Long-term benzodiazepine use in patients taking antidepressants in a public health setting in Brazil: a cross-sectional study

OBJECTIVE: The aims of the study were to investigate the prevalence of long-term use of benzodiazepines in patients taking antidepressants and to identify the risk factors associated with the prolonged use of benzodiazepines. DESIGN: Cross-sectional study. SETTING: Public health system in Brazil. PARTICIPANTS: Outpatients using antidepressants from January 2008 to December 2009 were included. The data were obtained from pharmacy databases and medical records. All individuals in the database were included in the study and were classified into two categories: (1) patients who had not used benzodiazepines combined with antidepressants or had combined the use of antidepressants with benzodiazepines for a short period (up to 4 weeks), and (2) those who used antidepressants plus benzodiazepines for a longer period (more than 4 weeks). MAIN OUTCOME MEASURE: The outcome measure is prolonged use of benzodiazepines (more than 4 weeks). We conducted a multivariate analysis to identify the factors associated with prolonged use of benzodiazepines. RESULTS: Forty per cent of the 870 patients evaluated had prolonged use of benzodiazepines (more than 4 weeks). The risk factors associated with prolonged use were age above 35 years (prevalence ratio (PR): 2.18, 95% CI 1.55 to 3.06, P<0.001), female sex (PR: 1.47, 95% CI 1.07 to 2.02, P=0.019), diagnosis at least 3 years prior (PR: 2.1, 95% CI 1.6 to 2.8, P<0.001), use of selective serotonin reuptake inhibitor antidepressants (PR: 1.7, 95% CI 1.3 to 2.2, P<0.001) and having a prescription from a psychiatrist (PR: 6.5, 95% CI 3.2 to 13.2, P<0.001). CONCLUSIONS: Prolonged use of benzodiazepines occurs more frequently in women, adults diagnosed several years earlier, users of selective serotonin reuptake inhibitor antidepressants and those who received a prescription from a psychiatrist. Education of clinicians, especially with regard to these populations, may decrease the overuse and misuse of benzodiazepines.