U.S. physician knowledge of the FDA-approved indications and evidence base for commonly prescribed drugs: results of a national survey

Authors

  • Donna T. Chen MD, MPH,

    1. Department of Public Health Sciences, University of Virginia, Charlottesville, VA, USA
    2. Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA, USA
    3. Center for Biomedical Ethics and Humanities, University of Virginia, Charlottesville, VA, USA
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  • Matthew K. Wynia MD, MPH,

    1. Institute for Ethics, American Medical Association, Chicago, IL, USA
    2. Division of Infectious Diseases, Department of Medicine, University of Chicago Hospitals, Chicago, IL, USA
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  • Rachael M. Moloney BA,

    1. Section of General Internal Medicine, Department of Medicine, University of Chicago, Chicago, IL, USA
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  • G. Caleb Alexander MD, MS

    Corresponding author
    1. Section of General Internal Medicine, Department of Medicine, University of Chicago, Chicago, IL, USA
    2. Center for Health and the Social Sciences, University of Chicago, Chicago, IL, USA
    3. MacLean Center for Clinical Medical Ethics, University of Chicago, Chicago, IL, USA
    4. Department of Pharmacy Practice, University of Illinois at Chicago School of Pharmacy, Chicago, IL, USA
    • The University of Chicago, 5841 S. Maryland, MC 2007, Chicago, IL 60637, USA.
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  • The funding sources had no role in the design and conduct of the study, analysis or interpretation of the data; and preparation or final approval of the manuscript prior to publication. The views expressed are the authors' and the article should not be construed as representing policies of the American Medical Association or any of the other organizations with which the authors are affiliated.

Abstract

Purpose

The Food and Drug Administration (FDA) regulates prescription drug marketing, not prescribing. However, off-label use is common, often lacks supporting evidence, and may expose patients to unwarranted risk. We sought to determine physicians' knowledge of the FDA-approved indications of commonly prescribed drugs, and to assess whether physicians' belief that an indication is FDA-approved increases with level of evidence supporting such use.

Methods

We conducted a national random sample mail survey of 599 primary care physicians and 600 psychiatrists from November 2007 to August 2008. Physicians were presented with 14 drug-indication pairs (e.g., gabapentin [Neurontin®] for diabetic neuropathy) that varied in their FDA-approval status and levels of supporting evidence.

Results

The adjusted response rate was 47%, respondents were similar to non-respondents, and physicians commonly prescribed the drugs examined. The average respondent accurately identified the FDA-approval status of just over half of the drug-indication pairs queried (mean 55%; median 57%). Accuracy increased modestly (mean 60%, median 63%) when limited to drugs the respondent reported having prescribed during the previous 12 months. There was a strong association between physicians' belief that an indication was FDA-approved and greater evidence supporting efficacy for that use (Spearman's ρ 0.74, p < 0.001). However, 41% of physicians believed at least one drug-indication pair with uncertain or no supporting evidence (e.g., quetiapine [Seroquel®] for dementia with agitation) was FDA approved.

Conclusions

These findings highlight a pressing need for more effective methods to inform physicians about the evidence base, or lack thereof, for drugs they prescribe off label. Copyright © 2009 John Wiley & Sons, Ltd.

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