I've done this, used Imodium as a preventive by taking it the evening or night before I had to travel or go to work. When I was at my worst, I knew I would always have a morning attack and my doctor said it was fine to use as a preventive. Sometimes waiting until morning would be too late and once I got started going I couldn't stop - even after taking the Imodium (it usually takes an hour or longer for it to kick in for me, I don't know about the others). HTH!