methoctramine

Methoctramine is a polymethylene tetraamine and selective muscarinic receptor antagonist, primarily acting on the M2 subtype of the muscarinic acetylcholine receptor, which is predominantly found in cardiac tissue. It acts as a competitive antagonist, demonstrating high cardioselectivity with significantly greater antagonistic activity at M2 receptors compared to other muscarinic receptor subtypes (notably 54–132 times less potent in intestinal tissue than in cardiac tissue). Methoctramine inhibits parasympathetic control of the heart, thereby increasing heart rate by blocking the action of acetylcholine at M2 receptors in the sinoatrial and atrioventricular nodes. At higher concentrations, methoctramine may show some activity at other muscarinic receptors or even interact with nicotinic acetylcholine receptors and adenosine A3 receptors, but these effects are less characterized. The drug has been used extensively in research to probe muscarinic receptor subtype function, but it is not approved for clinical use in humans. Investigated applications include the management of bradycardia, overactive bladder, and other conditions involving smooth muscle contraction, but it remains in the research-only stage.

Other names

Methoctramine free baseCHEBI:73339104807-40-1NVJ76B897DNVJ-76B897DNVJ 76B897DUNII-NVJ76B897DUNII-NVJ-76B897DUNII-NVJ 76B897D