Table 1. Current TB Drugs Approved by the FDA/EMA.

	primary protein target	mechanism of action	pro-drug
First-Line TB Drugs, Primarily Used for Drug-Sensitive TB Treatment
isoniazid INH, H	enoyl acyl-carrier protein reductase InhA	inhibits mycolic acid synthesis	activated by catalase-peroxidase-peroxynitritase (KatG) to form an adduct with NAD+/NADP+
rifampicin RIF, R	RNA polymerase β subunit RpoB	inhibits RNA synthesis/transcription	N/Aa
pyrazinamide PZA, Z	pleiotropic	possible targets include FAS I, QAPRTase, RpsA, PanD, Rv2783	converted by pyrazinamidase (PZase) to pyrazinoic acid
ethambutol EMB, E	arabinosyl transferase EmbB	inhibits arabinogalactan synthesis	N/A
Second-Line TB Drugs, Primarily Used for Drug-Resistant TB Treatment
streptomycin	16S rRNA subunit	inhibits protein synthesis	N/A
kanamycin amikacin capreomycin	30S rRNA subunit	inhibit protein synthesis	N/A
ofloxacin levofloxacin moxifloxacin	DNA gyrase and topoisomerase	inhibit DNA synthesis	N/A
p-amino salicylic acid	dihydrofolate reductase	inhibits DNA precursor synthesis	converted by dihydropteroate synthase (DHPS) and dihydrofolate synthase (DHFS) to an antifolate metabolite
ethionamide prothionamide	enoyl acyl-carrier protein reductase InhA	inhibit mycolic acid biosynthesis	activated by a monooxygenase (EthA) to form an adduct with NAD+/NADP+
cycloserine	alanine racemase and d-alanine:d-alanine ligase	inhibits cell wall biosynthesis	N/A
bedaquiline	ATP synthase subunit ε	inhibits ATP production	N/A
delamanid pretomanid	not specific	generates NO and inhibits energy metabolism	activated by a nitroreductase (Ddn)

^aN/A: not applicable.