Stepwise approach to designing a multidrug-resistant (MDR) tuberculosis (TB) regimen
| Step 1 | Choose an injectable drug from WHO group 2 | Kanamycin Amikacin Capreomycin | Choose a drug based on DST and treatment history Streptomycin is generally not used because of high rates of resistance in patients with MDR-TB |
| Step 2 | Choose a later-generation fluoroquinolone from WHO group 3 | Levofloxacin Moxifloxacin | Use a later-generation fluoroquinolone If levofloxacin (or ofloxacin) resistance is documented, use moxifloxacin Avoid moxifloxacin if possible when using bedaquiline |
| Step 3 | Add WHO group 4 drugs | Cycloserine/terizidone PAS Ethionamide/prothionamide | Add two or more group 4 drugs until there are at least four second-line anti-TB drugs likely to be effective Ethionamide/prothionamide is considered the most effective Group 4 drug Consider treatment history, side-effect profile and cost DST is not considered reliable for the drugs in this group |
| Step 4 | Add WHO group 1 drugs | Pyrazinamide Ethambutol | Pyrazinamide is routinely added in most regimens Ethambutol can be added if the criteria for an effective drug are met If isoniazid is unknown or pending, it can be added to the regimen until DST results become available |
| Step 5 | Add WHO group 5 drugs | Bedaquiline Linezolid Clofazimine Amoxicillin/clavulanate Imipenem/cilastatin plus clavulanate Meropenem plus clavulanate High-dose isoniazid Clarithromycin Thioacetazone | Consider adding group 5 drugs if four second-line anti-TB drugs are not likely to be effective from WHO groups 2–4 If drugs are needed from this group, ensure to use two or more of them DST is not standardised for the drugs in this group |
WHO: World Health Organization; DST: drug susceptibility testing; PAS: para-aminosalicylic acid. Reproduced and modified from [6] with permission from the publisher.