I use Imodium as my last resort. Since I'm IBS-C, if I use Imodium, I can expect to be bloated, gassy, and completely stopped BM wise for a couple days after.
However, sometimes there are moments were you just have to be there. For example, I was at the airport about to get on the shuttle bus that would take me to my cruise ship in 30 minutes.. and I started having diarrea and cramps. Since I knew I had to be on that bus in 30 minutes, I resorted to Imodium and it stopped the diarrea within 10 minutes. It took me 4-5 days before I even started having the urge for a BM, but I didn't really have a choice.