Salivary flow rate in patients with schizophrenia on clozapine

Aims: To assess the change in salivary flow rate in patients with schizophrenia on clozapine and whether the change in salivary flow rate was dose related. Methods: Twenty male inpatients with a diagnosis of schizophrenia according to the International Statistical Classification of Diseases, 10th Revision diagnostic criteria for research who were started on clozapine were recruited for the study. Unstimulated salivary flow rate was assessed at baseline and then weekly for 4 weeks using cotton swab method in 17 patients. Results: Repeated-measures analysis of variance showed a significant increase in salivary flow rate over time (F [2.37/37.94] = 3.134, P = 0.047, Greenhouse-Geisser correction, η = 0.16). Also, there was a significant increase in salivary flow rate between weeks 2 and 3 (P < 0.05). There was no correlation between salivary flow rate and mean clozapine dose. Conclusions: There was a significant increase in salivary flow rate from baseline after starting clozapine, with a significant increase from the second to the third week followed by a "plateau.".