Antimycobacterials are used to treat tuberculosis (TB) and leprosy. First-line drugs — isoniazid (mycolic acid synthesis inhibitor), rifampicin (DNA-dependent RNA polymerase inhibitor), pyrazinamide (active in acidic pH within macrophages) and ethambutol (arabinogalactan synthesis inhibitor) — constitute the RIPE regimen, gold standard for drug-sensitive pulmonary TB (minimum 6 months, WHO/ATS guidelines). Second-line agents include amikacin and capreomycin (injectable aminoglycosides — ototoxicity risk), cycloserine (D-alanine analogue — cell wall synthesis blockade), ethionamide and protionamide (thioamides — mycolic acid synthesis inhibition), terizidone (oxazolidinone) and bedaquiline (ATP synthase inhibitor — novel mechanism, MDR-TB). Clofazimine, originally an anti-leprosy agent (J04BA01), is now essential in multidrug-resistant TB treatment. (Sources: DailyMed/FDA, EMC-UK/MHRA, WHO Guidelines 2024)
