Pharmacokinetics of Alcuronium in Elderly Patients Undergoing Total Hip Replacement or Aortic Reconstructive Surgery

Abstract

The pharmacokinetic behaviour of alcuronium was studied in three patients undergoing resection of an aortic aneurysm, and in another two patients undergoing total hip replacement (group I). A control group of five elderly patients undergoing relatively minor surgery was included (group II). In group I patients, the values of the pharmacokinetic parameters such as plasma clearance, elimination half-life and the apparent volume of distribution of the drug were found to be comparable to those obtained in normal young patients in previous studies. The group II patients, however, were found to have a prolonged elimination half-life as a result of reduced plasma clearance, possibly an age-related effect. The differences between these two groups of patients may be explained by the differences in the extent of haemorrhage and fluid replacement or changes in blood circulation, or both. However, alcuronium must still be used cautiously in both groups of patients, especially in the light of a recent finding that patients undergoing aortic reconstructive surgery have a high frequency of functional renal failure after operation.

Adverse Effects of Neuromuscular Blocking Drugs

“…In the elderly this increased sensitivity is probably accounted for by slower metabolism and excretion of drugs, in contrast to the neonate, in whom it is more likely to be related to a decreased number of post-synaptic receptors. Thus a decreased clearance of pancuronium (McLeod, Hull and Watson, 1979), alcuronium (Stephens et al, 1984) and tubocurarine (Matteo et al, 1985) have all been demonstrated in the elderly. Both the onset and the duration of action of vecuronium 0.07 mg kg" 1 have been shown to be prolonged in old age (d'Hollander et al, 1982;d'Hollander, Nevelsteen et al, 1983).…”