MONDAY, April 16 (HealthDay News) -- Off-label prescribing of medications is common, but the practice varies according to drug, and patient and doctor characteristics, a Canadian study finds.
In off-label prescribing, a doctor prescribes drugs for uses that have not been approved by regulators. For example, some medicines approved to treat depression are also prescribed for chronic pain.
The practice, which is legal but unregulated, is believed to contribute to preventable medication-related harm in patients, according to Dr. Tewodros Eguale, of McGill University in Montreal, and colleagues.
For the study, they examined more than 250,000 electronic prescriptions for more than 50,000 patients written from 2005 through 2009 by 113 doctors in a primary care network in Canada.
The study results were released online in advance of print publication in the journal Archives of Internal Medicine as part of the journal's health-care reform series.
About 11 percent of the medications were prescribed for off-label use, and 79 percent of off-label use lacked strong scientific evidence, the researchers found. The amount of off-label use in this study was less than in a previous U.S. study, the authors noted in a journal news release.
The investigators found that the highest rate of off-label use involved central nervous system drugs (26 percent), anti-infective agents (17 percent), and ear-nose-throat medications (15 percent). The study also found that drugs with three or four approved uses were less likely to be prescribed off-label than those with one or two approved uses.
Medications approved after 1995 were less likely to be prescribed off-label than those approved before 1981, and doctors with high scores on evidence-based practice were less likely to prescribe off-label, the findings showed.
"Our findings indicate that off-label prescribing is common in primary care and varies by drug class, the number of approved indications for the drug, the age of the drug, patients' sex and physicians' attitude toward evidence-based medicine," the researchers concluded.
"Electronic health records can be used to document treatment indication at the time of prescribing and may pave the way for enhanced post-marketing evaluation of drugs if linked to treatment outcomes," Eguale and colleagues wrote.
The U.S. Agency for Healthcare Research and Quality has more about off-label prescribing.
-- Robert Preidt
SOURCE: Archives of Internal Medicine, news release, April 16, 2012
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