Magic Mouthwash Really Works, Says Phase 3 Trial

Lidocaine-Based Rinse for Oral Mucositis

Nick Mulcahy

September 27, 2016

UPDATED September 27, 2016 // BOSTON ― Although magic mouthwash might not fulfill science fiction author Arthur C. Clarke's notion that "any sufficiently advanced technology is indistinguishable from magic," the stuff does in fact work in cancer patients, according to the results of a large phase 3 trial.

"Magic mouthwash" is a term that encompasses as many as 50 varieties of lidocaine-based rinses that are widely used for oral mucositis pain. However, no large, multicentered, randomized controlled trial has been conducted to evaluate efficacy, until now.

New results show that a lidocaine-based mouthwash is effective in reducing radiotherapy-related oral mucositis pain, concludes a team led by Robert Miller, MD, of Mayo Clinic, Jacksonville, Florida.

"The study confirms what we thought — that it works," Dr Miller told Medscape Medical News here at the American Society for Radiation Oncology (ASTRO) 2016 Annual Meeting, where study results were presented.

After patients rinsed once with the mouthwash, there was a 35% reduction in pain over a 4-hour period in comparison with placebo, said Dr Miller.

"It's always good to see what we are using has a solid scientific basis," said Thomas Galloway, MD, a radiation oncologist at Fox Chase Cancer Center in Philadelphia, Pennsylvania, who was not involved in the study.

Always good to see what we are using has a solid scientific basis. Dr Thomas Galloway

The magic mouthwash in the new study consisted of a diphenhydramine/lidocaine/antacid (DLA) preparation that is used at Mayo Clinic sites. The three agents in the mix are the most commonly used elements in the many manifestations of the mouth rinse, said Dr Miller.

Oral mucositis is a major cause of morbidity during radiotherapy for head and neck cancers, he explained.

Painful mucositis impairs the ability to eat and drink, affects quality of life, and can cause interruptions of cancer treatment to enable healing, he said.

Various approaches to minimize these side effects have been tried, including oral cryotherapy, low-level laser therapy, and rinses containing a mucoadhesive hydrogel.

Magic mouthwashes containing lidocaine are also widely used, but the lack of robust evidence of efficacy led the American Academy of Nursing to issue a 2015 advisory against their use as part of the Choosing Wisely campaign. "Don't use mixed medication mouthwash, commonly termed 'magic mouthwash,' to prevent or manage cancer treatment–induced oral mucositis," reads the statement.

Study Details

In the new study, patients underwent definitive head and neck radiotherapy (> 45 Gy) and had oral mucositis pain rated at least 4 on a scale of 1 to 10 in a commonly used pain questionnaire.

A group of 275 patients were randomly allocated individually to blindly receive one of three agents: magic mouthwash (DLA), doxepin oral rinse, or a placebo rinse.

Doxepin has previously been shown to reduce oral mucositis pain in another sizeable phase 3 trial led by Dr Miller, as reported by Medscape Medical News in 2012.

After rinsing, the patients then filled out the pain questionnaire at intervals out to 4 hours.

The primary endpoint was pain reduction, as measured by the area under the curve (AUC) of the pain scale over the 4 hours following a single dose of the rinse.

Analysis of the primary endpoint revealed significant differences in mean AUC reduction in pain between DLA and placebo (11.7 vs 8.7, P = .004). The numbers translated into the above-mentioned 35% reduction in pain over the 4-hour test period, said Dr Miller.

Doxepin was also significantly effective for the same measure compared to placebo (11.9 vs. 8.7, P = .01).

"Both agents were significantly better than placebo," said Dr Miller.

The new trial was not powered to compare DLA and doxepin, pointed out Dr Miller. Thus, the results simply indicate that both DLA and doxepin were effective in the treatment of the pain.

Only 15% of patients who received doxepin used additional analgesics at 4 hours post oral rinse compared with 28% in the placebo arm (P < .05). However, there was no significant difference between DLA and placebo for this measure (19% vs 28%, P = .22).

Fox Chases' Dr Galloway said that the results were "expected," given the fact that he sees "a lot of patients who feel better" after a rinse with magic mouthwash. The rinse used at Fox Chase is very similar to the study formulation, he added.

Dr Galloway also observed that new rinses for oral mucositis appear in the marketplace regularly. "I don't think we know what product works best," he told Medscape Medical News.

Dr Miller has financial ties to Tekcapital and Belluscura. Dr Galloway has disclosed no relevant financial relationships.

American Society for Radiation Oncology (ASTRO) 2016 Annual Meeting. Abstract LBA-3. Presented September 27.

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