Studies have shown that formulary restrictions can be an effective means of controlling drug use, but concerns have arisen about clinical consequences, say researchers from Canada. One retrospective study, for example, suggested that restricting fluoroquinolones drug could lead to more hospitalizations for pyelonephritis and bronchitis. To confirm these findings, the researchers conducted a study using a database of 1.4 million older adults.
Immediately after the fluoroquinolone policy was introduced, prescription rates dropped to approximately 70% of the expected rates. Within one year, prescriptions of sulfonamide and urinary anti-infective agents were about 30% higher than expected. No significant increases were observed in generic macrolide or cephalosporin tablets use—an important observation, the researchers say, given that some had predicted a reciprocal increase in other classes of antimicrobials, especially for respiratory tract infections.
Overall, the rates of infection-related hospital admissions among patients using antibiotics did not change significantly, but the rate of hospital admissions for gastrointestinal infections was 32% lower than expected in the year after the policy change. The number of admissions for urinary tract infections was slightly higher (8%).
(Source: Am J Med 2007;120:893-900.)