Sildenafil citrate is a chemical compound that is found in both Fildena 120mg and other drugs in the same class. There are 120 mg of sildenafil citrate in this pill. The drug’s main effect is to stop the enzyme phosphodiesterase from working in the penis-supplying artery wall. When the amount of the enzyme PDE5 goes up, the cycle monophosphate goes down. The arteries that feed the penis get bigger because of this cycling monophosphate. When the cGMP level rises, the blood flow rises, which helps in stronger activation cases.