PHRM 211 Lecture 17: NEUR Pharmacology of Headaches (Part 1)
Document Summary
Abortive therapy may be effective for some patients. Moa: selective agonist for 5-ht1d and 5-ht-1b receptors. Binds with high affinity and selectivity to 5-ht1d and 5-ht1b receptors. Acts on receptors located on the perivascular trigeminal axons. Binds to postjunctional 5-ht1b receptors vasoconstriction: decreases impulse transmission to caudalis neurons. Binds to prejunctional 5-ht1d receptors decreased release of cgrp & substance p: prevents vasodilation of blood vessel. Activation of both 5ht1b and 5ht1d receptors act synergistically to dampen down process of migraine pain. Sumatriptan also acts at the level of the nucleus caudalis (in the brainstem) to inhibit. Tgt neurons activated by perivascular trigeminal afferent fibers. Most effective when given in early stages of migraine. Onset of action 15 minutes with sc or iv route. Poor oral bioavailability (15%) newer agents 50-70% Sumatriptan (and related drugs) exert their anti-migraine actions by acting at: Peripheral perivascular trigeminal synapse (pre- and postjunctional sites) Useful agent for aborting sudden or uncontrolled attack.
