Side effects Side effects of oral ED medicines are often mild. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help. The products discussed in this site may have different product labeling in different countries. If you are taking sildenafil for erectile dysfunction, you are unlikely to miss a dose since this medication is taken as needed, not on a regular dosing schedule.Best subscription service for Viagra and generic Viagra: Rex MD Viagra Although erectile dysfunction (ED) may be an upsetting diagnosis for some, many people find their . DRUG_DESCRPTION Compare DRUG_NAME prices and find coupons that could save you up to 80% instantly at pharmacies near you such as CVS, Walgreens, Walmart, and . The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide.