Amrinone [Chemical/Ingredient] Milrinone [Chemical/Ingredient] C23440 (3,4'-Bipyridine)-5-carbonitrile, 6-dihydro-2-methyl-6-oxo- D020105 N0000006546 A positive inotropic cardiotonic agent with vasodilator properties. It inhibits cAMP phosphodiesterase type 3 activity in myocardium and vascular smooth muscle. Milrinone is a derivative of amrinone and has 20-30 times the inotropic potency of amrinone. 52769 Milrinone Milrinone C0128513 Milrinone M0029839