Influence of bethanechol on salivary parameters in irradiated patients

Some studies have shown evidence that the prophylactic use of bethanechol chloride (BC) may be useful in preventing the incidence and/or severity of xerostomia (XT). However, the indication of BC in irradiated patients with XT needs to be better characterized. The study aimed to evaluate the influence of BC on XT, salivary flow rate, and salivary composition in patients previously submitted to head and neck radiotherapy. Forty five irradiated patients complaining of XT used 50 mg/day of BC for 3 months, and the salivary parameters were evaluated in 4 Phases (Before BC therapy, after one month of BC, 2 months of BC, and 3 months of BC). Biochemical analysis included buffering capacity; pH; total protein concentration (TP); amylase concentration (AM); catalase (CAT) and peroxidase (PX) activities. In addition, unstimulated and stimulated salivary flow rates were determined and XT was classified. According to the XT grading system used, patients showed improvement in XT between Phase 1, and Phases 2, 3 and 4. In addition, some changes were observed in TP concentration (decreased); AM concentration (increased); and PX and CAT activities (decreased and increased, respectively) after Phase 2, for stimulated saliva collection (p<0.05). Our results suggested that when BC was used to treat salivary gland dysfunction induced by head and neck radiotherapy, improvement in XT symptoms, and some changes in saliva composition were shown.