Which of the following is a bactericidal drug in tuberculosis treatment, EXCEPT?& x20; - NORCET 9 Mains - 2025

NORCET 9 Mains - 2025

Pharmacology

Easy

Appeared in: NORCET 9 Mains - 2025

Explanation

The question requires identifying the drug that is not bactericidal, which means finding the bacteriostatic agent.
Ethambutol is a first-line anti-tuberculosis drug that is classified as bacteriostatic.
Its primary role in a multi-drug regimen is to prevent the emergence of drug-resistant strains of M. tuberculosis.
It works by inhibiting the enzyme arabinosyl transferase, which disrupts the synthesis of the mycobacterial cell wall, thereby halting bacterial multiplication.

Option B: Streptomycin is incorrect because it is a bactericidal drug.
Option C: Rifampicin is incorrect because it is a powerful bactericidal drug.
Option D: Isoniazid is incorrect because it is a potent bactericidal drug.

Visual 1: Table: Comparison of First-Line Anti-Tuberculosis Drugs - This table summarizes the classification (bactericidal/bacteriostatic), mechanism, and key nursing considerations for each drug, providing a quick reference for learners.

Clinical Relevance

Nursing practice connection: Knowing Classification of Anti-Tuberculosis Drugs (Bactericidal vs. Bacteriostatic) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Understanding the difference between bactericidal and bacteriostatic drugs is crucial for designing effective multi-drug TB regimens. Combination therapy with bactericidal agents ensures rapid killing of bacilli, while bacteriostatic agents help prevent the emergence of resistance.
A key nursing responsibility for patients on Ethambutol is to monitor for optic neuritis. Patients must be educated to immediately report any changes in vision, such as blurred vision or difficulty distinguishing between red and green.
Patient education about the duration of treatment and adherence is critical, as non-compliance with the multi-drug regimen is a primary cause of treatment failure and the development of multidrug-resistant TB (MDR-TB).

How to Approach the Question

First, identify the negative keyword 'EXCEPT' in the question stem. This indicates you are looking for the option that does not fit the stated category.
The question asks for a drug that is NOT bactericidal. This means you need to find the bacteriostatic drug among the options.
Recall the classification of the primary (first-line) anti-tuberculosis drugs.
Categorize each option: Streptomycin (bactericidal), Rifampicin (bactericidal), and Isoniazid (bactericidal).
Identify Ethambutol as the only bacteriostatic drug in the list.
Therefore, Ethambutol is the correct answer as it is the exception.

Concept Tested & Keywords

Concept Tested: Classification of Anti-Tuberculosis Drugs (Bactericidal vs. Bacteriostatic)
Stem keywords: bactericidal drug, tuberculosis treatment
Lead-in keywords: EXCEPT
Negative lead-in flag: The question asks for the option that does NOT fit the description (is not bactericidal).

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