A comparison of magnesium sulfate and nimodipine for the prevention of eclampsia.
OBJECTIVE
Magnesium sulfate may prevent eclampsia by reducing cerebral vasoconstriction and ischemia. Nimodipine is a calcium-channel blocker with specific cerebral vasodilator activity. Our objective was to determine whether nimodipine is more effective than magnesium sulfate for seizure prophylaxis in women with severe preeclampsia.


METHODS
We conducted an unblinded, multicenter trial in which 1650 women with severe preeclampsia were randomly assigned to receive either nimodipine (60 mg orally every 4 hours) or intravenous magnesium sulfate (given according to the institutional protocol) from enrollment until 24 hours post partum. High blood pressure was controlled with intravenous hydralazine as needed. The primary outcome measure was the development of eclampsia, as defined by a witnessed tonic-clonic seizure.


RESULTS
Demographic and clinical characteristics were similar in the two groups. The women who received nimodipine were more likely to have a seizure than those who received magnesium sulfate (21 of 819 [2.6 percent] vs. 7 of 831 [0.8 percent], P=0.01). The adjusted risk ratio for eclampsia associated with nimodipine, as compared with magnesium sulfate, was 3.2 (95 percent confidence interval, 1.1 to 9.1). The antepartum seizure rates did not differ significantly between groups, but the nimodipine group had a higher rate of postpartum seizures (9 of 819 [1.1 percent] vs. 0 of 831, P=0.01). There were no significant differences in neonatal outcome between the two groups. More women in the magnesium sulfate group than in the nimodipine group needed hydralazine to control blood pressure (54.3 percent vs. 45.7 percent, P<0.001).


CONCLUSIONS
Magnesium sulfate is more effective than nimodipine for prophylaxis against seizures in women with severe preeclampsia.
Belfort
Michael A
MA
Department of Obstetrics and Gynecology, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. uvmbelfo@ihc.com
Anthony
John
J
Saade
George R
GR
Allen
John C
JC
D000927:Anticonvulsants / Q000627:therapeutic use; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D004461:Eclampsia / Q000517:prevention & control*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D009543:Nifedipine / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000188:drug therapy*; D011247:Pregnancy; D012306:Risk; D012640:Seizures / Q000517:prevention & control; D014665:Vasodilator Agents / Q000627:therapeutic use*; D020301:Vasospasm, Intracranial / Q000517:prevention & control
D000927:Anticonvulsants; D002121:Calcium Channel Blockers; D014665:Vasodilator Agents; D008278:Magnesium Sulfate; D009543:Nifedipine