Dose-response effect of serum butyrylcholinesterase activity after clinical doses of pancuronium

Introduction Low-dose pancuronium is known to affect serum cholinesterase activity (BChE); however, the dose-response effect of clinical doses of pancuronium on BChE has not been investigated. Methods Thirteen ASA I-II patients scheduled for elective surgery requiring muscle relaxation were enrolled in this study. All patients had normal BChE before surgery. Incremental doses of pancuronium ( 10, 20, 50, and 100 mu g/kg) were injected in accordance with surgical needs every 45 min. BChE was measured 3 min after injection by an automatic colorimetric method. Results BChE decreased significantly in all except one patient in comparison to the baseline (P< 0.05). However all values remained within normal clinical range. A dose of 100 mu g/kg yielded significant decrease in comparison to 10 mu g/kg but not to other dosages. Linear regression was not significant for the dose-response relationship (P= 0.05). Conclusion After clinical incremental doses of pancuronium, BChE remained within clinical range.