Goserelin is a synthetic gonadotropin-releasing hormone (GnRH) agonist, also referred to as a luteinizing hormone-releasing hormone (LHRH) analogue. It is used primarily in the management of hormone-sensitive cancers and hormone-dependent conditions, including prostate cancer, breast cancer, endometriosis, and uterine fibroids. Continuous administration of goserelin suppresses the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), resulting in reduced production of sex hormones such as testosterone and estrogen.

Mechanism of Action

Goserelin initially stimulates pituitary GnRH receptors, causing a temporary increase in LH and FSH secretion. Continued exposure subsequently leads to receptor down-regulation and suppression of gonadotropin release, producing a marked reduction in:

• Testosterone levels in males
• Estrogen levels in females

This pharmacologic effect creates a reversible state of hormonal suppression ("chemical castration"), which helps reduce the growth and activity of hormone-dependent tumors and conditions.

Indications

Goserelin may be used for:

• Advanced prostate cancer
• Hormone receptor-positive breast cancer
• Endometriosis
• Uterine fibroids (leiomyoma)
• Endometrial thinning before surgery
• Selected infertility and reproductive medicine protocols

Available Dosage Forms

Goserelin is commonly available as a subcutaneous depot implant with prolonged release formulations:

• 3.6 mg implant
• 10.8 mg implant

Adult Dosage

Prostate cancer

• 3.6 mg subcutaneous implant every 28 days
• Alternative: 10.8 mg subcutaneous implant every 12 weeks

Endometriosis

• 3.6 mg subcutaneous implant every 28 days
• Treatment duration is commonly limited to 6 months because of concerns regarding bone mineral density reduction.

Breast cancer

• 3.6 mg subcutaneous implant every 28 days (dose may vary according to treatment regimen and oncology protocol).

Common Adverse Effects

Common adverse reactions are related to suppression of sex hormones and may include:

• Hot flashes
• Sweating
• Headache
• Mood changes
• Loss of libido
• Erectile dysfunction
• Vaginal dryness
• Weight gain
• Nausea
• Injection-site reactions
• Reduced bone mineral density with prolonged use

Serious Adverse Effects

Less common but clinically important reactions include:

• Tumor flare phenomenon during initial treatment
• Hyperglycemia or diabetes risk
• Osteoporosis with long-term use
• Hypersensitivity reactions
• Rare pituitary complications

Contraindications and Precautions

Goserelin should generally be avoided or used cautiously in:

• Pregnancy
• Breastfeeding
• Patients with severe osteoporosis risk
• Patients with urinary obstruction or spinal cord compression (particularly during initiation of prostate cancer therapy because of tumor flare risk)

Monitoring may include hormonal response, bone health assessment, and disease-specific clinical parameters.

Patient Disclaimer:
This information is intended for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. Patients should consult their physician, oncologist, or pharmacist before starting or modifying goserelin therapy and should not discontinue prescribed treatment without medical supervision.