8.3 Drugs for drug-susceptible tuberculosis

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    All drugs used for DS-TB treatment are taken 7 days a week.

    8.3.1 First-line drugs

    Table 8.2 – Main characteristics of first-line TB drugs

     

    TB drugs

    Activity

    Resistance

    Isoniazid

    Bactericidal

    • High level of resistance in some regions.
    • Cross-resistance with thionamides.

    Rifampicin

    Rifabutin

    Rifapentine

    Bactericidal

    • High level of resistance to rifampicin in some regions.
    • High level of cross-resistance between rifamycins.

    Ethambutol

    Bacteriostatic

    Unknown (no reliable drug susceptibility test for ethambutol).

    Pyrazinamide

    Weakly bactericidal

    High level of resistance in regions where rifampicin resistance is frequent.  

     

    Isoniazid

    Isoniazid is usually well tolerated at recommended doses.

    It may cause peripheral neuropathy, hepatotoxicity, and hypersensitivity reactions.

    Peripheral neuropathy should be prevented by administration of pyridoxine (vitamin B6). See Appendix 17.

    Rifamycins (rifampicin, rifabutin, rifapentine)

    Rifamycins are usually well tolerated at recommended doses.

    They may cause hypersensitivity reactions, hepatotoxicity, and thrombocytopenia.

    They are strong inducers of cytochrome P450 (CYP450) and can affect the plasma concentrations of many drugs (Appendix 19).

    Rifampicin is the most used rifamycin in the treatment of DS-TB.

    Rifabutin is used instead of rifampicin in patients taking certain antiretrovirals (Appendix 19).

    Rifapentine is only used in the 4-month regimen 2HPZ-Mfx/2HP-Mfx.

     

    Note: rifampicin and rifapentine are also used to treat latent TB infection (Chapter 16).

    Ethambutol

    Ethambutol is usually well tolerated, including in children, particularly with respect to ocular toxicity [1] Citation 1. World Health Organization. Guidance for national tuberculosis programmes on the management of tuberculosis in children. Geneva: World Health Organization; 2014.
    https://apps.who.int/iris/bitstream/handle/10665/112360/9789241548748_eng.pdf?sequence=1
    . Ocular toxicity is dose- and duration-dependent. It is uncommon when ethambutol is used at the recommended dose for 2 months.

    Pyrazinamide

    Pyrazinamide is usually well tolerated however, it may cause hepatotoxicity, gout, arthralgias and photosensitivity.

    8.3.2 Other drugs

    Two second-line drugs are also used in the treatment of DS-TB: moxifloxacin (Section 8.4.1) and ethionamide (Section 8.4.3).

     

    References