Patient is on 2nd line ATT, now complaining about numbness & acidosis then which drug should be withdrawn?

INI-CET EXAM -2025

Pharmacology

Hard

Appeared in: INI-CET EXAM -2025

Explanation

Linezolid is an oxazolidinone antibiotic, a crucial component of regimens for multidrug-resistant tuberculosis (MDR-TB).
A significant and well-documented toxicity of Linezolid, particularly with prolonged use, is mitochondrial dysfunction.
This mitochondrial toxicity manifests clinically as peripheral neuropathy (causing numbness and tingling) and potentially fatal lactic acidosis.
The presence of both numbness and acidosis in a patient on a regimen containing Linezolid makes it the most likely causative agent that needs to be discontinued.

Option B: Bedaquiline's most critical adverse effect is QT interval prolongation, which increases the risk of life-threatening cardiac arrhythmias like Torsades de Pointes. It is not typically associated with neuropathy or lactic acidosis.
Option C: Similar to Bedaquiline, Delamanid's primary safety concern is the prolongation of the QT interval. It is not a recognized cause of lactic acidosis or significant peripheral neuropathy.
Option D: Levofloxacin is a fluoroquinolone antibiotic. While it can cause peripheral neuropathy, it is not characteristically associated with lactic acidosis. The combination of both symptoms makes Linezolid the correct answer.

Visual 1: Table: A comparative table showing the major adverse effects of second-line anti-TB drugs (Linezolid, Bedaquiline, Delamanid, Levofloxacin), highlighting the unique combination of neuropathy and lactic acidosis for Linezolid.

Clinical Relevance

Nursing practice connection: Use the key finding related to Adverse effects of second-line anti-tubercular drugs to guide bedside assessment, documentation, and the next nursing action.
Nurses play a vital role in monitoring patients on complex MDR-TB regimens for adverse drug reactions.
It is crucial to educate patients to report symptoms like numbness, tingling, muscle pain, or unexplained nausea and fatigue, as these can be early signs of Linezolid toxicity.
Prompt identification and reporting of these symptoms to the physician are essential for preventing irreversible neuropathy and life-threatening lactic acidosis.

How to Approach the Question

First, identify the core clinical problem: a patient on second-line ATT presenting with specific symptoms (numbness and acidosis).
Next, analyze the options provided, which are all second-line anti-TB drugs.
Recall or deduce the most prominent and distinguishing adverse effects of each drug.
Systematically match the patient's unique combination of symptoms to the known toxicity profile of one of the drugs.
Recognize that while Levofloxacin can cause neuropathy, the addition of acidosis is a classic sign of Linezolid toxicity.
Conclude that Linezolid is the drug that must be withdrawn.

Concept Tested & Keywords

Concept Tested: Adverse effects of second-line anti-tubercular drugs.
Stem keywords: 2nd line ATT, numbness, acidosis, drug withdrawn
Lead-in keywords: which drug
Clinical cues: Patient on 2nd line ATT: This indicates treatment for drug-resistant tuberculosis.
Clinical cues: Numbness & acidosis: These are the key symptoms pointing to a specific drug's toxicity profile.

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