There appears to be a misunderstanding in the question, as Fildena CT 50 mg is a chewable tablet used for treating erectile dysfunction, not a programming model or software concept. It contains Sildenafil Citrate 50 mg and is used to improve blood flow to the penis by inhibiting the PDE5 enzyme.

On the other hand, the concurrent programming model is a concept in computer science, used to manage multiple processes running at the same time in software systems. It has no relationship with pharmaceutical products like Fildena CT.

If you're asking metaphorically or humorously about when Fildena CT 50 mg was "revolutionary" in the context of its effectiveness or innovation in drug delivery, then the chewable formulation itself could be considered a user-friendly advancement for ED treatment. Unlike traditional pills, chewable tablets are absorbed faster, potentially offering quicker onset of action for men who prefer not to swallow tablets.