Relationship of clozapine serum levels with gender, smoking and symptom severity (tur)

Abstract

INTRODUCTION: We planned to analyze the variations in clozapine levels with regard to gender and smoking which are variables with effects on drug metabolism in patients with psychotic disorders. METHODS: The records of patients with the diagnosis of schizophrenia and related psychotic disorders, who were attending the Community Mental Health Center (CMHC) were investigated retrospectively for clozapine serum levels and clinical features. Symptom severity at the time of the clozapine level detection was evaluated by Brief Psychiatric Rating Scale (BPRS), UKU side effects rating scale (UKU) and Personal and Social Performance Scale (PSP). Clozapine daily dose, clozapine levels, and the scores of BPRS, UKU and PSP scales were compared according to smoking habits and gender. RESULTS: There was no significant difference in clozapine dose, clozapine level and the scales of BPRS, UKU and PSP for the comparison of gender. Smoking was more frequent in males (p=0.008). Mean clozapine doses of the smoking patients were 318.1 +- 154.72 mg/day and non-smoking patients were 360.0 +- 142.98 mg/day (p>0.05). Clozapine levels of smoking patients (384.4 +- 226.80 ng/mL) were lower than non-smoking patients (835.6 +- 444.95 ng/mL) (p=0.003). The only clinical scale score which was correlated with the clozapine levels was the activation subscale of BPRS. DISCUSSION AND CONCLUSION: The possibility of clozapine levels being lower than the therapeutic dose in smoking patients and higher than safety limits in non-smoking patients should be taken into consideration.

Keywords

• clozapine
• schizophrenia
• serum levels
• smoking
• gender
• treatment resistance