Carbapenem Appropriateness in a Rural Facility

Inappropriate carbapenem prescribing leads to increased resistance, secondary infections, serious side effects, and wasted resources. A history of penicillin allergy has been identified as a potential trigger for inappropriate carbapenem prescribing. The PEN-FAST score is a validated tool that provides a high negative predictive value for allergic reaction with low scores. The objectives of this study were to determine the proportion of imipenem/cilastatin and meropenem prescriptions deemed appropriate according to published criteria and to evaluate the proportion of penicillin allergies with a low PEN-FAST score. A convenience sample of 100 carbapenem prescriptions (imipenem/cilastatin [n = 50] and meropenem [n = 50]) was evaluated with a retrospective chart review. Objective published criteria were used to assign a score of appropriate, suboptimal, or inappropriate. In patients with a history of penicillin allergy, a PEN-FAST score was retrospectively applied. Indications for use and risk factors for resistant infections were also recorded. Analysis was largely descriptive statistics, with a χ2 used to compare drug cohorts in R Studio. Prescribing was considered appropriate (25%), suboptimal (20%), and inappropriate (55%) in the combined cohort. Inappropriate prescribing was more common with imipenem/cilastatin (66% vs. 44%, P = 0.03). In 28 patients with a historical penicillin allergy, the PEN-FAST score was 0 (low risk for reaction) in the majority of cases (93%). Inappropriate carbapenem prescribing is common at the study facility and may benefit from directed antimicrobial stewardship measures. Implementing the PEN-FAST scoring method may be beneficial in a multifaceted intervention.