Migraines

The condition affects more people than diabetes, asthma and epilepsy combined and is the sixth most common cause of disability in the world. Patients make lifestyle changes, take painkillers, and are prescribed drugs including beta blockers, antidepressants and anticonvulsant drugs. Tablets called triptans relieve symptoms but over time these can cause headaches themselves.

If chronic migraine does not respond to at least three drug treatments, patients may be offered jabs of the muscle-freezing drug Botox, because of its nerve-blocking effects, but this can involve 31 separate injections per treatment and has to be done in a specialist clinic.

Fremanezumab is among a new wave of drugs which targets a certain protein – in this case, calcitonin gene-related peptide (CGRP), which is responsible for the pain and nausea associated with a migraine. CGRP causes blood vessels intertwined with nerve endings in the head to swell up. Fremanezumab, which must be given by injection either every month or three months, depending on dose, contains an antibody that blocks that process