Do not take a double dose to make up for a missed one. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking sildenafil. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Its effects might last longer if you have mild to moderate ED. Often, these are prescribed for chest pain called angina. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED.AdSay Goodbye to Performance Anxiety and Hello to Improved Sexual Stamina! Reviews and Comparisons Of The Best Male Enhancement Products. See Which Products Brands Voted By Men · Over 20 Years Online · Over Products Tested. Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or . Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult .