Mexiletine, Serum or Plasma

Casandra

Casandra Test Code LC04808Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 716076CPT Code 80299

Mexiletine, Serum or Plasma

Clinical Use

Use

This Class 1B drug is used to suppress premature ventricular arrhythmias and may be as effective as quinidine or procainamide for this purpose. Mexiletine is less effective in patients with recurrent refractory ventricular tachycardia and fibrillation, and extracardiac side effects may limit its long-term usefulness. Approximately 45% of all patients experience side effects within the commonly accepted therapeutic range of 0.5−2.0 μg/mL.1 Concurrent administration of a Class 1A antiarrhythmic drug (eg, quinidine, disopyramide) or propranolol may provide better control of the arrhythmia and permit a reduction in the dose of mexiletine, thus reducing side effects. Supraventricular arrhythmias are not controlled by mexiletine.

Special Instructions

Trough levels are most reproducible, indicating the timing of specimen collection can impact results. It's important to transfer separated serum or plasma to a plastic transport tube for submission.

Limitations

This test was developed and its performance characteristics have been determined by Labcorp. However, it has not been cleared or approved by the Food and Drug Administration. This means that while the test is performed according to established procedures, it should be interpreted in conjunction with clinical findings.

Test Details