Erenumab

How it works

It blocks the calcitonin gene-related peptide (CGRP) receptor, preventing CGRP-mediated vasodilation and pain signalling implicated in migraine.

Prescribing in practice

• Hypersensitivity reactions including rash, angioedema and anaphylaxis have been reported and constipation can be severe, occasionally requiring further intervention.
• It is recommended for patients with frequent migraine in whom previous preventive treatments have failed, consistent with NICE criteria.
• Assess response after an adequate period and discontinue if migraine frequency is not meaningfully reduced.

Monitoring

No routine blood monitoring is needed, but headache frequency should be reviewed and patients asked about constipation and blood-pressure changes.

Counselling the patient

• This is a preventive injection to reduce migraine frequency, not a treatment for an acute attack.
• Report severe or persistent constipation, and tell us about any rash or swelling.
• You can be taught to give the injection yourself using the prefilled device.

Evidence & guidelines

NICE recommends erenumab for migraine prophylaxis in defined circumstances, supported by randomised trials showing reduced monthly migraine days versus placebo.