Medical knowledge about clinical indications for medications is transferred to new generations of clinicians frequently without the caveat that the indication is, by the way, “off label."
Off-label use is the practice of prescribing pharmaceuticals for: 1) an unapproved indication; 2) in an unapproved age group; 3) using an unapproved dose; or 4) using an unapproved form of administration. Likely not many of us have recently reviewed the package insert for trazodone, for example, to find out that insomnia is not a Food and Drug Administration–approved indication. But what else do we do?
A fascinating piece of work was published recently that pulls back the curtain on off-label prescribing patterns for certain medications (Arch. Intern. Med. Published online April 16, 2012. doi:10.1001/archinternmed.2012.340).
The study evaluated prescribing practices – including off-label uses – in a Canadian primary care network covering 113 primary care clinicians who wrote 253,347 electronic prescriptions for 50,823 patients. Overall, 11% of medications were prescribed for off-label uses, of which 79% lacked scientific evidence of efficacy. Older drugs and those with fewer approved indications had higher rates of off-label use.
The top 10 clinical indications treated with off-label drugs and the most frequent off-label drugs used for them included the following: 1) benign paroxysmal positional vertigo – betahistine (not available in U.S.); 2) nocturnal leg pain – quinine; 3) neurogenic pain – gabapentin; 4) chronic pain – nortriptyline; 5) fibromyalgia – cyclobenzaprine; 6) arrhythmia – metoprolol; 7) generalized anxiety disorder – citalopram; 8) insomnia – oxazepam; 9) bipolar disorder – lamotrigine; and 10) diabetic neuropathy – gabapentin.
Antimigraine, lipid-lowering agents and antidiabetic medications had the lowest rates of off-label use. Patients who had more medical problems were less likely to receive off-label medications probably because, as the authors point out, clinicians might feel they had less room to “experiment” with a medication.
Keep in mind that this study looked at indications approved by Health Canada, which may differ from indications approved by the Food and Drug Administration in the United States. Health Canada can approve generic drugs for the Canadian market 5 years earlier than the FDA can in the United States, and drugs may not be approved at the same time in the two countries.
Clinical “tricks of the trade” are handed down through generations of physicians. As practicing clinicians, we need to seek out and remind ourselves of the evidence base supporting the use of the medications we prescribe. Prescribing ineffective pharmacotherapeutics to our trusting patients will take the magic out of what we do.
Dr. Ebbert is a professor of medicine and a primary care clinician at the Mayo Clinic in Rochester, Minn. He does not promote the off-label use of medications. The opinions expressed are solely those of the author. E-mail him at ebbert.jon@mayo.edu.