Probiotics for Antibiotic-Associated Diarrhea: What, When, and How Long?

Probiotics have been formally defined as “live microorganisms that confer a health benefit on the host when administered in adequate amounts.” Although a range of applications has been explored for probiotics, their utility in antibiotic-associated diarrhea (AAD) is both biologically plausible and supported by abundant clinical evidence. However, the strength of evidence underlying the efficacy of specific strains and formulations for AAD varies widely. This review leverages recent meta-analyses and systematic reviews to clarify some outstanding issues on the utility of probiotics for AAD, including which strains have evidence for efficacy in AAD, what doses have been demonstrated to be effective, and the optimal duration of probiotic therapy, and provides practical guidance on how to select an appropriate product. Some trends emerged in this analysis of recent meta-analyses and systematic reviews, including: 1) Certain probiotics, such as Saccharomyces boulardii and some Lactobacilli-containing products, are consistently found to be effective for the management of AAD; 2) Dosing thresholds for efficacy exist that must be achieved through the administration of probiotics that reliably contain the labeled amounts of probiotic constituents; 3) Most effective probiotics are initiated at the same time as antibiotic therapy and continued for between 1 and 3 weeks after the cessation of therapy. These data suggest that attention must be paid to species, dose, and duration when selecting an appropriate product for patients initiating antibiotic therapy; further considerations may include the antibiotic used and the patient’s baseline risk for AAD.