Efficacy and safety of tipepidine as adjunctive therapy in major depressive disorder: A randomized, double-blind, placebo-controlled clinical trial

Aim Tipepidine, a synthetic, non-opioid expectorant, has been shown to improve depressive-like behavior in animal models of depression. In this study, we assessed the efficacy and tolerability of tipepidine combination therapy with citalopram in treatment of major depressive disorder (MDD). Methods In a randomized, double-blinded, placebo-controlled clinical trial, 62 patients with MDD were assigned into two parallel groups to receive citalopram (up to 40 mg/day) plus placebo or citalopram plus tipepidine (30 mg twice daily) for 6 weeks. Participants were assessed with the Hamilton Rating Scale for Depression (HAM-D) at baseline and Weeks 2, 4, and 6. Results Fifty-eight patients completed the trial. The tipepidine group showed greater improvement in HAM-D scores from baseline to all three study time points (P = 0.048 for all). The remission and response-to-treatment rates were significantly higher in the tipepidine group (53.6% and 100%) compared to the placebo group (25.0% and 75%) at the study end-point (P = 0.029 and 0.005, respectively). The remission and response times in patients in the tipepidine group were also shorter compared with the placebo group (log-rank P = 0.020 and 0.004). There was no significant difference between the two groups in baseline parameters or frequency of side-effects. Conclusion Tipepidine combination therapy with citalopram can effectively improve symptoms of patients with MDD in a shorter period of treatment. However, further studies with larger sample sizes and longer follow-up treatment are needed to confirm our findings.