Pearlman says it can often take months to get an appointment with a healthcare provider who can prescribe the medications commonly used to treat ED. 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. Generic versions of sildenafil, vardenafil and tadalafil are available. A newer form of the medicine that dissolves on the tongue might work faster than the pill that you swallow. Avanafil Stendra. Oral medicines for ED usually work well and cause few side effects. If you have an erection that lasts more than 4 hours, get medical help right away.The Savings Offer and Program expire on 12/31/ For further information, call , visit , or write: Viatris Inc., P.O. Box , Mission, KS See risks & benefits. Learn more about what VIAGRA® (sildenafil citrate), a prescription . Viagra (sildenafil) and cost. Viagra (sildenafil) is a brand-name oral tablet prescribed for erectile dysfunction. The cost of the drug with and without insurance can depend on several factors. Compare prices and print coupons for Sildenafil (Generic Revatio and Viagra) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $