Based upon measurements of sildenafil in semen of healthy volunteers 90 minutes after dosing, less than 0. Especially tell your healthcare provider if you take any of the following: medicines called nitrates medicines called guanylate cyclase stimulators such as Adempas riociguat medicines called alpha-blockers, such as Hytrin terazosin HCl , Flomax tamsulosin HCl , Cardura doxazosin mesylate , Minipress prazosin HCl , Uroxatral alfuzosin HCl , Jalyn dutasteride and tamsulosin HCl , or Rapaflo silodosin. 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. By controlling the enzyme, sildenafil helps to maintain an erection after the penis is stroked. Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss. The mean steady state volume of distribution Vss for sildenafil is L, indicating distribution into the tissues. · Brand names: Revatio, Viagra Drug classes: Agents for pulmonary hypertension, Impotence agents. Medically reviewed by Kaci Durbin, MD. Last updated on Uses; Warnings; Before taking; Dosage; Side effects; Interactions; FAQ; What is sildenafil? Sildenafil relaxes muscles of the blood vessels and increases blood flow .  · Descriptions Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where . CHOOSE BRAND-NAME VIAGRA. The original little blue pill prescribed by doctors for over 20 years. Clinically proven to treat men with erectile dysfunction (ED) Ongoing commitment to product quality and safety monitoring.