Ocular pharmacology: beta-blockers: practice question

A Ophthalmology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Ophthalmology · Ocular pharmacology: beta-blockers

Sample item

A 60-year-old man with open-angle glaucoma and well-controlled asthma is started on timolol 0.5% eye drops. He returns with wheeze and breathlessness. What explains this?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Systemic absorption of the non-selective beta-blocker causes bronchospasm

Timolol lowers intraocular pressure by reducing aqueous production, but it is absorbed through the nasolacrimal mucosa and can reach the systemic circulation, where non-selective beta-blockade causes bronchospasm and bradycardia. It is avoided in asthma, COPD and heart block. Punctal occlusion reduces systemic absorption. Prostaglandin analogues are alternatives.

Option by option

  • A. Systemic absorption of the non-selective beta-blocker causes bronchospasm (correct)

    Correct. Systemic beta-2 blockade causes bronchospasm in susceptible patients.

  • B. Timolol blocks muscarinic receptors in the bronchi

    Timolol acts on beta receptors, not muscarinic receptors.

  • C. The wheeze is unrelated to the drug and is due to glaucoma

    Glaucoma does not cause wheeze; the timing implicates the drug.

  • D. Timolol is a prostaglandin analogue that constricts bronchi

    Timolol is a beta-blocker, not a prostaglandin analogue.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Ophthalmology question

What is the answer to this Ophthalmology question?

The best answer is A, Systemic absorption of the non-selective beta-blocker causes bronchospasm. Timolol lowers intraocular pressure by reducing aqueous production, but it is absorbed through the nasolacrimal mucosa and can reach the systemic circulation, where non-selective beta-blockade causes bronchospasm and bradycardia.

Why is "Timolol blocks muscarinic receptors in the bronchi" not the answer?

Timolol acts on beta receptors, not muscarinic receptors.

Why is "The wheeze is unrelated to the drug and is due to glaucoma" not the answer?

Glaucoma does not cause wheeze; the timing implicates the drug.

Why is "Timolol is a prostaglandin analogue that constricts bronchi" not the answer?

Timolol is a beta-blocker, not a prostaglandin analogue.

What concept does this question test?

It tests Ocular pharmacology: beta-blockers in Ophthalmology. It is avoided in asthma, COPD and heart block. Punctal occlusion reduces systemic absorption. Prostaglandin analogues are alternatives.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Ocular pharmacology: beta-blockers?

Group the red eye by what to examine and what the pupil does. Then use the flashcards and the other Ophthalmology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.