Methoxamine is another 1-agonist and parenteralvasopressor used therapeutically and so have fewcardiac stimulatory properties. It is bioactivated byO-demethylation to an active m-phenolic metabolite. In fact,it tends to slow the ventricular rate because of activation ofthe carotid sinus reflex. It is less potent than phenylephrineas a vasoconstrictor. Methoxamine is used primarily duringsurgery to maintain adequate arterial blood pressure, especiallyin conjunction with spinal anesthesia. It does not stimulatethe CNS. Because it is not a substrate for COMT, itsDOA is significantly longer than NE.
