Viagra (Viagra) is secondhand to care for cavernous disfunction (impotence; inability to aim or hold an erection) in work force. Sildenafil citrate is in a class of medications known as phosphodiesterase (PDE) inhibitors. Viagra treats erectile disfunction by increasing descent flow rate to the penis during intimate stimulus. Viagra treats PAH by reposeful the line vessels in the lungs to countenance line to course easily. If you select Viagra for short-condition handling of erecting problems...