AlternativeProstap (leuprorelin) / Zoladex (goserelin)
GnRH agonists (leuprorelin, goserelin)
GnRH receptor agonist (with initial flare → downregulation)
Endometriosis, fibroids, IVF downregulation, hormone-sensitive cancers.
SC / IM depot
First-line for
- Severe endometriosis symptom control
- Fibroid shrinkage pre-surgery
- IVF long-protocol downregulation
- Adjuvant in premenopausal ER+ breast cancer (with tamoxifen/AI)
Mechanism
Continuous stimulation desensitises pituitary GnRH receptors → suppressed LH/FSH → hypogonadism.
"Flare then fall"
- Initial 1–2 week flare — worse symptoms
- Then hypogonadal state
- Add-back HRT if > 6 months
Dosing
- Leuprorelin
- 3.75 mg IM/SC monthly or 11.25 mg 3-monthly
- Goserelin
- 3.6 mg SC monthly or 10.8 mg 3-monthly
Contraindications
- AbsolutePregnancy, undiagnosed vaginal bleeding
- CautionOsteoporosis risk
Side effects
- Hot flushes, night sweats
- Mood change
- BMD loss (add-back HRT if > 6 months)
- Initial disease flare
Fetal & maternal notes
- • Contraindicated — barrier contraception advised until first menses after last dose
Key interactions
Hormonal contraceptives
CautionNot needed contraceptively but barrier still required in some indications
Clinical pearls
- 💡 Add-back HRT (tibolone or low-dose combined) mitigates BMD/vasomotor effects
- 💡 Cover flare with progestogen in endometriosis
Content last reviewed: REPLACE_ME (e.g. 2026-07)
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