Reduced distribution and clearance of acetaminophen in patients with congestive heart failure.
Acetaminophen is a widely prescribed analgesic/antipyretic metabolized by hepatic glucuronide and sulfate conjugation. Twelve patients, 30-66 years of age, with stable Class III or IV congestive heart failure (CHF) and 12 healthy controls matched for age, sex, and weight received single 650-mg intravenous doses of acetaminophen. Pharmacokinetic variables were determined from multiple plasma acetaminophen concentrations measured by liquid chromatography during 12 h after the dose. Compared with controls, mean total clearance of acetaminophen was reduced in CHF patients (3.56 vs. 4.59 ml/min/kg, p less than 0.025), indicating reduced biotransformation capacity in this disease. Volume of distribution was also significantly reduced in CHF patients (0.85 vs. 1.02 L/kg, p less than 0.05). Since elimination half-life depends on both volume of distribution and clearance (both of which were reduced), the half-life was similar between groups (2.87 vs. 2.34 h, NS). Thus, hepatic conjugation of acetaminophen is impaired in CHF. The finding may also apply to other drugs biotransformed by conjugation.
D000082:Acetaminophen / Q000378:metabolism*; D000328:Adult; D005260:Female; D006333:Heart Failure / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D014018:Tissue Distribution
D000082:Acetaminophen