Cyclic guanosine monophosphate-specific phosphodiesterase type 5 (PDE5)

Cyclic guanosine monophosphate-specific phosphodiesterase type 5 Overview

Cyclic guanosine monophosphate-specific phosphodiesterase type 5 (PDE5) is an enzyme primarily involved in the hydrolysis of cyclic GMP (cGMP) to 5′-GMP in vascular smooth muscle and other tissues, including the corpus cavernosum of the penis and clitoris, as well as the lungs and retina[1][4]. By regulating cGMP levels, PDE5 controls smooth muscle tone and facilitates vasodilation, making it a crucial target for drugs treating erectile dysfunction and pulmonary hypertension[2][3][5][6]. Selective inhibition of PDE5 leads to increased cGMP, promoting smooth muscle relaxation and increased blood flow. Several drugs (e.g., sildenafil, tadalafil, vardenafil, avanafil) are approved oral inhibitors of PDE5 used for these indications. Safety concerns include severe hypotension when combined with nitrates and specific side effects such as headaches, flushing, and, more rarely, visual disturbances due to off-target action on related PDE isoforms[6][4].

Mechanism of Action

Enzyme inhibition (PDE5 inhibition), Prevention of cGMP breakdown, Promotion of smooth muscle relaxation and vasodilation

Biological Functions

Safety Considerations

Interacting Drugs