merck sharp

Viagra 100 mg 4 tablet is a prescription medicine used to treat erectile dysfunction (ED). This medicine helps the blood to flow into the penis and helps to keep an erection if there is sexual stimulation. Viagra does not affect sexual desire or libido. This medicine should be taken approximately 1 hour before sexual activity and for best results, should be taken with water. It should not be taken more than once a day. This medicine is not for women or children.