Vidalista Black functions by boosting blood flow to the penis. This helps men achieve and maintain an erection. It belongs to the group of drugs called phosphodiesterase type 5 inhibitors. If you do not have erectile dysfunction, you should not take this drug. Avoid taking it more than once a day, as indicated. The most common side effects of this drug are flushing, headache, dizziness, blurred vision, sore muscles, upset stomach, and rash. See your doctor if you have any side effects that bother you or do not go away. Because productivity varies throughout individuals, working can take anywhere from 30 to 60 minutes.