Acute diarrhea is the abnormal frequent passage of watery stools. It may be secondary to infection, toxins, food or drugs and may be accompanied by flatulence, abdominal cramping, fever and vomiting. Medications may cause diarrhea by either altering the normal gut flora (i.e. antibiotics) or by irritating the intestinal mucosa such that intestinal motility is altered.

Chronic diarrhea lasts greater than 2 weeks and may be due to an underlying medical condition or chronic laxative use. If untreated, diarrhea can lead to serious illness in the elderly. It may cause severe dehydration due to excess loss of water that is normally reabsorbed from the gut, electrolyte disturbances and cardiovascular collapse. Therefore, if the diarrhea does not respond to simple over-the-counter medications, a physician should be consulted.

Drugs that cause Diarrhea Antibiotics Magnesium antacids Laxatives Misoprostol Colchicine

Diarrhea is generally self-limiting and can be self-treated with over-the-counter (OTC) medications such as loperamide (Imodium™), Kaopectate and Peptol-Bismol. Loperamide inhibits the normal movements of the intestines and colon and relieves cramping and stool frequency. It does not prevent water loss. Kaopectate™ is an adsorbent and works by adsorbing toxins, bacteria and other noxious materials in the gut. Peptol-Bismol™ is also effective however its bismuth subsalicylate component makes it irritating to the gastrointestinal mucosa and can cause additive toxicity to those patients on aspirin therapy. Atropine-diphenoxylate or Lomotil™ is obtained by prescription and should be generally avoided in the elderly unless the above measures have failed. Atropine is an anticholinergic and inhibits normal movement of the intestines. It should not be used to treat diarrhea caused by the bacteria Clostridium difficile since its action may prolong the severity of the symptoms by causing retention of the bacterial toxin.