Other uses for this medicine This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information. The combination can cause a dangerous fall in your blood pressure. Please expect up to 4 to 6 weeks for reimbursement. The usual adult dose is 20mg taken 3 times a day. The most common side effects of VIAGRA: headache; flushing; upset stomach; abnormal vision, such as changes in color vision such as having a blue color tinge and blurred vision; stuffy or runny nose; back pain; muscle pain; nausea; dizziness; rash. It works for up to 36 hours. From Mayo Clinic to your inbox Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health.Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the . Brand names: Viagra, Revatio. Sildenafil comes in three forms: an oral tablet, an oral suspension (liquid), and an injection that’s only given by a doctor. Sildenafil oral tablet is . Viagra (sildenafil) is an oral drug that is used for treating impotence (or erectile disfunction, ED, (Viagra) is a blue, film-coated, rounded, diamond-shaped tablet that comes in 25, 50, and mg tablets for treating impotence. How should I keep sildenafil stored? Tablets should be kept at room temperature between 15 C and 30 C .