Abstract

Therapeutic drug monitoring (TDM) is a clinical pharmacokinetics technique that involves determining plasma drug concentrations and adjusting dosages to maintain them within a targeted therapeutic window. It is useful for drugs with a narrow therapeutic index, which are the only ones that require TDM. TDM is necessary for about 50-60 substances and considers factors like patient compliance, bioavailability, serum drug level, rate of elimination, drug access to the receptor site, and receptor sensitivity. When clinical response and medication concentration are well correlated, TDM is highly useful. Regular TDM can also be used to evaluate treatment failure due to non-compliance. Therapeutic drug monitoring (TDM) is crucial for ensuring the safe and effective use of antiarrhythmic drugs, which can have significant toxicities. TDM helps optimize dosing, minimize adverse effects, and improve therapeutic outcomes by monitoring drug levels in the blood. Antiarrhythmic drugs like amiodarone, sotalol, lidocaine, and flecainide need to be closely monitored to effectively manage arrhythmias while lowering toxicity. TDM helps maintain plasma drug concentrations within a therapeutic range, balancing effectiveness and safety. It can assist in adjusting pharmaceutical dosages, identify early toxicity warnings, and allow dose adjustments before severe side effects. TDM is not always necessary for all agents, but can be used more broadly to customize antiarrhythmic treatment, particularly for high-risk individuals. In conclusion, Future advancements in pharmacogenetics and analytical techniques are expected to enhance the accuracy and usefulness of TDM, thereby enhancing its personalization. For example, quinidine has a toxicity starting at 3μg/ml, while procainamide has early toxicity at 8 to 10μg/ml. Disopyramide has an effective range of 2.5 to 6.0μg/ml, while lignocaine has an effective range between 1.5 and 5.5μg/ml. Mexiletine has a very low therapeutic index. However, challenges such as lack of therapeutic ranges and potential pro-arrhythmic effects need to be addressed to fully realize the benefits of TDM in antiarrhythmic therapy.