They do two different things.The Hyomax sublingual is more for pain/cramps than for stopping up the diarrhea like Imodium does.So you may need some combinations. Sometimes relaxing the smooth muscles will prevent the diarrhea attack but it isn't likely to stop you up.Antispasmodics like the Hyomax are commonly prescribe to take 20-30 minutes before a meal and from what I've seen with a similar drug it usually does more good when you have it in place rather than trying to play catch up once the pain is bad.Antispasmodics are a little bit constipating, so that may be enough, but some people don't get enough diarrhea relief from them. On the other hand Immodium really doesn't do anything for the pain.