Imodium usually works for me a longer time, I would try it before bed and it should last through out the morning...if you want to prevent it. Each person is different and depending on the motility of your gut, definitely read the instructions and tailor it to the activities you have planned. For me I just started taking fiber...I still have diarrhea, and it can last all morning but some of the anti diarrhea agents last too long for me. I have found taking an anti spasmodic helpful if I have plans, but it comes with the side effect of a very dry mouth. Do you know your cause of diarrhea??