Doxepin Hydrochloride in Treating Esophageal Pain in Patients With Thoracic Cancer Receiving Radiation Therapy to the Thorax With or Without Chemotherapy

PRIMARY OBJECTIVES: I. To provide baseline data regarding the effectiveness of doxepin (doxepin hydrochloride) in reducing esophagitis-related pain in patients undergoing radiation therapy (RT) to the thorax, as measured by a patient-reported questionnaire at 5 minutes, 15 minutes, 30 minutes, 1 hour and then at 2 and 4 hours on day 1. SECONDARY OBJECTIVES: I. To assess the adverse event profile of doxepin swish and swallow using a patient-reported questionnaire at 5 minutes, 15 minutes, 30 minutes, 1 hour and then at 2 and 4 hours using Common Terminology Criteria for Adverse Events (CTCAE) and Radiation Therapy Oncology Group (RTOG) acute toxicity criteria, and also for domains of unpleasant taste, burning/stinging discomfort, and drowsiness. II. To evaluate the effectiveness of doxepin in reducing esophagitis-related pain in patients undergoing RT to the thorax, as measured by a patient-reported questionnaire at 5 minutes, 15 minutes, 30 minutes, 1 hours and then at 2 and 4 hours on days 1 and 3 (including the cross-over phase). III. To compare and provide baseline data regarding alternative analgesic use between the doxepin and placebo arms. IV. To provide baseline data regarding the patients? preference for continued therapy with doxepin or placebo after initial test dose or after the cross-over phase, as measured by items 9 and 10 in the patient-reported questionnaire at 4 hours after administration of the study medication and the actual participation rate. TERTIARY OBJECTIVES: I. To assess pain reduction and other adverse event profile in the optional continuation phase of doxepin oral rinse therapy. (Only applies to patients who have the optional continuation of doxepin oral rinse after the first two phases) OUTLINE: Patients are randomized to 1 of 2 treatment groups. GROUP I: Patients receive doxepin hydrochloride oral solution (swish, gargle for 30 seconds, and slowly swallow) on day 1. Patients then crossover to Arm II on day 3. GROUP II: Patients receive placebo oral solution (swish, gargle for 30 seconds, and slowly swallow) on day 1. Patients then crossover to Arm I on day 3. In both arms, patients may continue to receive doxepin hydrochloride oral solution every 4 hours as needed during radiation therapy.