Treatment Regimens

TB is usually curable if effective treatment is instituted without delay. Because of the increase in multidrug-resistant TB (MDR-TB), nearly all persons with TB should be started on a four-drug regimen of INH, rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB) or streptomycin (SM) until the drug susceptibility results are known. A less than four-drug initial regimen should only be considered if there is little possibility of drug resistance (i.e., less than 4% primary resistance to isoniazid in the community and the patient has had no previous treatment with TB drugs, is not from a country with a high prevalence of drug resistance, and has no known exposure to a patient with drug-resistant disease). If the drugs are given daily at the start of therapy and susceptibility results show no drug resistance, EMB or SM can be discontinued and the other drugs continued until PZA has been given for 2 months. INH and RIF should then be continued for another 4 months, including at least 3 months of therapy after the culture has converted to negative. Several options for daily and intermittent therapy have been published. Persons given anti-TB therapy should be monitored monthly for drug side effects.

The recommendations for the duration of TB treatment for HIV-infected persons are generally the same as for persons not infected with HIV. However, in HIV-infected patients, it is critically important to assess the clinical and bacteriologic response to therapy. Treatment should be prolonged if the response is slow or otherwise suboptimal.

Adherence

A major cause of treatment failure and drug-resistant TB is non-adherence to treatment. Treatment failure and drug-resistant TB threaten the health of TB patients. These factors also pose serious public health risks because they can lead to prolonged infectiousness and the transmission of TB within the community.

One way to ensure that patients adhere to therapy is to use directly observed therapy (DOT). DOT means that a health care worker or another designated person watches the patient swallow each dose of TB medication. DOT should be considered for all patients because clinicians are often inaccurate in predicting which patients will adhere to medication on their own.

In many areas, patients are routinely given DOT. DOT has been shown to be cost-effective when intermittent regimens are used. Nearly all the treatment regimens for drug-susceptible TB can be given intermittently if they are directly observed; using intermittent regimens reduces the total number of doses a patient must take, as well as the total number of encounters with the health care provider or outreach worker. Furthermore, DOT can significantly reduce the frequency of acquired drug resistance and relapse.

Other measures commonly used to promote adherence include:

• Developing an individualized treatment plan for each patient
• Working with outreach staff from the same cultural and linguistic background as the patient
• Educating the patient about TB medication dosage and possible adverse reactions
• Using incentives and enablers to remove barriers to adherence (e.g., transportation tokens and food vouchers)
• Facilitating access to health and social services