Same Ingredient But Not Working

I've been a t2-t3 para for almost 6 years now. When I was at Kessler they trained me on the Magic Bullet for my bowel regiment. I've been using the Magic Bullet since then. Recently, my insurance decided not to pay for it anymore so I have to find a cheaper alternative. I ordered the G&W Bisac-Evac from my local Walgreen for $22 for 72ct. It has the same active ingredient found in the Magic Bullet (Bisacodyl 10mg). The Magic Bullet usually works within 15 minutes and I usually don't have to do anything besides putting a circular pressure on my stomach and everything would come out. I've been using the G&W brand for the past two days and it doesn't seem to work. I sat there for over an hr and nothing happens. Even after digi stim it would take for ever to move my bowel. If it has the same active ingredient why doesn't it work? I am thinking of ordering the Major Biscolax, which has the Bisacodyl 10mg, on Amazon and try that out. Has anyone ever used that brand?

Same Ingredient But Not Working