Therapy with both magnesium sulfate and nifedipine does not increase the risk of serious magnesium-related maternal side effects in women with preeclampsia.
OBJECTIVE
Does the use of nifedipine and magnesium sulfate together increase serious magnesium-related effects?


METHODS
This was a retrospective chart review of women who were admitted to BC Women's Hospital and Health Centre (1997-2001) and were given intravenous magnesium sulfate for preeclampsia. Serious magnesium-related effects were compared among 162 cases who received magnesium sulfate and contemporaneous nifedipine and 215 control subjects who received magnesium sulfate and either another antihypertensive (n=32 women) or no antihypertensive (n=183 women) medication. Chi-squared test, Fisher's exact test, or the Student t test was used for data comparison between cases and each control group. A probability value of <.05 was considered statistically significant.


RESULTS
The cases had more severe preeclampsia and a longer magnesium sulfate infusion. However, cases had no excess of neuromuscular weakness (53.1%) versus control subjects who received antihypertensive medication (53.1%; P=.99) or control subjects who received no antihypertensive medication (44.8%; P=.13) or other serious magnesium-related effects. Cases versus control subjects who received antihypertensive medication had less neuromuscular blockade (odds ratio, 0.04; 95% CI, 0.002-0.80). Cases versus control subjects who received no antihypertensive medication had less maternal hypotension (41.4% vs 53.0%; P=.04).


CONCLUSIONS
The use of nifedipine and magnesium sulfate together does not increase the risk of serious magnesium-related effects.
Magee
Laura A
LA
Centre for Healthcare Innovation and Improvement, British Columbia Research Institute for Children's and Women's Health, Department of Specialized Women's Health, BC Women's Hospital and Health Centre, Canada. LMagee@cw.bc.ca
Miremadi
Saman
S
Li
Jing
J
Cheng
Carol
C
Ensom
Mary H H
MH
Carleton
Bruce
B
Côté
Anne-Marie
AM
von Dadelszen
Peter
P
D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D016022:Case-Control Studies; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D015994:Incidence; D007275:Injections, Intravenous; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use*; D009468:Neuromuscular Diseases / Q000139:chemically induced / Q000453:epidemiology; D009543:Nifedipine / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000188:drug therapy*; D011247:Pregnancy; D012189:Retrospective Studies; D012306:Risk
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D008278:Magnesium Sulfate; D009543:Nifedipine