Pizotifen is a serotonin (5-HT2) receptor antagonist with additional antihistaminic and anticholinergic effects. It blocks 5-HT2 receptors involved in vasodilation and neurotransmitter release that contribute to migraine and cluster headache pathogenesis. By inhibiting serotonin-induced vasodilation and platelet aggregation, pizotifen reduces headache frequency. Its antihistamine and anticholinergic properties contribute to sedation and modulation of central neurotransmission.