**Question:** Which antitubercular drug combination is safer in a patient who develops hepatitis while on ATT: March 2005

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**Core Concept**
The question is asking about the choice of a safer antitubercular drug regimen for a patient who experiences hepatitis as a side effect while undergoing treatment for Tuberculosis (TB). In this context, we need to consider a drug regimen that would minimize the risk of worsening liver injury and maintain treatment effectiveness.

**Why the Correct Answer is Right**

**Correct Answer: Option C**

The correct answer is Option C, "Rifampicin, Isoniazid, Pyrazinamide, Ethambutol" (RHZE) because it is a modified regimen of the standard 6-month regimen containing Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol.

Rifampicin is a bactericidal drug targeting the bacterial RNA polymerase, which is essential for DNA transcription. It is effective against Mycobacterium tuberculosis but also has a high risk of hepatotoxicity. By omitting Rifampicin, the risk of liver injury is reduced while the core components (isoniazid, pyrazinamide, and ethambutol) remain intact to maintain treatment effectiveness.

**Why Each Wrong Option is Incorrect**

**Option A (Rifampicin, Isoniazid, Pyrazinamide, Ethambutol)**
This option includes Rifampicin, which carries a higher risk of hepatotoxicity. Omitting Rifampicin is the key to reducing the risk of liver injury in patients experiencing side effects.

**Option B (Isoniazid, Pyrazinamide, Ethambutol, Rifampicin)**
Including Rifampicin in the regimen increases the risk of hepatotoxicity. Omitting Rifampicin is essential for reducing liver injury risk in patients with hepatitis.

**Option D (Isoniazid, Pyrazinamide, Ethambutol)**
This regimen lacks Rifampicin, which is essential against M. tuberculosis. By omitting Rifampicin, we compromise the overall treatment effectiveness.

**Clinical Pearl**

**Clinical Pearl:** In patients with TB experiencing hepatotoxicity, a modification of the standard regimen by omitting Rifampicin is crucial to minimize the risk of liver injury. However, it is essential to maintain the core components (isoniazid, pyrazinamide, and ethambutol) to ensure treatment efficacy. Monitoring liver function tests regularly is advised during the modified regimen.

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**Why the Correct Answer is Right**

The correct answer, Option C, is chosen because it maintains the core components (isoniazid, pyrazinamide, and ethambutol) while removing Rifampicin, which is associated with a higher risk of liver toxicity. By adjusting the regimen, the risk of liver injury can be reduced, while still maintaining the overall treatment effectiveness. Monitoring liver function tests is recommended during the modified regimen.