In multibacillary leprosy, clofazimine exerts its antimycobacterial and anti-inflammatory effects by:

• A Inhibiting mycobacterial cell wall arabinogalactan synthesis
• B Inhibiting dihydropteroate synthetase, blocking folate synthesis
• C Binding to mycobacterial DNA and preferentially to guanine-cytosine base pairs; also generating reactive oxygen species via redox cycling ✓
• D Irreversible inhibition of mycobacterial RNA polymerase beta-subunit

Explanation

Clofazimine, a riminophenazine dye, intercalates into mycobacterial DNA preferentially at GC-rich regions and also undergoes redox cycling (accepting electrons from NADH, then donating to oxygen), generating reactive oxygen species that damage the bacterial membrane. This dual bactericidal mechanism explains both its antimycobacterial activity and anti-inflammatory properties (ROS can also modulate neutrophil function). RNA polymerase inhibition is rifampicin's mechanism.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.