Danazol

證據等級: L5

預測適應症: 10 個

Danazol: From Endometriosis to Amenorrhea

One-Sentence Summary

Danazol is a synthetic attenuated androgen (derivative of 17α-ethinyltestosterone) historically used for endometriosis, fibrocystic breast disease, and hereditary angioedema, though it is not currently marketed in Canada. The TxGNN model predicts it may be effective for Amenorrhea (disease) as a formal therapeutic indication, with 0 registered clinical trials and 20 publications currently supporting this direction.

Quick Overview

Item	Content
Original Indication	Endometriosis, fibrocystic breast disease, hereditary angioedema (US FDA–approved; no Canadian DINs issued)
Predicted New Indication	Amenorrhea (disease)
TxGNN Prediction Score	99.9995%
Evidence Level	L2
Canada Market Status	✗ Not marketed
Number of DINs	0
Recommended Decision	Proceed with Guardrails

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available in the evidence pack. Based on well-established pharmacological knowledge from the literature, Danazol is a synthetic impeded androgen that acts through multiple complementary pathways: it suppresses the hypothalamic-pituitary-ovarian (HPO) axis by inhibiting pulsatile LH and FSH secretion, directly reduces gonadal and adrenal steroidogenesis via specific enzyme systems, and binds androgen and progesterone receptors in endometrial tissue — collectively causing endometrial atrophy and a hypoestrogenic state. These actions reliably produce amenorrhea as a measurable pharmacodynamic endpoint (PMID 2404115, 6819580).

The relationship between Danazol’s approved indications and amenorrhea is mechanistically direct rather than coincidental. In the treatment of endometriosis, amenorrhea is not a side effect to be managed but a therapeutic goal: estrogen-dependent endometrial lesions regress when deprived of hormonal stimulation during the anovulatory, amenorrheic state induced by Danazol (PMID 16280355). The same HPO suppression mechanism underlies its long-standing use in hereditary angioedema, where irregular menstruation is a documented consequence of the drug’s systemic hormonal effects (PMID 2013670).

The TxGNN model’s prediction is therefore pharmacologically highly plausible. The evidence base spans from classical RCTs in endometriosis (PMID 2140996, 2523321) to a contemporary retrospective cohort documenting deliberate amenorrhea induction with Danazol in transgender and nonbinary individuals (PMID 39051650, 2024). This modern use case demonstrates that the drug’s amenorrheic effect is not only established but is being actively leveraged as a primary therapeutic target in clinical practice.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
2140996	1990	RCT	Fertility and Sterility	Double-blind RCT of nafarelin 400 µg/d vs danazol 600 mg/d in 82 endometriosis patients over 6 months; both produced significant active disease regression, with amenorrhea as the central pharmacodynamic endpoint
2523321	1989	RCT	Fertility and Sterility	RCT comparing gestrinone twice-weekly vs danazol 600 mg/d in 39 infertile patients with endometriosis; amenorrhea achievement was the primary treatment criterion, with dose escalation mandated if not attained within 1 month
36434439	2023	Systematic Review	Archives of Gynecology and Obstetrics	Systematic review and meta-analysis of gestrinone for endometriosis; contextualises amenorrhea induction as a shared mechanism of action with danazol class agents, supporting transferability of evidence
39051650	2024	Retrospective Cohort	Women’s Health	Multi-site cohort of transgender/nonbinary individuals using Danazol specifically for menstrual suppression; directly quantifies amenorrhea induction rates and androgenic side-effect profile in a modern clinical context
6819580	1982	Clinical Study	Progress in Clinical and Biological Research	Early foundational study demonstrating Danazol’s suppression of ovarian function and gonadotropin secretion, with amenorrhea as the mechanism enabling endometriosis regression and subsequent fertility improvement
2404115	1990	Review	The Journal of Reproductive Medicine	Comprehensive mechanistic review: Danazol binds steroid transport proteins and tissue receptors, centrally inhibits gonadotropins, suppresses steroidogenesis, and exerts immunoregulatory effects — all contributing to the amenorrheic state
1533675	1992	Review	Journal of the Royal Army Medical Corps	Comparative review of therapeutic amenorrhea induction methods; Danazol evaluated alongside GnRH analogues and continuous oral contraceptives for contexts requiring reliable menstrual suppression
16280355	2006	Review	Human Reproduction Update	Endometriosis lesions become inactive and regress during ovarian down-regulation states such as amenorrhea or menopause; frames danazol-induced amenorrhea as the mechanistic basis of efficacy
21701432	2011	Review	Menopause	Evidence-based review of pharmacological options for abnormal uterine bleeding; Danazol cited as effective for heavy menstrual bleeding reduction and amenorrhea induction, with consideration of adverse effect profile
2013670	1991	Clinical Study	Journal of Allergy and Clinical Immunology	13-year long-term follow-up of 56 hereditary angioedema patients on attenuated androgens (danazol ≤200 mg/d); irregular menstruation documented as a consistent systemic effect, confirming sustained HPO suppression at maintenance doses

Canada Market Information

Danazol is currently not marketed in Canada. Health Canada has issued no Drug Identification Numbers (DINs) for any formulation of Danazol. Any clinical use in Canada would require an importation authorization or a Special Access Programme (SAP) request.

Safety Considerations

Please refer to the package insert for safety information.

Note: Key warnings, contraindications, and drug interaction data were not available in this evidence pack. Clinicians should be aware that Danazol carries androgenic and anabolic effects (virilization, acne, voice changes), hepatotoxicity risk, and is absolutely contraindicated in pregnancy and breastfeeding. Drug interaction data with warfarin and statins (e.g., lovastatin — risk of rhabdomyolysis and pancreatitis, PMID 18691993) have been reported in the broader literature.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: The TxGNN prediction is mechanistically highly credible — amenorrhea is an established, deliberate pharmacodynamic outcome of Danazol therapy supported by RCT-level evidence and decades of clinical use, and contemporary literature documents active exploitation of this effect for menstrual suppression. However, Danazol is not currently marketed in Canada, formal regulatory and safety documentation is unavailable, and the specific amenorrhea subtype (functional hypothalamic, drug-induced suppression, or otherwise) requiring treatment must be defined before clinical translation.

To proceed, the following is needed:

Clarify the target amenorrhea subtype (e.g., functional hypothalamic amenorrhea vs. therapeutic menstrual suppression) to define the precise patient population
Assess Health Canada regulatory pathway: Special Access Programme, New Drug Submission, or indication-specific off-label framework
Retrieve complete Canadian product monograph or FDA prescribing information to populate safety warnings, contraindications, and drug interactions
Conduct a comparative effectiveness review vs. established alternatives (GnRH analogues, levonorgestrel IUD, combined oral contraceptives) for the target indication
Develop a pharmacovigilance and monitoring plan addressing androgenic adverse effects, hepatotoxicity, and teratogenicity risk in women of reproductive age
Disclaimer

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