A nurse should carefully monitor a client for the following side effect of MgSO4?

NORCET 5 mains

Pharmacology

Easy

Appeared in: NORCET 5 mains

Explanation

Magnesium sulfate (MgSO₄) is a central nervous system (CNS) depressant that relaxes smooth muscles.
At toxic levels, this relaxation effect extends to the muscles of respiration, including the diaphragm.
This can lead to a dangerously slow respiratory rate (bradypnea), which can progress to respiratory paralysis and arrest.
Respiratory depression is the most critical and life-threatening adverse effect of MgSO₄ toxicity.
Nursing assessment of respiratory rate (ensuring it stays above 12 breaths/min) is a priority intervention.

Option A: Visual blurring is a potential but less common sign of magnesium toxicity. It typically appears at higher serum levels, usually after more definitive signs like loss of reflexes have already occurred.
Option B: Tachypnea is rapid breathing. As a CNS depressant, MgSO₄ causes bradypnea (slowed breathing). Tachypnea is the opposite of the expected toxic effect.
Option C: Epigastric pain is a classic symptom of severe preeclampsia or HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. It indicates liver swelling and is a sign of the underlying disease, not a side effect of the MgSO₄ treatment.

Visual 1: Table: Stages of Magnesium Sulfate Toxicity. This visual would clearly link serum magnesium levels (in mEq/L or mg/dL) to the progressive clinical signs: therapeutic effect, loss of deep tendon reflexes, respiratory depression, and cardiac arrest. This helps in quick recognition of toxicity stages.
Visual 2: Infographic: Nursing Assessment for MgSO₄ Therapy. This would illustrate the key monitoring points for a nurse: checking respiratory rate, assessing deep tendon reflexes with a reflex hammer, and measuring hourly urine output. It would also show the antidote, Calcium Gluconate, being readily available.

Clinical Relevance

Nursing practice connection: Use the key finding related to Adverse effects and toxicity of Magnesium Sulfate (MgSO4) to guide bedside assessment, documentation, and the next nursing action.
The primary nursing responsibility for a patient on MgSO₄ is vigilant monitoring for toxicity. This includes assessing respiratory rate every hour, checking deep tendon reflexes, and monitoring urine output to ensure it's at least 30 mL/hr, as the drug is cleared by the kidneys.
The antidote for magnesium sulfate toxicity, calcium gluconate, must be immediately accessible at the bedside whenever a patient is receiving an MgSO₄ infusion.
What if? If the nurse assesses the patient and finds that the respiratory rate has dropped to 10 breaths/min and the patellar reflexes are absent, the immediate actions are to stop the magnesium sulfate infusion, notify the healthcare provider, and prepare to administer calcium gluconate intravenously.

How to Approach the Question

First, identify the drug in the question: Magnesium Sulfate (MgSO₄).
Recall the drug's class and primary action. MgSO₄ is a central nervous system depressant and smooth muscle relaxant.
Think about what happens when a depressant drug reaches toxic levels. It will slow down or stop vital functions.
Evaluate the options based on this understanding:
Visual blurring: Possible, but is it the most critical?
Tachypnea (fast breathing): This is stimulation, the opposite of a depressant effect.

Concept Tested & Keywords

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