100 Migraine drugs, A to Z: flunarizine

Flunarizine (Sibelium) is a calcium channel blocker approved for the preventive treatment of migraines in most countries, except for the US and Japan. In many countries, flunarizine is considered to be a first-line drug for the prevention of migraines.

It is as effective as propranolol (Inderal), a beta blocker which is approved world-wide for migraine prophylaxis (and hypertension). Flunarizine, 10 mg was found to be more effective than 50 mg of topiramate (Topamax), although the average dose of topiramate for migraines is 100 mg. It can take 6 to 8 weeks before flunarizine becomes effective.

Vestibular migraine is characterized by vertigo which can occur with or without headache and is often difficult to treat. One observational study suggested that flunarizine may improve the attacks of vertigo.

The two most common side effects of flunarizine are drowsiness and weight gain, but can also cause nausea, anxiety, depression, insomnia, and dry mouth. I’ve recommended purchasing flunarizine abroad to a few of my patients who exhausted other options. None have remained on it, either because of side effects or lack of efficacy. Clearly, giving it to the most severely affected patients is not a fair way to evaluate a drug, but I’ve stopped recommending it. This is also because of legal and logistical problems in getting flunarizine from outside the US.

In the US, we do have a different calcium channel blocker, verapamil (Calan). It is not FDA-approved for migraines (only for high blood pressure) and it is not as effective as flunarizine for migraines, but is the first-line drug for the prevention of cluster headaches.