Clozapine levels in hospitalised schizophrenic patients does not predict re-hospitalisation: a naturalistic study
A. M. Mach, P. Bieńkowski, A. Wnorowska, M. Sypniewski, M. Radziwoń-Zaleska, M. WojnarIntroduction
Clozapine (CLO) is an atypical antipsychotic drug effective in the management of treatment-resistant schizophrenia and prevention of relapses in ambulatory care. Therapeutic drug monitoring (TDM) is the recommended method for personalised CLO dose titration.
Objectives
The aim of this real-life study was to assess whether CLO and norclozapine (NCLO) concentrations at the time of hospitalisation could predict the risk of psychiatric re-hospitalisation during outpatient care.
Methods
A total of 141 blood samples (71 females and 70 males, aged from 18 to 74 years) were analysed for serum CLO and NCLO levels with high-performance liquid chromatography coupled with a UV detector. All the patients received inpatient and outpatient care in a single academic psychiatric center from 2016 to 2022. The occurrence of re-hospitalisation was assessed for each patient up to 360 days.
Results
At all analysed time intervals (90, 180, 360 days), no correlation was observed between either CLO or NCLO concentrations and the risk of psychiatric re-hospitalisation. Patients on CLO monotherapy presented a significantly lower risk of re-hospitalisation at 180-day and 360-day follow-up (p<0.001) as compared to patients receiving CLO in combination with other psychotropic medications. The risk of re-hospitalisation was increased in patients with a higher number of previous psychiatric hospitalisations (OR =1.15, p<0.01) and in patients taking one or more psychotropic medications other than clozapine (OR=1.51, p<0.05).
Conclusions
Our study suggest that: 1) in-hospital, steady-state CLO or NCLO levels do not predict the risk of psychiatric re-hospitalisation after discharge; 2) the use of CLO in polytherapy with other psychotropic medications and the number of previous psychiatric hospitalisations may increase the risk of re-hospitalisation.
Disclosure of Interest
None Declared