The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Keep from freezing. It works for up to 36 hours. You may take this medicine with or without food. You can take this medicine with or without food 30 minutes before sex, depending on the dose. For oral dosage form tablets : Adults 65 years and older—5 milligrams mg as a single dose, no more than once per day, approximately 1 hour before sexual activity. Do not use more of it and do not use it more often than your doctor ordered.What is vardenafil? Vardenafil is used in adult men to treat erectile dysfunction (impotence). Vardenafil may also be used for purposes not listed in this .  · Descriptions. Vardenafil is used to treat men with erectile dysfunction (sexual impotence). It belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from . Brand name: Levitra Drug class: Impotence agents Medically reviewed by Last updated on Uses Before taking Warnings Dosage Side .