Changes in Ciprofloxacin Utilization as Shown in a Large Pharmacy Claims Database: Effects of Proximity to Criminal Anthrax Exposure in October 2001

To identify, during the period of criminal anthrax exposures in October 2001, changes in utilization of ciprofloxacin and geographic patterns of any identified variations. Observational. United States. Individuals making prescription claims through a pharmacy benefits management company. Analysis of AdvancePCS pharmacy claims database. Percentage change in ciprofloxacin utilization for 2000 and 2001 and, by locale, for September and October 2001. Utilization of ciprofloxacin tablets was significantly lower in calendar year 2001 than in calendar year 2000 (median decline, 10.3%) for all months except October, when utilization of ciprofloxacin increased 9.8%. During the period of anthrax exposures (October 2001 versus September 2001), affected geographic areas, including New York (an increase of 62.5%), some other Mid-Atlantic states, and Florida (28.5%), had some of the highest percentage increases in the rate of ciprofloxacin utilization. Many Americans actively sought prophylaxis with ciprofloxacin during the course of the October 2001 anthrax attack and that utilization was higher in, but not limited to, locales with publicized cases of disease. Pharmacists, clinicians, and public health officials should note that such behavior may be expected in the event of a similar attack and should be familiar with current recommendations for the assessment and management of anthrax exposure.