There aren't "trace amounts of opiates" in Imodium. The drug Loperamide is an opiate, and a pretty strong one too, but it does not cross the blood brain barrier very well, so it mostly binds to opiate receptors in the gut rather than those in the brain.

It takes only about four to six pills to ward off withdraw symptoms, and the constipation it causes is pretty much the same as typical opiates which addicts take every day, so that's not as big an issue as people make it out to be. Now there are other drugs you can take with loperamide to increase permeability of the blood brain barrier, or to inhibit the enzyme that pushes out back the little bit that normally gets through. Mixing those drugs with Loperamide can get you high - dangerous game though. Better off taking just enough to settle the gut and stop the kicking and then smoke some weed to get high.