Influence of age, renal function and heart failure on procainamide clearance and n-acetylprocainamide serum concentrations.

Twenty Caucasian adult patients with ventricular tachycardia were treated with intravenous procainamide. Seven patients also had moderate congestive heart failure. Steady-state procainamide (PA) and n-acetylprocainamide (NAPA) concentrations were used to compute procainamide clearance and NAPA/PA concentration ratio. Using stepwise multiple linear regression age, creatinine clearance and congestive heart failure were found to influence procainamide clearance significantly (p less than 0.05). Age and creatinine clearance effected the NAPA/PA concentration ratio (p less than 0.05). Based on this data, age appears to have an independent effect on both procainamide clearance and the NAPA/PA ratio that is separate from the decline in renal function that occurs in elderly patients.