Zoladex

🔹 1. Basic Information

Generic name: Goserelin acetate
Brand name: Zoladex 10.8 mg
Drug class: Luteinizing hormone–releasing hormone (LHRH) analogue / Gonadotropin-releasing hormone (GnRH) agonist
Formulation: Subcutaneous depot injection (pre-filled syringe)
Strength: 10.8 mg
Mechanism of Action:
Synthetic LHRH analogue → initially stimulates pituitary LH & FSH release → transient rise in testosterone (men) or oestradiol (women) → chronic administration suppresses LH/FSH → ↓ testosterone and oestradiol to castrate levels → inhibition of hormone-dependent tumour growth.

🔹 2. Indications

In males:

• Prostate cancer suitable for hormonal manipulation.

In females:

• Endometriosis: Relief of symptoms.
• Uterine fibroids: Reduction in fibroid size before surgery.
• Breast cancer: Oestrogen receptor–positive breast cancer in premenopausal women.

⚠️ For gynaecological indications, use ≤ 6 months only (risk of bone loss).

🔹 3. Dosing & Administration

• Men: 10.8 mg subcutaneously into anterior abdominal wall every 3 months.
• Women: 10.8 mg subcutaneously every 12 weeks.
• Notes:
  • No dosage adjustment required for renal/hepatic impairment or elderly.
  • Not for paediatric use.
  • Administer as per pre-loaded syringe instructions.

🔹 4. Contraindications

• Hypersensitivity to goserelin or excipients.
• Pregnancy and breastfeeding.
• Use in children (<18 years).

🔹 5. Warnings and Precautions

• Initial testosterone surge may transiently worsen symptoms in prostate cancer (e.g. bone pain, ureteric obstruction, spinal cord compression).
• Bone loss: Risk of ↓ bone mineral density with prolonged use.
  • In women, bone loss may recover after stopping.
  • Consider hormone replacement (HRT) or bisphosphonates for bone protection.
• Hyperglycaemia/Diabetes: Reduced glucose tolerance possible — monitor blood glucose.
• Cervical resistance: May increase during gynaecological procedures.
• Menses: Delayed return after cessation; some women may enter natural menopause.
• Pituitary tumours (animal data): No proven relevance in humans.

🔹 6. Drug Interactions

• None known (no significant pharmacokinetic or pharmacodynamic interactions reported).

🔹 7. Fertility, Pregnancy & Lactation

• Pregnancy: Contraindicated — risk of foetal harm. Confirm non-pregnancy before starting.
• Contraception: Use non-hormonal contraception during therapy and until menses return.
• Breastfeeding: Contraindicated.
• Fertility: Suppression is reversible; menses and fertility typically return after treatment cessation.

🔹 8. Side Effects & Management

🔹 9. Overdose

No reported human cases. Animal data suggest no additional toxicity beyond hormone suppression. Manage symptomatically if occurs.

🔹 10. Pharmacology

Pharmacotherapeutic group: LHRH agonist
Produces reversible hypogonadism by pituitary downregulation.
Testosterone suppression to castrate levels within ~21 days (males).
Oestradiol suppression to postmenopausal levels in females.

Pharmacokinetics:
Poor protein binding; elimination half-life 2–4 h. Extended-release depot ensures sustained suppression for 3 months. No dose adjustment needed in renal/hepatic impairment.

🔹 11. Storage & Handling

• Store sealed, ≤ 25°C.
• Supplied as pre-loaded single-use syringe.
• No special disposal requirements.

REFERENCES: 

https://myzoladexjourney.co.za/wp-content/uploads/2024/11/PI_Zoladex-108-mg-injection_20220802.pdf