What is the antidote for magnesium sulfate toxicity?

The antidote for magnesium sulfate toxicity is calcium gluconate. Magnesium sulfate is often administered in various clinical situations, such as for severe asthma exacerbations, pre-eclampsia, or as a tocolytic agent in preterm labor. However, excessive levels of magnesium can lead to toxicity, presenting with symptoms like respiratory depression, decreased deep tendon reflexes, and cardiovascular effects such as hypotension.

Calcium gluconate acts as a protective agent because it helps to stabilize the cardiac membrane and counteracts some of the effects of elevated magnesium levels. By offering a protective effect on the heart and aiding in the normal physiological actions that magnesium can interfere with at high levels, calcium gluconate provides a critical intervention in these situations.

The other options listed do not address magnesium toxicity directly. For instance, sodium bicarbonate is often utilized in cases of metabolic acidosis, atropine is used for bradycardia or to counteract specific drug effects, and vitamin K is crucial for managing anticoagulation issues related to warfarin; none of these would mitigate the effects of magnesium sulfate toxicity.