Which drug is the drug of choice in pre-eclampsia?

NORCET 9 Mains - 2025

Obstetrics & Gynaecology

Easy

Appeared in: NORCET 9 Mains - 2025

Explanation

Magnesium sulfate is the internationally recognized first-line anticonvulsant for both the prevention of seizures in severe pre-eclampsia and the treatment of active eclamptic seizures.
Large-scale, high-quality clinical trials, such as the Magpie Trial, have definitively shown its superiority over placebo, phenytoin, and diazepam in reducing the risk of eclampsia and improving maternal outcomes.
It acts primarily as a central nervous system depressant, raising the seizure threshold. It also has a secondary benefit of mild vasodilation.
Its use requires strict monitoring for signs of toxicity, as the therapeutic range is narrow.

Option B: Diazepam, a benzodiazepine, is less effective for eclamptic seizure control compared to magnesium sulfate and carries a higher risk of maternal sedation and neonatal respiratory depression.
Option C: Clinical trials have demonstrated that phenytoin is significantly less effective than magnesium sulfate in preventing recurrent seizures in women with eclampsia.
Option D: Haloperidol is an antipsychotic medication used to treat psychiatric conditions like schizophrenia and acute psychosis. It has no therapeutic role in managing pre-eclampsia or eclamptic seizures.

Visual 1: Infographic: Signs of Magnesium Sulfate Toxicity and Nursing Actions. This visual should list the signs in order of appearance (loss of deep tendon reflexes, respiratory depression, cardiac arrest) and the corresponding nursing interventions, including stopping the infusion and administering the antidote, calcium gluconate.
Visual 2: Flowchart: Management of a Patient with Severe Pre-eclampsia. This chart would show the initial assessment, administration of MgSO4 (loading and maintenance dose), and the critical hourly monitoring parameters.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological management of pre-eclampsia and eclampsia helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses are at the forefront of managing patients on magnesium sulfate. Safe administration and meticulous hourly monitoring are critical nursing responsibilities because the margin between therapeutic and toxic levels is very narrow.
Prompt recognition of toxicity signs (e.g., loss of patellar reflex, respiratory rate below 12/min, decreased urine output) and immediate intervention (stopping the infusion, notifying the provider, preparing the antidote) are essential to prevent life-threatening complications like respiratory or cardiac arrest.
Patient education is also key. The nurse should explain the purpose of the medication and the importance of reporting symptoms like feeling excessively weak, drowsy, or having blurred vision.

How to Approach the Question

First, identify the core of the question. It asks for the 'drug of choice' for a specific, high-risk obstetric condition: pre-eclampsia. This signals a factual recall question about a first-line treatment.
Recall the primary life-threatening complication of pre-eclampsia, which is eclampsia (seizures). Therefore, the 'drug of choice' will be an anticonvulsant.
Evaluate the options provided. Magnesium sulfate, Diazepam, and Phenytoin are all anticonvulsants. Haloperidol is an antipsychotic and can be immediately eliminated.
Differentiate among the remaining anticonvulsants. In the context of obstetrics, Magnesium sulfate is uniquely established as the primary agent for eclampsia prophylaxis and treatment.
Confirm this by recalling that major clinical trials have established its superiority over other agents like diazepam and phenytoin for this specific indication.
Select Magnesium sulfate as the correct answer because it is the evidence-based, first-line therapy.

Concept Tested & Keywords

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