Online kamagra 100mg treat impotence by targeting the physiological process that underlies the condition. Its active ingredient, sildenafil citrate, belongs to a class of medications known as phosphodiesterase type 5 (PDE5) inhibitors. This sildenafil citrate which relaxes smooth muscle cells and dilates blood vessels in the penis. As a result, blood flow to the penis increases, leading to an erection. Men should use this tablet with doctor advice.