Aging and renal clearance of procainamide and acetylprocainamide.
Thirty-two patients had blood and urine collected simultaneously for measurement of procainamide, acetylprocainamide, and creatinine. The ratios of drug clearance to creatinine clearance were calculated for each. The procainamide:creatinine clearance ratio averaged 2.9 +/- 1.6 (SD) and fell as age of the patients rose (r = 0.5, p < 0.01). The acetylprocainamide:creatinine clearance ratio averaged 1.7 +/- 0.8 and also fell with age. The combination of decline in overall renal function with age with this decrease in the rate of renal tubular secretion of these drugs led to a progressive age-related rise in the steady-state serum level of procainamide (r = 0.56, p < 0.01) and acetylprocainamide (r = 0.36, p < 0.1) achieved by any dose of procainamide. Thus, the dosage of procainamide must be individualized for both overall renal function (GFR) and the age-related variations in renal tubular secretion that are of most note in children and the elderly.
D000120:Acecainide / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000375:Aging; D002648:Child; D003404:Creatinine / Q000378:metabolism; D006801:Humans; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011342:Procainamide / Q000031:analogs & derivatives* / Q000378:metabolism*
D000120:Acecainide; D003404:Creatinine; D011342:Procainamide