These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. Category ‘N’ N ‘N’ stands for neutral. Vardenafil usually works for 4 to 5 hours. You can take this medicine with or without food 30 minutes before sex, depending on the dose. When oral medications might not be safe Check with your health care team before you take any medicine for erectile dysfunction. You fill out an online questionnaire about your lifestyle and medical history and then connect with a telehealth provider who prescribes treatment.What’s What with All the ED Pills. Viagra. Still the leading brand in ED pills, Viagra should be taken at least an hour before sex and on an empty stomach. That . Ask your doctor Q&A Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription . Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes .