Migranil® 0.5 mg Tablet contains Pizotifen, a tricyclic compound that acts as a serotonin antagonist. It is primarily used for the prophylactic treatment of vascular headaches, including classical migraine, common migraine, and cluster headaches. Pizotifen works by inhibiting serotonin and histamine receptors, thereby preventing the dilation of blood vessels in the brain that can lead to migraine attacks.