They may suggest adjusting your dosage of Viagra, making certain changes to the way you use this medication or switching to a different ED treatment. This allows the smooth muscles in the penis to relax and fill with blood. VIAGRA improved these aspects of sexual function: frequency, firmness and maintenance of erections; frequency of orgasm; frequency and level of desire; frequency, satisfaction and enjoyment of intercourse; and overall relationship satisfaction. In some cases, ED can cause a strain on relationships and impact self-esteem. Sildenafil is also sometimes used to treat pulmonary hypertension high blood pressure in the blood vessels that supply the lungs. You should only be treated with one of these products at a time. PDE5 Inhibitors.According to price-comparison site , generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s compared with more than $50 per. About sildenafil (Viagra) Sildenafil is a medicine used to treat erection problems (erectile dysfunction). Sildenafil is also sometimes used to treat pulmonary hypertension (high blood pressure in the blood vessels that supply the lungs). If you have erection problems sildenafil works by temporarily increasing blood flow to your penis when. 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.