Transdermal blonanserin in schizophrenia: a real-world comparison with oral tablets

Blonanserin, a dopamine D2 and serotonin 5-HT2A receptor antagonist, is available in both oral and transdermal formulations. While the transdermal patch represents a novel delivery system, its clinical and pharmacological implications remain insufficiently characterized in real-world practice. In particular, differences in antipsychotic exposure, tolerability, and treatment adherence between formulations have not been fully elucidated. The patch formulation may provide more stable drug exposure and improved adherence compared with oral administration by avoiding fluctuations associated with gastrointestinal absorption and first-pass metabolism. In addition, transdermal delivery may contribute to more continuous receptor occupancy, which could be relevant for relapse prevention. This study aimed to compare effectiveness, safety, and pharmacological burden between blonanserin patch and oral tablets.

This retrospective observational study included outpatients diagnosed with schizophrenia (ICD-10 F20) who initiated blonanserin between 2020 and 2022 at a single center. Patients receiving the transdermal patch (n=25) or oral tablets (n=22) were analyzed. Clinical outcomes included Clinical Global Impression-Severity (CGI-S) and Global Assessment of Functioning (GAF), which were assessed longitudinally. Safety was evaluated based on reported adverse events. Pharmacological burden was assessed using chlorpromazine-equivalent dose and concomitant medication use as indices of overall antipsychotic exposure. Treatment persistence was analyzed using Kaplan–Meier methods with log-rank testing. Additional exploratory analyses were performed to examine trends in medication patterns over time. The study was approved by the Ethics Committee of Showa Medical University and conducted in accordance with the Declaration of Helsinki.

Both groups demonstrated improvement in clinical severity and functioning over time, as reflected by reductions in CGI-S scores and increases in GAF scores. There was no significant difference in treatment persistence between formulations (log-rank p=0.26), suggesting comparable long-term acceptability. The chlorpromazine-equivalent dose was consistently and significantly lower in the patch group at baseline and across most follow-up time points, indicating a reduced antipsychotic dose burden. Concomitant medication use remained generally stable in both groups throughout the observation period. Adverse event profiles differed between formulations, with fewer extrapyramidal symptoms observed in the patch group, while mild skin-related events were noted but were generally manageable. Baseline characteristics were broadly comparable between groups, although some differences were observed.

The blonanserin transdermal patch demonstrated clinical effectiveness comparable to oral tablets in a real-world setting. Importantly, the patch formulation was associated with a reduced antipsychotic dose burden, suggesting potential pharmacological advantages in terms of drug exposure and tolerability. These findings support the clinical utility of a transdermal delivery system as a novel approach to optimizing antipsychotic treatment. However, these findings should be interpreted with caution due to the observational nature of the study and potential confounding factors. Further prospective studies, including comparisons with oral and long-acting injectable formulations, are warranted to better define the clinical positioning of transdermal antipsychotics. These findings may have important implications for future individualized treatment strategies.

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