Doxepin Solution for Alleviation of Stubborn Breakthrough Pain Induced by Swallowing in Patients Receiving Radiotherapy for Nasopharyngeal Carcinoma

Patients with nasopharyngeal carcinoma receiving radical radiotherapy or chemoradiotherapy who developed oral mucositis and had a swallowing-induced pain score ≥ 4 were recruited and randomly assigned 1:1 to the experimental group and the control group. Patients in the experimental group received a doxepin solution spray to the posterior pharyngeal wall 10 minutes before eating. At least 12 hours later, when the swallowing-induced pain score ≥4, a placebo spray was administered to the posterior pharyngeal wall 10 minutes before eating. Patients in the control group received a placebo spray to the posterior pharyngeal wall 10 minutes before eating. At least 12 hours later, when the swallowing-induced pain score ≥4, a doxepin solution spray was administered to the posterior pharyngeal wall 10 minutes before eating. The swallowing-induced pain and incidence of adverse events were assessed at 10 minutes, 20 minutes, 30 minutes, and 1 hour after medication using a patient-reported questionnaire, and safety evaluation was conducted 1 day after treatment.