Dosulepin

證據等級: L5

預測適應症: 10 個

Dosulepin: From Depression to Melancholia

One-Sentence Summary

Dosulepin (dothiepin) is a tricyclic antidepressant (TCA) with over 60 years of clinical use in the UK and Ireland for depressive disorders, though it is not currently registered or marketed in Australia. The TxGNN model ranks Melancholia as one of its highest-evidence predicted indications, with 0 registered clinical trials but 20 publications identified — including a direct head-to-head randomised controlled trial (RCT) against amitriptyline from 1978 and a large nation-wide comparative population study from 2024 — collectively supporting an L2 evidence level.

Note on indication selection: The TxGNN model generated 10 predictions for Dosulepin. The top-ranked prediction by score (Benign Paroxysmal Torticollis of Infancy, score 98.97%) carries L5 evidence with no clinical or mechanistic support, and is assessed as a likely graph neural network false positive. This report focuses on Melancholia (TxGNN score 98.23%), which carries the strongest clinical evidence base and the highest actionable recommendation among all predictions.

Quick Overview

Item	Content
Original Indication	Depression (established use in UK/Ireland markets; not registered in Australia)
Predicted New Indication	Melancholia
TxGNN Prediction Score	98.23%
Evidence Level	L2
Australia Market Status	Not marketed
Number of ARTG Entries	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Detailed mechanism of action data for Dosulepin was not available in this evidence pack. Based on published pharmacological literature (PMID 2670509, Lancaster & Gonzalez, Drugs, 1989), Dosulepin is a TCA structurally related to amitriptyline. Its antidepressant activity is mediated primarily through inhibition of noradrenaline reuptake (NET inhibition), with additional facilitation of serotonergic neurotransmission (SERT inhibition). Secondary receptor effects include histamine H1 antagonism (contributing to sedation and anxiolysis) and anticholinergic activity.

Melancholia is a biologically distinct, endogenous subtype of major depressive disorder characterised by prominent anhedonia, psychomotor disturbance (retardation or agitation), diurnal mood variation (worse in the morning), and prominent biological features including early morning awakening, loss of appetite, and weight loss. The core neurobiological deficit involves dysregulation of both noradrenergic and serotonergic neurotransmitter systems — precisely the primary targets of TCAs. Meta-analytical evidence (PMID 11719915) suggests TCAs may offer superior efficacy over SSRIs specifically in melancholic and severely depressed patients, owing to their dual monoamine reuptake inhibition profile.

The TxGNN prediction is mechanistically well-grounded. Dosulepin’s dual SERT/NET reuptake inhibition directly addresses the core pathophysiology of melancholia, and there is a direct clinical evidence trail: a 1978 RCT (PMID 386873) compared Dosulepin head-to-head against amitriptyline (the historical benchmark TCA for melancholia and severe depression), a 2009 naturalistic cohort study (PMID 19347769) confirmed real-world antidepressant effectiveness, and a landmark 2024 population-based study (PMID 38379028) positioned Dosulepin within the broader comparative landscape of 17 antidepressants in major depressive disorder.

Clinical Trial Evidence

No registered clinical trials for Dosulepin in Melancholia were identified in ClinicalTrials.gov or ICTRP at the time of this report (data cut-off: 4 April 2026).

Literature Evidence

PMID	Year	Type	Journal	Key Findings
386873	1978	RCT	Annales medico-psychologiques	Direct comparative trial of Dosulepin vs. amitriptyline in depression; demonstrates comparable antidepressant efficacy — the most direct dosulepin-specific evidence available
38379028	2024	Large Comparative Study	Acta Psychiatrica Scandinavica	Nation-wide Danish 2-year population-based study comparing non-response rates among 17 antidepressants in MDD; contextualises long-term effectiveness of Dosulepin vs. newer agents
2670509	1989	Review	Drugs	Comprehensive pharmacodynamic and pharmacokinetic review of dothiepin; confirms efficacy comparable to amitriptyline, imipramine, doxepin, maprotiline, mianserin, and fluoxetine across depressive disorders
25911132	2015	Meta-analysis	Journal of Affective Disorders	RCT-based dose equivalence recommendations for antidepressants; includes dosulepin dose conversion data relevant to clinical practice
11719915	2001	Meta-analysis	British Medical Bulletin	Systematic review of 108 antidepressant meta-analyses; finds little overall efficacy difference between TCAs and newer agents, with superior SNRIs/TCAs in severely depressed patients — directly relevant to melancholia
40430530	2025	Systematic Review	Pharmaceuticals (Basel)	Umbrella review of systematic reviews on fluvoxamine efficacy; uses dothiepin as an active comparator in multiple included meta-analyses, providing indirect comparative data
19347769	2009	Cohort (Naturalistic)	Nordic Journal of Psychiatry	Copenhagen University Hospital naturalistic comparison of Dosulepin and venlafaxine for depressive episodes; evaluates real-world treatment outcomes beyond controlled trial populations
15311996	2004	Observational	Physiological Research	ECG monitoring in 28 outpatients on prophylactic-dose Dosulepin; documents statistically significant increase in QT dispersion vs. 37 healthy volunteers — key cardiac safety signal
15354946	2004	Observational	Prague Medical Report	Body surface potential mapping in 27 Dosulepin-treated patients; confirms QTc prolongation, corroborating cardiotoxicity findings using a more comprehensive ECG methodology
20139216	2010	Nested Case-Control	BMJ	Compares sudden cardiac death or near-death risk of venlafaxine vs. other antidepressants including dothiepin in a large real-world population; provides comparative cardiac safety context

Australia Market Information

Dosulepin is not registered on the Australian Register of Therapeutic Goods (ARTG) and is not commercially available in Australia.

There are no ARTG entries for this drug.

Note for Australian Clinicians: Dosulepin has no TGA approval. Any clinical use in Australia would require access through the TGA Special Access Scheme (SAS) Category B or an Authorised Prescriber (AP) application. Safety and prescribing information should be sourced from the MHRA-approved UK Summary of Product Characteristics (SmPC) and relevant pharmacological reference compendia (e.g., Martindale, BNF).

Safety Considerations

No TGA-approved Product Information (PI) exists as Dosulepin is not registered in Australia. Please refer to the UK MHRA-approved Summary of Product Characteristics (SmPC) for comprehensive safety information, including contraindications, warnings, and drug interactions.

Cardiotoxicity — identified from literature:

Two independent observational studies (PMID 15311996 and PMID 15354946, both 2004) consistently document QT interval prolongation in psychiatric outpatients receiving prophylactic doses of Dosulepin, compared to healthy controls. This is consistent with the known class-effect of TCAs on cardiac conduction. Australian clinicians should be aware of the following:

Obtain baseline ECG with QTc measurement prior to initiation
Perform ongoing QTc monitoring during treatment
Screen for pre-existing cardiac conduction abnormalities as a contraindication
Assess for concomitant QT-prolonging medications (drug-drug interaction risk)
Apply standard TCA overdose risk management (limited dispensing quantities, carer awareness)

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: The TxGNN prediction of Dosulepin for Melancholia is mechanistically coherent and supported by over four decades of clinical evidence, including a direct RCT (1978) and a 2024 large-scale comparative population study. The dual SERT/NET reuptake inhibition profile of this TCA directly targets the monoaminergic deficits central to melancholic depression. However, Dosulepin is not registered in Australia, cardiotoxicity (QT prolongation) has been documented in observational studies, and no dedicated melancholia-specific trials exist.

To proceed, the following is needed:

Regulatory pathway: TGA SAS Category B or Authorised Prescriber application if clinical use is being considered in Australia
Formal MOA documentation: Complete DrugBank API query (DB09167) to confirm receptor binding profile and pharmacokinetics
Cardiac safety protocol: Mandatory baseline and monitoring ECG (QTc) plan before prescribing
TGA safety review: Obtain and review MHRA SmPC or equivalent for full contraindications, warnings, and drug interactions
Comparative effectiveness assessment: Evaluate whether Dosulepin offers clinically meaningful advantages over TGA-approved antidepressants currently available for melancholic depression in Australia (e.g., nortriptyline, imipramine, venlafaxine)
Specialist consultation: Psychiatrist review recommended given the complexity of melancholia diagnosis and TCA management requirements

This report is generated for research purposes only. Dosulepin is not TGA-approved in Australia. All findings require clinical validation before therapeutic application. This material does not constitute medical advice.

Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.