Doxepin and a Topical Rinse in the Treatment of Acute Oral Mucositis Pain in Patients Receiving Radiotherapy With or Without Chemotherapy

1. Documentation of Disease: Histologic documentation of malignancy currently undergoing a course of RT (with or without chemotherapy) including the oral cavity and/or oropharyngeal area to a dose of at least 4500 cGy using more than 5 fractions (i.e., stereotactic body radiation therapy [SBRT] is not allowed).

2. Physical exam demonstrating evidence of radiotherapy-related mucositis in the visible oral cavity and/or oropharynx consistent with mucous membrane toxicity greater than 0 using the Acute Radiation Morbidity Scoring Criteria.

3. At least 4 (out of 10) patient-reported oral pain related to oral mucositis secondary to RT for which the patient seeks relief, as measured on the Oral Pain Assessment.

Note: The pain score must be at least 4 at the time that the patient starts the first dose of study medication. The patient may be enrolled to the study if s/he, at times, has a pain score of at least 4, so long as initiation of study treatment begins when the pain score is at least 4.

4. Ability to complete questionnaire(s) by themselves or with assistance.

5. No known allergy to diphenhydramine, lidocaine, antacid (aluminum hydroxide, magnesium hydroxide, and simethicone), doxepin, tricyclic antidepressants, or any known component of the drug formulation in the testing arms.

6. No use of any anti-arrhythmic medication (except for beta-blockers) including lidocaine, linezolid, ipratropium, or medications with high anti-cholinergic potency (including neostigmine, a tricyclic antidepressant or a monoamine oxidase inhibitor) within 2 weeks prior to registration.

7. No current diagnosed untreated or unresolved oral candidiasis or oral HSV infection.

8. No history of untreated narrow angle glaucoma within 6 weeks prior to registration.

9. No untreated urinary retention within 6 weeks prior to registration.

10. No current use of glutamine or sucralfate powders at the time of registration (no washout required).

11. No cryotherapy for prophylactic mucosal protection within 6 weeks prior to registration.

12. Not pregnant, because patients eligible for this study will be receiving radiotherapy, which has known genotoxic, mutagenic and teratogenic effects. Therefore, for women of childbearing potential only, a negative pregnancy test done ≤ 28 days prior to registration is required.

13. Age ≥ 18 years

14. ECOG Performance Status 0, 1, or 2