What are Multidrug-resistant TB (MDR-TB) and Extensively drug-resistant TB (XDR-TB)?
Multidrug-resistant TB (MDR-TB)
MDR-TB is a specific form of TB which is resistant to at least isoniazid and rifampicin, two of the main first line drugs used in the treatment of TB. MDR-TB therefore is much more difficult to treat. It takes longer to treat with second line drugs which are more expensive and have more side-effects.
Extensively drug-resistant TB (XDR-TB)
XDR-TB is a rare type of MDR-TB which is also resistant to any of a group of drugs called fluoroquinolones and at least one of three injectable second line anti-TB drugs (capreomycin, kanamycin or amikacin). Because XDR-TB is resistant to first line and second line drugs, treatment options are more limited.
Further information on XDR-TB can be found on the WHO website at: http://www.who.int/tb/areas-of-work/drug-resistant-tb/xdr-tb-faq/en/
WHO has prepared frequently asked questions on TB that is "resistant to all drugs": http://www.who.int/tb/challenges/mdr/faqs/en
In August 2018, WHO published Rapid Communication: key changes to treatment of multidrug- and rifampicin-resistant tuberculosis. They subsequently published Frequently Asked Questions on the Rapid Communication: key changes to treatment of multidrug- and rifampicin-resistant tuberculosis.
Last updated: 8 October 2018