Which one of the following anti-tuberculosis drugs cannot be given during pregnancy?

Appeared in: OSSSC Nursing Officer-2021

Explanation

Streptomycin is an aminoglycoside antibiotic, a class of drugs known for potential toxicity.
It is contraindicated in pregnancy because it can cross the placenta and reach the fetus.
The primary risk is ototoxicity, which can damage the fetus's 8th cranial nerve, leading to irreversible congenital deafness.

Option A: Rifampicin is a first-line anti-TB drug that is considered safe for use during pregnancy.
Option B: Ethambutol is another first-line anti-TB drug deemed safe for use in pregnant patients.
Option D: INH (Isoniazid) is a cornerstone of TB treatment and is safe during pregnancy. It is typically supplemented with pyridoxine (Vitamin B6) to prevent peripheral neuropathy.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology: Contraindications of Anti-Tuberculosis Drugs in Pregnancy as background academic context rather than a clinical decision trigger.
A nurse's primary responsibility is patient safety. When administering medications to a pregnant patient, it is crucial to verify that the drug is not contraindicated, as many substances can cross the placenta and harm the fetus.
Patient education is key. The nurse must explain the importance of adhering to the prescribed safe medications for TB to ensure both maternal health and fetal safety.
What if? If a pregnant patient has multidrug-resistant TB (MDR-TB), the treatment becomes complex. A specialist team would conduct a thorough risk-benefit analysis, and second-line drugs like streptomycin might be considered only if no safer alternatives exist and the mother's life is at risk, with extensive counseling about the potential fetal risks.

How to Approach the Question

First, identify the core of the question: it asks for a drug that is UNSAFE ('cannot be given') during pregnancy.
Next, categorize the options. All are anti-tuberculosis drugs.
Recall the safety profiles of common anti-TB drugs in pregnancy. The first-line drugs (Rifampicin, Isoniazid, Ethambutol) are generally safe.
Focus on drugs that are known to have teratogenic or fetotoxic effects. Aminoglycosides are a well-known class with such risks.
Identify Streptomycin as an aminoglycoside. This classification is a strong clue to its potential for toxicity in pregnancy (ototoxicity).
Conclude that Streptomycin is the contraindicated drug among the choices.

Concept Tested & Keywords

Concept Tested: Pharmacology: Contraindications of Anti-Tuberculosis Drugs in Pregnancy
Stem keywords: anti-tuberculosis drugs, pregnancy
Lead-in keywords: cannot be given
Negative lead-in flag: NOT changes the reasoning strategy; look for the exception or incorrect statement rather than the true statement.

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E6 Medicine Harrison 22e Part 1 p. 1467-1469

E6 Pharmacology KD Tripathi Essentials 9e Part 3 p. 93-95

Practise the full OSSSC Nursing Officer-2021

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