Main Research Findings

Mexiletine, an antiarrhythmic agent structurally similar to lidocaine but useful orally as well as intravenously, was statistically more effective (P less than .05) than quinidine in a double-blind, parallel, randomized study of patients with chronic ventricular ectopia of various causes, although the total number of patients studied was small. 1

The relationships between plasma mexiletine levels and the presence of ventricular arrhythmias and side effects were studied on patients from IMPACT (International Mexiletine and Placebo Antiarrhythmic Coronary Trial). For all these variables, except the presence of PVCs, trigeminy and runs, the association with plasma level was significant: the higher the plasma level, the lower the rate of occurrence of the particular arrhythmia. This was true whether or not the patient had the arrhythmia at baseline. 2

Reasons for Side Effects

Mexiletine, like quinidine, has side effects that may limit its usefulness in certain patients. However, these side effects are quite distinct from those of quinidine and other type I antiarrhythmic drugs. 1

Common Side Effects

Tremor

Analyses based on the same model showed a significant correlation between plasma level and tremor. 2

Constipation

Analyses based on the same model showed a significant correlation between plasma level and constipation. 2

Sexual problems

Analyses based on the same model showed a significant correlation between plasma level and sexual problems. 2

Side Effect Countermeasures

Tremor

If you are concerned about tremor, you may need to reduce your dose of mexiletine or change to another medication. 2

Constipation

If you are concerned about constipation, you may want to try dietary and exercise therapy. 2

Sexual problems

If you are concerned about sexual problems, consult your doctor. 2

Comparison between Studies

Commonalities in Research

Both studies show that mexiletine is effective in treating ventricular arrhythmias. 1 2

Differences in Research

The first study is a comparative study of mexiletine and quinidine, showing that mexiletine is more effective. 1

The second study investigated the relationship between mexiletine plasma levels and side effects, showing that higher mexiletine plasma levels are associated with higher incidence of side effects. 2

Considerations for Real-Life Application

Mexiletine is an effective drug for treating ventricular arrhythmias, but it is important to remember that there is a risk of side effects. Before starting mexiletine, it is important to talk to your doctor and understand the risks and benefits of treatment. 1 2

Limitations of Current Research

Research on mexiletine is still limited. In particular, research on long-term safety and efficacy is lacking. Further research is needed to investigate the long-term effects of mexiletine in more detail. 1 2

Future Research Directions

Future research is needed on the long-term safety and efficacy of mexiletine, as well as the relationship between mexiletine dosage and side effects. 1 2

Conclusion

Mexiletine is an effective drug for treating ventricular arrhythmias, but it carries a risk of side effects. Before starting mexiletine, it is important to talk to your doctor and understand the risks and benefits of treatment. Further research is needed to investigate the long-term effects of mexiletine in more detail. 1 2