Alfentanil kinetics in the elderly.
Alfentanil disposition after an intravenous bolus of 50 micrograms/kg was followed in 15 elderly surgical patients and was compared to that in nine young adults. A two-compartment open model described alfentanil disappearance from plasma. Apparent volumes of distribution of the central compartment (201 and 211 ml/kg; means), at steady state (460 and 543 ml/kg), and of the AUC (746 and 722 ml/kg) in young adults and in elderly subjects did not differ. Plasma clearance was lower in elderly subjects (4.4 ml/min/kg) than in young adults (6.5 ml/min/kg), whereas terminal plasma t1/2 was longer in the elderly patients (137 and 83 min). Alfentanil dosage should therefore be reduced in elderly patients when large single doses, multiple doses, or long-term infusions are required.
D000328:Adult; D000367:Age Factors; D000368:Aged; D015760:Alfentanil; D000701:Analgesics, Opioid / Q000378:metabolism*; D005260:Female; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male
D000701:Analgesics, Opioid; D015760:Alfentanil; D005283:Fentanyl