Answer In the United States, Cialis tadalafil is not slated to be available generically until September of Side effects Side effects of oral ED medicines are often mild. Avanafil Stendra. As with sildenafil, a high-fat meal or alcohol keep the body from absorbing it as quickly. This medicine works best when you take it on an empty stomach an hour before sex. Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. This medication is taken with or without food an hour before sex.Is generic Cialis or tadalafil as effective as Cialis? Cialis and tadalafil are equally effective. The FDA works to ensure that the generic versions of all brand-name . Is generic tadalafil any different from brand-name Cialis? No. Both tadalafil and Cialis are used to treat erectile dysfunction and benign prostatic . Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the .