Failure to take the anti-TB drugs correctly as prescribed (non-compliance). If doses of the drugs are missed repeatedly, the tuberculosis will not be cured and drug resistance may develop. Resistance to both INH and rifampicin is called multidrug resistant (MDR) TB. This is very difficult to treat. In multidrug resistance, the TB bacilli continue to multiply and are not killed by the usual combination of anti-TB drugs. Multidrug resistant TB develops because of incorrect treatment or poor adherence. Multidrug resistant TB can be transmitted to close contacts, including children and is becoming a major problem in some regions.
Resistance to 3 or more antituberculous drugs is called extreme drug resistant (EDR) TB. It is usually fatal.
If the treatment is stopped too soon the tuberculosis can also return (relapse). In many poor countries it is common for TB patients not to complete their full course of treatment. Once they feel well again they stop their treatment. As a result, relapse of TB occurs and many people die of TB.
Treatment of tuberculosis is difficult as it is lengthy and requires good compliance.
Adults with tuberculosis have a responsibility, not only to themselves, but also to their household and community to complete their treatment correctly.