Zoladex

Goserelin is primarily indicated for hormone-sensitive conditions where suppression of gonadal steroid hormone production is desired:

• Prostate Cancer:
  • Advanced prostate cancer to reduce testosterone production, slowing disease progression.
• Breast Cancer:
  • Hormone receptor-positive breast cancer in premenopausal women to suppress ovarian estrogen production.
• Endometriosis:
  • Moderate to severe endometriosis to reduce endometrial lesions and relieve associated pain.
• Uterine Fibroids:
  • Preoperative management to reduce fibroid size and control symptoms such as heavy menstrual bleeding.
• Central Precocious Puberty (CPP):
  • Treatment in children with early onset puberty to delay further development by suppressing pituitary gonadotropin release.
• Off-label Uses:
  • Occasionally used in assisted reproduction protocols or other hormone-dependent conditions.

• Route:
  • Administered by subcutaneous or intramuscular injection, usually via a prefilled implant or syringe.
• Prostate Cancer:
  • Typical dose: 3.6 mg every 28 days subcutaneously or 10.8 mg every 12 weeks (3-month depot).
  • Treatment is continuous, often lifelong or until disease progression.
• Breast Cancer:
  • Same dosing as prostate cancer: 3.6 mg monthly or 10.8 mg every 12 weeks.
• Endometriosis:
  • 3.6 mg every 28 days for 3 to 6 months. Extended use beyond 6 months requires add-back therapy due to hypoestrogenic side effects.
• Uterine Fibroids:
  • 3.6 mg every 28 days for up to 6 months preoperatively.
• Central Precocious Puberty:
  • Dose varies by body weight and age, typically 3.6 mg monthly. Adjustments based on clinical and laboratory response.
• Special Populations:
  • Pediatric use limited to CPP; dosing individualized.
  • No dose adjustment recommended for renal or hepatic impairment.
• Administration Notes:
  • Rotate injection sites.
  • Administer by healthcare professional or trained caregiver.

Goserelin is a synthetic decapeptide analog of gonadotropin-releasing hormone (GnRH). It initially stimulates the pituitary GnRH receptors causing a transient increase in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion. Continuous administration desensitizes these receptors, leading to downregulation of LH and FSH release. This suppresses gonadal steroidogenesis, drastically lowering testosterone production in males and estrogen production in females. The resultant hypogonadal state inhibits hormone-dependent tumor growth in prostate and breast cancer, reduces ectopic endometrial tissue activity in endometriosis, and halts premature puberty progression in CPP.

• Absorption:
  • Following subcutaneous administration, Goserelin is slowly absorbed with peak plasma levels within a few hours.
• Distribution:
  • Widely distributed with a moderate volume of distribution.
• Metabolism:
  • Metabolized enzymatically to smaller peptides and amino acids.
• Elimination Half-life:
  • Approximately 3 to 4 hours after subcutaneous injection; depot formulation maintains steady levels over weeks.
• Excretion:
  • Metabolites excreted primarily via urine.

• Pregnancy:
  • FDA Pregnancy Category X.
  • Contraindicated during pregnancy due to potential fetal harm from sex hormone suppression.
• Lactation:
  • Use not recommended during breastfeeding due to potential hormonal effects and lack of safety data.

• Primary Class: Gonadotropin-Releasing Hormone (GnRH) agonist
• Subclass: Synthetic GnRH analog

• Known hypersensitivity to Goserelin or any formulation components.
• Pregnancy and lactation.
• Undiagnosed abnormal vaginal bleeding.
• Severe hepatic impairment (use with caution).
• Hormone-sensitive tumors without appropriate evaluation.

• Tumor Flare:
  • Initial transient increase in hormone levels may worsen symptoms or cause tumor flare, especially in prostate cancer. Anti-androgens may be used to mitigate.
• Bone Loss:
  • Prolonged hypoestrogenism or hypoandrogenism can lead to decreased bone mineral density; monitor and consider bone protection strategies.
• Cardiovascular Effects:
  • Potential risk of QT prolongation; monitor in patients with risk factors.
• Injection Site Reactions:
  • May include pain, erythema, swelling.
• Mood Changes:
  • Depression or mood swings reported; monitor patients accordingly.
• Pediatric Use:
  • Monitor growth and pubertal development closely.

• Common:
  • Hot flashes, sweating, headache, injection site reactions, mood changes, decreased libido, vaginal dryness.
• Serious/Rare:
  • Osteoporosis, cardiovascular events, allergic reactions, tumor flare symptoms (bone pain, urinary obstruction in prostate cancer).
• Onset:
  • Side effects related to hormone suppression typically appear within weeks of starting therapy.

• Major Interactions:
  • Potential additive QT prolongation with other QT-prolonging drugs.
  • May alter metabolism of concomitant medications metabolized via hormonal pathways, but direct CYP450 interactions are minimal.
• Drug-Food and Drug-Alcohol:
  • No significant interactions reported.

• Emphasis on bone health monitoring and use of add-back therapy to reduce hypoestrogenic side effects in long-term treatment.
• Updated prostate cancer guidelines recommend GnRH agonists like Goserelin as standard androgen deprivation therapy.
• Safety reviews continue regarding cardiovascular risk, especially in elderly populations.

• Store refrigerated at 2°C to 8°C (36°F to 46°F).
• Protect from light and moisture.
• Do not freeze.
• Keep in original packaging until use.
• Allow to reach room temperature before injection.