Practical optimisation of antiarrhythmic drug therapy using pharmacokinetic principles.

The optimisation of antiarrhythmic drug therapy is dependent on the definitions and methods of short term efficacy testing and the characteristics of those drugs used for rhythm disturbances. The choice of an initial antiarrhythmic drug dosage is highly empirical, and will remain so until the measurement of free concentrations, enantiomeric fractions and genetic phenotyping becomes routine. However, the clinician can devise an efficient initial dosage for efficacy testing procedures based on pharmacokinetic principles and disposition variables in the literature. In this regard, a nomogram for commonly used agents and dosages was constructed and is offered as a guide to accomplish this goal. Verification of the accuracy and usefulness of this nomogram in a prospective manner in patients with symptomatic tachyarrhythmias is still required. On a long term basis, dosage regimens can be modified by the use of pharmacokinetic principles and patient-specific target concentrations, in accordance with the methods used to monitor arrhythmia recurrence and drug-related side effects.