The Effect of 1% Pilocarpine Mouthwash on Salivary Flow Rate in Patients with Radiation-Induced Xerostomia: A Double-Blind Randomized Clinical Trial

Background: Radiation-induced hyposalivation is a common complication of radiotherapy for head and neck cancers. The most commonly prescribed medication for hyposalivation is pilocarpine. However, due to the numerous systemic side-effects associated with pilocarpine, there has been a proposal to use it as a mouthwash. This study aimed to evaluate the impact of 1% pilocarpine mouthwash on salivary flow in patients with radiation-induced xerostomia. Method: This double-blind, randomized clinical trial involved 63 patients with radiation-induced xerostomia. The patients were randomly allocated into the pilocarpine hydrochloride 1% mouthwash group and the placebo one. Patients were instructed to use these mouthwashes four times a day, with 30 drops each time, for two minutes. Unstimulated saliva production in patients was measured using the spitting method at three stages: two weeks before the commencement of radiotherapy, two weeks after, and four weeks after the completion of radiotherapy. These measurements were then compared between the two groups. Statistical analysis included chi-square, independent t-test, and Analysis of Variance (ANOVA) with repeated measures and the Sidak post hoc test. Statistical analysis was conducted using SPSS 17, and a significance level of P < 0.05 was applied. Results: A comparison of saliva secretion between the pilocarpine mouthwash group and the control group at various time points after radiotherapy revealed that saliva secretion in the control group significantly decreased compared with the Conclusion: 1% pilocarpine mouthwash is recommended for managing radiationinduced xerostomia.