Dataset Information

Population Pharmacokinetics and Cerebrospinal Fluid Penetration of Fluconazole in Adults with Cryptococcal Meningitis.

ABSTRACT: Robust population pharmacokinetic (PK) data for fluconazole are scarce. The variability of fluconazole penetration into the central nervous system (CNS) is not known. A fluconazole PK study was conducted in 43 patients receiving oral fluconazole (usually 800 mg every 24 h [q24h]) in combination with amphotericin B deoxycholate (1 mg/kg q24h) for cryptococcal meningitis (CM). A four-compartment PK model was developed, and Monte Carlo simulations were performed for a range of fluconazole dosages. A meta-analysis of trials reporting outcomes of CM patients treated with fluconazole monotherapy was performed. Adjusted for bioavailability, the PK parameter means (standard deviation) were the following: clearance, 0.72 (0.24) liters/h; volume of the central compartment, 18.07 (6.31) liters; volume of the CNS compartment, 32.07 (17.60) liters; first-order rate constant from the central to peripheral compartment, 12.20 (11.17) h-1, from the peripheral to central compartment, 18.10 (8.25) h-1, from the central to CNS compartment, 35.43 (13.74) h-1, and from the CNS to central the compartment, 28.63 (10.03) h-1 Simulations of the area under concentration-time curve resulted in median (interquartile range) values of 1,143.2 (range, 988.4 to 1,378.0) mg · h/liter in plasma (AUCplasma) and 982.9 (range, 781.0 to 1,185.9) mg · h/liter in cerebrospinal fluid (AUCCSF) after a dosage of 1,200 mg q24h. The mean simulated ratio of AUCCSF/AUCplasma was 0.89 (standard deviation [SD], 0.44). The recommended dosage of fluconazole for CM induction therapy fails to attain the pharmacodynamic (PD) target in respect to the wild-type MIC distribution for C. neoformans The meta-analysis suggested modest improvements in both CSF sterility and mortality outcomes with escalating dosage. This study provides the pharmacodynamic rationale for the long-recognized fact that fluconazole monotherapy is an inadequate induction regimen for CM.

SUBMITTER: Stott KE

PROVIDER: S-EPMC6125572 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature

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Population Pharmacokinetics and Cerebrospinal Fluid Penetration of Fluconazole in Adults with Cryptococcal Meningitis.

Stott Katharine E KE Beardsley Justin J Kolamunnage-Dona Ruwanthi R Castelazo Anahi Santoyo AS Kibengo Freddie Mukasa FM Mai Nguyen Thi Hoang NTH Tùng Nguyễn Lê Nhu’ NLN Cuc Ngo Thi Kim NTK Day Jeremy J Hope William W

Antimicrobial agents and chemotherapy 20180827 9

Robust population pharmacokinetic (PK) data for fluconazole are scarce. The variability of fluconazole penetration into the central nervous system (CNS) is not known. A fluconazole PK study was conducted in 43 patients receiving oral fluconazole (usually 800 mg every 24 h [q24h]) in combination with amphotericin B deoxycholate (1 mg/kg q24h) for cryptococcal meningitis (CM). A four-compartment PK model was developed, and Monte Carlo simulations were performed for a range of fluconazole dosages. ...[more]

PMID: 29914943

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Project description:Background(1→3)-β-d-Glucan (BDG) is a helpful diagnostic marker for many invasive fungal infections. However, BDG is not thought to be useful in diagnosing cryptococcosis. We evaluated the utility of BDG as an adjunct diagnostic tool for patients infected with human immunodeficiency virus (HIV) and presenting with suspected cryptococcal meningitis.MethodsThe Fungitell assay was used to measure BDG concentrations in cerebrospinal fluid (CSF) (n = 177) and serum (n = 109) of HIV-infected Ugandans and South Africans with suspected meningitis. Correlations between BDG concentrations and quantitative CSF cryptococcal cultures, CSF cryptococcal antigen (CRAG) titers, and 18 different CSF cytokine concentrations were assessed using non-parametric tests. Mixed models evaluated longitudinal changes in CSF BDG concentrations. Survival analyses were used to evaluate BDG's relationship with mortality.ResultsThe Fungitell BDG assay provided 89% sensitivity and 85% specificity in CSF for cryptococcal meningitis. Serum sensitivity was suboptimal (79%). Cerebrospinal fluid BDG concentrations at diagnosis were median (interquartile range) 343 (200-597) pg/mL in cryptococcal patients and 37 (23-46) pg/mL in patients without cryptococcosis. Sensitivity in CSF improved to 98% (53 of 54) when initial fungal burdens were ≥10 000 colony-forming units/mL. (1→3)-β-d-Glucan normalized rapidly after initiating antifungal therapy. Baseline BDG concentrations correlated with CSF fungal burden (rho = 0.820; P < .001), CSF CRAG lateral flow assay titers (rho = 0.780, P < .001), and monocyte chemotactic protein-1 levels in CSF (P = .047). In patients with cryptococcal meningitis, BDG ≥500 pg/mL at diagnosis was associated with increased 10-week mortality.Conclusions(1→3)-β-d-Glucan is detectable in the CSF of HIV-infected patients with Cryptococcus, and it may provide useful prognostic information. Sensitivity is less than CRAG; however, BDG normalizes rapidly, unlike CRAG, making BDG potentially useful in diagnosing recurrent episodes.

Project description:BackgroundCryptococcal meningitis (CM) causes an estimated 180,000 deaths annually, predominantly in sub-Saharan Africa, where most patients receive fluconazole (FLC) monotherapy. While relapse after FLC monotherapy with resistant strains is frequently observed, the mechanisms and impact of emergence of FLC resistance in human CM are poorly understood. Heteroresistance (HetR) - a resistant subpopulation within a susceptible strain - is a recently described phenomenon in Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg), the significance of which has not previously been studied in humans.MethodsA cohort of 20 patients with HIV-associated CM in Tanzania was prospectively observed during therapy with either FLC monotherapy or in combination with flucytosine (5FC). Total and resistant subpopulations of Cryptococcus spp. were quantified directly from patient cerebrospinal fluid (CSF). Stored isolates underwent whole genome sequencing and phenotypic characterization.ResultsHeteroresistance was detectable in Cryptococcus spp. in the CSF of all patients at baseline (i.e., prior to initiation of therapy). During FLC monotherapy, the proportion of resistant colonies in the CSF increased during the first 2 weeks of treatment. In contrast, no resistant subpopulation was detectable in CSF by day 14 in those receiving a combination of FLC and 5FC. Genomic analysis revealed high rates of aneuploidy in heteroresistant colonies as well as in relapse isolates, with chromosome 1 (Chr1) disomy predominating. This is apparently due to the presence on Chr1 of ERG11, which is the FLC drug target, and AFR1, which encodes a drug efflux pump. In vitro efflux levels positively correlated with the level of heteroresistance.ConclusionOur findings demonstrate for what we believe is the first time the presence and emergence of aneuploidy-driven FLC heteroresistance in human CM, association of efflux levels with heteroresistance, and the successful suppression of heteroresistance with 5FC/FLC combination therapy.FundingThis work was supported by the Wellcome Trust Strategic Award for Medical Mycology and Fungal Immunology 097377/Z/11/Z and the Daniel Turnberg Travel Fellowship.

Dataset Information

Population Pharmacokinetics and Cerebrospinal Fluid Penetration of Fluconazole in Adults with Cryptococcal Meningitis.

Publications

Population Pharmacokinetics and Cerebrospinal Fluid Penetration of Fluconazole in Adults with Cryptococcal Meningitis.

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