Publications by authors named "Roeland Wasmann"

Background: In many sub-Saharan African countries, it is recommended that children with sickle cell anaemia receive malaria chemoprevention with monthly sulfadoxine-pyrimethamine or daily proguanil as the standard of care. However, the efficacy of these interventions is compromised by high-grade antifolate resistance of Plasmodium falciparum and poor adherence. We aimed to compare the efficacy of weekly dihydroartemisinin-piperaquine and monthly sulfadoxine-pyrimethamine for the prevention of clinical malaria in children with sickle cell anaemia in areas with high-grade sulfadoxine-pyrimethamine resistance of P falciparum in Uganda and Malawi.

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Background: Darunavir is a potent HIV protease inhibitor with a high barrier to resistance. We conducted a nested pharmacokinetic sub-study within CHAPAS-4 to evaluate darunavir exposure in African children with HIV, taking once-daily darunavir/ritonavir for second-line treatment.

Methods: We used data from the CHAPAS-4 pharmacokinetic sub-study treating children with once-daily darunavir/ritonavir (600/100 mg if 14-24.

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We characterized population pharmacokinetics in 42 African children receiving once-daily 25 mg (14 to <20 kg) or 50 mg (>20 kg) dolutegravir. Coadministration with emtricitabine and tenofovir alafenamide reduced dolutegravir bioavailability by 19.6% (95% confidence interval: 8.

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In adults requiring protease inhibitor (PI)-based antiretroviral therapy (ART), replacing rifampicin with rifabutin is a preferred option, but there is lack of evidence to guide rifabutin dosing in children, especially with PIs. We aimed to characterize the population pharmacokinetics of rifabutin and 25-O-desacetyl rifabutin (des-rifabutin) in children and optimize its dose. We included children from three age cohorts: (i) <1-year-old cohort and (ii) 1- to 3-year-old cohort, who were ART naïve and received 15- to 20-mg/kg/day rifabutin for 2 weeks followed by lopinavir/ritonavir (LPV/r)-based ART with 5.

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Cefazolin is an antibiotic used to prevent surgical site infections. During cardiac surgery with cardiopulmonary bypass (CPB), its efficacy target could be underachieved. We aimed to develop a population pharmacokinetic model for cefazolin in children and optimize the prophylactic dosing regimen.

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Standardized dosing of antitubercular drugs leads to variable plasma drug levels, which are associated with adverse drug reactions, delayed treatment response, and relapse. Mutations in genes affecting drug metabolism explain considerable interindividual pharmacokinetic variability; however, pharmacogenomic assays that predict metabolism of antitubercular drugs have been lacking. We sought to develop a Nanopore sequencing panel and validate its performance in patients with active tuberculosis (TB) to personalize treatment dosing.

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Aims: Dolutegravir increases serum creatinine by inhibiting its renal tubular secretion and elimination. We investigated determinants of early changes in serum creatinine in a southern African cohort starting first-line dolutegravir-based antiretroviral therapy (ART).

Methods: We conducted a secondary analysis of data from participants in a randomized controlled trial of dolutegravir, emtricitabine and tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide fumarate (TAF) (ADVANCE, NCT03122262).

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Background: The current World Health Organization (WHO) pediatric tuberculosis dosing guidelines lead to suboptimal drug exposures. Identifying factors altering the exposure of these drugs in children is essential for dose optimization. Pediatric pharmacokinetic studies are usually small, leading to high variability and uncertainty in pharmacokinetic results between studies.

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Background: Poor medication adherence leads to poor health outcomes and increased healthcare costs among patients with heart failure (HF). This study aimed to objectively assess medication adherence by measuring carvedilol and enalaprilat plasma concentrations among patients with HF.

Methods: The present sub-study of the Safety, Tolerability, and Efficacy of Rapid Optimization, helped by NT-proBNP testing, of Heart Failure therapies (STRONG-HF) study involved adult patients with acute HF admitted in two Mozambican and two Nigerian hospitals who were not optimally treated with oral enalapril and carvedilol.

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Rationale: Standardized dosing of anti-tubercular (TB) drugs leads to variable plasma drug levels, which are associated with adverse drug reactions, delayed treatment response, and relapse. Mutations in genes affecting drug metabolism explain considerable interindividual pharmacokinetic variability; however, pharmacogenomic (PGx) assays that predict metabolism of anti-TB drugs have been lacking.

Objectives: To develop a Nanopore sequencing panel and validate its performance in active TB patients to personalize treatment dosing.

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Article Synopsis
  • * Children were divided into groups to receive either emtricitabine/TAF or standard HIV treatments, with doses determined by their weight, and blood samples were analyzed for drug concentration.
  • * Results showed that TAF levels in children were similar to those seen in adults, suggesting these treatments are effective and safe for young patients in Africa.
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Following infection with , young children are at high risk of developing severe forms of tuberculosis (TB) disease, including TB meningitis (TBM), which is associated with significant morbidity and mortality. In 2022, the World Health Organization (WHO) conditionally recommended that a 6-month treatment regimen composed of higher doses of isoniazid (H) and rifampicin (R), with pyrazinamide (Z) and ethionamide (Eto) (6HRZEto), be used as an alternative to the standard 12-month regimen (2HRZ-Ethambutol/10HR) in children and adolescents with bacteriologically confirmed or clinically diagnosed TBM. This regimen has been used in South Africa since 1985, in a complex dosing scheme across weight bands using fixed-dose combinations (FDC) available locally at the time.

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Background: Tenofovir is a component of preferred combination antiretroviral therapy (ART) regimens in Africa. Few pharmacogenetic studies have been conducted on tenofovir exposure in Africa, where genetic diversity is greatest.

Objective: We characterized the pharmacogenetics of plasma tenofovir clearance in Southern Africans receiving tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF).

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Article Synopsis
  • - Tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) are both prodrugs that inhibit HIV replication but have different effects on the body; TDF can cause kidney and bone toxicity while TAF generally has lower toxicity and can be given in smaller doses.
  • - A study involving 41 South African adults living with HIV evaluated the pharmacokinetics of tenofovir derived from TAF and TDF, showing that TAF primarily converts to tenofovir inside cells, leading to different absorption and release patterns compared to TDF.
  • - The research used a semimechanistic model to describe how tenofovir is processed in the body after taking T
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Rifampicin, a potent enzyme inducer, causes marked reduction of dolutegravir exposure. Rifabutin, a less potent enzyme inducer, may offer an alternative to rifampicin. We aimed to characterize the population pharmacokinetics of dolutegravir when co-administered with rifabutin.

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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.

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Article Synopsis
  • The study evaluates how (morbid) obesity affects the pharmacokinetics of ciprofloxacin, a commonly used antibiotic, during oral and intravenous administration.
  • A total of 28 participants were analyzed, revealing no significant differences in drug absorption, clearance, or distribution between obese and non-obese individuals, despite predictions of lower soft tissue concentrations in obese patients.
  • The conclusion suggests that standard ciprofloxacin dosages are generally sufficient for treating infections in obese individuals, though higher doses might be needed for infections in tissues with poor drug penetration.
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Background: Fluconazole is commonly used to treat or prevent fungal infections. It is typically used orally but in critical situations, IV administration is needed. Obesity may influence the pharmacokinetics and therapeutic efficacy of a drug.

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Dolutegravir-based regimens are recommended as first-line therapy for HIV in low- and middle-income countries where tuberculosis is the most common opportunistic infection. Concurrent HIV/tuberculosis treatment is challenging because of drug-drug interactions. Our analysis aimed to characterize dolutegravir's population pharmacokinetics when coadministered with rifampicin and assess alternative dolutegravir dosing regimens.

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Article Synopsis
  • - Esomeprazole, a proton pump inhibitor, is being studied for preeclampsia treatment, but its effects during pregnancy are not well understood.
  • - A study involving 10 pregnant participants and 49 non-pregnant participants developed a two-compartment pharmacokinetic model showing that clearance of esomeprazole in pregnant individuals is significantly lower (42.2% less) due to the inhibition of the enzyme CYP2C19.
  • - In non-pregnant participants, repeated dosing results in lower clearance (54.9% less) and higher bioavailability (33% more) likely due to autoinhibition of CYP2C19, but pregnant individuals may experience a lesser increase in drug
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Background: Dolutegravir is a component of preferred antiretroviral therapy (ART) regimens. We characterized the pharmacogenetics of dolutegravir exposure after ART initiation in the ADVANCE trial in South Africa.

Methods: Genome-wide genotyping followed by imputation was performed.

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Dolutegravir is associated with more weight gain than efavirenz in people starting antiretroviral therapy (ART). We investigated the concentration-response relationships of efavirenz and dolutegravir with weight gain. We determined concentration-response relationships of dolutegravir and efavirenz (both combined with tenofovir disoproxil fumarate and emtricitabine) with changes in weight and fat distribution, derived from dual-energy x-ray absorptiometry scans, in a nested study of ART-naïve participants from a randomised controlled trial.

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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.

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Background: In sub-Saharan Africa, artemisinin-containing therapies for malaria treatment are regularly co-administered with ART. Currently, dolutegravir-based regimens are recommended as first-line therapy for HIV across most of Africa.

Objectives: To investigate the population pharmacokinetics of dolutegravir during co-administration with artemether/lumefantrine or artesunate/amodiaquine, two commonly used antimalarial therapies.

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