Scientists find effective treatment for oral pain caused by radiation therapy

JACKSONVILLE, Fla., U.S.: Scientists have recently discovered that an oral rinse referred to as magic mouthwash significantly reduces the pain caused by oral mucositis and mouth ulcers in patients receiving radiation therapy for head and neck cancers. The mouthwash contains diphenhydramine, lidocaine and antacids.

The study was led by Dr. Robert C. Miller, Professor of Radiation Oncology at Mayo Clinic. The findings emerged from a multi-institutional randomized, double-blind, placebo-controlled Phase III clinical trial.

“Our group published a study in 2012 showing that an oral rinse of doxepin reduced oral mucositis-related pain, compared to placebo,” said Miller. “However, there were no large randomized controlled trials studying the potential benefits of magic mouthwash.”

In the new study, conducted between November 2014 and May 2016, Miller and his colleagues studied 275 patients who underwent definitive head and neck radiotherapy and had an oral mucositis pain score of 4 points or greater. The participants were followed up for a maximum of 28 days. The research team found that pain related to oral mucositis was reduced by 11.6 points after using doxepin mouthwash and by 11.7 points after using diphenhydramine-lidocaine-antacid mouthwash, within 4 hours of administration. There was a reduction of 8.7 points for placebo mouthwash. Both experimental rinses were also well-tolerated by patients.

“Radiation therapy may cause mouth sores because it is designed to kill rapidly growing cells, such as cancer cells,” said co-author Dr. Terence T. Sio, a radiation oncologist at the clinic. “Unfortunately, healthy cells in your mouth also divide and grow rapidly, and may be damaged during radiation therapy, which can cause discomfort. We’re glad to have identified a proven method to help treat the discomfort of this side effect,” he concluded.

The study, titled “Effect of doxepin mouthwash or diphenhydramine-lidocaine-antacid mouthwash vs placebo on radiotherapy-related oral mucositis pain: The Alliance A221304 randomized clinical trial,” was published online on April 16, 2019, in JAMA.