Intrapartum magnesium sulfate and the potential for cardiopulmonary drug-drug interactions.
BACKGROUND
This study sought to determine the frequency of possible cardiopulmonary drug-drug interactions among pregnant women who received intrapartum magnesium sulfate (MgSO4).


METHODS
Pregnant women admitted to an Intermountain Healthcare facility between January 2009 and October 2011 were studied, if they received 1 or more doses of MgSO4. Concomitant medications were electronically queried from an electronic health records system. Adverse events were identified using administrative discharge codes. The frequency of cardiopulmonary drug-drug interactions was compared among women who did, and did not, receive aminoglycoside antibiotics, antacids/laxatives, calcium channel blockers, corticosteroids, diuretics, neuromuscular blocking agents, and vitamin D analogs, all of which were contraindicated for patients receiving MgSO4.


RESULTS
Overall, 683 women received intrapartum MgSO4 during the study period. A total of 219 MgSO4 potentially interacting drugs were identified among 155 (23%) unique patients. The most commonly identified potentially interacting agents included calcium channel blockers (26%), diuretics (25%), and antacids/laxatives (19%). Longer hospital stays were significantly associated with increasing numbers of MgSO4 interacting drugs (P < 0.001). Three of 53 (6%) women who received furosemide experienced a cardiac arrest, compared with 0 of 618 (0%) women who did not receive furosemide (Fisher exact test, P < 0.001).


CONCLUSIONS
Intrapartum administration of drugs that interact with MgSO4 is common and associated with prolonged hospital stays and potentially cardiopulmonary drug-drug interactions. Caution is warranted when prescribing MgSO4 in combination with known interacting medications.
*Division of Clinical Pharmacology, Department of Pediatrics, University of Utah; †Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah School of Medicine; ‡Intermountain Healthcare, Women and Newborns Clinical Program; §Intermountain Healthcare, Pediatric Clinical Program; and ¶Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah.
Sarah C
SC
Campbell
Chris
C
Stockmann
Alfred
A
Balch
Erin A S
EA
Clark
Manijeh
M
Kamyar
Michael
M
Varner
E Kent
EK
Korgenski
Joshua L
JL
Bonkowsky
Michael G
MG
Spigarelli
Catherine M T
CM
Sherwin
D000328:Adult; D004347:Drug Interactions / Q000502:physiology*; D005260:Female; D006801:Humans; D008278:Magnesium Sulfate / Q000009:adverse effects*; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D011247:Pregnancy; D012189:Retrospective Studies
D004364:Pharmaceutical Preparations; D008278:Magnesium Sulfate