Phosphodiesterase type 5 inhibitors, abbreviated as PDE-5 inhibitors, refer to a group of drugs used for erectile dysfunction treatment. Viagra (sildenafil citrate), Cialis (tadalafil) and Levitra (vardenafil) are among the most prominent medicines containing PDE-5 inhibitors.
How do PDE-5 inhibitors work?
PDE-5 inhibitors work on an enzyme called phosphodiesterase type 5 (PDE-5). This enzyme can reduce blood flow to the penis by breaking down a cyclic nucleotide called cGMP, causing weak or no erection at the time of sexual arousal. cGMP can help the smooth muscles in the penis relax, which in turn, can dilate the penile arteries for increased blood flow. Phosphodiesterase type 5 is a naturally occurring enzyme in the corpus cavernosa chambers of the penis. When you are sexually stimulated, neurones in the corpus cavernosa chambers release nitric oxide – a chemical that aids in formation of cGMP. So for you to get and maintain an erection, the presence of cGMP is a must.
Source: What are PDE-5 inhibitors?
