Intravenous dihydroergotamine (DHE) acts as a potent vasoconstrictor and serotonin receptor agonist, targeting both alpha-adrenergic and serotonergic receptors to reduce cerebral blood vessel dilation and interrupt neurogenic inflammatory processes. By binding to 5-HT1B/1D receptors, it inhibits neuropeptide release and provides rapid abortive treatment for acute cluster headache episodes, effectively reducing pain intensity and duration through its direct central and peripheral mechanisms.