Avanafil is an oral drug used for treating impotence. Impotence condition in man is an inability for attaining or maintaining a stiffer penile erection, which is also known as erectile dysfunction (ED). The drug is in a class of medication known as phosphodiesterase inhibitors, which also includes Tadalafil, Sildenafil Citrate, and Vardenafil.

Penile erection occurs by the filling of the penile region with blood. It occurs because the blood vessels bring blood to the penile region by enhancing in size and deliver more amount of blood in the penile region, and, at the same time, the blood vessels carrying blood away from the penile lower in size and remove less blood from the penile.

Sexual stimulation, which leads to penile erection, causes the production and release of nitric oxide in the penile. This particular nitric oxide leads to an enzyme, guanylate cyclase, for producing cyclic guanosine monophosphate (cGMP). It is cGMP, which is primarily responsible for enhancing and lowering the size of blood vessels carrying blood to and from the penile region, respectively, and causing a penile erection. When the cGMP is destroyed by some another enzyme, phosphodiesterase-5, which is the blood vessels for returning to their normal size, blood leaves the penile, and the erection comes to an end.

Avanafil drug prevents phosphodiesterase-5 from destroying cGMP so that the cGMP stays around for a longer time. The persistence of cGMP leads to a more prolonged engorgement of the penile along with blood. Avanafil was approved by the FDA in April 2012

For most of the individuals, recommended a starting dose of this drug is 100 mg per day, which is to be consumed about 30 minutes before planned lovemaking session. Depending on the adequacy of the response or side effects, the dosage might be enhanced or decreased. Individuals that are consuming such impotence treating medications that moderately enhances the blood levels of Avanafil should not exceed a total dose of 50 mg in 24 hours

Avanafil drug might also lead to some low blood pressure, blurred vision and changes in color vision, and abnormal ejaculation. These side effects of the drug are nothing to worry about as they do not last for longer time. Avanafil drug might lead to prolonged penile erection or priapism, which is a painful erection that lasts for more than 6 hours. Patients are recommended to seek immediate medical help in the case; they experience a stiffer penile erection that lasts for more than 4 hours.