Sustained Use of Benzodiazepines and Escalation to High Doses in a Canadian Population.

Objective: "Antibenzodiazepine" campaigns have been conducted worldwide to limit the prescribing of these drugs because of concerns about inappropriate use and addiction. The causal relationship between long-term use and escalation to high doses has not been proven. This study assessed the extent of dose escalation among individuals who were long-term users of benzodiazepines or Z-hypnotics.

Methods: A population-based study was conducted in the Canadian province of Manitoba using administrative health databases. Sustained use was defined as continuous use for at least two years (N=12,598). Dose escalation, measured in diazepam milligram equivalents (DMEs) per day and observed at six-month intervals, was assessed by using latent-class trajectory analysis. Characteristics of individuals with sustained use were described.

Results: The analysis revealed four distinct groups. Two groups (<8% of the cohort) showed escalation to high doses (over 40 DMEs). More than 55% of high-dose escalators were in the 0- to 44-year age group, 75% lived in urban areas, and approximately 75% had a diagnosis of depression. Clonazepam was the drug most commonly involved with dose escalation; among individuals escalating to doses higher than 60 DMEs, 91% were using clonazepam. Rates of "doctor shopping" and "pharmacy hopping" were higher among younger adults, compared with older adults. Younger adults also had higher rates of concomitant antidepressant therapy.

Conclusions: A limited segment of a population that received benzodiazepine prescriptions was classified as sustained users, and a small proportion of that group escalated to doses higher than those recommended by product monographs and clinical guidelines.