Antidiarrheal agents for the management of treatment-related diarrhea in cancer patients

The efficacy and use of antidiarrheal agents in patients who diarrhea associated with cancer treatments are reviewed. Diarrhea is common in cancer patients and may interfere with cancer treatment. Diarrhea may be induced by chemotherapy, radiation therapy, surgery, graft-versus-hot disease (GVHD) or infection after bone marrow transplantation, and other causes. The general goal of antidiarrheal therapy is to reduce fluid loss in the stool by inhibiting intestinal secretion, promoting absorption, and decreasing intestinal motility. Antidiarrheal agents may be classified as intestinal transit inhibitors, intraluminal agents, proabsorptive agents, and antisecretory drugs. Opiate agonists are the most commonly used intestinal transit inhibitors; they can be effective in treating cancer treatment-related diarrheas but must be used cautiously. Intraluminal agents include clays, activated charcoal, and cholestyramine; these adsorbents and other binding resins can interfere with the absorption of orally administered antidiarrheals and other drugs and are unlikely candidates for use in most cases of diarrhea in cancer patients. Clonidine, a proabsorptive agent, should be used only in patients with secretory diarrhea refractory to opiate agonist treatment. Octreotide is an antisecretory drug that has shown considerable efficacy in clinical trails as a treatment for diarrhea caused by chemotherapy of GVHD; its use for radiation therapy-induced diarrhea, although not studied clinically, is nevertheless an option. In general, opiate agonists and octreotide appears to offer the most efficacy and flexibility. Opiate agonists and octreotide are effective agents for cancer treatment-related diarrhea.