HealthDay News — The off-label use of a drug, especially when scientific evidence is lacking, puts patients at risk of serious adverse events, according to a study published in JAMA Internal Medicine.

Tewodros Eguale, MD, PhD, who led a research team at McGill University in Montreal, and colleagues analyzed electronic health record data for 46,021 adults patients who received 151,305 prescriptions from primary care clinics in Quebec from 2005 through 2009. More than one in 10 prescriptions in the study were for an off-label use. Of those, more than 80% were for off-label uses lacking strong scientific evidence.

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Patients prescribed off-label drugs without strong scientific evidence were 54% more likely to experience an adverse event, such as a drug reaction, drug interaction, or allergic response, forcing them to stop taking the drugs. Rates of adverse events involving on-label use and off-label use with strong scientific evidence were about the same. In all, the study authors identified 3,484 adverse drug events. The average cost per adverse event, considering possible emergency department visits and hospitalizations, ranges from $759 to $1,214, the study authors estimated.

In a related journal commentary, doctors at the Veterans Affairs Pittsburgh Healthcare System highlighted a recent U.S. federal court ruling against a U.S. Food and Drug Administration ban on off-label drug promotion. This study provides “compelling evidence” that the FDA and courts must carefully consider before relaxing the ban, they concluded.


  1. Eguale T, Buckeridge DL, Verma A, et al. Association of Off-Label Drug Use and Adverse Drug Events in an Adult Population. JAMA Intern Med. 2015; doi:10.1001/jamainternmed.2015.6058.