Side by side

1. 1.Binds GnRH receptors in the pituitary far more tightly than natural GnRH.
2. 2.Continuous receptor occupancy desensitises the pituitary and reduces GnRH receptor numbers.
3. 3.LH and FSH secretion falls, so testosterone or oestrogen production drops to castrate levels.
4. 4.An initial flare of hormone release occurs in the first week before suppression takes hold.
5. 5.In children, removing the pubertal hormone signal pauses pubertal progression.

• Advanced prostate cancer
• Endometriosis
• Uterine fibroids before surgery
• Central precocious puberty
• Breast cancer in premenopausal women (with aromatase inhibitor strategies)
• Ovarian suppression in assisted reproduction

• Testosterone suppressed below castrate level (50 ng/dL) within about four weeks
• Roughly 60 to 80% reduction in endometriosis pain scores in trials
• Reduced fibroid and uterine volume
• Pausing of pubertal development in central precocious puberty
• Menopausal symptoms and bone loss from induced hormone suppression

• Hot flushes and sweats
• Loss of libido and erectile dysfunction
• Bone mineral density loss with prolonged use
• Mood change and fatigue
• Tumour or symptom flare in the first weeks
• Injection-site reactions
• Raised liver enzymes (uncommon)

Research context only - prescription medicine. Licensed regimens include 3.75 mg intramuscularly monthly or 11.25 mg every three months for prostate cancer, 3.75 mg monthly for endometriosis for up to six months, and weight-based depot dosing in central precocious puberty. Trials use testosterone below 50 ng/dL or oestradiol suppression as the biochemical endpoint and follow bone density over months.

Research context only