Pharmacology · GnRH analogues (agonists and antagonists)
Goserelin !
A small implant placed under the skin of the abdomen that releases a GnRH agonist for weeks. It treats prostate and breast cancer and endometriosis.
Updated 2026-11-01
Mechanism of action
Goserelin is a long-acting GnRH agonist released steadily from a biodegradable implant. Continuous stimulation first raises LH, FSH and sex steroids for a few weeks, then desensitises the pituitary GnRH receptors, so testosterone in men and oestrogen in premenopausal women fall to castration levels.
- The implant releases goserelin steadily
- Hormones rise in the first weeks (flare)
- Pituitary GnRH receptors desensitise
- Testosterone or oestrogen fall to castration levels
Pharmacokinetics
- Absorption
- Released slowly from a subcutaneous implant in the abdomen over 4 or 12 weeks, depending on the product
- Onset and duration
- Hormone levels rise during the first weeks before falling
Indications
- Prostate cancer Prostate cancer →
- Hormone-sensitive breast cancer Breast cancer →
- Endometriosis Endometriosis →
- Thinning of the endometrium before ablation for abnormal uterine bleeding Abnormal uterine bleeding →
Adverse effects
Common
- Hot flushes and sweating
- Headache
- Decreased libido
- Decrease in breast size in women
- Acne and skin changes
Contraindications
- Hypersensitivity to goserelin
- Pregnancy, except in advanced breast cancer
Key interactions
- Drugs that prolong the QT interval
- Androgen deprivation can prolong the QT interval; effects may add up.
What is monitored
- Testosterone and PSA in prostate cancer
- Blood glucose
- Cardiovascular symptoms
- Bone density with long treatment
- Mood
Administration and safety
- Subcutaneous implant inserted into the abdominal wall by a health professional, every 4 or 12 weeks depending on the strength.
- Insertion dates follow the schedule set by the treating team; the site is checked after insertion.
Nursing care
- Ask about long-term alcohol or tobacco use and family history of osteoporosis, which add to bone loss.
- Watch for new bone pain, urinary trouble or leg weakness in the first weeks of prostate cancer treatment.
- Confirm a negative pregnancy test before use in women of reproductive age; non-hormonal contraception is used.
- Teach to report chest pain, weakness on one side, extreme thirst or new low mood.
Pregnancy and breastfeeding
Not used in pregnancy except for advanced breast cancer; a pregnancy test may be required before treatment.
Test yourself
Think of the answer, then tap the question to see it.
How is goserelin given?
As a small biodegradable implant inserted under the skin of the abdomen, which releases the drug over 4 or 12 weeks.
Why can goserelin worsen symptoms in the first weeks?
As a GnRH agonist it first stimulates the pituitary, so sex hormones rise before they fall.
Which gynaecological uses does goserelin have besides breast cancer?
Endometriosis, and thinning the endometrium before ablation for abnormal uterine bleeding.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Goserelin Implant: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 46 (McGraw Hill, 2023).
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Representative model, for educational purposes only.