April 25th, 2019

Robert C. Miller, MD, MBA, FASTRO

An oral rinse containing diphenhydramine, lidocaine and antacid relieves pain from mouth sores caused by radiation therapy in cancer patients, according to a study published this month in the Journal of the American Medical Association.

The study, led by Robert C. Miller, MD, MBA, FASTRO, Professor of Radiation Oncology at the University of Maryland School of Medicine and Medical Director of the Maryland Proton Treatment Center, demonstrated that the use of these rinses, often called Magic Mouthwash, provided pain relief in head and neck cancer patients suffering from oral mucositis as a result of radiation therapy. Relief was felt almost immediately and continued for at least 4 hours.

The study published on April 16 is the first that gives high-level scientific evidence to support what had long been common practice in the medical field. It is also significant because publication in JAMA significantly raises the profile of the difficulty in dealing with supportive care issues during cancer treatment.

“We actually didn’t think Magic Mouthwash worked as well as it did when we designed the study,” said Dr. Miller, who was the national principal investigator of the study. “It was quite a surprise.”

Mouth sores are one of the most common side effects in head and neck patients treated with radiation. Over time, millions of people could receive relief from the Magic Mouthwash. Mouth sores can become so painful that patients are unable to eat. In extreme cases they can require a feeding tube, hospitalization, or an interruption in their radiation treatment. Reducing pain can contribute to more successful treatment, Dr. Miller said.

Dr. Miller and his team conducted the study from November 1, 2014 to May 16, 2016 while working at the Mayo Clinic. He joined the staff of the Maryland Proton Treatment Center this April.

Rinses containing diphenhydramine, lidocaine, and antacid have been used for years. But there were no randomized, placebo-controlled research to prove that they worked. Moreover, in 2015, the American Academy of Nursing recommended against using the mouthwash in cancer patients.

The study is part of federally funded research that examines whether commonly used treatments for various illnesses are effective. Often the research outcome supports the practices but occasionally doctors are surprised at what studies show.

Researchers found that using Magic Mouthwash reduced pain by as much as 25 percent, which can help add to the relief brought about by pain relievers. Dr. Miller believes the findings will change the guidelines now used to treat oral mucositis. Relieving pain is not only important for the patient’s quality of life, but it also can affect the patient’s health.

Cancer treatment is not without unwanted side effects. In more than 80 percent of patients who receive radiation to their head and neck, a common unintended side effect is painful mouth sores called oral mucositis. Dr. Miller said that the use of proton therapy can also reduce the rates of oral mucositis.

The double blind, randomized, placebo-controlled phase III trial took place across 30 participating sites. Some 270 patients were enrolled, and 227 completed the study. Patients were divided into three groups, and given either a placebo, the Magic Mouthwash or an oral rinse made with doxepin. Doxepin is FDA approved for treating anxiety and depression and pruritis. It works through the central and peripheral nervous systems. Earlier research by the Alliance for Clinical Trials in Oncology demonstrated that an oral rinse made with doxepin helped reduce oral mucositis pain.

Study participants whose pain measured at least 4 out of 10 severity level were provided an oral rinse that they were instructed to rinse, gargle and then spit out. The rinse was either a placebo, doxepin oral rinse, or the “magic mouthwash” oral rinse made with diphenhydramine, lidocaine and antacid. Participants recorded their pain before the dose, then 5, 15, 30 and 60 minutes after the dose while still at the clinic. They recorded pain levels at two hours and four hours after the dose after they’d gone home.

Researchers compared the doxepin group and the Magic Mouthwash group to the placebo group. They did not compare the doxepin group and the Magic Mouthwash group to each other. Researchers found that both doxepin and Magic Mouthwash oral rinses were well tolerated and more effective than placebo. Five patients who used the doxepin rinse reported drowsiness, but none of the Magic Mouthwash patients did. Patients who used the doxepin rinse also reported unpleasant tastes and stinging or burning more often than did the placebo group. There were no reported significant differences of unpleasant taste or stinging and burning between the Magic Mouthwash group and the placebo group.

Dr. Miller said the work complements research done by University of Maryland School of Medicine’s Isabel Lauren Jackson on ways to counteract radiation effects.

About The Maryland Proton Treatment Center
The Maryland Proton Treatment Center is the first center in the region to fight cancer with proton therapy. More than 1500 people have chosen treatment at MPTC, which has the most experienced proton team in the area. MPTC offers the most advanced form of proton therapy in the world – called pencil beam scanning. This technique is highly effective for a wide variety of solid, localized tumors in adults and children.


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