Clozapine-induced hypersalivation: an estimate of prevalence, severity and impact on quality of life

Objectives: The objective of this study was to evaluate the prevalence and severity of clozapine-induced hypersalivation, and assess the impact hypersalivation has on global functioning. Methods: Participants attending a dedicated clozapine clinic were invited to undertake a structured interview regarding their experiences of clozapine-induced hypersalivation. Two psychometric instruments to measure hypersalivation, the Nocturnal Hypersalivation Rating Scale and the Drooling Severity and Frequency Scale were used. Results: Clozapine-induced hypersalivation was experienced by 92% of participants, with nocturnal hypersalivation more prevalent compared to daytime hypersalivation (85% versus 48%). Daytime drooling was severe in 18% of cases and was present on a frequent or constant basis for 20% of individuals. Hypersalivation had at least a moderate impact on the quality of life of 15% of study participants. Conclusions: Clozapine-induced hypersalivation is the most prevalent adverse effect experienced by patients treated with clozapine and negatively impacts on quality of life, particularly if daytime drooling is present. The development of further strategies to ameliorate this adverse effect is required given the demonstrated lack of success to date in managing this condition.