Fildena 100 is a class of PDE-5 inhibitor drugs with sildenafil citrate as a key component. The entire working of Fildena 100mg or Fildena 150mg tablets is based on sildenafil while sildenafil relies on s*xual stimulation to occur. Once s*xual arousal is observed, Sildenafil reacts to lower the overall body pressure. Its main function is to stimulate the production of cGMP enzymes, relieve stress formed with the smooth muscles of the pelvic organs, and improve blood flow in the penis. Second, it unblocks the veins that carry blood to the male genitalia. Therefore, more rigid and lasting erections are maintained for 4-5 hours. For a missed or missed dose, you can take it as soon as you remember. But this does not apply to cases where your next scheduled dose is close. Please do not take two pills together.