Study Warns On Off-label Antidepressant Use

Primary care doctors increasingly are prescribing antidepressant medications for conditions other than depression, suggests a new study by McGill University researchers.

Depression only accounts for slightly more than half the antidepressant prescriptions issued by Quebec physicians during the past decade, the study found. The remainder included such conditions as insomnia, digestive disorders and sexual dysfunction.

The researchers used data from an electronic medical record and prescribing system that has been used by primary care physicians in community-based, fee-for-service practices around 2 major urban centers in Quebec, Canada.

“The findings indicate that the mere presence of an antidepressant prescription is a poor proxy for depression treatment, and they highlight the need to evaluate the evidence supporting off-label antidepressant use,” the authors write.

In the US, antidepressant usage grew nearly 400 percent between 1988-1994 and 2005-2008. Most recent figures show 11 percent of teens and adults take antidepressants, according to the U.S. Centers for Disease Control and Prevention.

The McGill study included more than 100,000 prescriptions written for adults between January 2006 and September 2015 for all antidepressants except monoamine oxidase inhibitors. Physicians participating in the study had to document at least 1 treatment indication per prescription using a drop-down menu containing a list of indications or by typing the indications.

Off-Label Use

For 29 percent of all antidepressant prescriptions, 66 percent of prescriptions not for depression, physicians prescribed a drug for an off-label indication, especially insomnia and pain. Physicians also prescribed antidepressants for several indications that were off-label for all antidepressants, including migraine, vasomotor symptoms of menopause, attention deficit hyperactivity disorder, and digestive system disorders.

Wong’s research team wanted to study a specific gap in depression research. Although similar studies have found equally large percentages of off-label prescribing, not many had looked directly into the original prescription records created by the prescribing physicians.

Because McGill University has long kept an electronic database system enabling Quebec physicians to keep track of their patients’ prescriptions and medical records, it was relatively easy to address this gap.

Off-label use, the prescribing of pharmaceutical drugs for an unapproved indication or in an unapproved age group, dosage, or route of administration, is quite common. The SSRI medication Zoloft, for example, is approved as an anti-depressant but is also commonly prescribed off-label to help men suffering from premature ejaculation.

Generic drugs generally have no sponsor as their indications and use expands, and incentives are limited to initiate new clinical trials to generate additional data for approval agencies to expand indications of proprietary drugs.

Wong J, Motulsky A, Eguale T, Buckeridge DL, Abrahamowicz M, Tamblyn R.
Treatment Indications for Antidepressants Prescribed in Primary Care in Quebec, Canada, 2006-2015
JAMA. 2016;315(20):2230-2232. doi:10.1001/jama.2016.3445

Image: Blaupause GFDL or CC-BY-SA-3.0, via Wikimedia Commons