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Journal of the Formosan Medical... Dec 2010Timely and intensive monitoring for, and management of, adverse effects caused by anti-tuberculosis drugs are essential components of control programs for...
Timely and intensive monitoring for, and management of, adverse effects caused by anti-tuberculosis drugs are essential components of control programs for multidrug-resistant tuberculosis (MDR-TB). This retrospective case series was conducted in northern Taiwan from January 2007 to December 2008 at Taipei Medical University-Wan Fang Hospital, a 750-bed tertiary-care center and MDR-TB referral center. Hepatitis associated with prothionamide was defined as the recurrence of hepatitis after a second prothionamide treatment re-challenge. In total, 47 patients with MDR-TB enrolled in the Directly Observed Therapy, Short Course-Plus Program were identified during the study period, and 44 (93.6%) were treated with prothionamide. Seven of these 44 patients (15.9%) developed hepatitis after being treated with prothionamide concurrent with other anti-tuberculosis agents. Hepatitis associated with prothionamide occurred in three of these seven patients (6.8%). In these three patients, hepatitis developed following treatment with prothionamide for 28 days, 39 days or 45 days. Hepatitis developed rapidly after re-challenge with prothionamide at 4 days, 4 days and 3 days, respectively. Liver function returned to the normal range after cessation of prothionamide treatment for 19 days, 27 days or 28 days. Close monitoring of liver function was necessary in MDR-TB patients who received prothionamide treatment.
Topics: Antitubercular Agents; Bilirubin; Chemical and Drug Induced Liver Injury; Drug Monitoring; Humans; Mycobacterium tuberculosis; Prothionamide; Retrospective Studies; Taiwan; Transaminases; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Withholding Treatment
PubMed: 21195892
DOI: 10.1016/S0929-6646(10)60141-6 -
Chemico-biological Interactions Jun 2011The thioamide and thiourea class of antituberculosis agents encompasses prodrugs that are oxidatively converted to their active forms by the flavin monooxygenase EtaA of...
The thioamide and thiourea class of antituberculosis agents encompasses prodrugs that are oxidatively converted to their active forms by the flavin monooxygenase EtaA of Mycobacterium tuberculosis. Reactive intermediates produced in the EtaA-catalyzed transformations of ethionamide and prothionamide result in NAD(+)/NADH adducts that inhibit the enoyl CoA reductase InhA, the ultimate target of these drugs. In the case of thiacetazone and isoxyl, EtaA produces electrophilic metabolites that mediate the antibacterial activity of these agents. The oxidation of the thioamide/thiourea drugs by the human flavin monooxygenases yields similar reactive metabolites that contribute to the toxicities associated with these second line antituberculosis drugs.
Topics: Antitubercular Agents; Biotransformation; Flavins; Humans; Mixed Function Oxygenases; Oxidation-Reduction; Prodrugs; Thioamides; Thiourea
PubMed: 20863819
DOI: 10.1016/j.cbi.2010.09.015 -
Journal of Clinical Microbiology Aug 2010The mycobacterium growth indicator tube (MGIT960) automated liquid medium testing method is becoming the international gold standard for second-line drug susceptibility... (Comparative Study)
Comparative Study
The mycobacterium growth indicator tube (MGIT960) automated liquid medium testing method is becoming the international gold standard for second-line drug susceptibility testing of multidrug- and extensively drug-resistant Mycobacterium tuberculosis complex isolates. We performed a comparative study of the current gold standard in the Netherlands, the Middlebrook 7H10 agar dilution method, the MGIT960 system, and the GenoType MTBDRsl genotypic method for rapid screening of aminoglycoside and fluoroquinolone resistance. We selected 28 clinical multidrug- and extensively drug-resistant M. tuberculosis complex strains and M. tuberculosis H37Rv. We included amikacin, capreomycin, moxifloxacin, prothionamide, clofazimine, linezolid, and rifabutin in the phenotypic test panels. For prothionamide and moxifloxacin, the various proposed breakpoint concentrations were tested by using the MGIT960 method. The MGIT960 method yielded results 10 days faster than the agar dilution method. For amikacin, capreomycin, linezolid, and rifabutin, results obtained by all methods were fully concordant. Applying a breakpoint of 0.5 microg/ml for moxifloxacin led to results concordant with those of both the agar dilution method and the genotypic method. For prothionamide, concordance was noted only at the lowest and highest MICs. The phenotypic methods yielded largely identical results, except for those for prothionamide. Our study supports the following breakpoints for the MGIT960 method: 1 microg/ml for amikacin, linezolid, and clofazimine, 0.5 microg/ml for moxifloxacin and rifabutin, and 2.5 microg/ml for capreomycin. No breakpoint was previously proposed for clofazimine. For prothionamide, a division into susceptible, intermediate, and resistant seems warranted, although the boundaries require additional study. The genotypic assay proved a reliable and rapid method for predicting aminoglycoside and fluoroquinolone resistance.
Topics: Aminoglycosides; Antitubercular Agents; DNA, Bacterial; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Genotype; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Netherlands; Phenotype; Tuberculosis, Multidrug-Resistant
PubMed: 20554815
DOI: 10.1128/JCM.00652-10 -
International Journal of Infectious... May 2010Extensively drug-resistant tuberculosis (XDR-TB) has recently been identified as a major threat to global health. XDR-TB poses a risk of higher failure rates and death...
BACKGROUND
Extensively drug-resistant tuberculosis (XDR-TB) has recently been identified as a major threat to global health. XDR-TB poses a risk of higher failure rates and death during TB treatment. We report herein the outcomes of XDR-TB in patients treated with the standardized regimen in Iran.
PATIENTS AND METHODS
Between 2002 and 2006, seven patients were diagnosed with XDR-TB. All patients were treated with the standardized second-line regimen containing cycloserine, prothionamide, amikacin, and ofloxacin. First-line drugs, such as ethambutol and pyrazinamide, were added to the regimen if drug susceptibility testing showed sensitivity to these drugs.
RESULTS
Four (57.1%) patients were male. All seven patients were HIV-negative. The patient age range was 22-79 years. Of the seven cases, the final outcome was 'cure' in two (28.6%), 'relapse' in one, 'treatment failure' in one, and 'death' in two; the outcome for one patient was unknown.
CONCLUSION
Our study shows a poor prognosis in patients with XDR-TB. This indicates the necessity of detecting XDR-TB cases earlier, as well as the need to gain access to more second-line agents. This is particularly important in resource-limited settings in order to administer individualized regimens.
Topics: Adult; Aged; Antitubercular Agents; Cohort Studies; Extensively Drug-Resistant Tuberculosis; Female; Humans; Iran; Male; Microbial Sensitivity Tests; Middle Aged; Mycobacterium tuberculosis; Young Adult
PubMed: 19818664
DOI: 10.1016/j.ijid.2009.07.002 -
The Journal of Experimental Medicine Jan 2007Thioamide drugs, ethionamide (ETH) and prothionamide (PTH), are clinically effective in the treatment of Mycobacterium tuberculosis, M. leprae, and M. avium complex...
Thioamide drugs, ethionamide (ETH) and prothionamide (PTH), are clinically effective in the treatment of Mycobacterium tuberculosis, M. leprae, and M. avium complex infections. Although generally considered second-line drugs for tuberculosis, their use has increased considerably as the number of multidrug resistant and extensively drug resistant tuberculosis cases continues to rise. Despite the widespread use of thioamide drugs to treat tuberculosis and leprosy, their precise mechanisms of action remain unknown. Using a cell-based activation method, we now have definitive evidence that both thioamides form covalent adducts with nicotinamide adenine dinucleotide (NAD) and that these adducts are tight-binding inhibitors of M. tuberculosis and M. leprae InhA. The crystal structures of the inhibited M. leprae and M. tuberculosis InhA complexes provide the molecular details of target-drug interactions. The purified ETH-NAD and PTH-NAD adducts both showed nanomolar Kis against M. tuberculosis and M. leprae InhA. Knowledge of the precise structures and mechanisms of action of these drugs provides insights into designing new drugs that can overcome drug resistance.
Topics: Antitubercular Agents; Bacterial Proteins; Crystallography, X-Ray; Drug Design; Drug Resistance, Multiple, Bacterial; Ethionamide; Humans; In Vitro Techniques; Leprostatic Agents; Leprosy; Models, Molecular; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; Mycobacterium leprae; Mycobacterium tuberculosis; NAD; Oxidoreductases; Prothionamide; Tuberculosis; Tuberculosis, Multidrug-Resistant
PubMed: 17227913
DOI: 10.1084/jem.20062100 -
Journal of Clinical Microbiology Mar 2006The objectives of this study were to (i) compare agreement of the MGIT 960 system for first-line drugs with a methodology (the resistance ratio method [RRM]) that had... (Comparative Study)
Comparative Study
Evaluation of MGIT 960-based antimicrobial testing and determination of critical concentrations of first- and second-line antimicrobial drugs with drug-resistant clinical strains of Mycobacterium tuberculosis.
The objectives of this study were to (i) compare agreement of the MGIT 960 system for first-line drugs with a methodology (the resistance ratio method [RRM]) that had been used in clinical trials, relating drug susceptibility to clinical outcome; (ii) compare the performance of the MGIT 960, RRM, and microtiter plate assay (MPA) methodologies for second-line drug testing; and (iii) define critical concentrations for ciprofloxacin and moxifloxacin for liquid-culture-based testing. The large collection of clinical isolates of Mycobacterium tuberculosis (n = 247) used included 176 (71%) multidrug-resistant isolates. The results for MGIT 960 and the RRM for rifampin and isoniazid (n = 200) were in excellent (99 to 100%) agreement for all strains. For streptomycin, 97% of the results at the critical concentration and 92% at high concentration, and for pyrazinamide 92% of results overall, were concordant, but for ethambutol, fewer than 85% (65% for the critical concentration and 84% for the high concentration) of the MGIT-based results were concordant with those for the RRM. The MGIT 960, RRM, and MPA assays (n = 133) correlated well for most second-line drugs tested. For susceptibility to ofloxacin, the MGIT 960 and MPA results were in full agreement. The amikacin and rifabutin results obtained by MGIT 960 agreed with the RRM results in 131 (99%) cases, and for capreomycin, they agreed for 129 of 133 isolates tested (97%). For prothionamide testing, only a limited number of drug-resistant isolates were available for testing and drawing definitive conclusions. We propose critical concentrations of 1.0 microg/ml and 0.125 microg/ml for ciprofloxacin and moxifloxacin, respectively, for liquid-culture-based testing.
Topics: Antitubercular Agents; Aza Compounds; Ciprofloxacin; Drug Resistance, Multiple, Bacterial; Fluoroquinolones; Humans; In Vitro Techniques; Isoniazid; Microbial Sensitivity Tests; Moxifloxacin; Mycobacterium tuberculosis; Quinolines; Rifampin; Tuberculosis, Pulmonary
PubMed: 16517859
DOI: 10.1128/JCM.44.3.811-818.2006 -
Antimicrobial Agents and Chemotherapy Oct 1994A total of 307 patients with lepromatous leprosy and borderline lepromatous leprosy were randomized to dapsone monotherapy or to one of two types of drug combinations. A... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
A total of 307 patients with lepromatous leprosy and borderline lepromatous leprosy were randomized to dapsone monotherapy or to one of two types of drug combinations. A 3-year treatment phase was followed by a 5-year observation phase. The evaluation included 233 patients for whom together there were 1,404 years of observation. A total of 1,956 blinded histopathological specimens were processed centrally. When entering the trial isolates from 13 patients (5.6%) showed dapsone resistance in the mouse footpad test, and these patients were evaluated separately. Dapsone monotherapy (68 patients) had the same frequency of cure as the combination of dapsone and rifampin (77 patients) or the four-drug regimen consisting of dapsone, rifampin, isoniazid, and prothionamide (75 patients). We did not find a significant difference in the clearance of bacteria either between the monotherapy and the two-drug combination or the monotherapy and the four-drug combination. Six months after the initiation of treatment, disease in 15% of the patients who received dapsone monotherapy but none of the patients who received combined treatment were clinically progressive. After another 1 to 9 months of treatment the disease in all patients was stable or regressive. There was no difference in the type or frequency of reactions. Only after the end of the scheduled observation phase three relapses were reported. All three treatment regimens well tolerated. Dapsone monotherapy is highly effective in the treatment of multibacillary leprosy under the conditions of well-controlled treatment. Combination regimens seem only to accelerate the regression of the active disease when they are compared with monotherapy with dapsone. The mouse footpad test does not reflect the clinical resistance and cannot be recommended for use in making therapeutic decisions.
Topics: Adolescent; Adult; Child; Dapsone; Drug Resistance, Microbial; Drug Therapy, Combination; Female; Follow-Up Studies; Humans; Leprosy; Male; Middle Aged
PubMed: 7840553
DOI: 10.1128/AAC.38.10.2249 -
British Journal of Clinical Pharmacology Oct 19801. The possibility of using minute doses of the antituberculosis drug isoniazid (INH) or of its metabolites acetylisoniazid (AcINH) or isonicotinic acid (INA) as...
1. The possibility of using minute doses of the antituberculosis drug isoniazid (INH) or of its metabolites acetylisoniazid (AcINH) or isonicotinic acid (INA) as innocuous markers for monitoring patient compliance has been investigated. 2. The ingestion of these colourless and tasteless compounds can readily be demonstrated using a sensitive and specific colorimetric method for detecting INA and its metabolite isonicotinylglycine (INAG) in the urine that is rapid and simple to perform. 3. Studies on the kinetics of the urinary elimination of INA and INAG after the ingestion of 6 mg doses of either INH, AcINH or INA by small groups of volunteers indicated the potential suitability of INH or AcINH for monitoring daily or twice-daily self-medication and the appropriateness of INA as a marker for investigating the compliance of drugs prescribed for thrice-daily ingestion. 4. More extensive studies showed that over 99% of the urine samples collected within 18h of dosage with 6 mg INH would give positive results when tested for the presence of INA and INAG, and that doses of 2-6 mg INH could readily by incorporated into capsules or tablets and used as markers for monitoring the ingestion of the antituberculosis or antileprosy drugs dapsone, thiacetazone, ethionamide or prothionamide, or the antihypertensive oxprenolol. Such doses are less than a fiftieth of the normal therapeutic INH dose used in the treatment of tuberculosis. 5. Evidence is presented that INH, AcINH and INA possess most of the characteristics that one would hope to find in a marker for monitoring compliance including very limited inter-individual variability in the rates at which they are converted to the compounds being detected in the urine.
Topics: Glycine; Half-Life; Humans; Intestinal Absorption; Isoniazid; Isonicotinic Acids; Male; Patient Compliance; Riboflavin; Self Administration; Time Factors
PubMed: 7448108
DOI: 10.1111/j.1365-2125.1980.tb01773.x