Which of the following drugs is useful in the prophylaxis of migraine?

Drugs such as topiramate, valproate, propanolol, timolol, candesaan, verapamil and amitryptilline are indicated in migraine prophylaxis. Migraine prophylaxis is indicated when migraine headaches occur more than two or three times a month or when it is associated with significant disability. After initiation of therapy,it should be continued for several months. Once the patient remains headache free, the dose is tapered and the drug is eventually withdrawn. Botulinum toxin type A was approved by the US Food and Drug Administration (FDA) for migraine prevention in late 2010. Ref: Current Medical Diagnosis and treatment 2012, Chapter 24