Abstract
Doxacurium (30 micrograms/kg) pharmacokinetics and pharmacodynamics were evaluated in nine elderly (age range, 70 to 83 years) and nine young (age range, 19 to 39 years) patients under nitrous oxide-isoflurane anesthesia. The force of contraction of the adductor pollicis was monitored and plasma samples were collected for an 8-hour period. In the elderly group, doxacurium elimination half-life was prolonged (119.7 versus 75.9 minutes) and plasma clearance was significantly reduced (1.75 versus 2.54 ml/min/kg) without any change in volume of distribution. Onset (12.9 versus 8.9 minutes) and recovery times (113.4 versus 48.1 minutes) were longer in the elderly group. The equilibrium rate constant to the effect compartment (kco) was decreased in the elderly (0.039 versus 0.051 min-1), whereas the effect compartment concentration at 50% block was similar in both groups (44.7 versus 54.1 ng/ml). An age-related reduction in muscle blood flow may be responsible for the decrease in kco. The pharmacokinetic changes observed in the elderly are consistent with a decreased function in the organs of elimination.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
