بررسی اثر پیلوکارپین در پیشگیری از خشکی دهان ناشی از رادیوتراپی سر و گردن

Xerostomia is one of the disturbing side-effects of the radiotherapy to the head and neck region. Pilocarpine has been approved for the treatmentof this condition in the chronic phase, but its use concurrent with radiation could also be beneficial for prevention or reducing the subsequent radiation-induced xerostomia. We undertook to test this hypothesis in a clinical trial.Materials and Methods: All 18- to 70-year old patients who were to be irradiated to the head and neck, with both parotid glands in the radiation fields, were eligible for this study. Patients with any medical contraindications for pilocarpine were excluded. Randomization was performed at the start of radiotherapy to either pilocarpine 5 mg three times daily or placebo in a double-blind setting. The drug was started with irradiation and continued until 3 months after the end of radiotherapy. Serum pilocapine levels were measured in a randomly selected number of patients by high-pressure liquid chromatography (HPCL). Xerostomia was evaluated about 6 months after the end of radiation by an analog-scale questionnaire, and the objective grading of xerostomia was recorded by two separate observers.Results: A total number of 60 patients were randomized into the trial (31 pilocarpine, 29 placebo), mostly with nasopharyngeal carcinomas. Mean parotid dose was 5, 818 cGy. Mean pilocarpine serum level was 14.65 ng/ml. No serous side-effect was observed. Thirty-nine patients were analyzed for xerostomia at a median time of 7 months after radiotherapy, 18 in pilocarpine and 21 in placebo groups (9 patients died and 12 patients did not come back for xerostomia evaluation). Mean subjective xerostomia was 40.3 mm in the pilocarpine group and 57 mm in the placebo group (p= 0.02). Also mean objective xerostomia grade was 2.2 in the pilocarpine group and 2.6 in the placebo group (p= 0.01). Subjective and objective xerostomia results were positively correlated (level 0.01). Age and the parotid dose did not have a significant effect on xerostomia.Conclusion: Pilocarpine as prescribed in our trial produced the standard serum level required, and no serious side-effect. Compared to polacebo, pilocarpine used with radiotherapy could lead to a diminishment of subsequent radiation-induced xerostomia.