Background: Pulmonary arterial hypertension (PAH) is a life threatening disease for which phosphodiesterase-5 inhibitor sildenafil is recently approved. We aimed to evaluate the efficacy and safety of tadalafil, a long acting congener of sildenafil, in treatment of PAH related to previous left to right shunt lesions.
Methods: In this blinded, cross over study, 11 patients with severe PAH related to congenital left to right shunt lesions (Eisenmenger syndrome) were randomly assigned to tadalafil (20 mg daily) or placebo for 4 weeks period, separated by a wash out period of at least 2 weeks.