Goserelin

Summary

Goserelin is a long-acting GnRH agonist delivered as a subcutaneous implant (depot formulation). It is used in hormone-sensitive conditions including prostate cancer, breast cancer, endometriosis, uterine fibroids, and as part of assisted reproduction protocols. It produces medical castration reversibly upon discontinuation.

Mechanism of Action

Synthetic analogue of gonadotropin-releasing hormone (GnRH). Upon continuous administration, it causes sustained receptor downregulation and desensitization of pituitary GnRH receptors, leading to suppression of LH and FSH secretion, and subsequent reduction of sex hormone levels (testosterone in men, estradiol in women) to castrate levels.

Routes of Administration

Goals & Uses

• Ovarian protection during chemotherapyOncology/fertilityModerate
• Endometrial thinning before ablationGynecologyModerate
• Prostate cancer treatmentOncologyHigh
• Breast cancer treatmentOncologyHigh
• Uterine fibroids (leiomyomata)GynecologyHigh
• Endometriosis managementGynecologyHigh

Contraindications

• Undiagnosed vaginal bleedingGynecologicalModerate
• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationHighPotential transfer into breast milk or insufficient safety data
• Hypersensitivity to GnRH analoguesAllergy/ImmunologyHigh
• Osteoporosis (severe pre-existing)Metabolic/boneModerate

Adverse Effects

• Injection site reactionsLocalCommon
• Tumor flare (initial)OncologyUncommon
• Hot flashes/flushesVasomotorCommon
• Depression and mood changesPsychiatricUncommon
• Sexual dysfunction / decreased libidoEndocrine/sexualCommon
• Bone mineral density reductionMusculoskeletalCommon

Drug Interactions

• QT-prolonging drugsModerate
• Aromatase inhibitors (e.g., anastrozole, letrozole)Low
• Anti-androgens (e.g., bicalutamide, flutamide)Low
• Antidiabetic agents (insulin, oral hypoglycemics)Moderate

Population Constraints

• Pediatric patientsAgeRelative
• Patients with osteoporosis or high fracture riskMusculoskeletalRelative
• Patients with diabetes mellitusMetabolicRelative
• Patients with cardiovascular diseaseComorbidityRelative
• Patients with urinary tract obstruction (prostate cancer)UrologicalRelative

Regulatory Status

• European UnionApprovedApproved: Prostate cancer, Breast cancer, Endometriosis, Uterine fibroids, Assisted reproduction (controlled ovarian hyperstimulation)Approved by EMA; Zoladex and generic equivalents are available across EU member states.
• United StatesApprovedApproved: Palliative treatment of advanced prostate cancer, Stage B2–C prostate cancer (with radiotherapy), Advanced breast cancer (premenopausal and perimenopausal women), Endometriosis, Endometrial thinning prior to ablationFDA-approved as Zoladex (AstraZeneca); 3.6 mg monthly and 10.8 mg 3-monthly depot implants available.
• United KingdomApprovedApproved: Prostate cancer, Breast cancer, Endometriosis, Uterine fibroids, Endometrial thinning, Assisted reproductionApproved by MHRA; Zoladex is included in NHS formulary with established NICE guidance for relevant indications.

FDA-approved (Zoladex) for prostate cancer, breast cancer, endometriosis, and endometrial thinning. Also approved by EMA and MHRA. Available as 3.6 mg (monthly) and 10.8 mg (3-monthly) depot implants.

Evidence & Sources

No sources recorded yet.