Suicide-related risk among patients using branded and generic fluoxetine: a propensity score-matched, new-user design in Taiwan.

Background: To date, the clinical equivalence between branded and generic medications remains debate and may sometimes be a reason why psychiatrists are hesitant to prescribe generic medications. Depression is recognized to exacerbate suicide risk globally and selective serotonin reuptake inhibitors, such as fluoxetine are common treatment options. Therefore, this study aimed to explores differences in suicidal risks between users of branded and generic fluoxetine in Taiwan.

Methods: This cohort study used Taiwan Longitudinal Health Insurance Database, encompassing 2 million individuals covered by National Health Insurance (NHI) program. The full cohort consisted of 32,298 fluoxetine new users. Then, 7,380 branded and 7,380 propensity score matched (PSM) generic fluoxetine new users were identified. The study further utilized Cox proportional hazards models to assess risk of 5-year suicidal ideation, suicide mortality, and all-cause mortality.

Results: The study revealed that the adjusted hazard ratios (HRs) for suicidal ideation, suicide mortality and all-cause mortality in branded users were 0.766 (95% CI, 0.497 - 1.181), 0.660 (95% CI, 0.447 - 0.975), and 0.942 (95% CI, 0.849 - 1.045), respectively, when compared with matched generic fluoxetine users. Stratified and sensitivity analyses showed the lower risk of suicide mortality in specific subgroups, such as male (adjusted HRs = 0.536, 95% CI = 0.306-0.939) and young branded users (adjusted HRs = 0.549, 95% CI = 0.334-0.904).

Conclusion: This study observed trends in the prevention effects of suicide-related risks. However, only suicide mortality was statistically significant, especially in males and those aged < 40 years. These insights may assist clinicians and policymakers in decision-making.

Clinical trial number: NA (This study is a cohort study utilizing the national health insurance database, not a clinical trial).