Since the global withdrawal of rofecoxib (Vioxx) in 2004, concerns about public health effects of direct-to-consumer advertising (DTCA) have grown. A systematic review of the research evidence on behavioral, health, and cost effects, published in 2005, found four studies meeting inclusion criteria, which showed that DTCA increases prescribing volume and patient demand, and shifts prescribing. From 2005 to 2010, nine studies met similar criteria. These largely confirm previous results. Additional effects include a shift to less appropriate prescribing, differential effects by patient price sensitivity and drug type, switches to less cost-effective treatment, and sustained sales despite a price increase. Claimed effects on adherence do not stand up to scrutiny and are based mainly on negative trials. There is no evidence of improved treatment quality or early provision of needed care. If policy is to be informed by evidence, the strength of research methods and ability to assess causality need to be considered.
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