Prinoxodan (RGW2938) is a phosphodiesterase inhibitor. In Vitro Prinoxodan (RG W-2938) is an orally effective positive inotropic/vasodilator agent. Prinoxodan is a new nonglycoside, noncatecholamine cardiotonic/vasodilator agent is examined in vitro in isolated guinea pig hearts; in the latter, Prinoxodan 5 nmol-5 μmol increases contractility in a dose-related fashion. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo Prinoxodan (RG W-2938) is a new nonglycoside, noncatecholamine cardiotonic/vasodilator agent is examined in vivo in anesthetized and conscious dogs. Prinoxodan 30-300 μg/kg administered intravenously (i.v.) to anesthetized dogs increases contractile force while decreasing arterial pressure and total peripheral resistance (TPR) in a dose-related manner. Heart rate (HR) is only slightly increased, and aortic flow is not appreciably altered. A single oral dose of Prinoxodan 0.3 mg/kg administered to conscious chronically instrumented dogs produces a marked and sustained increase in contractility 15-240 min after treatment while only slightly increasing HR. The effects of Prinoxodan 30-300 μg/kg, i.v. are studied in a mecamylamine-propranolol-induced model of heart failure. Prinoxodan effectively reverses the drug-induced heart failure by increasing myocardial contractility and decreasing arterial pressure while only slightly affecting HR. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:Phosphodiesterase