What is the antidote for magnesium sulfate toxicity?

The antidote for magnesium sulfate toxicity is calcium gluconate. Magnesium sulfate is commonly used in obstetric care, particularly for managing preterm labor and preventing seizures in patients with preeclampsia. In cases of magnesium toxicity, which can manifest as respiratory depression or cardiac issues, calcium gluconate is effective in antagonizing the effects of magnesium at the neuromuscular junction and stabilizing cardiac myocytes.

Calcium gluconate works by increasing calcium availability in the body, which helps restore normal muscle and cardiac function that may be compromised due to elevated magnesium levels. This antidote is specifically chosen because it provides a source of calcium that competes with magnesium, thereby helping to alleviate the symptoms associated with toxicity.

Other options, such as calcium chloride, while also a calcium source, are often not preferred in this context due to their potential to cause tissue irritation and for other formulation differences. Potassium chloride and sodium bicarbonate are not relevant for magnesium sulfate toxicity; potassium chloride is used to treat hypokalemia and sodium bicarbonate for metabolic acidosis, neither of which directly addresses the complications arising from magnesium overload.