Fildena 100 contains Sildenafil Citrate and is part of the Phosphodiesterase Type 5 Inhibitors. Fildena 100 medication acts by blocking the PDE5 protein, which in turn improves the Cyclic Guanosine Monophosphate(cGMP) levels. When the cGMP level is higher, it causes the penile region muscles to relax and blood vessels expansion to increase. This allows blood to flow freely throughout the penis and results in a firmer erection. It is important to have a strong erection. Fildena should not be taken more than 100mg per day unless prescribed by your doctor.