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2002 > January
Tufts physician testifies at House hearing on bioterrorism
Editor's Note: Dr. Sherwood Gorbach, professor of family medicine and community health at the School of Medicine, was one of nine experts invited to testify at the House Government Reform Committee's hearing on "Comprehensive Medical Care for Bioterrorism Exposure: Are We Making Evidence-Based Decisions?" November 14 in Washington, D.C. The following is an excerpt from his testimony.
I am here to discuss nutritional and intestinal side effects of antibiotics, specifically relating to the use of antibiotics in preventing anthrax infection.
It is estimated that 32,000 persons are currently taking prophylactic antibiotics for this indication. Many will take these drugs for 60 days for potential exposure to anthrax in the workplace. It is fair to say that this is an unprecedented situation in that so many previously healthy people are taking these drugs for a long period of time to prevent a disease. Side effects to these antibiotics have already been reported and are likely to become a significant issue as more drugs are prescribed.
Cipro is a drug that has been used for the past 14 years in treating more than 300 million persons as outpatients and in the hospital. It has one best safety records of any antibiotic that is used to treat serious infections. Nevertheless, the package insert reports definite side effects in 7.3 percent of users and possible side effects in another 9.2 percent, for a total incidence of 16.5 percent of adverse events possibly or probably related to taking Cipro. Extrapolating to the 32,000 taking the drug currently, this could mean that between 2,000 and 5,000 of these people could experience side effects—and this relates to the usual duration of treatment, seven to 14 days. The number could be considerably higher during a 60-day period of exposure.
The most common side effects of oral antibiotics relate to the intestinal tract. Nausea, abdominal cramps, diarrhea and loose bowels are the major complaints. In the case of Cipro, intestinal problems outnumber all other side effects by about 5 to 1.
The mechanism by which antibiotics produce these intestinal side effects is unknown. The most popular theory is that antibiotics upset the normal balance of healthy bacteria that inhabit our intestines. These bacteria make up what is known as the normal flora. Restoring these healthy bacteria and normalizing this balance within our intestines is the way to recovery from the ill effects of antibiotics.
One approach to re-establishing the normal balance of healthy bacteria is to use a class of products that are known as probiotics. Many of you will recognize these products as consisting of Lactobacilli, the bacteria that have been used since biblical times to make fermented dairy products such as yogurt, sour cream and cottage cheese. In the past 20 years, new types of Lactobacilli have been developed that not only produce good dairy products but can also enhance human health. This new class of Lactobacilli is known as a probiotic, which is defined as living bacteria, which, when consumed in sufficient quantities, can improve human health by balancing and normalizing the intestinal flora. These Lactobacilli are considered dietary supplements and are recognized by the Food and Drug Administration as "Generally Regarded As Safe," the so-called GRAS designation. In our country, various probiotics are sold in the supermarkets as dairy products and over-the-counter as capsules and tablets.
I have worked in the field of probiotics and Lactobacilli for more than 35 years. Along with a colleague, Dr. Barry Goldin, we developed a probiotic in 1983 that was isolated from the intestinal tract of a healthy human being. It is known as Lactobacillus GG, or LGG. This product was patented in 1985 and is sold in this country as a capsule by ConAgra under the name Culturelle. It is also available in 30 countries in Europe, South American and Asia in pill form or as a dairy product. LGG is one of a family of about 15 probiotics that are sold under various trade names in many countries. What distinguishes LGG from other probiotics is the record of scientific research that has confirmed its efficacy and safety in human ailments. More than 100 articles in medical and scientific journals have documented the beneficial properties of LGG. No other probiotic has such a strong record of scientific investigations to support its claims.
In relation to this hearing, I would like to recount the results of three published studies of preventing antibiotic side effects with LGG. In 1999, scientists at the University of Nebraska and Creighton University reported in the Journal of Pediatrics on a trial of LGG in preventing side effects in 188 children who received antibiotics for common respiratory infections. These children were divided randomly into two groups, those given LGG along with the antibiotics and those given placebo with antibiotics. This was a double-blind study in that neither the children nor their parents nor the study nurses knew which treatment was given. At the end of 10 days, 25 (26%) children who received placebo developed diarrhea, compared to only seven (8%) of the LGG-treated children, a three-fold difference in diarrhea rate. Using a similar research design, a group from Tampere, Finland, published in Pediatrics also in 1999 that LGG reduced diarrhea rates in 119 Finnish children from 16 percent in the placebo group to 5 percent in the LGG-treated group, again a three-fold decrease in intestinal side effects. A third, but smaller study, reported in 1990 that side effects of diarrhea and abdominal pain with erythromycin treatment were reduced by LGG.
While these reports are encouraging for using probiotics to prevent side effects related to antibiotics, important caveats need to be issued with regard to the current situation of antibiotic prescriptions for anthrax prevention. These probiotic studies relate to antibiotics that were used in children, generally ampicillin, amoxicillin and erythromycin—not Cipro, a drug that is not prescribed for children. We have no information about using probiotics to prevent intestinal side effects due to Cipro. If the mechanism of disturbing the intestinal flora holds for all antibiotics, then probiotics, which restore healthy bacteria to the intestine, might work as well with Cipro, but that remains to be proven.
Another issue relates to the long course of Cipro usage, now recommended for 60 days. In the studies reported above, the antibiotics were used in children for an average of seven to 10 days. Whether the salutary effects of LGG would persist for a treatment course of 60 days remains to be proven. The final point is that these reported benefits relate to LGG, not to probiotics in general. Each type of probiotic is somewhat different from the others, and it must be shown by clinical trials that a specific brand has the same effects as those reported for LGG.
In summary, a probiotic such as LGG could provide some protection from the expected intestinal side effects associated with antibiotic prophylaxis for anthrax exposure. Based on published research, LGG could reduce these side effects by two-thirds. Probiotics offer a safe, reasonably inexpensive means to achieve a lower rate of such adverse events with antibiotic usage. I would urge, however, that additional research be conducted to establish whether a probiotic such as LGG can prevent antibiotic-associated intestinal side effects under the current circumstances, namely, a 60-day exposure of healthy persons to Cipro or similar drugs for prevention of anthrax exposure.