The drug used in XDR-Tuberculosis is?

DSSSB -28 August 2019 (Shift-2)

Pharmacology

Medium

Appeared in: DSSSB -28 August 2019 (Shift-2)

Explanation

Extensively Drug-Resistant Tuberculosis (XDR-TB) is a form of TB resistant to at least four core anti-TB drugs, including isoniazid, rifampicin, a fluoroquinolone, and a second-line injectable.
Capreomycin is a second-line injectable polypeptide antibiotic used in combination regimens to treat drug-resistant forms of tuberculosis, including XDR-TB, when the strain is susceptible.
While resistance to one second-line injectable (like amikacin or kanamycin) is part of the XDR-TB definition, the strain may still be susceptible to Capreomycin, making it a viable treatment option.
First-line drugs like Rifampicin and Ethambutol are ineffective by definition or due to high rates of associated resistance in XDR-TB.

Option A: Streptomycin is a first-line injectable aminoglycoside. Resistance to streptomycin is widespread among drug-resistant TB strains, making it an unsuitable choice for treating XDR-TB.
Option C: Rifampicin is a cornerstone first-line anti-TB drug. XDR-TB is, by definition, resistant to rifampicin, so this drug is ineffective.
Option D: Ethambutol is a first-line oral anti-TB drug. While not part of the defining criteria for XDR-TB, resistance to ethambutol is very common in these strains, rendering it ineffective.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological treatment of Extensively Drug-Resistant Tuberculosis (XDR-TB) helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Managing XDR-TB requires a specialized, multi-drug regimen for 18-24 months, demanding strict adherence and intensive monitoring from the nursing staff.
Nurses are critical in patient education regarding the long duration of therapy, managing severe side effects of second-line drugs (like ototoxicity from Capreomycin), and providing psychological support.
Strict airborne infection control measures are paramount in healthcare settings to prevent the transmission of XDR-TB to other patients and healthcare workers.

How to Approach the Question

First, define the term in the question: 'XDR-Tuberculosis'. Recall that 'Extensively Drug-Resistant' implies resistance to both first-line and key second-line drugs.
Break down the definition of XDR-TB: It is MDR-TB (resistant to Isoniazid and Rifampicin) plus resistance to a fluoroquinolone AND at least one second-line injectable (amikacin, kanamycin, or capreomycin).
Evaluate each option against this definition.
Eliminate Rifampicin immediately, as XDR-TB is defined by resistance to it.
Eliminate Streptomycin and Ethambutol, as they are first-line drugs and would likely be ineffective against a highly resistant strain.
Identify Capreomycin as a second-line injectable. Recognize that while XDR-TB involves resistance to at least one injectable, it doesn't mean resistance to all of them. Therefore, Capreomycin is a plausible drug used in an XDR-TB regimen.

Concept Tested & Keywords

Concept Tested: Pharmacological treatment of Extensively Drug-Resistant Tuberculosis (XDR-TB).
Stem keywords: XDR-Tuberculosis, drug
Lead-in keywords: is
Negative lead-in flag: false

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