Tadalafil is also used to treat pulmonary hypertension (PAH) under the trade name Adcirca. In this manner the usual starting dose is 40mg daily, and titrated up to 60mg (20 mg TID) depending on the response. You really have to be conscious of the nitrate interaction, or you’ll be found unconscious. Tadalafil - Pulmonary Hypertension AssociationAlright, so the effects of Cialis have really started to dwindle. Yesterday I took 20mg and I really couldn't even feel it. When I used to take 10 my penis would look large and in charge even when it was flaccid and I could get a rock hard erection in a moments notice. Has my body adapted to it? Whats the highest dosage anyone has tried? Any other input?