Background and methods: We evaluated pilocarpine hydrochloride for the treatment of radiation-induced xerostomia, a common complication of irradiation of the head and neck. A prospective, randomized, double-blind, placebo-controlled trial was undertaken to test the safety and efficacy of pilocarpine, particularly in reversing the decrease in the production of saliva and other manifestations of xerostomia. Patients received either placebo or pilocarpine (5 mg or 10 mg orally three times a day) for 12 weeks and were evaluated at base line and every 4 weeks.
Results: We studied 207 patients who had each received > or = 4000 cGy of radiation to the head and neck. In the patients receiving the 5-mg dose of pilocarpine, oral dryness improved in 44 percent, as compared with 25 percent of the patients receiving placebo (P = 0.027). There was overall improvement in 54 percent of the 5-mg group as compared with 25 percent of the placebo group (P = 0.003), and 31 percent of the 5-mg group had improved comfort of the mouth and tongue, as compared with 10 percent of the placebo group (P = 0.002). Speaking ability improved in 33 percent of the 5-mg group as compared with 18 percent of the placebo group (P = 0.037). Saliva production was improved, but it did not correlate with symptomatic relief. There were comparable improvements in the group receiving the 10-mg dose. The primary adverse effect was sweating, in addition to other minor cholinergic effects. Six and 29 percent of the patients in the 5-mg and 10-mg groups, respectively, withdrew from the study because of adverse effects. There were no serious adverse effects related to pilocarpine.
Conclusions: Pilocarpine improved saliva production and relieved symptoms of xerostomia after irradiation for cancer of the head and neck, with minor side effects that were predominantly limited to sweating.