Drug causing visual disturbance –
**Core Concept**
The question is testing the ability to identify a drug that can cause visual disturbances, which is a common side effect of various medications. This is related to the pharmacology of drugs that affect the visual pathway, including the retina and the optic nerve.
**Why the Correct Answer is Right**
The correct answer is a drug that inhibits the enzyme monoamine oxidase B (MAO-B), which breaks down dopamine in the retina. This leads to an accumulation of dopamine, causing visual disturbances such as blurred vision, flashers, and even temporary blindness. The drug is often used in the treatment of Parkinson's disease.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a drug that is commonly associated with visual disturbances. It is a different class of medication that is used for a different indication.
**Option B:** This option is incorrect because it is a drug that is used to treat conditions such as glaucoma, but it does not cause visual disturbances as a side effect.
**Option C:** This option is incorrect because it is a drug that is used to treat conditions such as migraines, but it does not cause visual disturbances as a side effect.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that certain medications can cause visual disturbances as a side effect, and patients should be warned about this potential risk. In particular, drugs that inhibit MAO-B can cause visual disturbances due to the accumulation of dopamine in the retina.
**Correct Answer:** C. Selegiline (Eldepryl)