Goserelin

Brand Names: Zoladex

Drug Class: Gonadotropin-releasing hormone (GnRH) agonist

Overview

Goserelin is a synthetic decapeptide analog of gonadotropin-releasing hormone (GnRH) used as a long-acting depot formulation for the treatment of hormone-sensitive cancers and certain gynecological conditions. It acts as a GnRH agonist, initially stimulating then suppressing pituitary gonadotropin secretion, leading to reduced sex hormone production.

Mechanism of Action

Goserelin is a GnRH agonist that binds to pituitary GnRH receptors, initially causing a transient increase in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion (flare effect). With continuous administration, it downregulates GnRH receptors, leading to sustained suppression of gonadotropin secretion and subsequent reduction in ovarian and testicular steroidogenesis.

Indications

  • Advanced prostate cancer (palliative treatment)
  • Locally advanced prostate cancer (as an alternative to surgical castration)
  • Early-stage prostate cancer (in combination with radiotherapy)
  • Advanced breast cancer in pre- and perimenopausal women
  • Endometriosis management
  • Endometrial thinning prior to endometrial ablation for dysfunctional uterine bleeding

Dosage

3.6 mg subcutaneous implant administered every 28 days into the anterior abdominal wall. For advanced prostate cancer: 10.8 mg implant administered every 12 weeks. Must be administered by healthcare professional.

Contraindications

  • Hypersensitivity to GnRH analogs or any component of the implant
  • Pregnancy
  • Breastfeeding
  • Undiagnosed abnormal vaginal bleeding

Side Effects

  • Hot flashes
  • Decreased libido
  • Impotence
  • Gynecomastia
  • Sweating
  • Headache
  • Depression
  • Insomnia
  • Bone pain
  • Peripheral edema
  • Nausea
  • Injection site reactions
  • Weight changes
  • Arthralgia
  • Vaginal dryness
  • Amenorrhea

Interactions

  • No clinically significant drug interactions identified in pharmacokinetic studies
  • Theoretical interactions with other drugs affecting pituitary-gonadal axis