Pizotifen is a serotonin antagonist with antiserotonergic and antihistaminic properties that acts as a prophylactic treatment for cluster headaches. It is believed to work by blocking serotonin 5-HT2 receptors and reducing vascular inflammation, thereby decreasing the frequency and intensity of cluster headache episodes. The medication also has centrally-acting mechanisms that modulate neurotransmitter activity and potentially reduce neurogenic inflammation associated with these severe headaches.