Mechanism of action
Magnesium sulphate
Magnesium, mainly an intracellular cation, decreases neuronal excitability and neuromuscular transmission. It is involved in numerous enzymatic reactions. It is a constitutive element; Half of the body’s magnesium is found in the bones.
Contraindications
hypersensitivity; not recommended in association with quinidine derivatives; tachycardia; insuf. cardiac; myocardial injury; heart attack; I.H.
Warnings and precautions
Manage at max speed 150 mg/min Mg sulfate (0.6 mmol/min Mg cation); monitor kidney function, blood pressure, and magnesium; reduce dosage in I.R. mild-moderate; do not administer with Ca salts; use in emergency situations (not mild-moderate Mg deficiency) and suspend treatment. if hypotension, bradycardia, serum concentrations > 2.5 nmol/L or if the patellar reflex (deep tendon reflex) is absent; myasthenia gravis or Eaton-Lambert syndrome.
Pregnancy
Magnesium Sulfate in Water for Injection, may cause fetal abnormalities when administered more than 5-7 days for pregnant women. It is recommended to monitor plasma magnesium levels, blood pressure, respiratory rate and deep tendon reflexes. There are retrospective epidemiological studies and clinical cases documenting fetal anomalies such as hypocalcaemia, and skeletal demineralization alterations. When given by intravenous infusion (not to be given within 2 hours of delivery) in toxemia of pregnancy, the newborn may show signs of magnesium toxicity, including neuromuscular depression or respiratory depression.
Therefore, the use of magnesium during pregnancy should only be considered if it is absolutely necessary.
