Clinical consequences of initial duloxetine dosing strategies: Comparison of 30 and 60 mg QD starting doses

Background: To reduce the risk for treatment-emergent adverse events and increase patient compliance, clinicians frequently prescribe a suboptimal starting dose of antidepressants, with the goal of increasing the dose once the patient has demonstrated tolerability.

Objective: The aim of this study was to examine the tolerability and effectiveness associated with an initial week of duloxetine hydrochloride treatment at 30 mg QD and subsequent dose increase to 60 mg QD, compared with a starting dose of 60 mg QD.

Methods: In this open-label study, all patients met the criteria for major depressive disorder (MDD) described in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision. Patients were required to wash out from previous antidepressant medications for 21 days, and were then randomized to receive duloxetine 30 or 60 mg QD for 1 week. After 1 week, patients receiving duloxetine 30 mg QD had their dose increased to 60 mg QD. Patients returned for assessments at weeks 2, 4, 6, 8, and 12. During the remainder of the 12-week study period, the duloxetine dose could be titrated based on the degree of response from 60 mg QD (minimum) to 120 mg QD (maximum), with 90 mg QD as an intermediate dose. Tolerability was assessed by means of discontinuation rates, spontaneously reported adverse events, changes in vital signs, and laboratory tests. Effectiveness measures included the 17-item Hamilton Rating Scale for Depression (HAMD17) total score, HAMD17 core and Maier subscales, individual HAMD17 items, the Hamilton Rating Scale for Anxiety total score, and the Clinical Global Impression of Severity.

Results: One hundred thirty-seven patients were enrolled (82 women, 55 men; mean age, 42 years; duloxetine 30 mg QD, 67 patients; duloxetine 60 mg QD, 70 patients). The rate of discontinuation due to adverse events did not differ significantly between patients starting duloxetine at 30 mg QD and 60 mg QD (13.4% vs 18.6%). The most frequently reported adverse events across both treatment groups were nausea, headache, dry mouth, insomnia, and diarrhea. In the first week of treatment, patients receiving duloxetine 30 mg QD had a significantly lower rate of nausea compared with patients receiving 60 mg QD (16.4% vs 32.9%; P = 0.03). Over the 12-week acute-treatment phase, patients starting duloxetine treatment at 30 mg QD had a significantly lower rate of nausea compared with patients initiating treatment at 60 mg QD (P = 0.047). Although between-group differences in the HAMD17 total score were not statistically significant at any visit, patients starting at 30 mg QD experienced significantly less improvement in HAMD17 core and Maier subscales at week 1 compared with patients starting at 60 mg QD (core, P= 0.044; Maier, P = 0.047). After 2 weeks of treatment, the magnitude of improvement among patients starting at 30 mg QD did not differ significantly from that observed in patients who started treatment at 60 mg QD, and there were no significant between-group differences in effectiveness at any subsequent visit.

Conclusions: Results from this open-label study in patients with MDD suggest that starting duloxetine treatment at 30 mg QD for 1 week, followed by escalation to 60 mg QD, might reduce the risk for treatment-emergent nausea in these patients while producing only a transitory impact on effectiveness compared with a starting dose of 60 mg QD.