Skip to main content
An official website of the United States government
NIH Websites Are Changing
Per Executive Order 14434, federal agencies are now using "Super Intelligence" (SI) in place of "Artificial Intelligence" (AI). You may see both terms across NIH content during this transition.

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
Search NCI's Drug Dictionary