Antibiotic Rotation—Worthwhile or Not?

Source: Vecchione A. Hospital Pharmacist Report. 2001;6:31-32.

This special report reviews the concept of antibiotic rotation (also known as antibiotic cycling) and its role in reducing antibiotic resistance. The theory is that by restricting certain antibiotics for preset periods of time, the lessened exposure of microbes to those antibiotics should lessen the likelihood of resistance. Unfortunately, there is little support for this concept in the literature, and few hospitals have actually implemented antibiotic rotation programs.

Of the few studies performed, one of the largest that looked at antibiotic rotation was in the 1980s at the Veterans Administration Medical Center in Minnesota. Due to a problem they were having with gentamicin resistant organisms, they switched from gentamicin to another agent and the gentamicin resistance disappeared.

In order to shed some light on this concept, the Centers for Disease Control and Prevention (CDC) have initiated a 3-year study with 3 academic medical centers to evaluate the efficacy of a scheduled rotation of antibiotics in the intensive care unit. Participating in the study are the Washington University in St. Louis, Mo, the University of Virginia in Charlottesville, and the Rush-Presbyterian-St. Luke’s Medical Center in Chicago, Ill. In this study, certain antibiotics will be rotated every 3-4 months. One of the key elements of this study will be to insure that patient care is not compromised as a result of antibiotic cycling. As a result, patient outcomes will be closely monitored to insure that length of stay and mortality do not trend in a negative direction. Other elements being studied are the cost factors associated with the cyclic rotation of antibiotics.

Comment by Thomas G. Schleis, MS, RPh

Antibiotic cycling has always been an interesting concept, but no one has actually investigated it in enough detail to garner any wide-range support. That is why the CDC study is desperately needed to help answer many of these questions.

Antibiotic formularies at most hospitals are driven by acquisition cost, with the primary goal being to lower overall antibiotic expenditures. Often I have heard the term "antibiotic cycling" as an enticement to change formulary items to a less expensive antibiotic. Unfortunately, there is no really good science at this time to support this. In fact, should antibiotic rotation be recommended, I feel most hospital pharmacists would be concerned over the potential formulary cost increases. Cost increases would result when more expensive antibiotics are used in the "rotation," the loss of contract pricing because of lack of ability to commit to volume and market share, and the increased personnel time needed to implement rotations and provide educational support. Pharmacists will need to look "outside the box" to evaluate the overall cost of patient care—the cost of antibiotic rotation and the cost of antibiotic resistance—in order to decide whether implementation of such a program at their institution is warranted.

While most experts agree that antibiotic rotation may not be the complete solution to the resistance problem, they support studies such as the one being conducted by the CDC. It is hoped that this study will help determine if antibiotic rotation has merit and when and where it should be performed. (Editor’s Note: As this issue went to press, Puzniak and colleagues reported failure of scheduled antibiotic rotation to reduce the rate of acquisition of enteric vancomycin-resistant enterococci in an ICU [Puzniak LA, et al. Clin Infect Dis. 2001;33:151-157].)

Dr. Schleis is Director of Pharmacy Services, Infections Limited, Tacoma, Wash.