Methylene Blue Mouthwash for Oral Mucositis Pain in Cancer: An Open-Label, Non-Randomized Study

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: < 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.