Imodium A-D is used to treat and control diarrhea, including traveler's diarrhea. Learn about side effects, interactions and indications. Learn about the side effects of Imodium (loperamide), from common to rare, for consumers and healthcare professionals. What do Imodium products treat? Imodium products are commonly used to treat diarrhea, including diarrhea that comes on suddenly (acute) and diarrhea that is long-term (chronic). The main active. Imodium is an over-the-counter drug used to treat diarrhea in adults and certain children. Learn about its dosage, including its forms, strengths, and more. Imodium is an OTC drug for acute diarrhea. It contains loperamide, which works by decreasing muscle contractions in your GI tract. Find out what IMODIUM® (loperamide) is, how it works to help treat diarrhea, gas, cramps, and bloating, as well as dosage information and side effects. Imodium, which is used to treat diarrhea, can cause side effects ranging from mild to severe. Read about the common side effects and when to see a doctor. Imodium (loperamide) is an over-the-counter drug used to treat diarrhea in adults and kids. Learn about dosage, uses, side effects, how it works, and more. Loperamide, sold under the brand name Imodium, among others, [1] is a medication of the opioid receptor agonist class used to decrease the frequency of diarrhea. [7][6] It is often used for this purpose in irritable bowel syndrome, inflammatory bowel disease, short bowel syndrome, [6] Crohn's disease, and ulcerative colitis. [7] Loperamide is taken by mouth. [6] Common side effects include. Loperamide may increase your risk for stomach or bowel problems. Check with your doctor right away if you have bloating, blood in the stools, constipation, fever, loss of appetite, nausea or vomiting, or stomach pain.