Objective: We examined the pain-relieving effect of duloxetine on chronic nonorganic orofacial pain (burning mouth syndrome and atypical odontalgia), considering the influence of baseline depressive symptoms.
Methods: In this study of 12 weeks, duloxetine was administered in a fixed-flexible dose of 20 to 40 mg/d to 41 patients with burning mouth syndrome and/or atypical odontalgia. Pain was evaluated using the visual analog scale (VAS) at baseline and at 2, 4, 6, 8, 10, and 12 weeks of treatment. Depressive symptoms were assessed using the Hamilton Depression Rating Scale at baseline and at 12 weeks of treatment.
Results: We analyzed the data from 29 patients who completed the study. The VAS score at 12 weeks of treatment was significantly lower than that at baseline. The time course of the VAS scores revealed its significant decrease from 2 weeks of treatment compared to the baseline score. To investigate the influence of baseline depressive symptoms on the pain-relieving effect of duloxetine, the subjects were divided into 2 groups based on the Hamilton Depression Rating Scale score on initial consultation: groups with (≥8) and without (≤7) depressive symptoms. Two-way repeated-measures analysis of variance revealed no significant interaction between time and initial presence or absence of depression. An additional intent-to-treat last-observation-carried-forward analysis including dropped-out patients revealed a similar result.
Conclusion: Duloxetine significantly relieved chronic nonorganic orofacial pain. Its pain-relieving effect appeared from 2 weeks of treatment. Furthermore, the pain-relieving effects of duloxetine similarly appeared regardless of the presence or absence of baseline depressive symptoms.