Studies have shown that drugs that inhibit CYP3A4 can increase tadalafil exposure. After 48 hours, the interaction was not detectable see Figure 1. Your doctor will probably tell you not to take tadalafil if you are taking nitrates. The only ophthalmological adverse event was a retinal artery occlusion in 1 patient in the placebo arm. Hemodialysis contributes negligibly to tadalafil elimination. N Engl J Med. The geometric mean sperm concentration was significantly lower in tadalafil-treated men at 9-month follow-up, Cialis, and its generic form Tadalafil, are popular medications to help with ED. But, as with most medications, there are ways to take them to help you get the most out of your treatment. For once daily Cialis, you want to take your dose every day at just about the same time each day for the best results. For as-needed Cialis, you will just. Find patient medical information for Cialis oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. Find patient medical information for Cialis oral on MD including its uses, side effects and safety, interactions, pictures, warnings and user ratings.