Buserelin

How it works

Continuous administration initially stimulates then desensitises pituitary GnRH receptors, causing downregulation and a sustained fall in gonadotrophin and sex hormone production.

Prescribing in practice

• An initial surge in sex hormones (the flare effect) occurs before suppression, which can transiently worsen symptoms and must be anticipated in hormone-sensitive disease.
• Prolonged use induces a hypo-oestrogenic state that reduces bone mineral density, so duration is limited and add-back therapy may be considered for longer courses.
• Effective non-hormonal contraception should be used during treatment for endometriosis as it is not a contraceptive.

Monitoring

Monitor for menopausal symptoms and, with prolonged use, consider assessment of bone mineral density.

Counselling the patient

• You may notice a short-term worsening of symptoms when starting before they improve.
• Expect menopausal-type effects such as hot flushes, and report troublesome symptoms.
• Use a reliable non-hormonal method of contraception while taking this treatment.

Evidence & guidelines

GnRH agonists are an established hormonal option for endometriosis where first-line treatments are inadequate, as recognised in NICE guidance.