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phentolamine mesylate

The mesylate salt of a synthetic imidazoline with alpha-adrenergic antagonist activity. As a competitive alpha-adrenergic antagonist, phentolamine binds to alpha-1 and alpha-2 receptors, resulting in a decrease in peripheral vascular resistance and vasodilatation. This agent also may block 5-hydroxytryptamine (5-HT) receptors and stimulate release of histamine from mast cells.
US brand name:Regitine
Chemical structure:2-[N-p'-tolyl-N-(m'-hydroxyphenyl)aminomethyl]imidazoline monomethanesulfonate
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