Go back to your doctor and ask for Welchol. It's what I'm on (and my MIL and a number of people on this board). It is a cholesterol medicine, but it has the interesting side effect of binding up bile in the inestinal tract.
Guess what all that yellow diarrhea consists of???
Anti-spasmodics have never done anything for me either, because the D is not caused by spasms pushing your food through too fast. It's caused by the bile not being timed to your food deposits anymore, so it's floating around in your intestinal tract with nothing to break down--so it comes out.
Some people get okay results with fiber, but for me it makes me worse! Makes the D worse AND makes my C worse if I have that for some reason. No fake fiber for me; only what comes in plants.
You can also try Caltrate 600 w/ Vitamin D. That's OTC. Some people on here get enough relief with it, that's all they need, but I actually take it and the Welchol both. I recommend that you try it and see if it helps enough. At the very least, calcium is good for your intestines, which is really good when you have excess bile, because that's pure acid floating around in there. Calcium was the cure to some gut pains I was having several years back.
Oh, and while I don't have to be as strict with my diet as many on here, I do have a list of no-no foods. Namely caffeine, fruit juices, raw apples and fried fast food. Milk seems to be getting there as well, although ice cream and yogurt are still okay (figure that one out).