Pharmacokinetics of the infusion of alfentanil in man

Abstract

The pharmacokinetics of alfentanil under the conditions of an empirically derived 1 -h continuous infusion of 3μg kg-1 min-1, with a bolus of 80 μg kg-1, both i.v., were determined in five patients. The distribution half-life (mean±SD) (7.4±3.1 min), elimination half-life (86.7 ± 15.8 min), apparent volume of distribution, Varea (0.44±0.15 litre kg-1) and elimination clearance (3.33 ± 0.75 ml kg-1 min-1) were nimilar to those previously reported for a single bolus of alfentanil. These values for apparent volume of distribution and clearance can be used to calculate correct bolus and infusion doses to maintain any desired steady state plasma concentration using standard formulae: for example, to maintain a steady state plasma concentration of 400 ng ml-1, a bolus doseof 176 μg kg-1 and an infusion of 1.3 μg kg-1min would be required. © 1983 The Macmillan Press Ltd.