Anti TB drug not toxic to liver is –
**Core Concept**
The question is testing the liver toxicity profile of anti-tubercular drugs. The correct answer will be a drug that is known for its relatively safe liver profile among the given options. This requires an understanding of the pharmacological properties and side effects of anti-tubercular medications.
**Why the Correct Answer is Right**
Ethambutol is a second-line antitubercular medication that primarily targets the cell wall synthesis of Mycobacterium tuberculosis. Unlike first-line antitubercular drugs such as isoniazid and rifampicin, ethambutol is not known to cause significant liver toxicity. It is often used in combination with other drugs to treat tuberculosis, especially in patients who cannot tolerate first-line medications.
**Why Each Wrong Option is Incorrect**
**Option A:** Isoniazid is a first-line antitubercular medication that is known to cause liver toxicity, particularly in individuals with pre-existing liver disease or those taking other hepatotoxic medications. It can cause an elevation in liver enzymes and, in rare cases, severe liver damage.
**Option B:** Rifampicin is another first-line antitubercular medication that can cause liver toxicity, although the risk is generally lower than with isoniazid. It can cause an elevation in liver enzymes and, in rare cases, severe liver damage, particularly in patients with pre-existing liver disease.
**Option C:** Pyrazinamide is a first-line antitubercular medication that can cause liver toxicity, particularly in individuals with pre-existing liver disease or those taking other hepatotoxic medications. It can cause an elevation in liver enzymes and, in rare cases, severe liver damage.
**Clinical Pearl / High-Yield Fact**
When using antitubercular medications, it is essential to monitor liver function regularly, especially in patients with pre-existing liver disease or those taking other hepatotoxic medications. Regular liver function tests can help identify any potential liver toxicity early, allowing for prompt intervention and minimizing the risk of severe liver damage.
**Correct Answer:** C. Pyrazinamide is not the answer.