Skip costlier probiotics, buy generic

Dear Dr. Roach: I have started a long-term treatment taking a “cocktail” of four different antibiotics (Bactrim, Rifadin, Zithromax and Myambutol). I have been advised that I may suffer gastrointestinal side effects because this group of antibiotics will not only be killing bacteria related to my MAC (mycobacterium avium complex) infection, but will also be killing off the “good” bacteria in my digestive tract. I have experienced a couple of episodes of diarrhea. This was typically the late night or early morning after taking the antibiotics. I have been advised to take a probiotic supplement to help offset the negative side effects, but no detail as to brand or composition of the probiotic.

Do I require a “recognized” (and pricey) brand, or can I use a less costly “generic” brand?

A.R.

Answer: There are no probiotic preparations specifically approved by the Food and Drug Administration, and no good trials comparing different preparations of probiotics. Further, there is not good evidence that probiotics prevent the dangerous overgrowth of C. difficile (one very unhealthy bacterial species) during long-term antibiotic use.

However, there is some evidence from published trials that antibioticassociated diarrhea can be lessened with the use of probiotics. In one review of 17 controlled trials, the incidence of diarrhea among those taking antibiotics was reduced from 17% to 8%. There were no significant differences among the types of probiotics used. Many of the successful trials used combinations of different healthy bacteria.

Probiotics have generally been regarded as safe, and most trials have confirmed this, but there is not longterm data on using probiotics for an extended period of time, such as the one or two years that people with mycobacterium avium complex typically are treated with antibiotics.

Although I do not recommend probiotics for prevention of disease, or for diarrhea that is self-limited, I do understand why in your specific case you have been recommended them. Based on the limited data available, I cannot recommend one specific brand, and so I see no reason to choose the costlier brand.