Drug Groups

approved

Description

A small colorless crystal used as an anticonvulsant, a cathartic, and an electrolyte replenisher in the treatment of pre-eclampsia and eclampsia. It causes direct inhibition of action potentials in myometrial muscle cells. Excitation and contraction are uncoupled, which decreases the frequency and force of contractions. (From AMA Drug Evaluations Annual, 1992, p1083)

Indication

Used for immediate control of life-threatening convulsions in the treatment of severe toxemias (pre-eclampsia and eclampsia) of pregnancy and in the treatment of acute nephritis in children. Also indicated for replacement therapy in magnesium deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those of hypocalcemia. Also used in uterine tetany as a myometriat relaxant.

Pharmacology

Magnesium sulfate is a small colorless crystal used as an anticonvulsant, a cathartic, and an electrolyte replenisher in the treatment of pre-eclampsia and eclampsia. It causes direct inhibition of action potentials in myometrial muscle cells. Excitation and contraction are uncoupled, which decreases the frequency and force of contractions. Magnesium sulfate is gaining popularity as an initial treatment in the management of various dysrhythmias, particularly torsades de pointes, and dyrhythmias secondary to TCA overdose or digitalis toxicity.

Toxicity

LD₅₀ = 1200 mg/kg (rat, subcutaneous). May be harmful if swallowed. May act as an irritant. Adverse reactions include hypotension, ECG changes, diarrhea, urinary retention, CNS depression and respiratory depression.

Affected Organisms

Biotransformation

None

Half Life

43.2 hours (for newborns)

Protein Binding

25-30%

Elimination

Magnesium is excreted solely by the kidney at a rate proportional to the serum concentration and glomerular filtration.

References

External Links