Efficacy Results in Subpopulations in Controlled Clinical Studies A review of population subgroups demonstrated efficacy regardless of baseline severity, etiology, race and age. Sorry something went wrong with your subscription Please, try again in a couple of minutes Retry. These PDE5 inhibitors may cause headache, flushing, drop in blood pressure, or other adverse effects. The mean steady state volume of distribution Vss for sildenafil is L, indicating distribution into the tissues. Figure 6 shows that regardless of the baseline levels of function, subsequent function in patients treated with VIAGRA was better than that seen in patients treated with placebo.Summary. Sildenafil is a medication prescribed for the treatment of impotence (erectile dysfunction, ED) caused by medical or psychological conditions. The most common side effects are facial flushing (1 in 10), headaches (1 in 6), stomach pain, nasal congestion, nausea, dizziness, rash, urinary tract infections (UTIs), diarrhea, and . What is Sildenafil (Viagra)? Drug Facts Common Brands Viagra Drug Class PDE-5 inhibitor Controlled Substance Classification Not a controlled medication Generic Status Lower-cost generic available Availability Prescription only How Sildenafil (Viagra) works Sildenafil (Viagra) is a phosphodiesterase-5 (PDE-5) inhibitor. AdSave Time & Money with Online Prescription for Viagra, Cialis, Sildenafil and Tadafil. Free & Private Online Consultant with Real Doctors. Reliable E.D. Meds Shipped has been visited by 10K+ users in the past monthDiscreet Packaging · Free Shipping · Real Doctors · Personalized PlanTypes: Sexual Health · Premature Ejaculation · Privacy Policy.