Monitoring of clozapine and norclozapine plasma concentration-time curves in acute overdose

Case Report: A 40-year-old schizophrenic man was found unconscious, with co nstricted pupils, sinus tachycardia, and twitching of the limbs. There were signs of lung infection, which was treated with antibiotics, and mild rhab domyolysis, De regained consciousness over 8 hours, and reported taking 3-4 g clozapine, Recovery was uneventful. Measured peak clozapine and norcloza pine concentrations were 3.53 mg/L and 0.70 mg/L, respectively. The concent ration-time curves were biphasic, with secondary peaks at approximately 36 hours postadmission, Terminal elimination half-lives were 16.9 hours and 22 .5 hours for clozapine and norclozapine, respectively. Conclusion: Clozapin e and its metabolite norclozapine can show biphasic plasma concentration-ti me curves after overdosage.