Used primarily in the prevention of migraine headaches, this compound acts as a serotonin and histamine receptor antagonist. It helps reduce the frequency and severity of migraine attacks when taken regularly. It is also occasionally prescribed for tension-type headaches and has been used off-label to manage appetite and prevent certain types of cluster headaches. Its sedative effect may benefit patients with insomnia related to headache disorders. Not intended for acute treatment during a migraine attack, but rather for long-term prophylactic use.