Effect of magnesium sulfate administration on cholinesterase enzyme activity in the sera of patients with severe preeclampsia: is there any lowering effect?

ABSTRACT

Serum cholinestrase activity was determined using a colorimetric method in 60 females. They were divided into 3 groups, each comprising 20 females. The first group included pregnant females at term with severe preeclampsia. The second group included healthy pregnant females at term. The third group included healthy nonpregnant females. Blood samples were collected from all patients on admission. In the preeclamptic group, second samples were drawn 24 hours after the start of magnesium sulfate therapy. The mean level of serum cholinestrase activities in nonpregnant, preeclamptic and healthy pregnant patients were 2837 +/- 753, 2218 +/- 752 and 1667 +/- 485 units/L respectively. Differences are statistically significant [P < 0.0001]. The enzyme was found to be significantly decreased after the magnesium sulfate administration [1843 +/- 631 units/L] [P < 0.0001]. Our data demonstrated that magnesium has a significant inhibiting effect on serum cholinestrase activity in preeclamptic patients. We conclude that the magnesium inhibiting effect of the already low level of serum cholinestrase activity is responsible for the prolonged duration of action of succinylcholine in preeclamptic patients treated with magnesium sulfate. We believe that both the obstetrician and the anesthesiologist should be aware, alert and cooperative in dealing with these critical cases