Nifedipine used in the treatment of eclampsia is?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Pharmacology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2016

Explanation

Nifedipine is classified as a dihydropyridine calcium channel blocker (CCB).
Its primary mechanism is to block the influx of calcium ions through L-type calcium channels in the smooth muscle cells of blood vessels.
This action leads to vasodilation (relaxation of the arteries), which reduces systemic vascular resistance and effectively lowers blood pressure.
In the context of eclampsia, it is a first-line agent used to treat acute severe hypertension, thereby reducing the risk of maternal complications like hemorrhagic stroke.

Option A: Nifedipine is a calcium channel blocker, not a beta-blocker. Beta-blockers work by blocking the effects of catecholamines (like adrenaline) on beta-receptors, primarily in the heart.
Option B: Prostaglandin inhibitors, such as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), are not used to treat hypertension in eclampsia. They can have adverse effects on fetal circulation and renal function.
Option D: While some antihypertensives are adrenergic antagonists, Nifedipine's primary mechanism is calcium channel blockade, not blocking adrenergic receptors (alpha or beta).

Clinical Relevance

Nursing practice connection: Knowing Pharmacological classification and mechanism of action of Nifedipine in the context of eclampsia treatment helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Rapidly controlling severe hypertension (systolic BP greater than 160 mmHg or diastolic BP greater than 110 mmHg) in pregnant women with eclampsia is a critical nursing priority to prevent maternal end-organ damage, particularly hemorrhagic stroke.
Nurses administering IV or oral Nifedipine for a hypertensive crisis must closely monitor the patient's blood pressure and heart rate, typically every 5-15 minutes, to assess effectiveness and prevent an unsafe drop in pressure (hypotension).
What if? If the patient presents with significant tachycardia alongside hypertension, a beta-blocker like Labetalol might be a more appropriate choice than Nifedipine, as Nifedipine can sometimes cause a reflex tachycardia.

How to Approach the Question

First, identify the core of the question: it asks for the drug class of Nifedipine.
Second, note the clinical context: its use in eclampsia. This suggests the drug is used to manage a key feature of this condition, which is severe hypertension.
Third, access your pharmacology knowledge about common antihypertensive agents.
Fourth, evaluate the options. 'Beta-blocker', 'Calcium channel blocker', and 'Adrenergic antagonist' are all known classes of antihypertensives.
Finally, specifically classify Nifedipine. It is a classic example of a calcium channel blocker. Select this option as the correct answer.

Concept Tested & Keywords

Concept Tested: Pharmacological classification and mechanism of action of Nifedipine in the context of eclampsia treatment.
Stem keywords: Nifedipine, treatment, eclampsia
Lead-in keywords: is
Negative lead-in flag: false

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E6 Pharmacology Katzung 16e pp. 311-313, 292-294

E6 Kaplan Sadock's Synopsis of Psychiatry-2022 (pp 1-3768 of 3768) p. 2108-2110