What does a Mydriatic drug do?

Appeared in: Bihar CHO - 2021

Explanation

Mydriatic drugs are agents that induce mydriasis, which is the dilation (widening) of the pupil.
This action is achieved by stimulating the radial (dilator) muscles of the iris, which are controlled by the sympathetic nervous system, or by blocking the parasympathetic nerves that cause constriction.
They are used clinically for eye examinations and before ocular surgeries to get a clear view of the retina and other internal structures of the eye.

Option B: This action is called miosis and is the opposite of what mydriatics do.
Option C: Mydriatics have a specific action; they only cause dilation of the pupil, not both dilation and contraction.
Option D: The primary and defining action of a mydriatic drug is pupil dilation, which is listed as an option.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological Action of Mydriatic Drugs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must educate patients about the expected side effects of mydriatics, such as blurred vision and photophobia (light sensitivity), and advise them to wear sunglasses and avoid driving until vision returns to normal.
A critical safety consideration is that mydriatics are contraindicated in patients with narrow-angle glaucoma because dilating the pupil can block aqueous humor drainage and dangerously increase intraocular pressure.
What if? If a patient had glaucoma, the provider would likely prescribe a miotic drug (e.g., pilocarpine) instead. This would constrict the pupil (miosis), which helps to increase the outflow of aqueous humor and lower intraocular pressure.

How to Approach the Question

First, identify the key term in the question: 'Mydriatic drug'.
This is a factual recall question. Access your knowledge of ophthalmic pharmacology.
Recall the definition: 'Mydriasis' means pupil dilation. Therefore, a 'mydriatic' drug causes dilation.
Contrast this with the opposite term, 'miosis' (pupil constriction), which is caused by 'miotic' drugs.
Select the option that matches the definition of mydriasis.

Concept Tested & Keywords

Q7w_OlVdJ9frjDGZjpZfCV

E6 Physiology Ganong 27e Vol 1 Part 2 p. 44-46

E6 Pharmacology Nursing Lilley 11e Part 3 p. 270-272

Practise the full Bihar CHO - 2021

Attempt every question from this paper in a timed mock, then review the full solution for each one.