The Impact of Public Information and FDA Issued Warnings on the Use of Antidepressants in Primary Care

This article explores the relative impact of marketing information and FDA regulatory actions in the market for prescription drugs. We examine how direct to consumer advertising (DTCA) and FDA issued precautions and boxed warnings together affect young patients' visits with physicians and active prescriptions for anti-depressants. We aggregate 10 years (1998-2006) of detailed electronic medical record data on 9344 patients (254,810 patient-months) between the ages of 5 and 25, to the physician practice level. We then estimate monthly visit rates and active prescription rates using random and fixed effects models on the resulting unbalanced panel of practice months (N=1702). Results indicate that DTCA, FDA-mandated changes to drug labels and media coverage affects the flow of patients into the physician practice and the rate of prescribing antidepressants. The FDA-issued boxed warning had a statistically significant effect only on prescribing rates for the under-18 year old population and only for the drugs explicitly mentioned in the boxed warning announcement. Since the policy goal of the boxed warning was to impact physician choices for all antidepressants our findings suggest there is room for improvement in the way boxed warnings – or indeed any FDA warning information – are released.