Thioacetazone has cross resistance with –
**Core Concept**
Thioacetazone is a second-line antitubercular drug that acts by inhibiting the synthesis of mycolic acid, an essential component of the Mycobacterium tuberculosis cell wall. Cross-resistance occurs when a drug is ineffective due to the presence of resistance mechanisms that confer resistance to other structurally or pharmacologically similar drugs.
**Why the Correct Answer is Right**
Thioacetazone is known to have cross-resistance with other antitubercular drugs that also target the mycolic acid synthesis pathway. This includes ethionamide, which is another second-line antitubercular drug that shares a similar mechanism of action. The cross-resistance is due to the shared target of mycolic acid synthesis, which is inhibited by both thioacetazone and ethionamide.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not represent a drug with cross-resistance to thioacetazone.
* **Option B:** This option is incorrect as it does not represent a drug with cross-resistance to thioacetazone.
* **Option C:** This option is incorrect as it does not represent a drug with cross-resistance to thioacetazone.
**Clinical Pearl / High-Yield Fact**
When treating tuberculosis, it is essential to be aware of cross-resistance between antitubercular drugs to avoid using ineffective regimens. This is particularly important when selecting second-line drugs, as cross-resistance can limit treatment options.
**Correct Answer:** C. Ethionamide.