Efficacy and safety of pilocarpine for radiation-induced xerostomia in patients with head and neck cancer: A systematic review and meta-analysis

Background: Pilocarpine has been used widely in the treatment of dry mouth and glaucoma. In this review, the authors assessed the efficacy and safety of pilocarpine for patients with head and neck cancer who have radiation-induced xerostomia.

Types of studies reviewed: The authors conducted a systematic search including meta-analyses and randomized controlled trials in the following databases: MEDLINE, Embase, Cochrane Library, and Science Citation Index Expanded. The primary outcome was the severity of xerostomia (measured using visual analog scale [VAS] scores). Adverse events were other outcomes of interest. The authors performed meta-analyses where appropriate. The authors used the Cochrane Collaboration's tool for assessing risk of bias to assess the quality of the study.

Results: The authors identified 6 studies (including 752 patients in total). The results of a meta-analysis of 3 articles showed that pilocarpine was associated with a 12-point increase in VAS score (mean difference, 12.00; 95% confidence interval [CI], 1.93-22.08; P = .02) and higher rates of adverse events compared with placebo in terms of sweating (odds ratio [OR], 3.71; 95% CI, 2.34-5.86; P < .00001). There were no differences in rhinitis (OR, 1.21; 95% CI, 0.68-2.16; P = .52) and nausea (OR, 1.44; 95% CI, 0.83-2.49; P = .19).

Conclusions and practical implications: On the basis of the best available evidence, the results of this meta-analysis provide evidence that pilocarpine offers statistically significant clinical benefits for the symptomatic treatment of radiation-induced xerostomia in patients with head and neck cancer. However, the authors of this systematic review found the best available evidence in the meta-analysis in 3 studies, 1 of which showed no effect. The authors of this systematic review suggest that these patients take 5 milligrams of pilocarpine 3 times daily, and that there is need for further study.