Background: Oral mucositis (OM) pain in patients undergoing cancer treatments remains inadequately managed with conventional treatments. This study aimed to examine pain outcomes associated with methylene blue (MB) mouthwash compared with a standard supportive care mouthrinse in hospitalized patients with OM.
Methods: In this open label, non-randomized clinical trial, patients selected MB (0.05%) or standard-of-care mixed medication mouthwash. Both groups performed an oral rinse every 8 h for three days. The primary outcome was change in pain numeric rating scores (0-10) from pre-administration to post-administration. Secondary outcomes included changes in daily oral intake volume and opioid use.
Results: Forty-three evaluable patients were included in the analysis. Using a linear mixed model with subject-specific intercepts, both treatment groups demonstrated statistically significant reductions in pain from pre- to post- administration (standard of care: estimate=-0.64, 95% CI [-1.23, -0.05], p = 0.034; MB estimate=-0.87, 95% CI [-1.31, -0.42], p < 0.001). The administration timing-by-treatment interaction effect was not statistically significant, indicating that pain reduction did not differ significantly between groups.
Conclusions: In this non-randomized study, MB mouthwash was associated with short-term pain reductions in OM-related pain similar to standard-of-care mouthwash. These findings support feasibility and tolerability and underscore the need for larger randomized trials.
Keywords: Oral mucositis; cancer treatment; methylene blue.