The difference between brand and generic drugs comes in the inactive ingredients, or ‘fillers’ as they are sometimes called. Which Is More Effective? In addition, consider the information below. Answered By: Dr. Cialis stays in your system for up to 36 hours, and you can take it daily.If a pharmacy, or someone in the United States is offering generic Cialis (tadalafil), be very wary as there is a good chance it is fraudulent. If you are getting it . Drug Facts Common Brands Cialis Drug Class PDE-5 inhibitor Controlled Substance Classification Not a controlled medication Generic Status No lower-cost . 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 .