top of page
< Back

Sildenafil


Mechanism of action:

Sildenafil is a phosphodiesterase type 5 inhibitor. Phosphodiesterase type 5 is the enzyme responsible for degrading cyclic guanosine monophosphate, or cGMP, and is especially abundant in the corpus cavernosum of the penis and in pulmonary vascular smooth muscle. Sildenafil selectively inhibits this enzyme and reduces the degradation of cGMP. cGMP activates protein kinase G, lowers intracellular calcium concentration, relaxes cavernosal and vascular smooth muscle, and increases blood flow.

Reference(s):

1. Boolell M et al. (1996). Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. Int J Impot Res. 


2. Cheitlin MD et al. (1999). ACC/AHA expert consensus document. Use of sildenafil (Viagra) in patients with cardiovascular disease. J Am Coll Cardiol. 


3. Fries R et al. (2005). Sildenafil in the treatment of Raynaud's phenomenon resistant to vasodilatory therapy. Circulation.

bottom of page