Goserelin acetate is a synthetic decapeptide analogue of luteinizing hormone-releasing hormone (LHRH or GnRH). It acts as a potent GnRH agonist. Following an initial transient stimulation of the pituitary-gonadal axis (flare-up), continuous administration leads to a sustained suppression of gonadotropin secretion (LH and FSH), resulting in a profound reduction of sex steroid (testosterone and estrogen) levels to castrate or post-menopausal ranges. The 3.6mg subcutaneous implant is designed for monthly administration.
Adult: 3.6 mg administered as a subcutaneous implant into the anterior abdominal wall every 28 days. For endometriosis/fibroids, treatment is usually limited to 6 months.
Note: For subcutaneous use only. Using the pre-assembled syringe applicator, inject the implant subcutaneously into the anterior abdominal wall, alternating sites each month. Ensure aseptic technique. The implant does not need to be removed, as it is biodegradable.
Goserelin is a potent agonist of gonadotropin-releasing hormone (GnRH) receptors in the anterior pituitary. Continuous, non-pulsatile stimulation desensitizes these receptors, leading to downregulation. This inhibits the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In males, the reduction in LH causes a fall in testicular testosterone production. In females, the reduction in FSH and LH leads to a suppression of ovarian follicular development and estrogen production.
Pregnancy: CONTRANDICATED (Category D). Can cause fetal harm based on mechanism. Exclude pregnancy before starting. Advise non-hormonal contraception during and for 12 weeks after treatment in women of childbearing potential.
Driving: May cause fatigue, dizziness, and visual disturbances. Patients should be cautioned about operating machinery or driving until they know how the drug affects them.
| Drugs that prolong QT interval (e.g., Antiarrhythmics - amiodarone, sotalol; Antipsychotics; Fluoroquinolones) | Additive risk of QT prolongation and cardiac arrhythmias. | Major |
| Other sex hormone therapies (e.g., testosterone, estrogen supplements) | Antagonizes the therapeutic effect of Goserelin. | Major |
| Corticosteroids (long-term, systemic) | Additive risk of osteoporosis and bone loss. | Moderate |
| Drugs metabolized by CYP450 enzymes | Goserelin is not a known inducer/inhibitor, but hypoestrogenic/hypogonadal state may alter drug metabolism indirectly. Clinical significance unclear. | Minor |