What is the treatment for diarrhea caused by antibiotics?

Treatment of Antibiotic-Associated Diarrhea

For most cases of antibiotic-associated diarrhea, stop the offending antibiotic and provide supportive care with hydration and dietary modifications; reserve antimicrobial treatment specifically for confirmed Clostridium difficile infection. 1

Initial Assessment and Risk Stratification

Evaluate severity based on stool frequency, fever, presence of blood, abdominal pain, and signs of dehydration (orthostatic symptoms, weakness). 1 Classify as either:

• Uncomplicated (mild): Loose stools without fever, blood, or severe abdominal pain 1
• Complicated (moderate-severe): Fever, bloody diarrhea, abdominal pain, leukocytosis, or signs of dehydration 1

Suspect C. difficile infection if any of the following are present: fever, abdominal pain, leukocytosis, bloody diarrhea, or symptoms persisting beyond 48 hours after stopping the antibiotic. 1

Diagnostic Testing

• Order stool testing for C. difficile toxin (tissue culture cytotoxicity assay is gold standard; ELISA is acceptable for rapid results) if symptoms are moderate-severe or persistent. 1, 2
• Consider bacterial stool culture for Salmonella, Shigella, and Campylobacter if symptoms are severe or bloody. 1
• Testing is not routinely needed for mild, self-limited diarrhea that resolves after stopping the antibiotic. 3

Management Strategy

For Non-C. difficile Antibiotic-Associated Diarrhea

Discontinue the offending antibiotic immediately or switch to a narrow-spectrum alternative if continued antimicrobial therapy is essential. 1, 4

Provide supportive care:

• Maintain fluid intake with 8-10 glasses of clear liquids daily (water, broth, electrolyte solutions). 1
• Eliminate lactose-containing products, alcohol, and high-osmolar supplements. 1
• Recommend bland diet (bananas, rice, applesauce, toast, plain pasta). 1

For symptomatic relief in adults with non-bloody diarrhea:

• Loperamide: Initial dose 4 mg orally, then 2 mg every 2-4 hours (maximum 16 mg/day). 1, 5
• Bismuth subsalicylate may be considered for mild symptoms. 1
• Do not use antimotility agents if bloody diarrhea, fever, or suspected C. difficile infection. 5

For Confirmed C. difficile Infection

Oral vancomycin 125 mg four times daily for 10 days is the treatment of choice. 1, 6 This regimen achieves clinical success rates of approximately 80% in clinical trials. 6

For severe C. difficile colitis (defined as WBC ≥15,000/mm³, serum creatinine >1.5 times baseline, or signs of severe colitis on imaging):

• Continue vancomycin 125 mg orally four times daily. 1, 6
• Consider higher doses (up to 500 mg four times daily) in fulminant cases, though standard dosing is typically adequate. 6

Alternative for mild-moderate C. difficile infection: Oral metronidazole may be considered, though vancomycin is preferred based on current evidence. 2, 4

For recurrent C. difficile infection (occurs in 18-25% of successfully treated patients):

• Use vancomycin with a tapered and pulsed regimen. 1, 6
• Consider fecal microbiota transplantation for multiple recurrences. 1

Refractory Cases

If diarrhea persists despite loperamide after 48 hours:

• Reassess for C. difficile or other infectious causes. 1
• Consider octreotide 500 mcg subcutaneously three times daily for severe refractory non-infectious diarrhea. 1
• Hospitalize patients with severe symptoms persisting >48 hours despite treatment. 1

Special Populations

Immunocompromised patients require more aggressive evaluation with lower threshold for stool testing and antimicrobial therapy. 5, 1

Avoid probiotics in immunocompromised patients due to risk of fungemia and bacteremia. 1

Common Pitfalls

• Do not empirically treat all antibiotic-associated diarrhea with antibiotics—this worsens antibiotic resistance and may prolong symptoms. 7
• Do not use loperamide or other antimotility agents in bloody diarrhea or suspected C. difficile infection—this can precipitate toxic megacolon. 5
• Do not use oral vancomycin for systemic infections—it is not absorbed and only effective for intestinal C. difficile and S. aureus enterocolitis. 6
• Do not assume resolution means cure—recurrence rates are 18-25% within 4 weeks after successful treatment. 6

Follow-Up

Reassess patients who do not respond within 24-48 hours of initial management. 1 For symptoms persisting ≥14 days, consider alternative diagnoses including inflammatory bowel disease, post-infectious irritable bowel syndrome, or other chronic conditions. 5, 1