Frequency of Simvastatin Prescriptions With Potentially Interacting Medications in a Veterans Affairs Health Care System

OBJECTIVES: The primary objective of this review is to quantify the proportion of patients on simvastatin, an HMG-CoA reductase inhibitor (commonly known as statin), who received concurrent prescriptions for potentially interacting chronic use medications. The secondary objective is to determine the frequency with which simvastatin was prescribed above its recommended dose when administered concomitantly with known interacting medications. METHODS: A retrospective review of computerized outpatient pharmacy records from a Veterans Affairs Medical Center and its associated ambulatory clinics was performed in September 2002. RESULTS: A total of 12,240 patients had an active prescription for a statin. The majority of patients (95%, N = 11,677) were on simvastatin therapy, and 1,231 (10.5%) of the patients on simvastatin were prescribed at least 1 potentially interacting medication. More than one half (57.8%) of simvastatin doses were above the maximum recommended daily dose when prescribed with potentially interacting medications. CONCLUSIONS: This analysis supports the need for vigilance in reviewing the dose of simvastatin in patients receiving interacting medications. Health care systems should consider strategies to educate health care professionals on prevention of drug interactions and adverse patient outcomes.