Prevalence of clozapine-induced sialorrhea and its effect on quality of life

Clozapine has proven to be superior to other antipsychotic drugs in the treatment of schizophrenia but is under-prescribed due to its potentially severe side effects. Clozapine-induced sialorrhea (CIS) is a frequent and extremely uncomfortable side effect, which remains understudied.

To examine the prevalence of diurnal and nocturnal CIS in a sample of patients treated with clozapine, and to evaluate its impact on quality of life.

We conducted a cross-sectional, observational study of 130 patients with schizophrenia spectrum disorders treated with clozapine. The prevalence of CIS was evaluated via specific sialorrhea scales. None of the patients included in the study was receiving a specific treatment for hypersalivation during the study period. Possible associations between sialorrhea and clinical and quality of life variables were analyzed.

Of 130 subjects, 120 (92.3%) suffered from CIS. Eighty-one (62.31%) suffered from diurnal CIS, 115 (88.56%) from nocturnal CIS, and 85 (65.38%) suffered from both. Significant positive associations between quality of life and diurnal CIS (B = 0.417; p = 2.1e - 6, R² = 0.156) and nocturnal CIS (B = 0.411; p = 7.7e - 6, R² = 0.139) were detected. Thirty per cent of the subjects reported a moderate to severe negative impact of sialorrhea on their quality of life.

The present study suggests that CIS is highly prevalent in patients with schizophrenia and has an important impact on quality of life in one-third of our sample. Therefore, the inclusion of a systematic evaluation and treatment of CIS in standard clinical practice is highly recommended.

Clinical Trials ( https://clinicaltrials.gov ) under reference NCT04197037.