A patient goes to his family doctor complaining of persistent and severe headaches. His physician diagnoses migraine headaches and prescribes sumatriptan. What is the mechanism of action of this drug?

Sumatriptan is a serotonin 1D agonist that is used to abo migraine headaches. It is also effective in the treatment of cluster headaches. Currently, no dopamine (D1) agonists, GABA antagonists, or muscarinic (M3) antagonists are used clinically. Propranolol is an example of a non-selective beta antagonist.