Concern about the potential pernicious effect of direct-to-consumer (DTC) drug advertising on physicians' prescribing patterns was heightened with the 2004 withdrawal of Vioxx, a heavily advertised treatment for osteoarthritis. We examine how DTC advertising has affected physicians' prescribing behavior for osteoarthritis patients. We analyzed monthly clinical information on fifty-seven primary care practices during 2000-2002, matched to monthly brand-specific advertising data for local and network television. DTC advertising of Vioxx and Celebrex increased the number of osteoarthritis patients seen by physicians each month. DTC advertising of Vioxx increased the likelihood that patients received both Vioxx and Celebrex, but Celebrex ads only affected Vioxx use.
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