Which anti-tuberculosis drug cause poor vision and difficulty in colour perception?

Chitranjjan National Cancer Institute Kolkata - 2021

Pharmacology

Easy

Appeared in: Chitranjjan National Cancer Institute Kolkata - 2021

Explanation

Ethambutol is a first-line anti-tuberculosis drug.
Its most significant adverse effect is dose-related optic neuritis, which is an inflammation of the optic nerve.
Optic neuritis manifests as a loss of visual acuity (blurred or poor vision) and difficulty in color perception, particularly red-green color blindness.
The risk of this side effect increases with higher doses (greater than 15-25 mg/kg/day), prolonged use, and in patients with renal impairment.
Due to this potential toxicity, baseline and monthly monitoring of visual acuity and color discrimination are essential for patients on Ethambutol therapy.

Option A: Streptomycin is an aminoglycoside antibiotic. Its primary toxicities are related to the eighth cranial nerve (ototoxicity), causing hearing loss and vertigo, and to the kidneys (nephrotoxicity). It does not typically cause vision problems.
Option C: Rifampicin's main side effects include hepatotoxicity (liver damage) and a characteristic, harmless orange-red discoloration of body fluids like urine, sweat, and tears. It is not associated with optic neuritis.
Option D: Pyrazinamide is known for causing hepatotoxicity and hyperuricemia (increased uric acid in the blood), which can precipitate an attack of gout. It does not affect vision.

Clinical Relevance

Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Adverse effects of anti-tuberculosis medications in acute care settings.
A nurse's primary role is patient safety, which includes monitoring for adverse drug reactions. For a patient on Ethambutol, it is critical to establish a baseline visual acuity and color perception at the start of therapy and monitor it monthly.
Patient education is crucial. The nurse must instruct the patient and their family to immediately report any changes in vision, such as blurriness, blind spots, or changes in color perception.
Early detection of optic neuritis can prevent permanent vision loss. If visual changes are reported, the drug is typically discontinued, and the effects are usually reversible.

How to Approach the Question

First, read the question carefully to identify the key elements: it asks for an 'anti-tuberculosis drug' with specific side effects: 'poor vision' and 'difficulty in colour perception'.
Next, systematically review each option, recalling the primary adverse effect profile for each drug.
For Option A (Streptomycin), recall its association with ototoxicity and nephrotoxicity.
For Option B (Ethambutol), recall its well-known link to optic neuritis and visual disturbances.
For Option C (Rifampicin), remember its effects on the liver and the orange discoloration of body fluids.
For Option D (Pyrazinamide), recall its association with liver toxicity and hyperuricemia.

Concept Tested & Keywords

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