Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure. Common ones include: Flushing of the skin. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Oral medicine for ED also might not be safe or work well if you have: Very low blood pressure, called hypotension, or uncontrolled high blood pressure, called hypertension. Its effects might last longer if you have mild to moderate ED. Sexual activity may be a strain on your heart, especially if you have heart disease.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 visit. Valid at all major chains including Walgreens, CVS Pharmacy, Target, WalMart Pharmacy, Duane Reade and 65, pharmacies nationwide. No manufacturer. Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken as needed about 1 hour. Cialis is only available by prescription in the United States. Viagra: Additionally, a study from Trusted Source. found that combining L-arginine and sildenafil (Viagra) worked better for.