Olanzapine overdose is associated with acute muscle toxicity

Abstract

<jats:p> Olanzapine is an atypical antipsychotic that is reported to cause myopathy and raised creatine kinase (CK) levels. The prevalence and severity of acute myopathy after deliberate olanzapine ingestion are unclear. Therefore, we reviewed casenotes from 64 consecutive patients admitted to our institution after olanzapine overdose. Overall, serum CK was higher than five times the upper limit of normal in 17% of patients. The prevalence of raised CK values was positively correlated with the stated quantity of olanzapine ingested, suggesting a dose-dependent relationship for acute muscle toxicity. There was an apparent delay of 12 hours or more between olanzapine ingestion and the occurrence of maximum CK. Despite the high prevalence of acute muscle toxicity after olanzapine ingestion, none of the patients developed renal failure. </jats:p>

Toxicology and Overdose of Atypical Antipsychotics

“…Overdoses have been characterized by CNS depression and unpredictable fluctuation between sedation and agitation (29,31). Olanzapine ingestions have been associated with increased creatine kinase, although the mechanism by which this occurs remains unclear (32).…”

Prolonged toxicity after massive olanzapine overdose: two cases with confirmatory laboratory data

“…Despite the very high serum olanzapine concentrations encountered in the present cases, neither patient developed any clinical or laboratory evidence of hepatic, renal or cardiac impairment. Transient elevation of serum creatine kinase activity has previously been reported after olanzapine overdose, but is rarely associated with a significant impact on the clinical course (Waring et al, 2006). A limitation of these data is that co-ingested drugs might have contributed to prolongation of toxicity in these cases.…”

Doxylamine toxicity: seizure, rhabdomyolysis and false positive urine drug screen for methadone

“…However, daily monitoring of doxylamine and its metabolites in the plasma would be needed to support such a hypothesis. Nonetheless, delayed muscle toxicity has been reported after overdose with other drugs (eg, venlafaxine and olanzapine) 8 , 9…”