This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: RNTCP, Subject name: Social & Preventive Medicine
All of the following drugs are used in the management of MDR-TB under RNTCP except 
Select and explain. 
A. Levofloxacin, B. PAS, C. Ethionamide, D. Cycloserine
B: PAS
Answer: B: PAS 
Explanation: PAS is an add-on agent(D GROUP) and is not a core pa of MDR-TB drug regimen. The remaining 3 drugs are being given in both intensive as well as continuation phase of the regimen.