A clozapine overdose with markedly elevated serum levels

Clozapine (Clazaril(R)) is an atypical antipsychatic agent used to treat sc hizophrenia refractory to other pharmacological agents. This report describ es an accidental clozapine overdose. The half-life of clozapine in this pat ient was determined from two blood levels, one obtained on admission and th e second 10.5 hours later. The calculated half-life of 8.11 hours is consis tent with published levels for single doses and suggests an apparent stabil ity in clozapine elimination half-life in the face of overdose. The maximum clozapine blood level attained was probably among the highest nonfatal lev els reported. The patient recovered fully following hospital admission for monitoring and supportive care. This case report illustrates the usefulness of following the time course of the changes in blood level at selected tim e intervals, as well as the importance of entertaining a diagnosis of drug overdose in patients presenting with acute mental status changes. Journal o f Clinical pharmacology, 1999;39:97-100 (C) 1999 the American College of Cl inical pharmacology.