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GnRH Agonist — Androgen Deprivation Therapy Pregnancy: Contraindicated in pregnancy and lactation (LHRH agonist; theoretical risk of abortion or foetal abnormality). US labelling: contraindicated in pregnancy unless used for palliative treatment of advanced breast cancer.

Goserelin

Brand names: Zoladex

Goserelin is a GnRH (LHRH) agonist given as a subcutaneous depot implant, used in urology principally for androgen-deprivation therapy in prostate cancer (and in other specialties for hormone-responsive conditions).

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: One 3.6 mg depot (Zoladex 3.6 mg implant)
Route: Subcutaneous injection into the anterior abdominal wall
Frequency: Every 28 days
Urological/prostate context. UK SPC (Zoladex 3.6 mg Implant): one 3.6 mg depot injected subcutaneously into the anterior abdominal wall every 28 days. No dosage adjustment for renal or hepatic impairment or in the elderly. In men at particular risk of ureteric obstruction or spinal cord compression, use with care and monitor closely during the first month; consider initial anti-androgen cover (e.g. cyproterone acetate 300 mg daily for three days before and three weeks after starting Zoladex) to prevent sequelae of the initial testosterone surge. US labelling (ZOLADEX 3.6 mg) for prostate cancer: 3.6 mg SC every 28 days; intended for long-term administration in advanced prostate cancer. For Stage T2b–T4 (B2–C) prostate cancer with radiotherapy and flutamide, start 8 weeks before radiotherapy and continue during it — e.g. a 3.6 mg depot 8 weeks before radiotherapy followed 28 days later by the 10.8 mg depot, or four 3.6 mg depots at 28-day intervals (two before and two during radiotherapy). Not indicated for use in children. Caution injecting near the inferior epigastric artery; extra care with low BMI or full anticoagulation.

Dose adjustments

Renal

No dosage adjustment necessary for patients with renal or hepatic impairment.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any excipient
  • Pregnancy and lactation (see section 4.6)

Side effects

  • Hot flush (very common)
  • Hyperhidrosis / sweating (very common)
  • Libido decreased (very common)
  • Erectile dysfunction (very common, males)
  • Injection site reactions; bone pain; tumour flare on initiation

Interactions

  • Medicinal products that prolong the QT interval — androgen deprivation therapy may prolong the QT interval; assess benefit-risk including Torsade de pointes risk before initiating
  • Diagnostic tests of pituitary-gonadotropic and gonadal function may be misleading during treatment (US labelling)

Clinical monograph

How it works

Continuous GnRH-receptor stimulation initially raises and then, through pituitary receptor downregulation, suppresses LH and FSH release, lowering testosterone to castrate levels.

Prescribing in practice

  • An initial testosterone surge ("flare") can transiently worsen prostate cancer symptoms such as bone pain or urinary obstruction, so cover with an anti-androgen around the first injection, especially in metastatic disease with spinal risk.
  • Administer the depot by deep subcutaneous injection into the anterior abdominal wall at the scheduled interval to maintain suppression.
  • Long-term androgen deprivation increases cardiovascular, metabolic and bone-density risks, so assess and manage these proactively.

Monitoring

Monitor testosterone and PSA response, together with bone health, glycaemic and cardiovascular risk during prolonged therapy.

Counselling the patient

  • Expect symptoms to possibly worsen briefly before improving when treatment starts.
  • Hot flushes, reduced libido and erectile dysfunction are common; report new or worsening bone pain or urinary difficulty.

Evidence & guidelines

GnRH agonists including goserelin are an established standard of care for androgen-deprivation therapy in prostate cancer, supported by long-term trial and guideline data.

Reference: NICE NG131 (Prostate Cancer); EAU Prostate Cancer Guidelines 2024; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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