Basic Principles for Management of Drug Resistant Tuberculosis
The successful management of MDR-TB requires specialized expertise. When initiating or revising therapy for MDR-TB, the process of selecting drugs should rely on prior treatment history, results of susceptibility testing and an evaluation of the patient's adherence. By definition, chemotherapy of MDR-TB cannot rely upon isoniazid and rifampicin, the two most powerful drugs for the treatment of tuberculosis. Depending on the individual susceptibility pattern, residual first-line drugs must be
appropriately combined with additional second-line drugs.
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Designing an Appropriate Regimen
The following basic principles are involved in any regimen design:
Regimens should be based on the history of drugs taken by the patient
Drugs and regimens commonly used in the country and the prevalence of resistance to first-line and second-line drugs
should be taken into consideration when designing a regimen
Regimens should consist of at least four drugs
with either certain, or almost certain, effectiveness
Drugs are administered at least six days a week. When possible, pyrazinamide, ethambutol and fluoroquinolones should be given once per day because the high serum levels attained in once-a-day dosing may be more efficacious. Once-a-day dosing is permitted for other second-line drugs
, depending on patient tolerance. However, ethionamide/prothionamide, cycloserine and PAS have traditionally been given in split doses during the day
The drug dosage should be determined by body weight
An injectable agent (an aminoglycoside or capreomycin) is used for a minimum of 6 months
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Treatment is for a minimum duration of 1 8 months beyond conversion
Each dose is given as Directly Observed Treatment (DOT) throughout the treatment. A treatment card is marked for each observed dose.
Drug susceptibility testing (DST), when available and from a reliable laboratory, should be used guide therapy.
Pyrazinamide can be used for the entire treatment if it is judged to be effective.
Early MDR-TB detection and prompt initiation of treatment are important factors in achieving successful outcomes
.