Ans. a. Bedaquiline (Ref: Harrison 19/e p1115. 205e- 7)Two novel drugs belonging to two new antibiotic classes--the diarylquinoline bedaquiline and the nitroimidazole delamanid--have recently been approved for use in severe cases of MDR-TB by stringent regulatory authorities."Two novel drugs belonging to two new antibiotic classes--the diarylquinoline bedaquiline and the nitroimidazole delamanid--have recently been approved for use in severe cases of MDR-TB by stringent regulatory authorities (the L .S. Food and Drug Administration (FDA} and the European Medicine Agency (EMA] in the case of bedaquiline; the EM A and the Pharmaceuticals and Medical Devices Agency of Japan in the case of delamanid). "-- Harrison 19/e p1115BedaquilineBedaquiline is a new diarylquinoline with a novel mechanism of action: inhibition of the mycobacterial ATP synthetase proton pumpQ.It is bactericidal for drug-susceptible and MDR strains of M. tuberculosisQ.Mechanism of action:Inhibition of the mycobacterial ATP synthetase proton pump.Therapeutic Uses:Provisional recommendation for the use of bedaquiline for 24 weeks in adults with laboratory-confirmed pulmonary MDR-TB when no other effective treatment regimen can be provided.Side-Effects:Arrhythmias (induce long QT syndrome by blocking the hERG channel)Resistance:Resistance has been reported and is due to point mutations in the atpE gene encoding for subunit c of ATP synthetase.Anti-Tubercular DrugsFirst line (WHO Group 1)Second lineThird line* EthambutolQ (EMB or E)* IsoniazidQ (INH or H )* PyrazinamideQ (PZA or Z)* RifampicinQ (RMP or R)* StreptomycinQ (SM or S)* Second line drugs (WHO groups 2, 3 & 4) are only used to treat disease that is resistant to first line therapy, i.e., for extensively drug-resistant tuberculosis (XDR-TB) or multidrug- resistant tuberculosis (MDR-TB).* Aminoglycosides (WHO group 2): Amikacin, kanamycinQ* Polypeptides (WHO group 2): Capreomycin, viomycin, enviomycinQ* Fluoroquinolones (WHO group 3): Ciprofloxacin, levofloxacin, moxifloxacinQ* Thioamides (WHO group 4): Ethionamide, prothionamideQ* CycloserineQ (WHO group 4)* TerizidoneQ (WHO group 5)* Third-line drugs (WHO group 5) include drugs that may be useful, but have doubtful or unproven efficacy.* RifabutinQ* ClarithromycinQ* LinezolidQ* ThioacetazoneQ* ThioridazineQ* Arginine* Vitamin D* BedaquilineQ* DeiamanidQ