Changes in pharmacokinetics in the elderly and therapeutic drug monitoring of antiarrhythmic drugs

Advanced-age is associated with significant changes in physiological functions and absorption, distribution, metabolism and elimination of drugs. Antiarrhythmic drugs are traditionally classified into four classes, according to Vaughan Williams’s classification. The renal and hepatic elimination of many antiarrhythmic drug classes are reduced in the elderly, predisposing this population to serious drug adverse effects. Therapeutic drug monitoring has been a useful clinical tool in the safe use of antiarrhythmic drugs, especially class I drugs and amiodarone, in the younger population. Given the changes in pharmacokinetics of antiarrhythmic drugs and increased risk of adverse effects in older patients, therapeutic drug monitoring may be of particularly importance for dosage adjustment and optimization of individual antiarrhythmic therapy in the elderly.