Multi-Drug Resistant TB
Like, all the other diseases, resistance to drugs has become one of the major concerns in the management of TB.
Now, strains that are resistant to a single drug have been documented in every country surveyed; what is more, strains of TB resistant to all major anti-TB drugs have emerged.
Drug-resistant TB is caused by discontinuations or partial treatment, when patients do not take all their medicines regularly for the required period because they start to feel better, because doctors and health workers prescribe the wrong treatment regimens, or because the drug supply is unreliable.
A particularly dangerous form of drug-resistant TB is multidrug-resistant TB (MDR-TB), which is defined as the disease caused by TB bacilli resistant to at least isoniazid and rifampicin, the two most powerful anti-TB drugs.
Rates of MDR-TB are high in some countries, especially in the former Soviet Union, and threaten TB control efforts.
While drug-resistant TB is generally treatable, it requires extensive chemotherapy (up to two years of treatment) with second-line anti-TB drugs which are more costly than first-line drugs, and which produce adverse drug reactions that are more severe though manageable.
Another resistance that has emerged is the extensively drug-resistant tuberculosis (XDR-TB). It is a relatively rare type of MDR TB. This XDRTB is also resistant to the best second-line medications: fluoroquinolones and at least one of three injectable drugs (i.e., amikacin, kanamycin, or capreomycin). The emergence of XDR-TB, particularly in settings where many TB patients are also infected with HIV, poses a serious threat to TB control.
Next page: TB - World wide strategies
Written by: Healthplus24 team
Date last updated: September 27, 2012