At the same time, on-treatment function was better in treated patients who were less impaired at baseline. Efficacy Results from Controlled Clinical Studies The effect on one of the major end points, maintenance of erections after penetration, is shown in Figure 6, for the pooled results of 5 fixed-dose, dose-response studies of greater than one month duration, showing response according to baseline function. They are PDE5 inhibitors that allow for increased blood flow to the penis, leading to more frequent and harder erections. There were highly statistically significant improvements on the two principal IIEF questions frequency of successful penetration during sexual activity and maintenance of erections after penetration on VIAGRA compared to placebo. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work.Viagra Increases Your Sex Drive. Another common myth about Viagra is that it can increase your sex drive and cause you to feel more motivated to have sex. Viagra is designed to improve your physical performance during sex — that is, your ability to get and maintain an erection. Buying Viagra Online: The 5 Best Online Viagra Sources of Medically reviewed by Philip Ngo, PharmD — By Iman Balagam and The Healthline Editorial Team . Call your doctor for medical advice about side effects. You may report side effects to FDA at FDA How should I store VIAGRA? • Store VIAGRA at room temperature between 68°F to 77°F (20°C to 25°C). Keep VIAGRA and all medicines out of the reach of children. General information about the safe and effective use of VIAGRA.