Atropine sulphate acts as a?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Pharmacology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2019

Explanation

Atropine is a classic anticholinergic (antimuscarinic) drug, and one of its primary actions is on the eye.
It functions as a mydriatic, which is a substance that causes dilation of the pupil (mydriasis).
The mechanism involves blocking muscarinic receptors in the iris sphincter muscle, preventing the pupil from constricting.
This action is often accompanied by cycloplegia (paralysis of the ciliary muscle), which results in loss of focus for near vision.
These effects are utilized clinically for ophthalmic examinations to get a clear view of the retina and other internal structures of the eye.

Option A: Atropine is not an antihypertensive. By blocking vagal tone on the heart's SA node, it causes tachycardia (increased heart rate), which can lead to an increase, not a decrease, in blood pressure.
Option B: Atropine has no primary anticonvulsant properties. In fact, at toxic or high doses, atropine can cause central nervous system excitement, restlessness, and even convulsions.
Option C: A miotic drug causes constriction of the pupil (miosis). Atropine has the exact opposite effect; it causes pupil dilation (mydriasis).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacological action of Atropine Sulphate as background academic context rather than a clinical decision trigger.
Nurses frequently administer atropine eye drops for ophthalmic procedures. Patient education is key, including warning them about temporary blurred vision and photophobia (light sensitivity) and advising them not to drive.
The most critical nursing responsibility is to assess for contraindications, especially a history of glaucoma. Administering atropine to a patient with narrow-angle glaucoma can trigger an acute attack, a medical emergency.
Atropine is also used systemically to treat bradycardia, as a pre-anesthetic medication to reduce secretions, and as an antidote for organophosphate poisoning.

How to Approach the Question

First, identify the drug mentioned in the question stem: Atropine sulphate.
Recall the pharmacological class of this drug. Atropine is the prototype anticholinergic (or antimuscarinic) agent.
Think about the effects of blocking the parasympathetic nervous system ('rest and digest'). This system normally constricts the pupil.
Therefore, blocking this system would lead to the opposite effect: pupil dilation (mydriasis).
Evaluate the given options. 'Mydriatic drug' directly describes an agent that dilates the pupil.
Eliminate the other options based on knowledge of atropine's effects: it causes tachycardia (ruling out antihypertensive), has no anticonvulsant action, and is the opposite of a miotic.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 1 pp. 155-157, 154-156

E6 Pharmacology Nurses Shanbhag 3e p. 73-75