| 1. |
- Bjugård Nyberg, Henrik, 1984-, et al.
(författare)
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Population Pharmacokinetics and Dosing of Ethionamide in Children with Tuberculosis
- 2020
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Ingår i: Antimicrobial Agents and Chemotherapy. - : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 64:3
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Tidskriftsartikel (refereegranskat)abstract
- Ethionamide has proven efficacy against both drug-susceptible and some drug-resistant strains of Mycobacterium tuberculosis. Limited information on its pharmacokinetics in children is available, and current doses are extrapolated from weight-based adult doses. Pediatric doses based on more robust evidence are expected to improve antituberculosis treatment, especially in small children. In this analysis, ethionamide concentrations in children from 2 observational clinical studies conducted in Cape Town, South Africa, were pooled. All children received ethionamide once daily at a weight-based dose of approximately 20 mg/kg of body weight (range, 10.4 to 25.3 mg/kg) in combination with other first- or second-line antituberculosis medications and with antiretroviral therapy in cases of HIV coinfection. Pharmacokinetic parameters were estimated using nonlinear mixed-effects modeling. The MDR-PK1 study contributed data for 110 children on treatment for multidrug-resistant tuberculosis, while the DATiC study contributed data for 9 children treated for drug-susceptible tuberculosis. The median age of the children in the studies combined was 2.6 years (range, 0.23 to 15 years), and the median weight was 12.5 kg (range, 2.5 to 66 kg). A one-compartment, transit absorption model with first-order elimination best described ethionamide pharmacokinetics in children. Allometric scaling of clearance (typical value, 8.88 liters/h), the volume of distribution (typical value, 21.4 liters), and maturation of clearance and absorption improved the model fit. HIV coinfection decreased the ethionamide bioavailability by 22%, rifampin coadministration increased clearance by 16%, and ethionamide administration by use of a nasogastric tube increased the rate, but the not extent, of absorption. The developed model was used to predict pediatric doses achieving the same drug exposure achieved in 50- to 70-kg adults receiving 750-mg once-daily dosing. Based on model predictions, we recommend a weight-banded pediatric dosing scheme using scored 125-mg tablets.
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| 2. |
- Cluver, Catherine Anne, et al.
(författare)
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Does metformin prolong pregnancy in preterm pre-eclampsia? A study protocol for a South African, hospital-based double-blind, randomised, placebo-controlled trial
- 2024
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Ingår i: BMJ OPEN. - 2044-6055. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Preterm pre-eclampsia is a leading cause of maternal morbidity and mortality. The Pre-eclampsia Intervention 2 (PI 2) trial suggested that metformin sustained release (XR) may prolong gestation by a week in pregnant women undergoing expectant management (7.6days, geometric mean ratio 1.39, 95% CI 0.99 to 1.95; p=0.057). These findings should be confirmed with a larger sample size, and we need to know if such a prolongation improves neonatal outcome. Here, we describe the protocol for such a follow-up trial. Methods The PI 3 trial is a phase III, intention-to-treat, double-blind, placebo-controlled randomised clinical trial to assess if metformin XR can prolong gestation and improve neonatal outcomes in women undergoing expectant management for preterm pre-eclampsia. We will recruit women who are between 26+0and 31+6 weeks pregnant. Women will be randomised to receive either 3 g metformin XR or an identical placebo in divided daily doses. The primary outcome is prolongation of pregnancy. Secondary outcomes are neonatal birth weight and length of neonatal care admission (an indicator of neonatal health at birth). All other outcomes will be exploratory. We will record tolerability and adverse events. We plan a sample size of 500 participants to be powered for the primary and secondary outcomes. Ethics and dissemination PI 3 has ethical approval (Health Research Ethics Committee 2, Stellenbosch University, Protocol number M21/03/007, Project ID 21639, Federal Wide Assurance Number 00001372, Institutional Review Board Number IRB0005239), and is registered with the Pan African Clinical Trial Registry (PACTR202104532026017) and the South African Medicine Control Council (20211211). Data will be presented at international conferences and published in peer-reviewed journals. Trial registration number PACTR202104532026017)
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| 3. |
- Denti, Paolo, et al.
(författare)
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Optimizing Dosing and Fixed-Dose Combinations of Rifampicin, Isoniazid, and Pyrazinamide in Pediatric Patients With Tuberculosis : A Prospective Population Pharmacokinetic Study
- 2022
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Ingår i: Clinical Infectious Diseases. - : OXFORD UNIV PRESS INC. - 1058-4838 .- 1537-6591. ; 75:1, s. 141-151
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Tidskriftsartikel (refereegranskat)abstract
- Background In 2010, the World Health Organization (WHO) revised dosing guidelines for treatment of childhood tuberculosis. Our aim was to investigate first-line antituberculosis drug exposures under these guidelines, explore dose optimization using the current dispersible fixed-dose combination (FDC) tablet of rifampicin/isoniazid/pyrazinamide; 75/50/150 mg, and suggest a new FDC with revised weight bands. Methods Children with drug-susceptible tuberculosis in Malawi and South Africa underwent pharmacokinetic sampling while receiving first-line tuberculosis drugs as single formulations according the 2010 WHO recommended doses. Nonlinear mixed-effects modeling and simulation was used to design the optimal FDC and weight-band dosing strategy for achieving the pharmacokinetic targets based on literature-derived adult AUC(0-24h) for rifampicin (38.7-72.9), isoniazid (11.6-26.3), and pyrazinamide (233-429 mg center dot h/L). Results In total, 180 children (42% female; 13.9% living with human immunodeficiency virus [HIV]; median [range] age 1.9 [0.22-12] years; weight 10.7 [3.20-28.8] kg) were administered 1, 2, 3, or 4 FDC tablets (rifampicin/isoniazid/pyrazinamide 75/50/150 mg) daily for 4-8, 8-12, 12-16, and 16-25 kg weight bands, respectively. Rifampicin exposure (for weight and age) was up to 50% lower than in adults. Increasing the tablet number resulted in adequate rifampicin but relatively high isoniazid and pyrazinamide exposures. Administering 1, 2, 3, or 4 optimized FDC tablets (rifampicin/isoniazid/pyrazinamide 120/35/130 mg) to children < 6, 6-13, 13-20. and 20-25 kg, and 0.5 tablet in < 3-month-olds with immature metabolism, improved exposures to all 3 drugs. Conclusions Current pediatric FDC doses resulted in low rifampicin exposures. Optimal dosing of all drugs cannot be achieved with the current FDCs. We propose a new FDC formulation and revised weight bands. Current pediatric dosing guidelines lead to infant rifampicin exposures much lower than in adults, whereas isoniazid and pyrazinamide exposures are similar. A new fixed-dose combination (FDC) with rifampicin/isoniazid/pyrazinamide 120/35/130 mg and weight bands of < 6, 6-13, 13-20, and 20-25 kg could improve treatment.
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| 4. |
- Gafar, Fajri, et al.
(författare)
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Global estimates and determinants of antituberculosis drug pharmacokinetics in children and adolescents : a systematic review and individual patient data meta-analysis
- 2023
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 61:3
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Forskningsöversikt (refereegranskat)abstract
- Background Suboptimal exposure to antituberculosis (anti-TB) drugs has been associated with unfavourable treatment outcomes. We aimed to investigate estimates and determinants of first-line anti-TB drug pharmacokinetics in children and adolescents at a global level.Methods We systematically searched MEDLINE, Embase and Web of Science (1990–2021) for pharmacokinetic studies of first-line anti-TB drugs in children and adolescents. Individual patient data were obtained from authors of eligible studies. Summary estimates of total/extrapolated area under the plasma concentration–time curve from 0 to 24 h post-dose (AUC0–24) and peak plasma concentration (Cmax) were assessed with random-effects models, normalised with current World Health Organization-recommended paediatric doses. Determinants of AUC0–24 and Cmax were assessed with linear mixed-effects models.Results Of 55 eligible studies, individual patient data were available for 39 (71%), including 1628 participants from 12 countries. Geometric means of steady-state AUC0–24 were summarised for isoniazid (18.7 (95% CI 15.5–22.6) h·mg·L−1), rifampicin (34.4 (95% CI 29.4–40.3) h·mg·L−1), pyrazinamide (375.0 (95% CI 339.9–413.7) h·mg·L−1) and ethambutol (8.0 (95% CI 6.4–10.0) h·mg·L−1). Our multivariate models indicated that younger age (especially <2 years) and HIV-positive status were associated with lower AUC0–24 for all first-line anti-TB drugs, while severe malnutrition was associated with lower AUC0–24 for isoniazid and pyrazinamide. N-acetyltransferase 2 rapid acetylators had lower isoniazid AUC0–24 and slow acetylators had higher isoniazid AUC0–24 than intermediate acetylators. Determinants of Cmax were generally similar to those for AUC0–24.Conclusions This study provides the most comprehensive estimates of plasma exposures to first-line anti-TB drugs in children and adolescents. Key determinants of drug exposures were identified. These may be relevant for population-specific dose adjustment or individualised therapeutic drug monitoring.
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