Phosphodiesterase type 5 inhibitors such as sildenafil and tadalafil ameliorate pulmonary arterial hypertension by increasing cGMP levels in pulmonary artery smooth-muscle cells.
A 46-year-old-woman presents with exertional dyspnea and syncope and receives a diagnosis of idiopathic pulmonary arterial hypertension. Treatment with sildenafil is recommended. Sildenafil and tadalafil are phosphodiesterase type 5 inhibitors that ameliorate pulmonary arterial hypertension by increasing levels of cyclic guanosine monophosphate in the smooth-muscle cells of the pulmonary artery.
Archer et al. (Wed,) studied this question.