Transitioning sildenafil to taladafil in PAH patients is safe

Background: Phosphodiesterase type-5 inhibitors (iPDE5) are one of the mainstays of Pulmonary Arterial Hypertension (PAH) treatment. Tadalafil is an alternative to sildenafil with the advantage of a less frequent dosing (once instead of 3-times daily). Aim: To examine the feasibility of transitioning PAH patients from sildenafil to taladafil. Methods: We studied twenty clinically stable PAH outpatients from a single pulmonary vascular disease centre receiving sildenafil that were transitioned to tadalafil. We compared validated biochemical and functional capacity measures from the last visit under sildenafil and last follow-up visit under taladafil. Results: Patients had a mean age of 48±18 years and 75% were female. No significant differences were found between the sildenafil and taladafil evaluations. The proportion of patients at NYHA functional class 1 or 2 (65% vs 60%; p=0.16) was similar, as was the Borg class (0.5±1.1 vs 0.5±1.0; p=1.00) and 6-minute walking distance (393±168 vs 368±199 m; p=0.31). Similarly, NT-pro-BNP was stable between evaluations (590 [247-1929] vs 496 [310-2393] ng/mL; p=0.32). The median time between evaluations was 6 [4-7] months. One patient reported lower limb myalgia and had to suspend tadalafil. No other significant adverse effects were reported. Conclusions: Transitioning from sildenafil to taladafil was feasible as it was not associated with clinical worsening of PAH patients. Tadalafil was well tolerated in all patients but one, who developed myalgia that prevented treatment continuation.