Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine. Sildenafil comes as a tablet and suspension liquid to take by mouth. Sildenafil treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. If you are taking sildenafil for erectile dysfunction, your doctor will probably start you on an average dose of sildenafil and increase or decrease your dose depending on your response to the medication. However, the dose is usually not more than 80 mg 3 times a day. Before starting, stopping, or changing any medications while taking sildenafil, please get the advice of your doctor or pharmacist.Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung . Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult .  · Proper Use Drug information provided by: Merative, Micromedex ® Use sildenafil exactly as directed by your doctor. Do not use more of it and do not use it more .