First-line TB medication is a combination of different antibiotics taken over a 6-8 month period. Directly Observed Treatment Short-Course (DOTS) is the WHO recommended first-line TB therapy, which ensures the continued compliance needed for complete eradication of the bacteria.
If patients become resistant to at least isoniazid and rifampicin they develop Multi Drug Resistant-TB, which requires extensive therapy (up to two years) with drugs that have more side effects.