Inhibitory effect of quinidine on plasma pseudocholinesterase activity in pregnant women.
The effect of quinidine at therapeutic and subtherapeutic concentrations on pseudocholinesterase activity in the plasma of 16 normal pregnant women was studied. The mean plasma pseudocholinesterase activity in the absence of quinidine (control) was 0.67 +/- 0.11 U/ml. The mean pseudocholinesterase activity in the presence of quinidine at concentrations of 0.5, 1.0, 2.0, and 5.0 micrograms/ml 0.48 +/- 0.09, 0.38 +/- 0.09, 0.29 +/- 0.10, and 0.19 +/- 0.09 U/ml, respectively. At therapeutic concentrations needed to treat cardiac arrhythmias (2 to 5 micrograms/ml), quinidine inhibited pseudocholinesterase activity by 60% to 70%. All the plasma samples had a normal dibucaine number (78 to 85). We recommend caution when succinylcholine and/or ester-type local anesthetics are used in pregnant women receiving quinidine.
Kambam
J R
JR
Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN.
Franks
J J
JJ
Smith
B E
BE
D000293:Adolescent; D000328:Adult; D002091:Butyrylcholinesterase; D002800:Cholinesterase Inhibitors; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000097:blood / Q000187:drug effects*; D011802:Quinidine / Q000494:pharmacology*; D012016:Reference Values
D002800:Cholinesterase Inhibitors; D002091:Butyrylcholinesterase; D011802:Quinidine