Patients suffering from multidrug resistant tuberculosis can be treated with all the following durgs except –
**Core Concept**
Multidrug-resistant tuberculosis (MDR-TB) is a form of tuberculosis that is resistant to treatment with at least two of the most powerful first-line anti-TB drugs, isoniazid and rifampicin. The treatment of MDR-TB requires the use of second-line anti-TB drugs, which are less effective and more toxic than first-line drugs.
**Why the Correct Answer is Right**
The treatment of MDR-TB involves a combination of second-line drugs, including aminoglycosides, polypeptides, thioamides, and quinolones. These drugs work by inhibiting the growth of M. tuberculosis through different mechanisms, such as inhibiting protein synthesis (aminoglycosides), disrupting cell wall synthesis (polypeptides), or inhibiting DNA replication (quinolones). For example, kanamycin (an aminoglycoside) inhibits protein synthesis by binding to the 30S ribosomal subunit, while moxifloxacin (a quinolone) inhibits DNA replication by binding to the bacterial DNA gyrase.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a first-line anti-TB drug that is commonly used to treat MDR-TB. Isoniazid is a key component of the standard TB regimen and is essential for the treatment of MDR-TB.
**Option B:** This option is incorrect because it is a first-line anti-TB drug that is often used in combination with isoniazid to treat MDR-TB. Rifampicin is a critical component of the standard TB regimen and is essential for the treatment of MDR-TB.
**Option C:** This option is incorrect because it is a first-line anti-TB drug that is commonly used to treat MDR-TB. Ethambutol is a key component of the standard TB regimen and is often used in combination with isoniazid and rifampicin to treat MDR-TB.
**Clinical Pearl / High-Yield Fact**
The treatment of MDR-TB requires a comprehensive approach that involves a combination of second-line drugs, as well as a thorough evaluation of the patient's medical history, laboratory results, and radiographic findings. A key challenge in treating MDR-TB is the risk of adverse effects associated with second-line drugs, which can be severe and even life-threatening.
**Correct Answer: D.**