Myotoxicity in acute clozapine overdose

Area of Science:

• Pharmacology
• Toxicology
• Neurology

Background:

• Clozapine, an atypical antipsychotic, is linked to various side effects including sialorrhoea, sedation, tachycardia, agranulocytosis, and seizures.
• Long-term clozapine use has been associated with myotoxicity and neurotoxicity.

Purpose of the Study:

• To report a rare case of myotoxicity following an acute clozapine overdose.
• To investigate the clinical presentation and diagnostic findings of clozapine-induced myotoxicity.

Main Methods:

• A case report of a 17-year-old patient who ingested 3.9 g of clozapine.
• Clinical assessment for myotoxicity, including monitoring for muscle weakness and tachycardia.
• Laboratory tests, including creatinine phosphokinase levels, and muscle biopsy to confirm myositis.

Main Results:

• Clinical features of myotoxicity appeared on the third day post-ingestion, after regaining consciousness.
• Elevated creatinine phosphokinase levels and muscle biopsy confirmed myositis.
• The patient experienced persistent tachycardia for 10 days.

Conclusions:

• Acute clozapine overdose can precipitate myotoxicity, presenting as myositis and muscle weakness.
• The combination of myositis-induced weakness and sustained tachycardia in clozapine overdose may indicate a poor prognosis.
• This case underscores the importance of recognizing and monitoring for rare toxic effects of clozapine, even after acute overdose.