Lidocaine efficacy and toxicity assessed by a new, rapid method

Area of Science:

• Cardiology
• Clinical Pharmacology
• Analytical Chemistry

Background:

• Ventricular arrhythmias are a common complication in Coronary Care Units.
• Lidocaine is a frequently used antiarrhythmic drug.
• Accurate and rapid therapeutic drug monitoring is crucial for optimizing lidocaine efficacy and safety.

Purpose of the Study:

• To compare the accuracy and speed of enzyme immunoassay (EMIT) with gas chromatography (GC) for measuring lidocaine levels.
• To evaluate the clinical effectiveness of lidocaine in treating ventricular arrhythmias.
• To assess the incidence and characteristics of lidocaine toxicity.

Main Methods:

• Lidocaine levels were measured in 50 Coronary Care Unit patients using both GC and EMIT.
• Clinical outcomes, including arrhythmia control and toxicity, were assessed.
• Correlation between serum lidocaine concentration and toxicity was analyzed.

Main Results:

• No significant difference was found between lidocaine levels measured by EMIT and GC.
• Lidocaine effectively eradicated or partially controlled ventricular arrhythmias in 94% of patients.
• Central nervous system toxicity was observed in 52% of patients, with all six patients above 5.9 microgram/ml exhibiting toxicity.
• EMIT proved to be significantly faster than GC.

Conclusions:

• EMIT is a validated, accurate, and rapid method for therapeutic drug monitoring of lidocaine.
• Lidocaine is effective for ventricular arrhythmias, but toxicity is associated with serum levels above 5.9 microgram/ml.
• Close monitoring of lidocaine levels is essential to maximize therapeutic benefit and minimize adverse effects.