off-label prescribing

Concerns are being raised about the clinical efficacy of off-label prescribing. McGill University researchers investigated whether off-label prescribing of a prescription drug is supported by rigorous research.

Pharmaceutical companies developing a new prescription drug are motivated to receive approval from the Food and Drug Administration (FDA) to begin marketing their drug. The FDA approves a drug when its safety and efficacy have been explored and confirmed through clinical trials for at least one indication. Thereafter, secondary uses of the drug are explored in order to expand the use of the prescription drug.

Drug companies are not incentivized to design and perform further expensive clinical trials once their drug is approved. In addition, doctors can prescribe off-label uses of a prescription drug based off of inexpensive exploratory trials. This raises a concern that off-label prescribing may be clinically ineffective.

Researchers at McGill University’s Biomedical Ethics Unit in Montreal, Canada investigated the off-label prescribing of pregabalin. Pregabalin is approved for its use in nerve pain and as an adjunctive treatment for partial onset seizures in adults. Off-label prescribing of pregabalin include generalized anxiety disorder, lower back pain, essential tremor, migraine, post-surgery pain, itchiness, restless legs syndrome, and vasomotor menopausal symptoms. Over 230 clinical trials exploring the efficacy of pregabalin were analyzed and the results were published in JAMA Internal Medicine.

Among the 33 new indications present in the selected studies, over half were only studied in exploratory studies. Most of the selected trials were exploratory and 61% showed positive results. Confirmatory studies are required to test the indication in a larger study to prove its safety and efficacy. This analysis shows that the majority of the research completed on the other indications for use of pregabalin were attempting to explore its use rather than prove that its use is safe and effective.

Exploratory studies that are not followed by confirmatory studies can result in health care providers using incomplete research to prescribe a drug with an off-label use. In this analysis, 63% of the exploratory studies were not followed up by confirmatory studies within the first five years of its publication.

Physicians, patients, and the health care system are left with incomplete information but a possibility for an effective off-label use of pregabalin. One example of this is the off-label use by confirmatory for lower back pain. Pregabalin never went through the appropriate confirmatory studies; therefore, it was never approved to treat lower back pain. Yet, studies show that pregabalin is often used to treat lower back pain. 

Exposing patients to ineffective treatments or for drugs with unproven indications is an unethical practice. Unfortunately, funding for large confirmatory trials is limited once a prescription drug is approved for use. The off-label prescribing of pregabalin is one example of potentially inappropriate uses of a prescription drug based on exploratory studies. The McGill University researchers reinforce the message to ethics committees, drug regulators, funding bodies and health care payers to use their authority to support confirmatory testing of off-label indications of prescription drugs.

Written by Jessica Caporuscio, PharmD


  1. Federico CA, Wang T,Doussau A, Mogil JS, Fergusson D, Kimmelman J.Assessmentof Pregabalin Postapproval Trials and the Suggestion of Efficacy for NewIndications: A Systematic Review. JAMA Intern Med. 2018.
  2. Pregabalin. Lexi-Drugs. Lexicomp. Wolters KluwerHealth, Inc. Riverwoods, IL. Available at: AccessedNovember 29, 2018.
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