If your doctor is concerned your ED is an indicator of a more serious problem, they may send you to a specialist who can run some additional tests. A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. If you do not have a plastic syringe or spoon, ask your pharmacist for one. Do not take it more than once a day. Take sildenafil at around the same times every day. This medicine works best when you take it on an empty stomach an hour before sex.Sildenafil tablets for erectile dysfunction come in different strengths ranging from 25mg to mg. The usual dose is 50mg, when you need it. Do not take it more than once a day. The dose can be increased to mg or decreased to 25mg depending on its effect. Take sildenafil up to 4 hours before you want to have sex. Sildenafil may be used to treat erectile dysfunction (ED or impotence) in men (Viagra brand) or pulmonary arterial hypertension in both men and women (Revatio brand), depending . Precautions Cost Pregnancy Birth control needs Breastfeeding For professionals Drug Images What is Viagra? Viagra is a brand-name prescription drug that’s approved to .