I use Imodium as instructed by my gastro doctors - both of them I have seen. They told me to be cautious - never use more than prescribed on bottle and adjust to your system. I can take 1/2 and works fine most of the time. Even if I don't have diarrhea - helps with spasms, etc. Also, eating light and only what you know will not bother you.
Have a fun trip!!