Plasma Concentration of Pyridostigmine During the Antagonism of Neuromuscular Block

Kelvin Chan, University of Wolverhampton, United Kingdom

Abstract

The plasma concentrations of pyridostigmine were measured in eight patients during the antagonism of non-depolarizing neuromuscular blockade. After the injection i.v. of pyridostigmine bromide 14.6 mg/70kg, the concentration of the drug rapidly decreased between 2 and 7 min, and then declined more slowly. After 2 h, significant amounts of pyridostigmine were still present in the plasma of all subjects. In the eight patients studied, the initial half-life was 1.0 ± 0.3min and the terminal half-life was 46.4 ± 6.5min (mean ± SEM). Total body clearance of pyridostigmine was 8.7 ± 1.5ml min-1 kg-1, and the total apparent volume of distribution was 536 ± 80 ml kg -1. Possible explanations for the differences between these results and previous studies are considered.