Magnesium sulfate

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Transcript of Magnesium sulfate

Pharmacological Management of Preeclampsia: Magnesium SulfatePresented by:Laura Nunez, BSN, RN

Magnesium Sulfate in ObstetricsThere are multiple conditions treated in the obstetrical setting with magnesium sulfate including:Pre-term onset of laborPregnancy induced hypertensive disordersManagement and prophylaxis of seizures. (Nicholas, 2016).

Preeclampsia: Pathophysiology in peripheral vascular resistance due to sensitivity to the vasoconstrictor angiotensin II and in vasodilators.Vasospasm occurs = BPEndothelial dysfunction, systemic inflammatory response, and increased capillary permeability occur triggering decreased circulation to the kidneys, liver, brain, and placenta. (Nettina, 2014).

Mechanism of ActionAnticonvulsantinhibits the N-methyl-D-aspartate (NMDA) receptors, limiting the effect of excitotoxic neurotransmitters such as glutamate and increasing the seizure threshold.

acute hypertensive event disruptions in the blood-brain barrier (BBB) allow passage of MgSO4 to the brain parenchyma enabling the drug to act as an anticonvulsant

(Euser & Cipolla, 2009) antihypertensiveexact mechanism of action is unknown

vasospasm induced by vasoconstrictor substances, such as endothelin-1, in vascular beds thus improving hypertension (Korish, 2012).

calcium antagonist propertiesblock calcium from entering into vascular smooth muscle intracellular calcium activity inactivation of calmodulin-dependent myosin light chain kinase activity and contraction = arterial relaxation and arterial blood pressure

(Euser & Cipolla, 2009; Zhou, et al., 2013)

Potential InteractionsIncreased CNS depressant effects:Barbiturates, hypnotics, narcotics, or systemic anestheticsIncreased hypotensive effects:Calcium channel blockersDecreases absorption of:Tetracycline's, quinolones, and thyroid medicationsChanges in cardiac conduction causing heart block:If calcium is used to treat magnesium toxicity in digitalized patients(L. Homburg, personal communication, February 6, 2017; Vallerand & Sanoski, 2017 ).

Adverse Drug ReactionsTypically result of magnesium toxicity

Loss of patellar reflexesRespiratory paralysisHeart blockCollapse of circulatory systemDeath

(L. Homburg, personal communication, February 6, 2017 ; Medscape, 2017)

Side EffectsVasodilatory effects:Feeling of warmthLethargyFacial flushinghypotensionOther side effects:SweatingDiminished reflexesConfusionIntense thirst

(Smith, et al., 2013; Vallerand & Sanoski, 2017).

PharmacokineticsIV absorption

Complete bioavailabiltyOnset= immediatePeak= unknownDuration = 30 minutes


widely distributed25-30% protein binding (albumin)1-2% total magnesium located in extracellular fluid spacePrimarily in serum and RBCsCrosses into placenta

(L. Homburg, personal communication, February 6, 2017; Epocrates Inc., 2017). MetabolismNot metabolizedExcretionPrimarily by kidneysHalf-lifeUnknown

Drug Binding IssuesClassification of drugs that affect binding of MgSO4DiureticsCyclosporinesAminoglycosidesResultsInduce renal excretion of magnesiumPotential binding issuesReduced effectiveness of the drug(L. Homburg, personal communication, February 6, 2017).

Improving CommunicationAccess to resources for drug information assist providers in ensuring MgSO4 is appropriately prescribed for the patients conditionThorough documentation of treatment plan improve communication between members of the interdisciplinary teamAdditional co-signer for administration reduce errors in medication administration Required documentation flowsheet for monitoring help identify early signs and symptoms of toxicity in patients receiving MgSO4

(L. Homburg, personal communication, February 6, 2017)

Application to Practice

Clinical settingEnhancing knowledge and understanding of benefits and serious risks for both mother and neonate.Improving patient safety by reducing medication administration errors, and early identification of MgSO4 toxicityEducation settingEnhance student knowledge of pharmacologic principles related to MgSO4 to assist in improving patient safety measures when they join the nursing workforce

ReferencesEpocrates Inc. (2017). magnesium sulfate. Retrieved from Epocrates:, A. G., & Cipolla, M. J. (2009). Magnesium sulfate treatment for the prevention of eclampsia: A brief review. Stroke, 40(4), 1169-1175. doi: 10.1161/STROKEAHA.108.527788.Korish, A. A. (2012). Magnesium sulfate therapy of preeclampsia: an old tool with new mechanism of action and prospect in management and prophylaxis. Hypertension Research, 35(1), 1005-1011. doi:10.1038/hr.2012.103.Medscape. (2017). Magnesium sulfate. Retrieved from Medscape:, S. M. (Ed.). (2014). Complications of the childbearing experience (10th ed.). Ambler, PA: Wolters Kluwer Health | Lippincott Williams & Wilkins.Nicholas, J. (2016). Drugs associated with pregnancy, labor and delivery, and lactation. In B. T. Smith (Ed.), Pharmacology for Nurses (pp. 327-342). Burlington, MA: Jones & Bartlett Learning.Smith , J. M., Lowe, R. F., Fullerton, J., Currie, S. M., Harris, L., & Felker-Kantor, E. (2013). An integrative review of the side effects related to the use of magnesium sulfate for preeclampsia and eclampsia management. BMC Pregnancy & Childbirth, 13(1), 1-11. doi:10.1186/1471-2393-13-34.Vallerand, A. H., & Sanoski, C. A. (2017). Magnesium sulfate. In Davis's Drug Guide for Nurses (15th ed.). Philadelphia, PA: F.A. Davis Company.Zhou, Q., Shen, J., Zhou, G., Shen, L., Zhou, S., & Li, X. (2013). Effects of magnesium sulfate on heart rate, blood pressure variability and baroreflex sensitivity in preeclamptic rats treated with L-NAME. Hypertension In Pregnancy, 32(4), 422-431. doi:10.3109/10641955.2013.824978.