Before taking antidiarrheals, patients should inform their physician if they have a fever or mucus or blood in their stools. In addition, patients with a history of liver or kidney disease may not be good candidates for antidiarrheals.

Patients who have any of the following conditions may not be good candidates for treatment with the antidiarrheal medicine bismuth subsalicylate:

• Stomach ulcer. Ulcer or open sore in the lining of the stomach.
  
  
• Dysentery. Infection of the colon characterized by severe, bloody diarrhea.
  
  
• Gout. Painful form of arthritis that usually affects single joints, most often in the feet.
  
  
• Hemophilia. Disorder that causes clotting problems or other bleeding problems.

Patients with colitis or dysentery may not be good candidates for treatment with loperamide.