Filitra 40 mg is a medication used to treat erectile dysfunction (ED) in men. It contains vardenafil hydrochloride as its active ingredient. Vardenafil belongs to a class of medications called phosphodiesterase type 5 (PDE5) inhibitors, which work by increasing blood flow to the penis during sexual stimulation, thereby facilitating the achievement and maintenance of an erection. Filitra 40 mg works by inhibiting the action of the PDE5 enzyme, which is responsible for breaking down cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the penis. By inhibiting PDE5, vardenafil helps to maintain higher levels of cGMP, which promotes relaxation of the smooth muscles and dilation of the blood vessels in the penis. This increased blood flow to the penis enhances erectile function, allowing for satisfactory sexual activity.