PHARMACEUTICAL COMPOSITIONS FOR THE TREATMENT OF CHRONIC HEART FAILURE COMPRISING PYRAZOLOPYRIMIDINONE DERIVATIVE COMPOUND

Disclosed herein is a therapeutic agent for chronic heart failure comprising, as an effective ingredient, 5- [2-propyloxy- 5- (l-methyl-2-pyrrolidinyleneamidosulfonyl) phenyl] - 1 -methyl - propyl-l,6-dihydro-7H-pyrazolo(4,3-d)pyrimidine-7-one. The compound inhibits phosphodiesterase-5 (PDE-5), which catalyzes the intracellular degradation of cyclic guanosine monophosphatase (cGMP), thereby mitigating several signs of chronic heart failure, that is, thereby preventing left ventricular dilatation, decreasing ventricular wall thinning, lowering elevated cardiac and circulating levels of atrial natriuretic peptide (ANP), and inhibiting ventricular fibrosis. Also, the compound has advantages in that it reaches the maximal plasma level in a short time, has an in vivo half-life longer than conventional PDE-5 inhibitors, allowing decreased administration frequency, and has fewer side effects, thus ensuring safety. Thus, the compound is useful as a therapeutic agent for chronic heart failure.