To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. Furthermore, the longer half-life is the basis for tadalafil’s daily therapeutic use in treating pulmonary arterial hypertension. Tadalafil was approved in in the United States for the treatment of pulmonary arterial hypertension [28] and is under regulatory review in other regions for this condition. Children—Use is not recommended. Read and follow these instructions carefully.agsaz / Shutterstock. Cialis is a brand-name version of tadalafil, a popular medication for treating erectile dysfunction (ED). Taking the medication helps you get the maximum effect while. Official answer. The maximum recommended dose of Cialis is 20mg daily. Increasing the dose to 40mg might just increase the intensity of side effects and may not actually deal with the erectile dysfunction problem. If 20mg dose is not working you might want to look for an another medicine. Sometimes even a medicine in the same class . tadalafil. erectile dysfunction (ED) benign prostatic hyperplasia, or BPH). Tadalafil (Cialis) is available both as brand-name and generic tablets. Common side effects of this medication include headache and indigestion. Tadalafil (Cialis) does interact with some medications.