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- Elkayal, Omar, et al.
(författare)
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A Population Pharmacokinetic Modeling and Simulation Study of Posaconazole Oral Suspension in Immunocompromised Pediatric Patients : A Short Communication
- 2021
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Ingår i: Therapeutic Drug Monitoring. - : Wolters Kluwer. - 0163-4356 .- 1536-3694. ; 43:4, s. 512-518
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Tidskriftsartikel (refereegranskat)abstract
- Background: Posaconazole oral suspension emerged as a promising candidate for prophylaxis of invasive fungal infections in immunocompromised children. Its pharmacodynamic advantages include a broad-spectrum activity and a favorable safety profile; however, they are overshadowed by its large pharmacokinetic (PK) variability, which might cause subtherapeutic exposure. The aim of this study was to develop a population (pop) PK model based on rich sampling data to better understand the PK of posaconazole oral suspension in pediatric patients. Methods: Data were obtained from a prospective interventional study involving hospitalized pediatric patients with a hematologic malignancy and prophylactically treated with posaconazole oral suspension. After constructing the popPK model, the probability of target attainment (PTA; 100% T >= 0.7 mg/L) for prophylaxis under fixed, body weight-based, and body surface area-based dosing was evaluated using Monte Carlo simulation. Results: Fourteen patients contributed 112 posaconazole plasma concentrations. The PK of posaconazole was adequately described by a 1-compartment model with lag time 2.71 hours [13%]; nonlinear bioavailability ED50 99.1 mg/m(2) (fixed); first-order absorption rate constant 0.325 hour(-1) [27%]; apparent volume of distribution 1150 L [34%]; and apparent clearance 15.4 L/h [24%] (similar to 70-kg individual). The bioavailability decreased in the presence of diarrhea and co-treatment with a proton pump inhibitor (PPI). The unexplained interindividual variability in posaconazole PK remained large. The PTA was <85%, irrespective of the simulated dosing strategy. Patients without diarrhea and not administered a PPI had the highest PTA (85% under the fixed 300-mg dosing 4 times per day). Conclusions: Therapeutic drug monitoring is recommended during prophylactic posaconazole therapy in immunocompromised pediatric patients. Large-scale comparative studies are needed to characterize the PK variability between different posaconazole formulations in this cohort.
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| 2. |
- Elkayal, Omar, et al.
(författare)
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Population pharmacokinetics of cefazolin in maternal and umbilical cord plasma, and simulated exposure in term neonates
- 2021
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press. - 0305-7453 .- 1460-2091. ; 76:12, s. 3229-3236
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundIntra-partum cefazolin is used to prevent group B Streptococcus (GBS) vertical transmission in mothers allergic to penicillin without a history of anaphylaxis.ObjectivesTo investigate the maternal cefazolin dose–exposure relationship and subsequent maternal and neonatal target attainment at delivery.MethodsData were obtained from 24 healthy, GBS-colonized pregnant women (20–41 years), undergoing vaginal delivery (gestational age ≥37 weeks). During labour, all women received a 2 g cefazolin IV infusion. Eight hours later, eight women received another 1 g in the event of delayed (>8 h) delivery. Next to maternal plasma concentrations (up to 10 per dosing interval, until delivery), venous and arterial umbilical cord concentrations were determined at delivery. Target attainment in maternal/neonatal plasma was set at 1 mg/L for 60% of the dosing interval (unbound cefazolin, worst-case clinical breakpoint). A population pharmacokinetic (popPK) model was built (NONMEM 7.4). ClinicalTrials.gov Identifier: NCT01295606.ResultsAt delivery, maternal blood and arterial umbilical cord unbound cefazolin concentrations were >1 mg/L in 23/24 (95.8%) and 11/12 (91.7%), respectively. The popPK of cefazolin in pregnant women was described by a two-compartment model with first-order elimination. Two additional compartments described the venous and arterial umbilical cord concentration data. Cefazolin target attainment was adequate in the studied cohort, where delivery occurred no later than 6.5 h after either the first or the second dose. PopPK simulations showed adequate maternal and umbilical cord exposure for 12 h following the first dose.ConclusionsPopPK simulations showed that standard pre-delivery maternal cefazolin dosing provided adequate target attainment up to the time of delivery.
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