Correlation of clinical findings and clozapine levels in patients with acute clozapine toxicity admitted in a 6 months period to Poison Control Center – Ain Shams University Hospitals (A prospective Study)

Abstract

Unlike other antipsychotic medications, a safe therapeutic dosage range for clozapine has not been clearly established (McKean et al., 2008). The clozapine blood level associated with toxicity remains unclear (Cormac et al., 2010). The aim of this study is that it is a trial to find the correlation between clinical findings with clozapine blood levels in patients with acute clozapine toxicity admitted to poison control center – Ain Shams University to: evaluate the value of clozapine blood levels in assessing severity of toxicity and guiding therapy for better outcome in patients with acute clozapine toxicity. A prospective study was conducted on all patients of both sexes with history of acute clozapine overdose, admitted to Poison Control Center of Ain Shams University Hospitals (PCC-ASUH) from March 2019 to August 2019. The total number of acutely intoxicated clozapine cases in this study was 25 patients, number admitted in 6 months period. The data collected for each patient included socio-demographic data, clinical data (intoxication data and clinical examination), laboratory investigation (including blood clozapine level), ECG, treatment, and outcome. The results showed that there was no statistically significant correlation between the blood level of clozapine and any of the studied parameters, except with the level of consciousness, where there was statistically significant increase in the level of clozapine in comatose patients compared to conscious ones. It was concluded that the most frequent neurological manifestation among studied patients was disturbed conscious level followed by pupil changes, slurred speech, ataxia, and hallucinations. The study suggests a potential benefit of blood clozapine level monitoring as a predictor and prognostic marker of coma in acute clozapine overdose. The results also highlighted the need to run similar studies but on a larger number of patients and for longer periods of time to further assess correlations between clozapine blood level and other demographic, clinical, and laboratory parameters; and to undertake further studies focusing specifically on psychiatric patients on long-term clozapine therapy, drug abuse patients who have been exposed to clozapine overdose, and elderly patients.