Zoladex Injection contains Goserelin acetate, a gonadotropin-releasing hormone (GnRH) agonist. It works by reducing the production of sex hormones — testosterone in men and estrogen in women. This makes it useful in treating hormone-sensitive cancers such as prostate cancer and breast cancer, as well as certain gynecological conditions like endometriosis and uterine fibroids. It is also sometimes used to thin the lining of the uterus before surgery.
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Dosage (Adults)
Prostate Cancer (men): 3.6 mg injection once every 28 days (1 month depot), or 10.8 mg injection every 12 weeks (3 months depot).
Breast Cancer (premenopausal women): 3.6 mg injection every 28 days.
Endometriosis & Uterine Fibroids: 3.6 mg injection every 28 days, usually up to 6 months.
Endometrial thinning (before surgery): 3.6 mg injection every 28 days, for 2 doses.
> Administered as a subcutaneous implant in the abdominal wall by a trained healthcare professional.
Side Effects
Common:
Hot flashes, night sweats
Headache, dizziness
Decreased libido
Vaginal dryness (women)
Erectile dysfunction (men)
Weight gain, mood changes
Pain, redness, or swelling at injection site
Serious (seek medical attention):
Severe allergic reactions (rash, swelling, difficulty breathing)
Bone thinning (osteoporosis) with long-term use
Tumor flare reaction in the first weeks (temporary worsening of symptoms in prostate or breast cancer)
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Warnings & Precautions
Not for use in pregnant or breastfeeding women.
May cause bone density loss with prolonged use—calcium and vitamin D supplements may be advised.
Men may experience temporary increase in testosterone at the start of treatment.
Regular monitoring of hormone levels, bone health, and treatment response is recommended.
