Alosetron
"I have been taking Lotronex for nearly 10 years (before and after it was pulled from the market). I'm male in my early 50s and have had irritable bowel syndrome since early childhood. Lotronex has been remarkably effective at controlling diarrhea and reasonably effective at moderating pain and intestinal cramps (though I still take dicyclomine) to help with that.  I was taking 2mg Lotronex a day with virtually no side effects. Occasional constipation but stopping the medicines for a day would fix that problem.  I recently cut back to 1/2 mg a day because my new insurance will not pay for it because I'm not female (maybe I should have a sex change operation).  If you suffer from IBS-D and have not considered Lotronex you should definitely talk to your doctor about it."