They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Vardenafil usually works for 4 to 5 hours. You are encouraged to report adverse events related to Viatris products by calling U. 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. Generic versions of sildenafil, vardenafil and tadalafil are available.AdSave Time & Money with Online Prescription for Viagra, Cialis, Sildenafil and Tadafil. Free & Private Online Consultant with Real Doctors. Reliable E.D. Meds Shipped Shipping · Real Doctors · Discreet Packaging · Personalized Plan/5 (3, reviews)Site visitors: Over 10K in the past month. 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 . CHOOSE BRAND-NAME VIAGRA. The original little blue pill prescribed by doctors for over 20 years. Clinically proven to treat men with erectile dysfunction (ED) Ongoing .