During Isoniazid (INH) therapy for tuberculosis, the nurse should most carefully monitor:

JIPMER Nursing Officer-2024

Medical & Surgical Nursing

Easy

Appeared in: JIPMER Nursing Officer-2024

Explanation

Isoniazid (INH), a primary drug for tuberculosis, carries a significant risk of causing drug-induced hepatitis (hepatotoxicity).
Therefore, the most critical parameter for the nurse to monitor is the patient's liver function.
This involves regularly checking Liver Function Tests (LFTs), specifically the levels of enzymes like Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST).
Elevated LFTs are an early indicator of liver injury, allowing for timely intervention to prevent severe or fatal hepatitis.

Option A: INH does not primarily affect blood glucose levels. This monitoring is not a priority unless the patient has other comorbidities like diabetes.
Option C: INH is metabolized by the liver, not the kidneys. Therefore, it does not pose a direct threat to renal function.
Option D: INH is not known to cause cardiotoxicity. Monitoring cardiac enzymes is irrelevant to the known side-effect profile of this drug.

Visual 1: Diagram: Illustration of the liver with callouts showing signs of hepatitis (jaundice, dark urine, right upper quadrant pain). This helps patients and students recognize the clinical manifestations of INH toxicity.
Visual 2: Chart: Sample Liver Function Test (LFT) report showing normal vs. elevated ALT and AST levels. This visualizes the specific lab values a nurse would monitor.

Clinical Relevance

Nursing practice connection: Knowing Pharmacological monitoring for Isoniazid (INH) adverse effects helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Patient education is a core nursing responsibility. The nurse must teach the patient to recognize and immediately report signs of hepatitis (jaundice, dark urine, fatigue, nausea, abdominal pain) and to avoid alcohol, which increases hepatotoxicity risk.
Nurses are responsible for administering pyridoxine (Vitamin B6) concurrently with INH to prevent peripheral neuropathy, another common side effect.
What if? If the patient has pre-existing liver disease (e.g., chronic hepatitis C or alcohol-related liver disease), the risk of INH-induced hepatitis is much higher. The prescriber may choose an alternative regimen or require more frequent LFT monitoring (e.g., monthly).

How to Approach the Question

First, identify the core of the question: it asks for the most important monitoring parameter for a specific drug, Isoniazid (INH).
This is a pharmacology-based question that requires recalling the primary adverse effect of a common medication.
Access your knowledge base about first-line anti-tubercular drugs. What is the most well-known, serious side effect of INH?
Evaluate the options based on this primary side effect. INH is famous for its hepatotoxicity (liver damage).
Match the side effect to the correct monitoring test. Liver damage is monitored by Liver Function Tests (LFTs).
Eliminate the other options by linking them to different drug toxicities or conditions (e.g., kidney function for streptomycin, cardiac enzymes for heart attack).

Concept Tested & Keywords

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