RESUMEN
OBJECTIVE: To investigate the influence of CYP2B6 516G>T polymorphism, as a covariate, and of interoccasion variability (IOV) on the oral clearance (CL/F) of efavirenz (EFV) in treatment-naïve black South African children over a period of 24 months post-antiretroviral therapy (ART) initiation. METHODS: HIV-infected black children (n = 60, aged 3-16 years), with no prior exposure to ART, eligible to commence ART and attending an outpatient clinic were enrolled into this study. Blood samples were taken at mid-dose interval at 1, 3, 6, 12, 18 and 24 months post-ART initiation. EFV plasma samples were determined with an adapted and validated LC/MS/MS method. Genotyping of the CYP2B6 G516T single nucleotide polymorphism (SNP) was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). NONMEM was used for the population pharmacokinetic modelling. RESULTS: EFV concentrations below 1 µg/mL accounted for 18% (116/649), EFV concentrations >4 µg/mL accounted for 29.5% (192/649) and concentrations within the therapeutic range (1-4 µg/mL) represented 52.5% (341/649) of all the samples determined. The covariates age, weight and CYP2B6 G516Tgenotype were included in the final model with population estimates for CL/F determined as 2.46, 4.60 and 7.33 L/h for the T/T, G/T and G/G genotype groups respectively. CONCLUSIONS: The inclusion of both age and weight to predict accurate EFV CL values for the respective genotype groups within this paediatric population was required, whereas the addition of gender and body surface area did not improve the predictions. The importance of introducing IOV in a PK model for a longitudinal study with sparsely collected data was again highlighted by this investigation.
Asunto(s)
Fármacos Anti-VIH/farmacocinética , Hidrocarburo de Aril Hidroxilasas/genética , Benzoxazinas/farmacocinética , Infecciones por VIH/genética , Oxidorreductasas N-Desmetilantes/genética , Inhibidores de la Transcriptasa Inversa/farmacocinética , Adolescente , Alquinos , Fármacos Anti-VIH/sangre , Hidrocarburo de Aril Hidroxilasas/metabolismo , Benzoxazinas/sangre , Niño , Preescolar , Ciclopropanos , Citocromo P-450 CYP2B6 , Femenino , Genotipo , Infecciones por VIH/metabolismo , Humanos , Masculino , Modelos Biológicos , Oxidorreductasas N-Desmetilantes/metabolismo , Polimorfismo Genético , Inhibidores de la Transcriptasa Inversa/sangre , SudáfricaRESUMEN
OBJECTIVE: Fungal septicemia is a devastating disease in the neonate, especially in the low birth weight preterm infant who is especially vulnerable to disseminated fungal sepsis. The objective of this study was to compare the efficacy, safety and overall convenience of fluconazole vs. amphotericin B for the treatment of disseminated fungal sepsis in neonates. DESIGN: A prospective, randomized, collaborative study conducted at two South African neonatal units. SUBJECTS: Twenty-four infants with proven fungal septicemia were treated from June, 1992, to June, 1993. Twelve received fluconazole, 11 received amphotericin B and 1 was excluded. Assessment of hepatic, renal and hematologic functions were performed before, during and after treatment. The two groups were comparable at the time of enrollment into the study. RESULTS: Infants receiving amphotericin B had significantly higher values of total and direct bilirubin and alkaline phosphatase values at the end of treatment, while the fluconazole group showed a significant increase in the platelet count. The cumulative total numbers of days receiving intravenous therapy for the administration of antifungal drugs were 57 for the fluconazole group and 162 for the amphotericin group; no central lines were needed in the fluconazole group, whereas 3 babies given amphotericin B had central catheters for a cumulative total of 27 days. The case fatality rate was 33% in the fluconazole group and 45% in the amphotericin B group; there was still proof of fungal septicemia at the time of death in 1 patient given amphotericin B and 2 given fluconazole. CONCLUSION: Fluconazole showed fewer side effects than amphotericin B and was more convenient to use.