• CKS recommends that therapy with gonadotrophin-releasing hormone (GnRH) analogues (e.g. leuprorelin and buserelin) should not be initiated in primary care.
• They produce a profound hypogonadal effect through downregulation, resulting in no ovulation and no menses.
• They may be used under specialist supervision before surgery or when all other treatment options for uterine fibroids, including surgery or uterine artery embolization, are contraindicated. They may also be used to produce temporary endometrial thinning and relief of bleeding before fibroid surgery.
• GnRH analogues are effective at treating menorrhagia. Evidence from two randomized controlled trials has shown:
• They are effective at reducing menstrual blood loss (RR 1.39, 95% CI 1.12 to 1.72).
• They cause amenorrhoea in most women (89%).
• GnRH analogues can cause significant adverse effects that often limit their use. These are principally perimenopausal in nature, including hot flushes, increased sweating, and vaginal dryness (due to oestrogen deficiency).
• GnRH analogues are given by subcutaneous or intramuscular injection, or intranasally, and they are usually used for less than 6 months. If treatment with these drugs is required for more than 6 months or if adverse affects are experienced, 'add-back' treatment with supplemental oestrogens and progestogens is recommended.

[National Collaborating Centre for Women's and Children's Health, 2007]