Chapter 11 - Challenges in Therapeutic Drug Monitoring of Digoxin and Other Anti-Arrhythmic Drugs

Abstract

Digoxin, due to its narrow therapeutic range, is a challenge for therapeutic drug monitoring because digoxin immunoassays are affected by a variety of drugs and herbal supplements as well as endogenous digoxin-like immunoreactive factors (DLIS). For therapeutic drug monitoring of procainamide, its active metabolite N -acetylprocainamide must also be monitored. Other cardioactive drugs, including the more recently introduced tocainide, flecainide, mexiletine, propafenone, amiodarone and verapamil, also require monitoring, but immunoassays are not available for these drugs and only chromatographic techniques are capable of determining their concentrations in human serum or plasma. Therefore, therapeutic drug monitoring services for these drugs are only offered in large medical centers and reference laboratories.