressant (also known as Dothiepin).

Route / Formulation

Capsules/Tablets (25 mg, 75 mg). (Prothiaden, Dothep)

Usual Dose & Max

PO 75-150 mg NOCTE. Max 225 mg/day.

Key Indication Doses

Depression: PO 75-150 mg NOCTE. Max 225 mg/day. Elderly / Frail: Avoid. High risk of falls, delirium, and sudden cardiac death.

Best Uses

Dosulepin is a TCA with no advantages over other antidepressants but the highest lethality in overdose of all TCAs, and should generally be avoided in new prescriptions.

Avoid / Cautions

Recent myocardial infarction, heart block, concurrent MAOIs, narrow-angle glaucoma, history of epilepsy.

Key Risks

Key Interactions

MAOIs, Tramadol (Serotonin Syndrome). Additive CNS depression with alcohol. CYP2D6 inhibitors (Fluoxetine, Paroxetine) spike levels into the lethal range.

Monitoring

Baseline and routine ECG (monitoring QTc and QRS width) is absolutely essential. Actively attempt to cross-taper the patient to an SSRI or Nortriptyline if they are admitted to the ward.

Clinical Pearl

Of all the TCAs (which are already dangerous), Dosulepin has the highest toxicity index. The gap between a dose that fixes depression and a dose that stops the heart is frighteningly small.

Access

Authority requiredProthiaden, Dothep25 mg tablet

Brand: Prothiaden, Dothep
PBS status: Authority required
Formulation: Capsules/Tablets (25 mg, 75 mg)