Almotriptan bonds with high affinity to 5-HT1D, 5-HT1B, and 5-HT1F receptors, and has an absolute bioavailability of approximately 70 percent. Peak plasma levels of Almotriptan occur roughly 1 to 3 hours after administration.
The therapeutic efficacy of Almotriptan is thought to be attributed to agonist effects at 5-HT1B/1D receptors. An activation of these receptors aids in cranial vessel constriction, reduced transmission in the trigeminal pain pathways and an inhibition of neuropeptide releases.
Almotriptan is metabolized by major pathways monoamine oxidase-mediated oxidative deamination and cytochrome P450-mediated oxidation. Renal excretion of Almotriptan is primary, about 70 percent of the dosage, with roughly 40 percent of an administered dose excreted unchanged in urine.
Patients with severe renal impairment or who have ischemic heart disease should not be administered Almotriptan. In patients with hepatic impairment the recommended starting dose of Almotriptan is 6.25 milligrams, not exceeding 12.5 milligrams in a 24 hour period. Typical side effects include reports of dizziness, nausea, tiredness and dry mouth.