NAPLEX Practice Question # 91

NAPLEX Examination.

Practice Question # 91.



The type 5A phosphodiesterase (PDE5A) is the target for sildenafi l (Revatio®) and tadalafi l (Adcirca®), which are also used to treat PAH. Guanylyl cyclase in vascular smooth muscle cells of the pulmonary circulation convert guanosine triphosphate to cyclic guanosine monophosphate that reduces intracellular calcium and leads to vasodilation (details discussed later in this chapter). The PDE5A inhibitors prevent the metabolism of cGMP; maintain its intracellular concentrations; and, thus, preserve its vasodilatory actions on smooth muscle. Sildenafi l and tadalafi l are also used to treat erectile dysfunction, so priapism is a potential adverse eff ect and other eff ects may include headache, nausea, mild hypotension, visual disturbances, and fl ushing of the skin.






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