U.S. physician knowledge of the FDA-approved indications and evidence base for commonly prescribed drugs: results of a national survey.
OBJECTIVE
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 rho 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.
Chen
Donna T
DT
Department of Public Health Sciences, University of Virginia, Charlottesville, VA, USA.
Wynia
Matthew K
MK
Moloney
Rachael M
RM
Alexander
G Caleb
GC
D000588:Amines / Q000008:administration & dosage / Q000627:therapeutic use; D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000627:therapeutic use; D003625:Data Collection; D003928:Diabetic Nephropathies / Q000188:drug therapy; D017277:Drug Approval; D004348:Drug Labeling; D011307:Drug Prescriptions / Q000706:statistics & numerical data*; D017723:Drug Utilization Review; D019317:Evidence-Based Medicine; D000077206:Gabapentin; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D056687:Off-Label Use; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D014481:United States; D014486:United States Food and Drug Administration; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000627:therapeutic use
D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin