The main objectives of tuberculosis therapy are to cure the patients and to minimize the possibility of transmission of the bacillus to healthy subjects. Adverse effects of antituberculosis drugs or drug interactions (among antituberculosis drugs or between antituberculosis drugs and other drugs) can make it necessary to modify or discontinue treatment. We briefly review the new guidelines for the pharmacological treatment of tuberculosis, introduced by the Brazilian National Ministry of Health in 2009, and describe the general mechanism of action, absorption, metabolization, and excretion of the first-line drugs used in the basic regimen. We describe adverse drug reactions and interactions (with other drugs, food, and antacids), as well as the most appropriate approach to special situations, such as pregnancy, breastfeeding, liver failure, and kidney failure. We also describe the mechanisms by which the interactions among the antituberculosis drugs used in the basic regimen can cause druginduced hepatitis, and we discuss the alternatives in this situation.Keywords: Tuberculosis; Drug interactions; Antibiotics, antitubercular; Pharmacologic actions; Drug toxicity; Drug-induced liver injury. ResumoOs objetivos principais do tratamento da tuberculose são curar o paciente e minimizar a possibilidade de transmissão do bacilo para indivíduos saudáveis. Reações adversas ou interações das drogas antituberculose entre si e com outros fármacos podem causar modificação ou descontinuação da terapêutica. Revisamos sucintamente o novo tratamento farmacológico da tuberculose introduzido pelo Ministério da Saúde do Brasil em 2009 e mostramos os mecanismos gerais de ação, absorção, metabolização e excreção dos medicamentos utilizados no esquema básico. Descrevemos as reações adversas e as interações (com medicamentos, alimentos e antiácidos) assim como a abordagem mais adequada para situações especiais, como gravidez, amamentação, insuficiência hepática e renal. Também descrevemos os mecanismos pelos quais as interações das drogas antituberculose do esquema básico podem causar hepatite medicamentosa e as possíveis alternativas nessa situação.Descritores: Tuberculose; Interações de medicamentos; Antibióticos antituberculose; Ações farmacológicas; Toxicidade de drogas; Doença hepática induzida por drogas.

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Os objetivos principais do tratamento da tuberculose são curar o paciente e minimizar a possibilidade de transmissão do bacilo para indivíduos saudáveis. Reações adversas ou interações das drogas antituberculose entre si e com outros fármacos podem causar modificação ou descontinuação da terapêutica. Descrevemos os mecanismos gerais de ação, absorção, metabolização e excreção dos medicamentos utilizados no tratamento da tuberculose multidroga resistente (aminoglicosídeos, fluoroquinolonas, cicloserina/terizidona, etionamida, capreomicina e ácido para-aminossalicílico). Descrevemos as reações adversas e as interações (com medicamentos, alimentos e antiácidos) assim como a abordagem mais adequada para situações especiais, como gravidez, amamentação, insuficiência hepática e renal.

BackgroundMultidrug resistance is a critical factor in tuberculosis control. To gain better understanding of multidrug resistant tuberculosis in Brazil, a retrospective study was performed to compare genotypic diversity and drug resistance associated mutations in Mycobacterium tuberculosis isolates from a national reference center.Methods and FindingsNinety-nine multidrug resistant isolates from 12 Brazilian states were studied. Drug-resistance patterns were determined and the rpoB and katG genes were screened for mutations. Genotypic diversity was investigated by IS6110-RFLP and Luminex 47 spoligotyping. Mutations in rpoB and katG were seen in 91% and 93% of the isolates, respectively. Codon 315 katG mutations occurred in 82.8% of the isolates with a predominance of the Ser315Thr substitution. Twenty-five isolates were clustered in 11 groups with identical IS6110-RFLP patterns while 74 showed unique patterns with no association between mutation frequencies or susceptibility profiles. The most prevalent spoligotyping lineages were LAM (47%), T (17%) and Haarlen (12%). The Haarlen lineage showed a higher frequency of codon 516 rpoB mutations while codon 531 mutations prevailed in the other isolates.ConclusionsOur data suggest that there were no major multidrug resistant M. tuberculosis strains transmitted among patients referred to the reference center, indicating an independent acquisition of resistance. In addition, drug resistance associated mutation profiles were well established among the main spoligotyping lineages found in these Brazilian multidrug resistant isolates, providing useful data for patient management and treatment.

Here, we report the cases of three patients diagnosed with extensively drug-resistant tuberculosis and admitted to a referral hospital in the state of São Paulo, Brazil, showing the clinical and radiological evolution, as well as laboratory test results, over a one-year period. Treatment was based on the World Health Organization guidelines, with the inclusion of a new proposal for the use of a combination of antituberculosis drugs (imipenem and linezolid). In the cases studied, we show the challenge of creating an acceptable, effective treatment regimen including drugs that are more toxic, are more expensive, and are administered for longer periods. We also show that treatment costs are significantly higher for such patients, which could have an impact on health care systems, even after hospital discharge. We highlight the fact that in extreme cases, such as those reported here, hospitalization at a referral center seems to be the most effective strategy for providing appropriate treatment and increasing the chance of cure. In conclusion, health professionals and governments must make every effort to prevent cases of multidrug-resistant and extensively drug-resistant tuberculosis.