Safety and efficacy of oral pilocarpine in radiation-induced xerostomia in oropharyngeal carcinoma patients

Context: Patients with head-and-neck cancers can develop salivary gland hypofunction after radiotherapy. Oral pilocarpine has been shown to be effective treatment for radiation-induced xerostomia, although its usefulness is being discussed. Aims: We aimed to evaluate the efficacy and safety profile of oral pilocarpine in radiation-induced xerostomia. Materials and Methods: Sixty patients with oropharyngeal carcinoma were planned for radiotherapy and divided into two arms randomly: Arm A (30 patients) received oral pilocarpine and Arm B (30 patients) received placebo tablets for 12 weeks after 3 months of completion of radiotherapy. Salivary gland scintigraphy and xerostomia questionnaire (XQ) were obtained from each patient at baseline and at 3 and 6 months of completion of radiotherapy. Results: There was a marked decrease in uptake ratio (UR) and excretion fraction (EF) after 3 months of completion of radiotherapy. There was a statistically significant difference between both the arms in relation to UR, but no significant difference was observed between the two arms in relation to EF after 6 months of completion of radiotherapy. A statistically significant difference was found comparing the XQ results in both the arms. The XQ results did not correlate with salivary gland dysfunction observed by means of salivary scintigraphy. Adverse effects due to xerostomia were generally mild and occasionally of moderate severity. Conclusion: The use of oral pilocarpine did not significantly improve salivary gland excretory function, despite better results on salivary uptake at 6 months. However, oral pilocarpine significantly improved symptoms of xerostomia with minor side effects that were predominantly limited to sweating.