Clinical course and outcome in class IC antiarrhythmic overdose

Area of Science:

• Cardiology
• Clinical Toxicology
• Pharmacology

Background:

• Drug overdose generally has a low mortality rate (<1%).
• Class IC antiarrhythmic drugs (e.g., propafenone, flecainide) present a significant overdose risk.
• Intoxication with these agents is associated with a substantially higher mortality (22.5%).

Purpose of the Study:

• To evaluate the clinical course, therapy, and outcomes of class IC antiarrhythmic overdose.
• To identify key symptoms, effective treatments, and prognostic factors.
• To emphasize the importance of early intervention in managing these overdoses.

Main Methods:

• Retrospective analysis of 120 cases of class IC antiarrhythmic overdose.
• Evaluation of clinical presentation, therapeutic interventions, and patient outcomes.
• Assessment of mortality rates and correlation with drug type and dosage.

Main Results:

• Nausea within 30 minutes was the earliest symptom; vomiting aided self-detoxification in some.
• Cardiac symptoms (bradycardia, tachyrhythmia) appeared 30 minutes to 2 hours post-ingestion.
• High mortality (22.5%) mainly due to cardiac conduction disturbances; resuscitation had limited success.
• Therapeutic measures included activated charcoal, catecholamines, sodium bicarbonate, pacemakers, and hemoperfusion.

Conclusions:

• Class IC antiarrhythmic overdose carries a high mortality risk, primarily from cardiac conduction issues.
• Specific antidotes are lacking, and supportive measures like sodium bicarbonate and pacemakers have limited efficacy.
• Early diagnosis and prompt primary detoxification are paramount for improving patient outcomes and preventing fatalities.