Read more on male sexual health on the Sexual Health Australia site. VIAGRA was administered to more than 3, patients aged 19 to 87 years, with ED of various etiologies organic, psychogenic, mixed with a mean duration of 5 years. This allows the smooth muscles in the penis to relax and fill with blood. They are PDE5 inhibitors that allow for increased blood flow to the penis, leading to more frequent and harder erections. Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours.Rarely reported side effects include: an erection that will not go away (priapism). If you have an erection that lasts more than 4 hours, get medical help right away. If it is not treated right away, priapism can permanently damage your penis. sudden vision loss in one or both eyes. Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in is also used to treat pulmonary arterial hypertension, a serious heart and lung drug is more popular than comparable drugs. It is available in generic and brand versions. Generic sildenafil is covered by most Medicare and insurance plans, but . Viagra is the trade name of a drug called sildenafil, which treats erectile dysfunction in males. Sildenafil can also treat pulmonary arterial hypertension in a person of any sex. About 10% of.