For control of diarrhea from irinotecan, Imodium was ineffective for me. I was prescribed Loperimide, Lomax, Lomatil and the generic form diphenoxylate atropine. These were all effective in controlling the diarrhea. I took the anti-diarrheal proactively, i.e., well ahead of the chemo to have a therapeutic level already in the circulation by the time I was being administered the irinotecan. I continued taking for two days after administration.