Which anti-tubercular drug can cause hearing loss?

Appeared in: AIIMS Delhi NO - 2017

Explanation

Streptomycin is an aminoglycoside antibiotic used as a second-line agent in treating tuberculosis.
A well-known and significant adverse effect of Streptomycin is ototoxicity, which results from damage to the eighth cranial nerve (vestibulocochlear nerve).
This damage can lead to irreversible hearing loss, tinnitus (ringing in the ears), and vestibular disturbances like vertigo and loss of balance.
Toxicity is dose-related and the risk increases in the elderly and in patients with renal impairment.

Option B: The primary toxicity of Ethambutol is optic neuritis, which affects the eyes, causing blurred vision and changes in color perception. It does not cause hearing loss.
Option C: The main adverse effects of Isoniazid are peripheral neuropathy (nerve damage) and hepatotoxicity (liver damage). It is not associated with ototoxicity.
Option D: This option is incorrect because Ethambutol and Isoniazid do not cause hearing loss. Only Streptomycin among the given options has ototoxicity as a major side effect.

Clinical Relevance

Nursing practice connection: Knowing Adverse effects of anti-tubercular drugs helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses must perform a baseline audiometry test before starting Streptomycin and monitor hearing function periodically throughout the treatment.
Patient education is a critical nursing responsibility. Instruct patients to immediately report any new onset of tinnitus (ringing in the ears), hearing difficulty, or dizziness/vertigo.
Early detection of ototoxicity is crucial, as the hearing loss can be irreversible. If symptoms occur, the nurse should withhold the drug and notify the physician immediately.

How to Approach the Question

This is a factual recall question focusing on the pharmacology of anti-tubercular medications.
First, identify the key concept in the question stem: 'hearing loss' as an adverse effect.
Next, systematically review the known major side effects of each drug listed in the options.
Recall that Streptomycin is an aminoglycoside, a class of antibiotics well-known for causing ototoxicity (ear toxicity) and nephrotoxicity (kidney toxicity).
Recall that Ethambutol's main side effect is optic neuritis (remember 'E' for Eye).
Recall that Isoniazid's main side effects are peripheral neuropathy and hepatotoxicity.

Concept Tested & Keywords

QUh-n0D1GdIL60O2veq7Ed

E6 Pharmacology Katzung 16e p. 1319-1321

E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 1836-1838

E6 Medicine Harrison 22e Part 1 p. 1467-1469

Practise the full AIIMS Delhi NO - 2017

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