A woman in the labor room is augmented with prostaglandins and develops uterine hyperstimulation. Which of the following drugs is used as an antidote for prostaglandin-induced hyperstimulation?

1. A

   Calcium gluconate

2. B

   Magnesium sulphate

3. C

   Terbutaline

4. D

   Hydralazine

Appeared in: NORCET 9 Mains - 2025

Explanation

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• Terbutaline is a beta-2 adrenergic agonist, a class of drugs known for relaxing smooth muscle.
• It acts rapidly on the beta-2 receptors of the myometrium (uterine muscle), causing it to relax.
• This rapid tocolytic (uterine-relaxing) effect makes it the first-line treatment for acute uterine hyperstimulation (tachysystole) caused by labor-inducing agents.
• Its quick action helps to restore adequate blood flow to the placenta, resolving fetal distress caused by excessive contractions.

Why Other Options Were Wrong

• Option A: Calcium gluconate is not a uterine relaxant. It promotes muscle contraction and is used as an antidote for magnesium sulfate toxicity, not for uterine hyperstimulation.
• Option B: While Magnesium sulfate is a tocolytic, its onset of action is too slow for the acute, emergency management of uterine hyperstimulation. Terbutaline is much more rapid.
• Option D: Hydralazine is an antihypertensive medication used to lower blood pressure. It has no direct effect on uterine contractility.

Related Visual

• Visual 1: Diagram: A flowchart showing the steps for managing uterine tachysystole, starting with discontinuing the uterotonic agent and ending with administration of a tocolytic like Terbutaline.
• Visual 2: Illustration: A diagram showing the mechanism of action of a beta-2 agonist on a uterine smooth muscle cell, illustrating how it leads to relaxation.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological management of uterine hyperstimulation during labor as background academic context rather than a clinical decision trigger.
• Recognizing and responding to uterine hyperstimulation is a critical nursing responsibility in the labor and delivery setting to prevent fetal compromise.
• Nurses must be prepared to act quickly: stop the uterotonic, reposition the patient, provide oxygen, and notify the provider, anticipating an order for a tocolytic like Terbutaline.
• What if the patient had a history of cardiac arrhythmia? The use of Terbutaline (a beta-agonist) would be relatively contraindicated due to its side effects of tachycardia and palpitations. In such a case, the provider might consider an alternative like a calcium channel blocker, although this is less common for acute rescue.

How to Approach the Question

• Identify the core clinical problem: The patient has uterine hyperstimulation caused by prostaglandins.
• Analyze the question: The question asks for the 'antidote' or treatment for this specific problem.
• Categorize the options: Classify each drug based on its primary pharmacological action (e.g., tocolytic, antihypertensive, electrolyte).
• Evaluate each option in the context of the problem: A drug that relaxes the uterus (a tocolytic) is needed. Terbutaline is a rapid-acting tocolytic.
• Eliminate incorrect options: Calcium gluconate is for magnesium toxicity. Hydralazine is for hypertension. Magnesium sulfate is a tocolytic, but not the first choice for acute rescue due to its slower onset.
• Select the best fit: Terbutaline is the most appropriate and rapid-acting medication for this specific emergency.

Concept Tested & Keywords

• Concept Tested: Pharmacological management of uterine hyperstimulation during labor.
• Stem keywords: labor room, prostaglandins, uterine hyperstimulation, antidote
• Lead-in keywords: Which of the following
• Clinical cues: A patient augmented with prostaglandins develops uterine hyperstimulation, indicating a need for a rapid-acting uterine relaxant (tocolytic).

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