Critical Care Pharmacy Specialist Veterans Health Care System of the Ozarks Fayetteville
Introduction: 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. An objective needs assessment identified carbapenem overprescribing and a need for quality improvement at the study facility. 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.
Methods: A convenience sample of 100 carbapenem prescriptions (imipenem/cilastatin n=50 and meropenem n=50) was evaluated with a retrospective chart review. Included adult inpatients who received at least one dose of empiric scheduled therapy were enrolled in reverse sequential order. Patients transferred from outside hospitals on carbapenem therapy and one-time, non-scheduled orders were excluded. 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 chi-square used to compare drug cohorts in R Studio.
Results: 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%).
Conclusions: 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 multi-faceted intervention.
