The body takes longer to absorb it after a high-fat meal or alcohol. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Avanafil Stendra. If you exceed the recommended dosage, you might experience side effects or even an overdose. You can take it in a small dose daily or in a larger dose as needed.Oral medicines for ED usually work well and cause few side effects. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. Levitra is a medication used to treat erectile dysfunction in men. Our page provides detailed information on how Levitra works, its dosage, potential side effects, and precautions to take before using it. Whether you’re a first-time user or looking to switch to a new medication, our comprehensive guide can help you make an informed decision about using Levitra.  · 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 working too quickly. The penis is one of the areas where this enzyme works.