Magnesium sulfate
Regulatory sources consulted
Approved indications
- Prevention of eclampsia in patients with pre-eclampsia and treatment of seizures and prevention of recurrent seizures in patients with eclampsia.
Contraindications
Absolute
- Heart block or myocardial damage.
- Diabetic coma.
- Myasthenia gravis.
Clinical warnings
- Major warning · Monitor magnesium and signs of toxicity, including diminished reflexes, respiratory depression and facial oedema. Stop for significant toxicity and keep an injectable calcium salt immediately available. — https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
- Major warning · Do not administer for longer than 5–7 days: prolonged exposure during pregnancy may cause fetal hypocalcaemia, skeletal demineralisation or osteopenia and neonatal fractures. — https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
Drug interactions
- HighNeuromuscular blocking agentsM03A
Mechanism: It may potentiate and prolong neuromuscular blockade.
Recommendation: Monitor respiration and depth of blockade and adjust the blocking and reversal agents.
https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
- HighNarcotics or propofol
Mechanism: It may potentiate and prolong analgesia and central nervous system depression.
Recommendation: Frequently monitor the depth of CNS depression and adjust the narcotic or propofol.
https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
- HighDihydropyridine calcium-channel blockersC08CA
Mechanism: It may cause an exaggerated hypotensive response.
Recommendation: Frequently monitor heart rate, blood pressure and respiration; supportive care or discontinuation of the calcium-channel blocker may be required.
https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
- ModerateDrugs that induce magnesium loss
Mechanism: Alcohol, aminoglycosides, amphotericin B, cisplatin, cyclosporine, digitalis and loop or thiazide diuretics may reduce magnesium concentrations and efficacy.
Recommendation: Frequently monitor magnesium and adjust the infusion to maintain the target range.
https://api.fda.gov/drug/label.json?search=id:%22ba12f8c6-c313-4649-9ce8-100a8abb3ba6%22&limit=1
Adverse events
Common (≥1%)
Flushing · Sweating · Hypotension · Depressed reflexes · Flaccid paralysis · Hypothermia
Rare but serious
Circulatory collapse · Cardiac depression and bradycardia · Central nervous system depression and respiratory paralysis · Pulmonary oedema · Myasthenic crisis
Pregnancy and lactation
FDA category: Uso obstétrico indicado; limitar duración
It is indicated during pregnancy for pre-eclampsia/eclampsia but not for preterm labour; avoid use beyond 5–7 days. IV magnesium increases milk magnesium only slightly and oral absorption by the infant is poor; weigh the benefits of breastfeeding against the mother's clinical need.
Recent literature (PubMed)
The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding w
The role of magnesium sulfate for treatment of eclampsia is well established. The medication proved to be superior to other anticonvulsants to reduce the incidence of recurrent convulsions among women with eclampsia. Additionally, magnesium sulfate has been indicated for women with preeclampsia with different severe features. However, despite these recommendations, many clinicians are still not confident with the use of magnesium sulfate, even in settings with high incidence of preeclampsia and unacceptable rates of maternal mortality. This review brings basic science and clinical information to endorse recommendations to encourage clinicians to use magnesium sulfate for patients with all severe features of preeclampsia, not only for women with neurological symptoms. Additionally, other benefits of magnesium sulfate in anesthesia and fetal neuroprotection are also presented. Finally, a comprehensive algorithm presents recommendations to manage patients with preeclampsia with severe features between 34 and 36+6 weeks.
To systematically review the evidence for the effectiveness and safety of magnesium sulfate as a fetal neuroprotective agent when given to individuals at risk of preterm birth. We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov , the World Health Organization International Clinical Trials Registry Platform (through March 17, 2023), and reference lists of relevant studies. Randomized controlled trials (RCTs) assessing magnesium sulfate for fetal neuroprotection in pregnant participants at risk of imminent preterm birth were eligible. Two authors assessed RCTs for inclusion, extracted data, and evaluated risk of bias, trustworthiness, and evidence certainty (GRADE [Grading of Recommendations Assessment, Development and Evaluation]). We included six RCTs (5,917 pregnant participants and 6,759 fetuses at less than 34 weeks of gestation at randomization). They were conducted in high-income countries (two in the United States, two across Australia and New Zealand, and one each in Denmark and France) and commenced between 1995 and 2018. Primary outcomes: up to 2 years of corrected age, magnesium sulfate compared with placebo reduced the risk of cerebral palsy (risk ratio [RR] 0.71, 95% CI, 0.57-0.89; six RCTs, 6,107 children) and death or cerebral palsy (RR 0.87, 95% CI, 0.77-0.98; six RCTs, 6,481 children) (high-certainty evidence). Magnesium sulfate had little or no effect on death up to 2 years of corrected age (moderate-certainty evidence) or these outcomes at school age (low-certainty evidence). Although there was little or no effect on death or cardiac or respiratory arrest for pregnant individuals (low-certainty evidence), magnesium sulfate increased adverse effects severe enough to stop treatment (RR 3.21, 95% CI, 1.88-5.48; three RCTs, 4,736 participants; moderate-certainty evidence). Secondary outcome: magnesium sulfate reduced the risk of severe neonatal intraventricular hemorrhage (moderate-certainty evidence). Magnesium sulfate
Hypertensive disorders of pregnancy affect approximately 5% to 10% of pregnant women. Eclampsia is a serious hypertensive disorder that is primarily characterized by the onset of grand mal seizure activity in the absence of other causative conditions. While eclampsia is diagnosed clinically, laboratory tests are recommended to assess for complications. Treatment strategies for eclampsia focus on controlling seizures and managing hypertension. Acute care during a seizure is critical because of the need for immediate medical interventions, including the management of the airway, breathing, and circulation, as well as ensuring the safety of the patient during convulsions. Magnesium sulfate is the preferred anticonvulsant drug. Care must be taken during administration to prevent magnesium toxicity. Antihypertensive drugs used in eclampsia include labetalol, hydralazine and nifedipine. The definitive treatment of eclampsia is delivery. Close monitoring of both mother and fetus is important to identify any indications for delivery. The timing and mode of delivery depend on obstetric indications, the severity of eclampsia, the gestational age of the fetus, and the overall clinical status of the patient. Neuraxial anesthesia is the anesthesia of choice for conscious, seizure-free, and with stable vital signs women undergoing cesarean section.
Fetal growth restriction (FGR) is a common pregnancy complication and a significant contributor of fetal and neonatal morbidity and mortality, mainly due to the lack of effective screening, prevention, and management policies. The aim of this study was to review and compare the most recently published influential guidelines on the management of pregnancies complicated by FGR. A descriptive review of guidelines from the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine, the International Federation of Gynecology and Obstetrics, the International Society of Ultrasound in Obstetrics and Gynecology, the Royal College of Obstetricians and Gynecologists, the Society of Obstetricians and Gynecologists of Canada (SOGC), the Perinatal Society of Australia and New Zealand, the Royal College of Physicians of Ireland, the French College of Gynecologists and Obstetricians (FCGO), and the German Society of Gynecology and Obstetrics on FGR was carried out. Several discrepancies were identified regarding the definition of FGR and small-for-gestational-age fetuses, the diagnostic criteria, and the need of testing for congenital infections. On the contrary, there is an overall agreement among the reviewed guidelines regarding the importance of early universal risk stratification for FGR to accordingly modify the surveillance protocols. Low-risk pregnancies should unanimously be evaluated by serial symphysis fundal height measurement, whereas the high-risk ones warrant increased sonographic surveillance. Following FGR diagnosis, all medical societies agree that umbilical artery Doppler assessment is required to further guide management, whereas amniotic fluid volume evaluation is also recommended by the ACOG, the SOGC, the Perinatal Society of Australia and New Zealand, the FCGO, and the German Society of Gynecology and Obstetrics. In case of early, severe FGR or FGR accompanied by structural abnormalities, the ACOG, the Society for Ma