Treatment for Small Intestinal Bacterial Overgrowth (SIBO)

Why Is My Naturopathic Doctor Prescribing Antibiotics?

Dr. Miranda Wiley, ND

By definition, SIBO is “bacterial overgrowth” (of the small intestine). Therefore, part of the treatment for SIBO involves a concerted effort to destroy the bacteria that are wreaking havoc in the small intestine. There are two options for killing the bacterial overgrowth: two weeks of a specific antibiotic called Rifaximin, or 4-6 weeks of a variety of herbs with antimicrobial properties. Both methods are effective but Rifaximin is faster and well studied.

While antibiotic abuse is a very real problem contributing to the production of superbugs it is important to understand how various antibiotics work, and where problems from improper or excessive use can arise. Rifaximin, when used appropriately, is highly effective and very safe for use in treating SIBO.

The Spectrum of an antibiotic refers to how targeted it is in killing the offending bacteria. Broad-spectrum antibiotics destroy a wide range of bacteria which is useful if the particular bacteria causing the problem is unclear, or there are multiple bacteria at play, however, these antibiotics also destroy a wide range of helpful probiotic bacteria as collateral damage. An antibiotic with too narrow a spectrum fails to be effective and can lead to persistent infection. Rifaximin falls midway on the spectrum, and targets the bacteria involved in SIBO with minimal impact on levels of friendly flora.

Efficacy of an antibiotic is also of prime importance. Of the handful of antibiotics that have been tested for use in IBS and/or SIBO, Rifaximin scores the highest with an efficacy of 70% [1]!

Of course, antibiotic Resistance is a major consideration for prescribers nowadays. There are two types of resistance: genomic and plasmid. Genomic resistance is limited to one strain of bacteria and resistance to an antibiotic only occurs with increased populations of that particular bacteria. Plasmid resistance is where the real problems come in. Plasmids are small blebs of genetic material that can move between different species of bacteria carrying genetic information through DNA, and are chiefly responsible for the development of superbugs. Rifaximin has not only shown minimal genomic resistance in the targeted bacteria, but it blocks plasmid generation! That means that Rifaximin can actually minimize the spread of antibiotic resistance.

The final two factors to consider for an antibiotic are Localization and Absorbability. Rifaximin is poorly absorbed (99.6% non-absorbed) [2] which means that it stays local to the gastrointestinal tract and doesn’t travel through the blood to affect other tissues in the body.

The use of an antibiotic might appear “Un-Naturopathic” but the role of Rifaximin in the treatment of SIBO still reflects one of the pillars of naturopathic medicine:   “Tolle Causum” or “Treat the root cause”. SIBO, and its sequelae, is a case in which bugs actually DO need the right drugs.

  1. DiStefano M, Aliment Pharm Ther. 2000
  2. Pimentel M. A New IBS Solution. Health Point Press, 2011.