Off-Label Prescription of Benzodiazepines: A Retrospective Cohort Study of Prescribing Prevalence in Primary Care.

Background and objectives: Benzodiazepines are commonly prescribed medications approved for and used in the treatment of anxiolytic and sleep disorders, as well as for seizures, and alcohol withdrawal. However, benzodiazepines are also controlled substances because of their potential for abuse and personal harm, which are especially prevalent among older people. It is therefore important to understand how benzodiazepines are being prescribed, and the prevalence of off-label benzodiazepine prescribing, of which very little is known because of challenges in documenting treatment indication. The aim of this study was to detail the prevalence of benzodiazepine off-label prescribing.

Methods: Data from the MOXXI (Medical Office of the XXIst century) electronic health record system in Quebec Canada were used, where specifying the treatment indication for each prescription is required, to estimate the prevalence of off-label prescribing and indications for off-label use of benzodiazepines. Each drug indication was retrospectively classified as either on-label or off-label according to the Health Canada drug database. Off-label prescriptions were further classified as having class congruence supporting their prescription if another benzodiazepine had been approved for the indication by Health Canada.

Results: There were 20,125 (17.0%) adult patients prescribed benzodiazepines out of the 118,223 patients enrolled in the MOXXI system. The patients were predominantly female (65.6%) and tended to be older with an average age of 60.14 years at the time of the first benzodiazepine prescription. A total of 101,583 unique prescriptions were written for 14 different benzodiazepines. An approximately equal number of benzodiazepines were prescribed on- and off-label (49.3% on-label, 49.2% off-label). Most off-label prescription indications were classified as having class congruence (95.2%).

Conclusions: Benzodiazepines were frequently prescribed in the province of Quebec and were prescribed off-label approximately half of the time. When prescribed off-label, we found that most of these prescriptions were for indications that were approved for other benzodiazepines. The most common indication for off-label benzodiazepine prescriptions with class congruence was insomnia.