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BMC Infectious Diseases Apr 2016Among the various forms of TB, tuberculous meningitis (TBM) is the most severe, with about 30% mortality and 50% of survivors left with neurological sequelae. Children...
BACKGROUND
Among the various forms of TB, tuberculous meningitis (TBM) is the most severe, with about 30% mortality and 50% of survivors left with neurological sequelae. Children suffer more frequently from TBM than adults and outcomes are often poor due to difficulties in making the diagnosis and uncertainty regarding the best anti-tuberculosis drug regimen. The aim of this prospective study was to describe the pharmacokinetics of pyrazinamide, isoniazid and rifampicin in plasma and cerebrospinal fluid of children with tuberculous meningitis treated with the standard TBM regimen.
METHODS
We performed a prospective observational study of 100 consecutively treated children (≤ 15 years of age) with tuberculous meningitis in Ho Chi Minh City, Vietnam. Children were treated according to the 2006 WHO recommended pediatric treatment regimen consisting of isoniazid (5 mg/kg), rifampicin (10 mg/kg) and ethambutol (15 mg/kg) for 8 months, with the addition of pyrazinamide (25 mg/kg) for the first 3 months and streptomycin (15 mg/kg) for the first 2 months. Pyrazinamide, isoniazid and rifampicin concentrations were measured in plasma at day 14 and in cerebrospinal fluid (CSF) at 1 month by HPLC-UV. A naïve-pooled non-compartmental data analysis was used to describe the pharmacokinetic properties of drugs in the two-age groups of children ≤ 4 years or > 4 years of age.
RESULTS
Younger children, when compared to older children, presented a higher body weight-normalized clearance and volume of distribution, and lower median total plasma exposures for the three studied drugs with -14%, -22% and -16% for Pyrazinamide, Isoniazid and Rifampicin, respectively. In CSF, individual concentrations of isoniazid and pyrazinamide were comparable to that in plasma in both age groups; but rifampicin concentrations were lower than the minimum inhibitory concentration of susceptible bacteria in all but two children.
CONCLUSIONS
There is an age-dependent variation in the plasma and cerebrospinal fluid pharmacokinetics of rifampicin, isoniazid and pyrazinamide. The safety and efficacy of higher doses of rifampicin should be investigated for the treatment of childhood tuberculous meningitis.
Topics: Adolescent; Antitubercular Agents; Arylamine N-Acetyltransferase; Asian People; Child; Child, Preschool; Female; Genotype; Half-Life; Humans; Infant; Isoniazid; Male; Prospective Studies; Pyrazinamide; Rifampin; Tuberculosis, Meningeal; Vietnam
PubMed: 27039088
DOI: 10.1186/s12879-016-1470-x -
ImmunoHorizons Jun 2023Mechanisms to shorten the duration of tuberculosis (TB) treatment include new drug formulations or schedules and the development of host-directed therapies (HDTs) that...
Mechanisms to shorten the duration of tuberculosis (TB) treatment include new drug formulations or schedules and the development of host-directed therapies (HDTs) that better enable the host immune system to eliminate Mycobacterium tuberculosis. Previous studies have shown that pyrazinamide, a first-line antibiotic, can also modulate immune function, making it an attractive target for combinatorial HDT/antibiotic therapy, with the goal to accelerate clearance of M. tuberculosis. In this study, we assessed the value of anti-IL-10R1 as an HDT along with pyrazinamide and show that short-term anti-IL-10R1 blockade during pyrazinamide treatment enhanced the antimycobacterial efficacy of pyrazinamide, resulting in faster clearance of M. tuberculosis in mice. Furthermore, 45 d of pyrazinamide treatment in a functionally IL-10-deficient environment resulted in sterilizing clearance of M. tuberculosis. Our data suggest that short-term IL-10 blockade with standard TB drugs has the potential to improve clinical outcome by reducing the treatment duration.
Topics: Animals; Mice; Pyrazinamide; Antitubercular Agents; Interleukin-10; Tuberculosis; Mycobacterium tuberculosis
PubMed: 37279084
DOI: 10.4049/immunohorizons.2200077 -
PloS One 2015Exposure to lower-than-therapeutic levels of anti-tuberculosis drugs is likely to cause selection of resistant strains of Mycobacterium tuberculosis and treatment... (Randomized Controlled Trial)
Randomized Controlled Trial
Exposure to lower-than-therapeutic levels of anti-tuberculosis drugs is likely to cause selection of resistant strains of Mycobacterium tuberculosis and treatment failure. The first-line anti-tuberculosis (TB) regimen consists of rifampicin, isoniazid, pyrazinamide, and ethambutol, and correct management reduces risk of TB relapse and development of drug resistance. In this study we aimed to investigate the effect of standard of care plus nutritional supplementation versus standard care on the pharmacokinetics of isoniazid, pyrazinamide and ethambutol among sputum smear positive TB patients with and without HIV. In a clinical trial in 100 Tanzanian TB patients, with or without HIV infection, drug concentrations were determined at 1 week and 2 months post initiation of anti-TB medication. Data was analysed using population pharmacokinetic modelling. The effect of body size was described using allometric scaling, and the effects of nutritional supplementation, HIV, age, sex, CD4+ count, weight-adjusted dose, NAT2 genotype, and time on TB treatment were investigated. The kinetics of all drugs was well characterised using first-order elimination and transit compartment absorption, with isoniazid and ethambutol described by two-compartment disposition models, and pyrazinamide by a one-compartment model. Patients with a slow NAT2 genotype had higher isoniazid exposure and a lower estimate of oral clearance (15.5 L/h) than rapid/intermediate NAT2 genotype (26.1 L/h). Pyrazinamide clearance had an estimated typical value of 3.32 L/h, and it was found to increase with time on treatment, with a 16.3% increase after the first 2 months of anti-TB treatment. The typical clearance of ethambutol was estimated to be 40.7 L/h, and was found to decrease with age, at a rate of 1.41% per year. Neither HIV status nor nutritional supplementations were found to affect the pharmacokinetics of these drugs in our cohort of patients.
Topics: Adult; Antitubercular Agents; Ethambutol; Female; Humans; Isoniazid; Male; Pyrazinamide; Tanzania; Tuberculosis, Pulmonary
PubMed: 26501782
DOI: 10.1371/journal.pone.0141002 -
Molecules (Basel, Switzerland) Mar 2020According to the World Health Organization, tuberculosis is still in the top ten causes of death from a single infectious agent, killing more than 1.7 million people...
According to the World Health Organization, tuberculosis is still in the top ten causes of death from a single infectious agent, killing more than 1.7 million people worldwide each year. The rising resistance developed by against currently used antituberculars is an imperative to develop new compounds with potential antimycobacterial activity. As a part of our continuous research on structural derivatives of the first-line antitubercular pyrazinamide, we have designed, prepared, and assessed the in vitro whole cell growth inhibition activity of forty-two novel 5-alkylamino--phenylpyrazine-2-carboxamides with various length of the alkylamino chain (propylamino to octylamino) and various simple substituents on the benzene ring. Final compounds were tested against H37Ra and four other mycobacterial strains (, , , ) in a modified Microplate Alamar Blue Assay. We identified several candidate molecules with micromolar MIC against H37Ra and low in vitro cytotoxicity in HepG2 cell line, for example, -(4-hydroxyphenyl)-5-(pentylamino)pyrazine-2-carboxamide (, MIC = 3.91 µg/mL or 13.02 µM, SI > 38) and 5-(heptylamino)--(-tolyl)pyrazine-2-carboxamide (, MIC = 0.78 µg/mL or 2.39 µM, SI > 20). In a complementary screening, we evaluated the in vitro activity against bacterial and fungal strains of clinical importance. We observed no antibacterial activity and sporadic antifungal activity against the genus.
Topics: Antitubercular Agents; Drug Design; Drug Development; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Pyrazinamide; Pyrazines; Structure-Activity Relationship
PubMed: 32231166
DOI: 10.3390/molecules25071561 -
Journal of Medicinal Chemistry Apr 2010The front-line tuberculosis (TB) chemotherapeutics isoniazid (INH), rifampicin (RIF), and pyrazinamide (PZA) have been labeled with carbon-11 and the biodistribution of...
The front-line tuberculosis (TB) chemotherapeutics isoniazid (INH), rifampicin (RIF), and pyrazinamide (PZA) have been labeled with carbon-11 and the biodistribution of each labeled drug has been determined in baboons using positron emission tomography (PET). Each radiosynthesis and formulation has been accomplished in 1 h, using [(11)C]CH(3)I to label RIF and [(11)C]HCN to label INH and PZA. Following iv administration, INH, PZA, RIF, and/or their radiolabeled metabolites clear rapidly from many tissues; however, INH, PZA, and/or their radiolabeled metabolites accumulate in the bladder while RIF and/or its radiolabeled metabolites accumulates in the liver and gall bladder, consistent with the known routes of excretion of the drugs. In addition, the biodistribution data demonstrate that the ability of the three drugs and their radiolabeled metabolites to cross the blood-brain barrier decreases in the order PZA > INH > RIF, although in all cases the estimated drug concentrations are greater than the minimum inhibitory concentration (MIC) values for inhibiting bacterial growth of Mycobacterium tuberculosis (MTB). The pharmacokinetic (PK) and drug distribution data have important implications for treatment of disseminated TB in the brain and pave the way for imaging the distribution of the pathogen in vivo.
Topics: Animals; Antitubercular Agents; Blood Proteins; Brain; Carbon Radioisotopes; Humans; Isoniazid; Papio; Positron-Emission Tomography; Pyrazinamide; Rifampin; Thorax; Tissue Distribution
PubMed: 20205479
DOI: 10.1021/jm901858n -
Antimicrobial Agents and Chemotherapy Dec 2022A critical barrier to codevelopment of tuberculosis (TB) regimens is a limited ability to identify optimal drug and dose combinations in early-phase clinical testing....
A critical barrier to codevelopment of tuberculosis (TB) regimens is a limited ability to identify optimal drug and dose combinations in early-phase clinical testing. While pharmacokinetic-pharmacodynamic (PKPD) target attainment is the primary tool for exposure-response optimization of TB drugs, the PD target is a static index that does not distinguish individual drug contributions to the efficacy of a multidrug combination. A PKPD model of bedaquiline-pretomanid-pyrazinamide (BPaZ) for the treatment of pulmonary TB was developed as part of a dynamic exposure-response approach to regimen development. The model describes a time course relationship between the drug concentrations in plasma and their individual as well as their combined effect on sputum bacillary load assessed by solid culture CFU counts and liquid culture time to positivity (TTP). The model parameters were estimated using data from the phase 2A studies NC-001-(J-M-Pa-Z) and NC-003-(C-J-Pa-Z). The results included a characterization of BPaZ activity as the most and least sensitive to changes in pyrazinamide and bedaquiline exposures, respectively, with antagonistic activity of BPa compensated by synergistic activity of BZ and PaZ. Simulations of the NC-003 study population with once-daily bedaquiline at 200 mg, pretomanid at 200 mg, and pyrazinamide at 1,500 mg showed BPaZ would require 3 months to attain liquid culture negativity in 90% of participants. These results for BPaZ were intended to be an example application with the general approach aimed at entirely novel drug combinations from a growing pipeline of new and repurposed TB drugs.
Topics: Humans; Pyrazinamide; Antitubercular Agents; Diarylquinolines; Tuberculosis, Pulmonary; Nitroimidazoles; Tuberculosis; Tuberculosis, Multidrug-Resistant
PubMed: 36377952
DOI: 10.1128/aac.00898-22 -
South African Medical Journal =... Mar 2023The clinical significance of low antituberculosis (anti-TB) drug concentrations has not been fully elucidated.
BACKGROUND
The clinical significance of low antituberculosis (anti-TB) drug concentrations has not been fully elucidated.
OBJECTIVES
To investigate the clinical consequences of first-line drug concentrations in adult patients with drug-susceptible pulmonary TBin South Africa (SA).
METHOD
We conducted a pharmacokinetic study nested within the control arm of the Improving Treatment Success (IMPRESS) trial(NCT02114684) in Durban, SA. During the first 2 months of treatment, participants received weight-based dosing of first-line anti-TBdrugs (rifampicin, isoniazid, pyrazinamide and ethambutol), and had plasma drug concentrations measured at 2 and 6 hours after drugadministration during the 8th week of treatment. Intermediate (8 weeks), end-of-treatment (6 months) and follow-up TB outcomes wereassessed using World Health Organization criteria.
RESULTS
We measured plasma drug concentrations on available samples in 43 participants. Peak drug concentrations were below thetherapeutic range in 39/43 (90.7%) for rifampicin, 32/43 (74.4%) for isoniazid, 27/42 (64.3%) for pyrazinamide and 5/41 (12.2%) forethambutol. At the end of the intensive phase of treatment (week 8), 20.9% (n=9/43) of participants remained culture positive. We did notfind a relationship between the concentrations of first-line drugs and treatment outcomes at week 8. All participants were cured at the endof treatment, and there were no relapses during the 12-month follow-up period.
CONCLUSION
Treatment outcomes were favourable despite low drug concentrations as defined by current reference thresholds.
Topics: Adult; Humans; Antitubercular Agents; Isoniazid; Pyrazinamide; Rifampin; South Africa
PubMed: 36876350
DOI: 10.7196/SAMJ.2023.v113i3.16761 -
Antimicrobial Agents and Chemotherapy Jul 2022Pyrazinamide is one of the first-line antituberculosis drugs. The efficacy of pyrazinamide is associated with the ratio of 24-h area under the concentration-time curve...
Pyrazinamide is one of the first-line antituberculosis drugs. The efficacy of pyrazinamide is associated with the ratio of 24-h area under the concentration-time curve (AUC) to MIC. The objective of this study was to develop and validate a limited sampling strategy (LSS) based on a population pharmacokinetic (popPK) model to predict AUC. A popPK model was developed using an iterative two-stage Bayesian procedure and was externally validated. Using data from 20 treatment-naive adult tuberculosis (TB) patients, a one compartment model with transit absorption and first-order elimination best described pyrazinamide pharmacokinetics and fed state was the only significant covariate for absorption rate constant (k). External validation, using data from 26 TB patients, showed that the popPK model predicted AUC with a slight underestimation of 2.1%. LSS were calculated using Monte Carlo simulation ( = 10,000). External validation showed LSS with time points 0 h, 2 h, and 6 h performed best with RMSE of 9.90% and bias of 0.06%. Food slowed absorption of pyrazinamide, but did not affect bioavailability, which may be advantageous in case of nausea or vomiting in which food can be used to diminish these effects. In this study, we successfully developed and validated a popPK model and LSS, using 0 h, 2 h, and 6 h postdose samples, that could be used to perform therapeutic drug monitoring (TDM) of pyrazinamide in TB patients.
Topics: Adult; Antitubercular Agents; Bayes Theorem; Drug Monitoring; Humans; Pyrazinamide; Tuberculosis
PubMed: 35727060
DOI: 10.1128/aac.00003-22 -
MBio Apr 2023Antituberculosis therapy (ATT) causes a rapid and distinct alteration in the composition of the intestinal microbiota that is long lasting in both mice and humans. This...
Antituberculosis therapy (ATT) causes a rapid and distinct alteration in the composition of the intestinal microbiota that is long lasting in both mice and humans. This observation raised the question of whether such antibiotic-induced changes in the microbiome might affect the absorption or gut metabolism of the tuberculosis (TB) drugs themselves. To address this issue, we utilized a murine model of antibiotic-induced dysbiosis to assay the bioavailability of rifampicin, moxifloxacin, pyrazinamide, and isoniazid in mouse plasma over a period of 12 h following individual oral administration. We found that 4-week pretreatment with a regimen of isoniazid, rifampicin, and pyrazinamide (HRZ), a drug combination used clinically for ATT, failed to reduce the exposure of any of the four antibiotics assayed. Nevertheless, mice that received a pretreatment cocktail of the broad-spectrum antibiotics vancomycin, ampicllin, neomycin, and metronidazole (VANM), which are known to deplete the intestinal microbiota, displayed a significant decrease in the plasma concentration of rifampicin and moxifloxacin during the assay period, an observation that was validated in germfree animals. In contrast, no major effects were observed when similarly pretreated mice were exposed to pyrazinamide or isoniazid. Thus, the data from this animal model study indicate that the dysbiosis induced by HRZ does not reduce the bioavailability of the drugs themselves. Nevertheless, our observations suggest that more extreme alterations of the microbiota, such as those occurring in patients on broad-spectrum antibiotics, could directly or indirectly affect the exposure of important TB drugs and thereby potentially influencing treatment outcome. Previous studies have shown that treatment of Mycobacterium tuberculosis infection with first-line antibiotics results in a long-lasting disruption of the host microbiota. Since the microbiome has been shown to influence the host availability of other drugs, we employed a mouse model to ask whether the dysbiosis resulting from either tuberculosis (TB) chemotherapy or a more aggressive course of broad-spectrum antibiotics might influence the pharmacokinetics of the TB antibiotics themselves. While drug exposure was not reduced in animals previously described as exhibiting the dysbiosis triggered by conventional TB chemotherapy, we found that mice with other alterations in the microbiome, such as those triggered by more intensive antibiotic treatment, displayed decreased availability of rifampicin and moxifloxacin, which in turn could impact their efficacy. The above findings are relevant not only to TB but also to other bacterial infections treated with these two broader spectrum antibiotics.
Topics: Humans; Animals; Mice; Antitubercular Agents; Rifampin; Isoniazid; Pyrazinamide; Biological Availability; Moxifloxacin; Dysbiosis; Tuberculosis
PubMed: 36877010
DOI: 10.1128/mbio.00353-23 -
Antimicrobial Agents and Chemotherapy Jun 2017Improved knowledge regarding the tissue penetration of antituberculosis drugs may help optimize drug management. Patients with drug-resistant pulmonary tuberculosis...
Improved knowledge regarding the tissue penetration of antituberculosis drugs may help optimize drug management. Patients with drug-resistant pulmonary tuberculosis undergoing adjunctive surgery were enrolled. Serial serum samples were collected, and microdialysis was performed using lung tissue to measure pyrazinamide concentrations. Among 10 patients, the median pyrazinamide dose was 24.7 mg/kg of body weight. Imaging revealed predominant lung lesions as cavitary ( = 6 patients), mass-like ( = 3 patients), or consolidative ( = 1 patient). On histopathology examination, all tissue samples had necrosis; eight had a pH of ≤5.5. Tissue samples from two patients were positive for by culture (pH 5.5 and 7.2). All 10 patients had maximal serum pyrazinamide concentrations within the recommended range of 20 to 60 μg/ml. The median lung tissue free pyrazinamide concentration was 20.96 μg/ml. The median tissue-to-serum pyrazinamide concentration ratio was 0.77 (range, 0.54 to 0.93). There was a significant inverse correlation between tissue pyrazinamide concentrations and the amounts of necrosis ( = -0.66, = 0.04) and acid-fast bacilli ( = -0.75, = 0.01) identified by histopathology. We found good penetration of pyrazinamide into lung tissue among patients with pulmonary tuberculosis with a variety of radiological lesion types. Our tissue pH results revealed that most lesions had a pH conducive to pyrazinamide activity. The tissue penetration of pyrazinamide highlights its importance in both drug-susceptible and drug-resistant antituberculosis treatment regimens.
Topics: Adolescent; Adult; Antitubercular Agents; Female; Humans; Isoniazid; Lung; Male; Middle Aged; Mycobacterium tuberculosis; Pyrazinamide; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Young Adult
PubMed: 28373198
DOI: 10.1128/AAC.00226-17