A patient with tuberculosis who is on isoniazid therapy should also be administered?

Appeared in: AIIMS Bhatinda NO - 2019

Explanation

Isoniazid (INH), a primary drug for tuberculosis, is known to cause a deficiency of Pyridoxine (Vitamin B6).
This deficiency can lead to peripheral neuropathy, characterized by symptoms like tingling, numbness, and pain in the hands and feet.
To prevent this adverse effect, prophylactic supplementation with pyridoxine is a standard part of INH therapy.
Isoniazid chemically resembles pyridoxine and competes with it, inhibiting the formation of the active form of the vitamin and increasing its excretion from the body.

Option A: Thiamine (Vitamin B1) deficiency is not a recognized side effect of isoniazid therapy.
Option B: Isoniazid does not interfere with the metabolism of Riboflavin (Vitamin B2).
Option C: Nicotinic acid (Niacin/Vitamin B3) levels are not affected by isoniazid.

Clinical Relevance

Nursing practice connection: Use the key finding related to Pharmacology: Side effect management of antitubercular drugs to guide bedside assessment, documentation, and the next nursing action.
A key nursing responsibility is to assess patients on INH for early signs of peripheral neuropathy, such as changes in sensation in their extremities.
Patient education is critical. The nurse must explain that pyridoxine is not just a vitamin but a required medication to prevent nerve damage from the TB drug.
Certain populations are at higher risk for INH-induced neuropathy, including those with diabetes, HIV, kidney failure, alcoholism, or malnutrition. These patients require vigilant monitoring.

How to Approach the Question

First, identify the key drug in the question stem, which is 'isoniazid'.
Recall the common and significant side effects associated with isoniazid. The most tested side effect is peripheral neuropathy.
Think about the mechanism of this side effect. Isoniazid causes a deficiency of a specific vitamin.
Recall which vitamin is used to prevent or treat this specific side effect. Isoniazid-induced neuropathy is prevented by Pyridoxine (Vitamin B6).
Scan the options to find 'Pyridoxine'.
Eliminate the other B vitamins (Thiamine, Riboflavin, Nicotinic acid) as they are associated with different deficiency diseases (Beriberi, Ariboflavinosis, Pellagra) not typically caused by isoniazid.

Concept Tested & Keywords

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E6 Pharmacology KD Tripathi Essentials 9e Part 3 p. 274-276

E6 Medicine Davidson Principles Practice 24e pp. 613-615, 734-736

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Attempt every question from this paper in a timed mock, then review the full solution for each one.