Antibiotic-Associated Diarrhea

Antibiotic-Associated  Diarrhea

Pathogenesis. Any antibiotic can lead to diarrhea with C. difficile, although clindamycin may have one of the highest frequencies of association.

Clinical Presentation and Diagnosis. If a patient develops diarrhea several days to weeks after using antibiotics, he or she should be evaluated with a stool toxin test for C. difficile. The diar- rhea may even develop after the use of the antibiotic has stopped.

Treatment. Metronidazole is the drug of choice. If the symptoms resolve and the patient has a recurrence, then he or she should be retreated with metronidazole. Oral vancomycin is only to be used in the very occasional case that does not resolve with metronidazole and there is no response to therapy. Intravenous metronidazole can be used to treat C. difficile colitis if the patient is unable to use oral medications. This is not true of vancomycin. Intravenous vancomycin will have no effect in the bowel because it does not pass the bowel wall. Oral vancomycin will have no systemic effect because it also does not pass the bowel wall. Fidaxomicin is not more effective than vancomycin or metronidazole for the first episode. Fidaxomicin seems to decrease the number of episodes of recurrent C. difficile colitis.

Note

•         TMP/SMX for Isopora

•         Doxycycline for Vibrio vulnificus

•         Rifaximin for travelers’ diarrhea

Note

Prophylactic antibiotics for traveler’s diarrhea is never a correct approach.

Clinical Pearl

Don’t confuse diarrhea caused by antibiotics which increase GI motility (e.g., erythromycin) with C. difficile-associated diarrhea.