Medicines that block an enzyme called CYP3A4. The products discussed in this site may have different product labeling in different countries. The body takes longer to absorb it after a high-fat meal or alcohol. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Please expect up to 4 to 6 weeks for reimbursement. Common ones include: Flushing of the skin.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 . Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes . 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 .