Prediction of duloxetine efficacy in addition to self-management in painful temporomandibular disorders: A randomised, placebo-controlled clinical trial.

Background: Conditioned pain modulation (CPM) is a potential predictor of treatment response that has not been studied in temporomandibular disorders (TMD).

Objectives: We conducted a randomised, double-blind, placebo-controlled trial (RCT) of duloxetine in addition to self-management (SM) strategies to investigate its efficacy to reduce pain intensity in painful TMD patients. Moreover, we investigated whether baseline CPM would predict the duloxetine efficacy to reduce TMD pain intensity.

Methods: Eighty participants were randomised to duloxetine 60 mg or placebo for 12 weeks. The primary outcomes were the change in the pain intensity from baseline to week-12 and CPM-sequential paradigm at baseline. Safety, physical and emotional functioning outcomes were also evaluated.

Results: Of 80 participants randomised, 78 were included in intention-to-treat analysis. Pain intensity decreased for SM-duloxetine and SM-placebo but did not differ between groups (p = .82). A more efficient CPM was associated with a greater pain intensity reduction regardless of the treatment group (p = .035). Physical and emotional functioning did not differ between groups, but adverse events (p = .014), sleep impairment (p = .003) and catastrophizing symptoms (p = .001) were more prevalent in SM-duloxetine group.

Conclusion: This study failed to provide evidence of a beneficial effect of adding duloxetine to SM strategies for treatment of painful TMD. Nonetheless, this RCT has shown the feasibility of applying pain modulation assessment to predict short-term treatment response in painful TMD patients, which confirms previous finds that CPM evaluation may serve a step forward in individualising pain treatment.