Sublingual Atropine Administration for Clozapine-Induced Sialorrhea in Bipolar Disorder: A Case Report Highlighting its Efficacy, Safety Concerns and Challenges

We discuss a case with off-label sublingual administration of atropine for clozapine-induced sialorrhea (CIS) after failure of two commonly used agents to manage CIS. Atropine had a demonstrable efficacy, as measured by means of sialometry conducted before and after its administration. The salivary rate, initially measured at 0.60 g/min one hour before atropine administration, reduced to 0.23 g/min two hours after administration. Sublingual administration of atropine was found to be an efficacious option for this patient, but safety issues particularly tachycardia and pragmatics such as risk of inadvertent overdose led to its discontinuation after the initial dose. Developing micro-dosing devices for sublingual atropine could enhance administration precision, reduce side effects, and provide a cost-effective solution. The case report also underscores the need to employ sialometry for the objective assessment of treatment outcomes in future research trials for hypersalivation.