Magnesium is a natural calcium channel blocker that is administered intravenously as magnesium sulfate. Clinically, magnesium is used to treat preeclampsia and eclampsia in pregnant women, and also is used to treat torsades de pointes.

Key Points

  • Magnesium
    • Delivered intravenously as magnesium sulfate
    • Mechanism
      • Natural calcium channel blocker
        • Magnesium competes with calcium for same receptors on cardiac tissue
    • Clinical Use
      • Pre-eclampsia/Eclampsia
        • Prevents seizures in these patients
      • Effective in torsades de pointes
        • Blockade of calcium channels suppresses early afterdepolarizations, terminating the arrhythmia
      • May be used in digoxin toxicity
        • Adjuvant used second-line with digoxin antibodies
    • Adverse Effects