Other uses for this medicine This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information. 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. Brand names Why is this medication prescribed? Tell your doctor if any of these symptoms are severe or do not go away: headache. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.Sildenafil is a generic drug, which is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. . Brand names for sildenafil include Viagra, Revatio, and Liqrev. The cost for sildenafil oral tablet mg is around $10 for a supply of 2 tablets, depending on the pharmacy you . your treatment plan. your insurance coverage. the pharmacy you use. whether Viagra has a savings program (see the “Financial and insurance assistance” section below) To find .