Contraindications to Magnesium Sulfate and Alternative Seizure Prophylaxis for Severe Preeclampsia [09L

Abstract

INTRODUCTION: Intravenous magnesium sulfate is considered first-line seizure prophylaxis for preeclampsia, reducing the risk of eclampsia by half. Absolute or relative contraindications to this medication include myasthenia gravis, severe renal failure, cardiac ischemia, heart block and pulmonary edema. Levetiracetam, an alternative antiepileptic drug considered safe in pregnancy, has been suggested in such cases though its efficacy remains uncertain. Our objective was to determine how frequently alternative anticonvulsant medications are administered for seizure prophylaxis in severe preeclampsia and to identify the documented indications in such cases. METHODS: IRB approved, retrospective cohort study of women with a diagnosis of preeclampsia at 34 weeks of gestation or greater who received seizure prophylaxis at a tertiary university hospital from 2014-2017. Demographics, clinical characteristics and contraindications to magnesium sulfate, if present, were evaluated. Patients were excluded if they had a pre-existing seizure disorders or incomplete medical records. RESULTS: A total of 1,370 patients were included; 3.2% (n=44) received levetiracetam for seizure prophylaxis. Most of the levetiracetam group (79.5%) initially received magnesium. The most commonly documented contraindication was pulmonary edema (n=14) which was confirmed by imaging (either ultrasound or chest x-ray) in less than half of cases; other reasons included changes in laboratory data (n=11; increasing serum creatinine, serum magnesium >7 mg/dL), development of additional signs/symptoms (n=11; hypotension, headache, vision changes, decreased urine output) and patient refusal (n=3). Five cases did not document any contraindication. CONCLUSION: The use of alternative anticonvulsant medications in preeclampsia, which may be less efficacious, must be reserved for true contraindications to magnesium sulfate.