Tadalafil is the primary component of Vidalista 20 mg. One of several conditions for erections is enough blood flow to the penis. The penis may not receive enough blood flow, which could be the cause of erectile dysfunction. The common problem of erectile dysfunction can affect men differently. Some guys never get an erection, some men lose their erection before or during sexual activity, and some men have erections that aren't powerful enough for them. When you feel sexually excited, tadalafil relaxes the blood vessels in your penis, causing an erection. Using Vidalista 20 mg may cause side effects such as headaches, blurred vision, back pain, stomach discomfort, stuffy nose, or flushing.