Cardiac Uses of Phosphodiesterase-5 Inhibitors

Bryan G. Schwartz, MD; Laurence A. Levine, MD; Gary Comstock, MD; Vera J. Stecher, PhD; Robert A. Kloner, MD, PhD


J Am Coll Cardiol. 2012;59(1):9-15. 

In This Article

Mechanism of Action

Vascular tone and blood flow is primarily regulated by endothelial-dependent vasodilation whereby endothelial cells produce nitric oxide (NO) that diffuses to the adjacent smooth muscle cells and enhances the production of cyclic guanosine monophosphate (cGMP), which relaxes smooth muscle, resulting in vasodilation. The cGMP is broken down by PDE5; thus, PDE5Is inhibit the breakdown of cGMP, resulting in enhanced vasodilation. By taking advantage of PDE5 located within the systemic and pulmonary vasculature, PDE5Is might benefit cardiovascular diseases. In addition to enhancing vasodilation, PDE5Is protect myocytes directly through complex mechanisms described in the following text.