Milrinone, a synthetic dimethylxanthine derivative structurally related to theophylline and caffeine, is used in the treatment of peripheral vascular diseases and in the management of cerebrovascular insufficiency, sickle cell disease, and diabetic neuropathy. Milrinone inhibits erythrocyte phosphodiesterase, resulting in an increase in erythrocyte cAMP activity. Subsequently, the erythrocyte membrane becomes more resistant to deformity. Along with erythrocyte activity, Milrinone also decreases blood viscosity by reducing plasma fibrinogen concentrations and increasing fibrinolytic activity. Milrinone is indicated for the treatment of congestive heart failure. Milrinone was marketed under the brand name Primacor.

Inamrinone (Amrinone) is a positive inotropic cardiotonic with vasodilator properties, phosphodiesterase inhibitory activity, and the ability to stimulate calcium ion influx into the cardiac cell. Inamrinone is a phosphodiesterase inhibitor (PDE3), resulting in increased cAMP and cGMP which leads to an increase in the calcium influx like that caused by beta-agonists resulting in increased inotropic effect. Inamrinone is used in the treatment of congestive heart failure.

Vesnarinone is a new and novel inotropic drug that has unique and complex mechanisms of action. It inhibits phosphodiesterase, thereby leading to increased intracellular calcium, and also affects numerous myocardial ion channels, resulting in the prolongation of the opening time of sodium channels and the decrease in the delayed outward and inward rectifying potassium current. In vitro, it has also demonstrated significant effects on cytokine production, which may account for some of its observed clinical benefits. Hemodynamic studies in humans with congestive heart failure reveal that vesnarinone can improve ventricular function. Placebo-controlled studies in large numbers of patients with heart failure have suggested a morbidity and mortality benefit with a 60 mg daily dose. In Japan, vesnarinone was approved in June 1990 and first marketed in September 1990.

Milrinone, a synthetic dimethylxanthine derivative structurally related to theophylline and caffeine, is used in the treatment of peripheral vascular diseases and in the management of cerebrovascular insufficiency, sickle cell disease, and diabetic neuropathy. Milrinone inhibits erythrocyte phosphodiesterase, resulting in an increase in erythrocyte cAMP activity. Subsequently, the erythrocyte membrane becomes more resistant to deformity. Along with erythrocyte activity, Milrinone also decreases blood viscosity by reducing plasma fibrinogen concentrations and increasing fibrinolytic activity. Milrinone is indicated for the treatment of congestive heart failure. Milrinone was marketed under the brand name Primacor.

Inamrinone (Amrinone) is a positive inotropic cardiotonic with vasodilator properties, phosphodiesterase inhibitory activity, and the ability to stimulate calcium ion influx into the cardiac cell. Inamrinone is a phosphodiesterase inhibitor (PDE3), resulting in increased cAMP and cGMP which leads to an increase in the calcium influx like that caused by beta-agonists resulting in increased inotropic effect. Inamrinone is used in the treatment of congestive heart failure.