The most common drug resistance that occurs in tuberculosis in India is to which drug?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Pharmacology

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Explanation

Isoniazid (INH) is a core first-line drug for treating tuberculosis, and its extensive, prolonged use increases the probability of resistance developing.
In India and globally, Isoniazid has the highest reported rate of primary drug resistance among the first-line anti-tubercular medications.
The most common mechanism of resistance involves mutations in the bacterial katG gene, which prevents the conversion of Isoniazid into its active, bacteria-killing form.

Option B: While resistance to Streptomycin exists, its prevalence is lower than that of Isoniazid. Furthermore, it is now classified as a second-line agent in India, reserved for treating specific cases of drug-resistant TB.
Option C: Resistance to Ethambutol is significantly less common than to Isoniazid. It typically emerges in strains that are already resistant to other drugs, particularly in cases of multidrug-resistant TB (MDR-TB).
Option D: Primary resistance to Pyrazinamide is considered rare. While it is a critical first-line drug, resistance to it is not the most common.

Clinical Relevance

Nursing practice connection: Knowing Drug resistance in Tuberculosis helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Nurses play a vital role in preventing drug resistance by educating patients on the absolute necessity of completing their full course of treatment without interruption (adherence).
A key nursing responsibility is monitoring for and managing the adverse effects of Isoniazid, especially peripheral neuropathy (prevented with Vitamin B6) and hepatotoxicity (requiring liver function monitoring).
What if? If a patient develops resistance to both Isoniazid and Rifampicin, they are diagnosed with Multidrug-Resistant TB (MDR-TB). The treatment plan must be changed to a complex regimen of second-line drugs, which are more toxic, less effective, and require a much longer treatment duration (up to 2 years).

How to Approach the Question

First, identify the key elements of the question: 'most common', 'drug resistance', 'tuberculosis', and the specific location 'India'.
Recall the standard first-line drugs for treating tuberculosis: Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), and Ethambutol (E).
Apply the principle of antimicrobial resistance: drugs that are used most widely and for the longest periods are often associated with the highest rates of resistance.
Based on this principle and factual knowledge, recognize that Isoniazid is the most widely used anti-TB drug and is known to have the highest prevalence of primary resistance.
Evaluate the other options to confirm they have lower resistance rates, solidifying the choice of Isoniazid.

Concept Tested & Keywords

Q93Y81XkRjCI38k6ETQbff

E6 Pharmacology Nurses Shanbhag 3e p. 312-314

E6 Medicine Davidson Principles Practice 24e p. 145-147