Effect of the phosphodiesterase type 5 inhibitor tadalafil on pulmonary hemodynamics in a canine model of pulmonary hypertension

摘要

Phosphodiesterase type 5 (PDE5) inhibitors are used for treating pulmonary arterial hypertension (PAH) in dogs. The long-acting PDE5 inhibitor tadalafil was recently approved for treatment of PAH in humans. Basic information related to the pharmacological and hemodynamic effects of tadalafil in dogs is scarce. In this study, the hemodynamic effects of tadalafil after intravenous (IV) and oral administration were investigated in a healthy vasoconstrictive PAH Beagle dog model induced by U46619, a thromboxane A(2) mimetic. Six healthy Beagle dogs were anesthetized with propofol and maintained with isoflurane. Fluid-filled catheters were placed into the descending aorta to measure systemic arterial pressure and in the pulmonary artery to measure pulmonary arterial pressure (PAP). 046619 was infused via the cephalic vein to induce PAH.