Therapy with both magnesium sulfate and nifedipine does not increase the risk of serious magnesium-related maternal side effects in women with preeclampsia

• DOI: 10.1016/j.ajog.2004.11.059
• Publication Date: 2005-07-15T09:34:03Z
• Authors: Laura A. Magee; Saman Miremadi; Jing Li; Carol Cheng; Mary H.H. Ensom; Bruce Carleton; Anne-Marie Côté; Peter von Dadelszen
• Keywords: Tocolytic

Does the use of nifedipine and magnesium sulfate together increase serious magnesium-related effects?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.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).The use of nifedipine and magnesium sulfate together does not increase the risk of serious magnesium-related effects.