Pharmacokinetics is the study of how the body changes the drug and what happens to it inside the human body. If you notice – the half life of Cialis is much higher than Viagra or Levitra- this translates to higher active window, remember it works for upto 36 hours. Again the increased half life means slower onset of action meaning it takes longer than Viagra and Levitra to work but stays in the body for longer.
The above statistic is interesting. What it tells us is that the effect of Cialis is unaffected with fatty food whereas Viagra and Levitra show decreased action time and concentration levels when a man eats fatty food.