Methoxamine (MOA)

Methoxamine is an α1-adrenergic receptor agonist, similar in structure to phenylephrine and 2,5-DMA. It was developed by Burroughs-Wellcome in the 1940s. The drug induces vasoconstriction of skin and splanchnic blood vessels, thereby increasing peripheral vascular resistance and raising mean arterial blood pressure. Because of its hypertensive effects, it may evoke a compensatory reflex bradycardia via the baroreceptors.

Topical phenylephrine has been shown to increase resting anal canal pressure in normal and incontinent individuals. However, high concentrations of gel (10-40 per cent) are required that may cause local side-effects. The aim of this study was to determine whether methoxamine, another alpha-1-adrenoceptor agonist, might be a more potent alternative to phenylephrine.