Fulvestrant

How it works

It binds the oestrogen receptor and promotes its degradation, downregulating receptor levels and abolishing oestrogen-driven tumour signalling.

Prescribing in practice

• Administer by slow intramuscular injection into the buttock and avoid in significant hepatic impairment without specialist assessment.
• Caution and additional monitoring are needed in patients on anticoagulants because of the intramuscular route and bleeding risk.
• It is increasingly given in combination with a CDK4/6 inhibitor; check compatibility and interactions against current prescribing references.

Monitoring

Periodically assess liver function and disease response, and watch injection sites for local reactions.

Counselling the patient

• Injection-site discomfort, hot flushes, joint pain and fatigue are common.
• Report any new or worsening bruising or bleeding, particularly if you take blood thinners.
• Attend appointments for your injections on schedule as directed by your oncology team.

Evidence & guidelines

Fulvestrant's role in advanced hormone-receptor-positive breast cancer is supported by trials such as FALCON and is reflected in NICE guidance.