Clinical use of phosphodiesterase-5 inhibitors in chronic heart failure.

Nowadays, the inhibitors of the phosphodiesterase enzyme type 5 (PDE5), thanks to a sustained relaxant activity on smooth muscles of the corpus cavernosum, are a widely used remedy for erectile dysfunction in man. This class of compounds was originally developed for the treatment of angina pectoris, based on the ability of oversignaling the pathway originated from nitric oxide (NO) and pursued via cGMP signaling. Because the clinical effects were not as promising as initially reported by experimental studies, PDE5 inhibitors1 were not regarded as a remarkable advancement over commonly used nitrates. Subsequently, however, it was realized that the clinical applicability of the enhanced NO/ cGMP pathway by inhibiting the PDE5 activity could be larger than previously thought. Over the last few years, the use of PDE5 inhibitors has been expanded to the therapeutic management of other cardiovascular disorders, including chronic heart failure (CHF). Their clinical applicability to CHF is the subject of this review.