Probiotics: 'Living Drugs'

Gary W. Elmer


Am J Health Syst Pharm. 2001;58(12) 

In This Article

Safety of Probiotics

The available probiotic microorganisms are considered nonpathogenic, but even benign microorganisms can be infective when a patient is severely debilitated or immunosuppressed. For example, lactobacilli are present in dairy products and are part of the normal flora, yet cases of lactobacillemia have been reported in patients with severe underlying conditions.[96,97] To date, there have been only isolated reports linking probiotics with adverse effects. A case of a liver abscess was associated with L. rhamnosus in a 74-year-old diabetic,[98] and cases of fungemia involving S. boulardii have been reported. [99,100,101] All patients responded to standard antimicrobial therapy. S. boulardii has been used, without complications, to treat chronic diarrhea in AIDS patients,[61,64] and L. reuteri has been safely given to HIV-infected patients.[102] There is a theoretical risk of transfer of antimicrobial resistance from the probiotic to other microorganisms with which it might come in contact, but this has not yet been observed during therapy.

On the basis of published findings, the risks of therapy with available probiotics seem small. However, published studies systematically evaluating the safety of probiotics are lacking. The use of probiotics must be carefully considered when these "living drugs" are used therapeutically in patients at high risk for opportunistic infections or when the gastrointestinal tract is badly damaged.


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