NCLEX Question of the Day – Thursday, March 05, 2026

Today’s question targets medication safety with high-alert OB drugs. You’ll practice recognizing magnesium sulfate toxicity fast and choosing the first, safest action. This matters on real shifts because magnesium prevents seizures in preeclampsia, but too much can depress breathing and reflexes within minutes.

Clinical Scenario

A 32-year-old G2P1 at 34 weeks is admitted to labor and delivery with severe preeclampsia (BP 168/104, 3+ proteinuria, severe headache). She received a 4 g IV loading dose of magnesium sulfate and is now on 2 g/hr. A Foley catheter is in place for strict intake and output. Over the last 2 hours, urine output has dropped from 30 mL/hr to 15 mL/hr. She reports “feeling very sleepy” and “heavy arms.”

Assessment: drowsy but arousable, respiratory rate 10/min, oxygen saturation 95% on room air, deep tendon reflexes 1+ at the patella, no clonus. Lungs clear. Fundal tone firm. Fetal heart rate 140 with moderate variability. IV fluids: LR at 75 mL/hr.

The Question

Which action should the nurse take first?

Answer Choices

1. Stop the magnesium sulfate infusion and prepare to administer IV calcium gluconate; notify the provider.
2. Reduce the magnesium sulfate rate by half and reassess in 30 minutes.
3. Continue the current infusion; these are expected effects of magnesium sulfate. Document and recheck in 1 hour.
4. Increase IV fluids to improve urine output before making magnesium changes.

Correct Answer

A — Stop the magnesium sulfate infusion and prepare to administer IV calcium gluconate; notify the provider.

Detailed Rationale

Why this is the priority: The client shows classic signs of magnesium toxicity: depressed respirations (10/min), hyporeflexia (1+), sedation, and oliguria (15 mL/hr). Magnesium is excreted by the kidneys. When urine output falls below 30 mL/hr, serum magnesium can rise quickly. Magnesium depresses the central nervous system and neuromuscular transmission. Left unchecked, this can progress to apnea and cardiac arrest.

Safe sequence (ABCs first):

• Airway/Breathing: Stop the magnesium to halt further depression. Prepare to give the antidote, calcium gluconate, to reverse neuromuscular effects. Have oxygen and suction ready. Be prepared for assisted ventilation if respirations decline further.
• Circulation: Maintain IV access. Keep the client in a lateral position to optimize uteroplacental perfusion.
• Notify the provider after stopping the infusion and initiating emergency measures, as per protocol.

What to assess next:

• Vital signs and respiratory rate every 5–15 minutes until stable.
• Deep tendon reflexes and level of consciousness frequently.
• Strict intake and output; target urine output ≥ 30 mL/hr.
• Serum magnesium level (therapeutic for seizure prophylaxis is typically 4–7 mEq/L); anticipate a stat level.
• Fetal status continuously, given maternal instability.

What to do: Administer calcium gluconate per protocol (commonly 10 mL of 10% solution = 1 g IV given slowly), monitor for improvement in respirations and reflexes, and follow provider orders on whether/when to restart magnesium at a lower rate once stable. Continue seizure precautions and blood pressure control.

Why the Other Options Are Wrong

• B: Reducing the rate delays reversal while toxicity is already present. With respiratory rate 10/min and oliguria, partial reduction does not remove the immediate threat. The infusion must be stopped and the antidote prepared.
• C: These are not “expected effects.” Drowsiness alone can occur, but hyporeflexia and respiratory depression are red flags. Waiting 1 hour risks progression to apnea and cardiac arrest.
• D: Increasing IV fluids can worsen pulmonary edema in preeclampsia and does not address the cause. The immediate problem is drug toxicity due to accumulation; the first step is to stop the drug and reverse its effects.

Key Takeaways

• Magnesium sulfate toxicity triad: depressed respirations, diminished or absent deep tendon reflexes, and low urine output.
• First action: stop magnesium; prepare calcium gluconate; support airway and breathing; notify the provider.
• Magnesium is renally cleared. Urine output < 30 mL/hr increases risk for rapid accumulation.
• Monitor hourly: respirations, reflexes, level of consciousness, and urine output. Keep the antidote at the bedside.
• Fetal monitoring continues during maternal instability; lateral positioning supports perfusion.

On-shift mini-checklist

• Before starting: baseline vitals, reflexes, lung sounds, and urine output; verify pump settings; ensure calcium gluconate is available.
• During infusion: check RR, DTRs, LOC, and UOP at least hourly; maintain strict I/O; continuous fetal monitoring.
• Thresholds to act: RR < 12, absent or markedly decreased DTRs, UOP < 30 mL/hr, or sudden sedation — stop magnesium and initiate reversal steps.
• After reversal: frequent reassessment, obtain magnesium level, and follow orders for any restart at a lower rate.

Quick Practice Extension

• You receive labs showing serum magnesium above the therapeutic range with normal respirations and 35 mL/hr urine output. What is your next nursing action and what will you monitor most closely?
• A postpartum client on magnesium sulfate develops crackles and mild dyspnea. What assessments and interventions take priority before considering fluid changes?

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com