Which of the following medications is considered an antidiarrheal?

The correct answer includes atropine and diphenoxylate (Lomotil) and loperamide (Imodium), which are both recognized as antidiarrheal medications. Antidiarrheals are specifically designed to treat diarrhea by slowing down gut movement, which allows for more water and electrolytes to be absorbed from the intestinal contents.

Lomotil combines an opioid (diphenoxylate) that decreases intestinal motility with atropine, which discourages misuse of the medication due to its unpleasant side effects when taken in higher doses. Loperamide works similarly by acting on the opioid receptors in the gut to slow peristalsis, thus reducing the number of bowel movements.

The other options listed comprise medications that serve different purposes. Bisacodyl (Dulcolax) and phenolphthalein (Ex-lax) are laxatives used to treat constipation rather than provide relief from diarrhea. Ferrous sulfate (Feosol) and calcium (Oscal) are dietary supplements that address nutrient deficiencies; they do not have an antidiarrheal effect. Finally, simethicone (Mylicon) is an anti-foaming agent that alleviates gas discomfort, while cimetidine (