Danazol and Gestrinone
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Direct answer
Danazol and gestrinone are synthetic androgen derivatives with antigonadotropic activity, suppressing the pituitary-ovarian axis to produce a hypo-oestrogenic state. Danazol is used for endometriosis, fibrocystic breast disease and hereditary angioedema, while gestrinone is used for endometriosis where it is available. Both cause androgenic effects such as acne, hirsutism, weight gain and voice change. Both are contraindicated in pregnancy because of virilisation risk.
What you must remember
- Mechanism: both suppress gonadotropin release, causing amenorrhoea and hypo-oestrogenism that regress endometriotic implants.
- Danazol uses: endometriosis, fibrocystic breast disease and hereditary angioedema.
- Gestrinone profile: androgenic, antiestrogenic, antiprogestogenic and antigonadotropic; used for endometriosis where licensed.
- Androgenic effects: acne, oily skin, hirsutism, weight gain and voice deepening, which may not fully reverse.
- Metabolic effects: lowers HDL cholesterol; prolonged danazol use is linked to rare peliosis hepatis.
- Thrombosis: both raise the risk of venous and arterial thromboembolic events, so history matters before starting.
- Pregnancy: contraindicated, with a risk of virilisation of a female foetus; a negative pregnancy test is required first.
A suppressive agent in a woman with endometriosis
A 30-year-old with severe endometriosis-related pain and infertility is considered for an androgen-based suppressive agent. The benefit is real, but counselling and monitoring decide whether the drug is safe for her. The agent is chosen only after pregnancy, thrombosis and metabolic risks have been checked. The steps below cover the usual pathway.
- Exclude pregnancy: a negative pregnancy test is confirmed before starting, since both agents harm a female foetus.
- Counsel on androgenic effects: acne, hirsutism and voice change may occur and may persist after stopping.
- Screen for thrombosis: a history of venous or arterial thrombosis argues against starting either agent.
- Titrate to tolerance: the lowest effective dose is used, with the dose adjusted to symptom control and side effects.
- Monitor lipids and liver: lipid profile and liver function are checked during therapy.
- Plan alternatives: GnRH analogues with add-back therapy are often preferred because they cause fewer androgenic effects.
Where the exam tries to catch you
Danazol questions test the drug's class, its pregnancy hazard and its androgenic profile.
- Trap: choosing danazol for a woman planning pregnancy Correct: both agents are contraindicated in pregnancy, so reliable contraception and a negative test are required.
- Trap: assuming androgenic side effects always resolve after stopping Correct: voice change may persist, so this must be counselled before starting.
- Trap: calling danazol an oestrogen or progestogen Correct: it is an androgen derivative with antigonadotropic action, not a hormone replacement.
Frequently asked questions
How do danazol and gestrinone suppress menstruation?
Danazol and gestrinone suppress the hypothalamic-pituitary-ovarian axis, reducing gonadotropin release and oestrogen production. This produces amenorrhoea and regression of endometriotic implants. The effect is reversible after stopping therapy.
What are the main adverse effects of danazol?
Danazol causes androgenic effects such as acne, hirsutism, weight gain and voice change. It lowers HDL cholesterol and has rare hepatic effects with prolonged use. Virilisation of a female foetus makes it contraindicated in pregnancy.
Is danazol safe in pregnancy?
Danazol is contraindicated in pregnancy because it can virilise a female foetus. A negative pregnancy test is needed before starting treatment. Effective contraception is advised for the duration of therapy.
Which endometriosis treatment has fewer androgenic effects than danazol?
GnRH analogues have fewer androgenic effects than danazol and are often preferred, usually with add-back therapy to limit bone loss. This choice reduces the risk of virilising side effects. The decision follows local guidelines and patient preference.
Where is gestrinone used?
Gestrinone is used for endometriosis, given its antigonadotropic and antiprogestogenic actions. Its availability varies by country, so local formulary status should be checked before prescribing it.