Erectile dysfunction can be caused by a variety of factors , including age, cardiovascular problems, diabetes, and other conditions that affect nerve function or blood flow. More serious side effects may include a drop in blood pressure or an erection that lasts longer than four hours. We considered cost, medications available, and whether generic versions were offered to help reduce costs. Here are some key factors to consider when deciding: Pricing: Know how much your monthly supply will cost with shipping and tax. Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. Common side effects include headache, facial flushing, indigestion, and dizziness.How GoodRx Works. Compare prices. Drug prices vary by pharmacy. Use GoodRx to find current prices and discounts. Get free coupons. GoodRx coupons can help you pay less than the cash price for your prescription. Show to your pharmacist. It’s easy. Just bring your free coupon to the pharmacy when picking up your prescription. Get sildenafil for as low as $, which is 99% off the average retail price of $ for the most common version, by using a GoodRx coupon. Prices Medicare Drug Info Side Effects Images Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. 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 condition. This drug is more popular than comparable drugs. It is available in generic and brand versions.