Which of the following drugs is the antidote for magnesium toxicity?

Appeared in: JODHPUR AIIMS SNO-2018

Explanation

Calcium gluconate is the specific antidote for magnesium toxicity (hypermagnesemia).
Magnesium toxicity can occur with high doses of magnesium sulfate, leading to symptoms like respiratory depression, loss of reflexes, and cardiac arrest.
Calcium directly antagonizes the neuromuscular and cardiac effects of elevated magnesium levels, effectively reversing the toxicity.
It is administered intravenously to provide rapid reversal of life-threatening symptoms.

Option B: Vitamin K is not the antidote for magnesium toxicity. Its primary role is in the synthesis of clotting factors in the liver.
Option C: Naloxone is an opioid antagonist and has no effect on magnesium levels or its toxicity.
Option D: Hydralazine is a vasodilator used to treat hypertension; it is not an antidote.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Antidotes for Drug Toxicity as background academic context rather than a clinical decision trigger.
When administering IV magnesium sulfate, nurses must monitor for early signs of toxicity, including loss of deep tendon reflexes, a drop in respiratory rate (below 12 breaths/min), and hypotension.
It is a standard of care and a critical patient safety measure for a vial of calcium gluconate and a syringe to be readily available at the bedside or in the medication room of any unit where magnesium sulfate is infused, particularly in labor and delivery.
What if? If a patient receiving magnesium sulfate develops a respiratory rate of 8 breaths/min and becomes unresponsive, the nurse's priority actions are to stop the magnesium infusion immediately, call for help, and prepare to administer IV calcium gluconate as ordered.

How to Approach the Question

First, identify the core of the question, which is asking for the specific antidote for 'magnesium toxicity'.
This is a factual recall question from pharmacology. Access your knowledge about common drug toxicities and their reversal agents.
Evaluate each option. Think about the primary use of each drug.
Option A, Calcium gluconate: Recall its use in electrolyte imbalances. It is known to counteract the effects of high magnesium.
Option B, Vitamin K: Recall its role in blood clotting and as the antidote for warfarin.
Option C, Naloxone: Recall its role as the classic opioid antagonist.

Concept Tested & Keywords

QHUbjRoNRrZmy9FNIKqbYe

E6 Ghai Essential Pediatrics(pp 26-904 of 913) p. 67-69

E6 Pharmacology Nursing Lilley 11e Part 3 p. 212-214

Practise the full JODHPUR AIIMS SNO-2018

Attempt every question from this paper in a timed mock, then review the full solution for each one.