femalegra 100 mg belongs to a class of medications called phosphodiesterase (PDE). This medicine is used to treat impotence by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Take Femalegra exactly as directed by your doctor. Do not take it in larger amounts or for longer than recommended by your doctor. Follow the directions on the prescription label. vilitra 40 mg can help achieve an erection when sexual stimulation occurs.