Key takeaways
Loperamide (Imodium A-D) and alosetron (Lotronex) are both antidiarrheal medications, but they have different uses and availability. Loperamide is available over-the-counter and by prescription, and it treats general diarrhea, including travelers' diarrhea and diarrhea from chronic gut conditions. It works by slowing down bowel movements and reducing fluid in the intestines. Alosetron, on the other hand, is prescription-only and specifically used for severe diarrhea-predominant irritable bowel syndrome (IBS-D) in women. It works by blocking serotonin receptors in the gut to reduce abdominal pain and discomfort. Loperamide can be used by both adults and children (with specific dosing), while alosetron is not indicated for men and has more restrictions due to serious gastrointestinal risks. Additionally, loperamide acts quickly, whereas alosetron may take a few weeks to show full effects. Both medications have potential side effects, but alosetron carries a higher risk of severe complications like ischemic colitis.
