Fildena 150 mg is a medication primarily prescribed for the treatment of erectile dysfunction (ED) in men. It contains sildenafil citrate, a potent and selective inhibitor of the phosphodiesterase type 5 (PDE5) enzyme. By inhibiting PDE5, Fildena 150 mg enhances the levels of cyclic guanosine monophosphate (cGMP) in the penile tissues. This results in relaxation of the smooth muscles in the blood vessels of the penis, allowing for increased blood flow during sexual arousal.