Answer In the United States, Cialis tadalafil is not slated to be available generically until September of Which Is More Effective? However, eating food, particularly high-fat food, can reduce the effectiveness of Viagra. Which Works Faster? Cialis vs.Summary. Cialis and Viagra are both pills for treating erectile dysfunction. They are PDE5 inhibitors that allow for increased blood flow to the penis, leading to more . Yes. The active ingredient for Cialis, tadalafil, is also the active ingredient for Adcirca, a brand-name drug used to treat pulmonary arterial hypertension, or high blood . Cialis is available as the generic drug tadalafil. A generic drug is an exact copy of the active drug in a brand-name medication and is considered just as safe and .