Prescriber compliance with black box warnings in older adult patients.

BACKGROUND: Patients prescribed medications with US Food and Drug Administration-issued black box warnings (BBWs) warrant additional vigilance by prescribers because these drugs can cause serious adverse drug events. Seniors are at greater risk for adverse drug events due to increased medication burden and greater health vulnerability. OBJECTIVE: To improve our understanding of the prescribing and patient-monitoring practices of physicians prescribing medications with a BBW to patients age >or=65 years in an ambulatory care setting. METHODS: A retrospective cohort study of administrative pharmacy and medical claims identified 58,190 patients age >or=65 years in the Horizon Blue Cross Blue Shield of New Jersey beneficiary population with >or=1 claim for >or=1 of the 8 targeted medications between January 1, 2005, and December 31, 2005. Medications included carbamazepine, amiodarone, ketoconazole, loop diuretics, methotrexate, cyclosporine, metformin and combinations, and cilostazol. Patients were followed 12 months from the index prescription date to evaluate prescriber compliance with BBWs using operationalized definitions of compliance. RESULTS: Patients prescribed drugs with a drug-laboratory warning had lower rates of prescriber BBW compliance (0.7%-24.9%) than patients prescribed drugs with a drug-disease warning (84.7%-90.2%). CONCLUSIONS: Administrative claims analysis identified low rates of prescriber compliance with BBWs in managing patients age >or=65 years. Claims analysis may be a cost-effective strategy to monitor prescriber compliance with BBWs in older patients at higher risk.