Plasma Voriconazole Concentrations Research Articles

Placental and breastmilk transfer of voriconazole to offspring from pregnant and lactating bottlenose dolphins (Tursiops truncatus).

Fungal pneumonia is a common disease in bottlenose dolphins (Tursiops truncatus), including pregnant and lactating ones. Voriconazole (VRCZ) is commonly used to treat respiratory fungal infections in this species; however, it is unknown whether VRCZ is transferred via the placenta and breastmilk and whether its usage is safe in pregnant and lactating dolphins. We measured VRCZ concentrations in breastmilk and dams', umbilical cord, and calves' plasma samples from four dam-calf dolphin pairs in the Port of Nagoya Public Aquarium, Japan, treated with or without VRCZ. Three pregnant and/or lactating dams were administered VRCZ (loading dose 1.5-2.3mg/kg, for 3 days; maintenance dose 1.5-3.1mg/kg, every 5-18 days), twice daily, orally, without side effects in dams or calves. VRCZ was detected in two dams' umbilical cord plasma (0.14 and 2.35μg/ml) and in one calf's plasma (0.18μg/ml), collected immediately after birth. Further, VRCZ was detected in breastmilk samples (maximum 13.45μg/ml) from three VRCZ-administered dams and in plasma from three calves (maximum 7.54μg/ml) given or nursed from VRCZ-administered dams' breastmilk. The calves' plasma VRCZ concentrations varied, depending on the amount of breastmilk and food consumed. VRCZ concentrations were higher in breastmilk samples than in dams' plasma. To our knowledge, this is the first report on placental and breastmilk VRCZ transfer to offspring in bottlenose dolphins. During VRCZ medication in pregnant and lactating bottlenose dolphins, it is crucial to monitor plasma VRCZ concentrations and any side effects in dams as well as in their calves.

Risk factors associated with insufficient and potentially toxic voriconazole plasma concentrations: an observational study

The aim of this study was to identify potential factors associated with insufficient/toxic voriconazole trough concentrations (VTCs) in patients in order to screen the high-risk population. A total of 119 VTCs were obtained from 67 patients. Multivariate regression analysis suggested that insufficient VTCs (<1.0 mg/L) were significantly associated with younger age and underlying hematological malignancy, and toxic VTCs (>5.5 mg/L) were significantly associated with lower serum albumin (ALB) level. Receiver operating characteristic curve analysis indicated that patients whose age < 47 years were the high-risk population of insufficient VTCs, and patients whose ALB <27 g/L were the high-risk population of toxic VTCs. Younger age and underlying hematological malignancy were significant predictors of insufficient VTCs, and lower ALB level was found to be a significant predictor of toxic VTCs. Therefore, we recommend to increase the monitoring on these high-risk population to avoid treatment failure and to prevent toxic adverse events.

Impact of flavin-containing monooxygenase 3 and CYP2C19 genotypes on plasma disposition and adverse effects of voriconazole administered orally in immunocompromised patients

Flavin-containing monooxygenase (FMO) 3 together with cytochrome P450 (CYP) 2C19 play a significant role in voriconazole N-oxidation. This study aimed to evaluate the influence of FMO3 and CYP2C19 genotypes on the plasma disposition and adverse effects of voriconazole in immunocompromised patients. Sixty-five Japanese immunocompromised patients receiving oral voriconazole were enrolled. Predose plasma concentrations of voriconazole and N-oxide were determined at day 5 or later. The adverse effects of voriconazole and the FMO3 and CYP2C19 genotypes were investigated. The patients with FMO3 E158K/E308G had a lower plasma concentration of voriconazole. The metabolic ratio to N-oxide was significantly higher in the FMO3 E158K/E308G group than in the wild group. In contrast, FMO3 V257M was not associated with the plasma concentration of voriconazole. No significant difference was observed in the saturation index, defined as a correlation coefficient of the regression line between the absolute plasma concentration of voriconazole and the inverse value of the metabolic ratio to N-oxide, between the FMO3 genotypes. CYP2C19 phenotype did not affect the plasma concentration and metabolic ratio of voriconazole. The saturation index of voriconazole rose in the order of CYP2C19 extensive, intermediate, and then poor metabolizer groups. However, the FMO3 and CYP2C19 genotypes and their associated voriconazole pharmacokinetics did not have an effect on the incidence of adverse effects. In conclusion, FMO3 E158K/E308G decreased the plasma concentration of voriconazole through its higher metabolic activity. The FMO3 genotype altered the plasma exposure of voriconazole, while the CYP2C19 phenotype affected the metabolic capacity in immunocompromised patients.

Frequency of the CYP2C19*17 polymorphism in a Chilean population and its effect on voriconazole plasma concentration in immunocompromised children

Invasive fungal infections (IFIs) are the most frequent cause of morbidity and mortality in immunocompromised children. Voriconazole is the first-line antifungal choice in the treatment of IFIs like aspergillosis. Voriconazole pharmacokinetics vary widely among patients and voriconazole is metabolized mainly in the liver by the CYP2C19 enzyme, which is highly polymorphic. The CYP2C19*17 allele is characterized by the presence of four single nucleotide polymorphisms expressing an ultra-rapid enzyme phenotype with an accelerated voriconazole metabolism, is associated with low (sub-therapeutic) plasma levels in patients treated with the standard dose. Considering that in our center a high percentage of children have sub-therapeutic levels of voriconazole when treated with standard doses, we sought to determine the frequency of the CYP2C19*17 polymorphism (rs12248560) in a Chilean population and determine the association between voriconazole concentrations and the rs12248560 variant in immunocompromised children. First, we evaluated the frequency of the rs12248560 variant in a group of 232 healthy Chilean children, and we found that 180 children (77.6%) were non-carriers of the rs12248560 variant, 49 children (21.1%) were heterozygous carriers for rs12248560 variant and only 3 children (1.3%) were homozygous carriers for rs12248560 variant, obtaining an allelic frequency of 12% for variant in a Chilean population. To determine the association between voriconazole concentrations and the rs12248560 variant, we analyzed voriconazole plasma concentrations in a second group of 33 children treated with voriconazole. In these patients, carriers of the rs12248560 variant presented significantly lower voriconazole plasma concentrations than non-carriers (p = 0,011). In this study, we show the presence of the rs12248560 variant in a Chilean population and its accelerating effect on the pharmacokinetics of voriconazole in pediatric patients. From these data, it would be advisable to consider the variant of the patient prior to calculating the dosage of voriconazole.

Impact of CYP3A5, POR, and CYP2C19 Polymorphisms on Trough Concentration to Dose Ratio of Tacrolimus in Allogeneic Hematopoietic Stem Cell Transplantation.

Single nucleotide polymorphisms in drug-metabolizing genes may affect tacrolimus pharmacokinetics. Here, we investigated the influence of genotypes of CYP3A5, CYP2C19, and POR on the concentration/dose (C/D) ratio of tacrolimus and episodes of acute graft-versus-host disease (GVHD) in Japanese recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Thirty-six patients receiving the first HSCT using tacrolimus-based GVHD prophylaxis were enrolled with written informed consent. During continuous intravenous infusion, HSCT recipients carrying the CYP3A5*1 allele, particularly those with at least one POR*28 allele, had a significantly lower tacrolimus C/D ratio throughout all three post-HSCT weeks compared to that in recipients with POR*1/*1 (p < 0.05). The CYP3A5*3/*3 genotype and the concomitant use of voriconazole were independent predictors of an increased tacrolimus C/D ratio during the switch from continuous intravenous infusion to oral administration (p < 0.05). In recipients receiving concomitant administration of voriconazole, our results suggest an impact of not only CYP3A5 and CYP2C19 genotypes, but also plasma voriconazole concentration. Although switching from intravenous to oral administration at a ratio of 1:5 was seemingly appropriate in recipients with CYP3A5*1, a lower conversion ratio (1:2–3) was appropriate in recipients with CYP3A5*3/*3. Our results suggest that CYP3A5, POR, and CYP2C19 polymorphisms are useful biomarkers for individualized dosage adjustment of tacrolimus in HSCT recipients.

The Influence of Proinflammatory Cytokines on Voriconazole Trough Concentration in Patients With Different Forms of Hematologic Disorders.

Even though multiple factors are involved in the high fluctuation of voriconazole (VCZ) plasma concentration, little is known regarding the influence of proinflammatory cytokines on VCZ concentration. The aim of this study was to investigate the influence of proinflammatory cytokines, namely, interleukin (IL)-1β, IL-6, IL-18, interferon-γ, tumor necrosis factor-α, and transforming growth factor (TGF)-β1 on VCZ trough concentration (VCZ-Cmin ) in Chinese patients with different forms of hematologic disorders. A total of 250 plasma samples from 113 patients were analyzed for VCZ-Cmin and proinflammatory cytokines using a validated liquid chromatography-tandem mass spectrometry and enzyme-linked immunosorbent assay methods, respectively. Patient demographics and clinical characteristics were obtained from hospital records. VCZ-Cmin was significantly correlated with IL-18 in acute myeloid leukemia (r = 0.456; P ˂ .0001), acute lymphoblastic leukemia (r = 0.317; P = .019), and chronic myeloid leukemia (r = 0.737; P = .004) while VCZ-Cmin and TGF-β1 were correlated (r = 0.436; P ˂ .001) in acute myeloid leukemia patients only. VCZ-Cmin at different concentration range showed significant inhibitory effect of IL-6. A backward multiple linear regression model revealed patient age (coefficient [β] = 0.025; P = .04), gamma-glutamyl transferase (β = 0.003; P = .023), IL-6 (β = -0.001; P = .024), proton pump inhibitor coadministration (β = 1.518; P = .002), and cytochrome P450 (CYP) 2C19 polymorphism as predictors of VCZ-Cmin ; however, these factors explained only 29% of VCZ-Cmin variation. In conclusion, IL-18 and TGF-β1 have correlation with VCZ-Cmin in Chinese patients with leukemia. Apparently, VCZ may have an inhibitory effect on IL-6 levels. Furthermore, patient age, gamma-glutamyl transferase, IL-6, PPI coadministration, and cytochrome P450 2C19 polymormorphism partially predicted the VCZ-Cmin . Therapeutic drug monitoring of VCZ in Chinese patients is highly encouraged.

Subtherapeutic levels of voriconazole in continuous renal replacement therapy patients

Voriconazole is an antifungal widely used in the treatment of invasive fungal infections, thus pharmacokinetic monitoring is highly important to achieve appropriate dosages. It has been described that patients undergoing continuous renal replacement therapy did not see plasma voriconazole concentrations altered. Two cases are presented in which subtherapeutic voriconazole plasma levels are obtained while the patients are in continuous venovenous hemodiafiltration.

Impact of voriconazole plasma concentrations on treatment response in critically ill patients.

Several authors have demonstrated the relationship between voriconazole concentrations and the risk of therapeutic failure and adverse events However, the information about voriconazole concentrations in the critically ill patient is scarce. The aim of this study was to analyse the plasma concentrations and pharmacokinetic behaviour of voriconazole in critically ill patients and their association with the treatment response and development of toxicity. A prospective, observational study was conducted. Patients admitted to an intensive care unit and on treatment with intravenous voriconazole were included. Plasma concentrations were measured between days 4 and 7 from the start of the treatment. The pharmacokinetic analysis was performed using the NONMEM® software. A regression model was used to evaluate the variables associated with the values outside the therapeutic range, as well as the relationship between the plasma concentrations and the treatment response and the development of hepatotoxicity. A total of 33 patients were included. Plasma concentrations outside the therapeutic range (1-5.5mg/L) were observed in 15 patients, being above the established range in 9 (27.3%) cases, and below it in 6 (18.2%) cases. The presence of a bilirubin value of >1.5mg/dL and a C-reactive protein >100mg/dL was associated with supra-therapeutic concentrations. Voriconazole concentrations greater than 5.5mg/dL were associated with the development of hepatotoxicity. There is a wide variation in voriconazole concentrations in critically ill patients, being associated with a high frequency of adverse events. Close monitoring of these values is required in order to decrease the risk of therapeutic failure and toxicity.

Optimization of Individual Pharmacotherapy Based on Multiple Evaluations of Patient Data

To date, limited drug information is available for the individual optimization of pharmacotherapy. The author attempted multiple evaluations of patient data on factors related to the pharmacokinetics, drug efficacy, and adverse reactions observed in clinical settings. Through the clinical studies, drug information on the individual optimization of pharmacotherapy needed by health professionals including physicians and pharmacists was identified. Major findings were: 1) Cachectic cancer patients had high plasma concentrations of oxycodone via the reduction of CYP3A activity. The metabolic reduction in cachectic cancer patients was potentially related to the elevated serum level of interleukin-6. 2) Dopamine receptor D2 (DRD2) genetic mutations and being female led to poor antiemetic efficacy of the treatment of opioid-induced nausea in prochlorperazine-treated patients. The opioid receptor μ1 (OPRM1) wild genotype in addition to being female and having high plasma concentrations of prochlorperazine increased prolactin secretion during oxycodone treatment. 3) Rheumatoid arthritis patients with a genetic mutation of ATP-binding cassette subfamily B member 1 (ABCB1) had high plasma concentrations of tacrolimus and its 13-O-demethylate. The ABCB1 genetic mutation and associated high plasma concentration of tacrolimus decreased kidney function. 4) Chronic inflammation increased the plasma voriconazole concentration via its poor metabolism, whereas it did not alter the plasma itraconazole concentration. Although co-administration of prednisolone did not affect the plasma concentration of triazole antifungals, it weakly increased voriconazole metabolism. 5) In breastfeeding women, the median milk/plasma concentration ratio of amlodipine was 0.85. However, the observed relative infant dose of amlodipine in most patients was less than 10%.

FORMULATION AND CHARACTERIZATION OF LONG CIRCULATING LIPOSOMES OF ANTI FUNGAL DRUG

Voriconazole is an effective antifungal drug, used as first line treatment for Invasive Aspergillosis. The present work focusses on formulation of PEGylated liposomes to achieve longer circulation in the blood, prevent the liposomes from opsonisation by mononuclear phagocytic system of RES. The higher plasma concentration of voriconazole leads to visual disturbance and dermatological side effect, which are minimized by PEGylation. Compatibility studies like FTIR (Fourier Transform IR) and DSC (Differential Scanning Calorimetry) showed that lipids or drug do not interact and are highly compatible. Liposomes were prepared by thin lipid film hydration method, applying 32 full factorial design with various molar ratio of phospholipids like DPPC /Cholesterol /DSPE mPEG2000. Vesicular size and zeta potential was found within desired range of 100-300 nm to effectively pass through intra venous circulation. Long circulating liposomes were found to have entrapment efficiency of 75-85%. TEM (Transmission Electron Microscopy) showed distinctive spherical shaped vesicles. Long circulatory effect was confirmed from biodistribution study. Stability studies of long circulating liposomes were carried out and Pegylated liposomes successfully showed long circulatory action inside the body and minimized side effect of drug with appreciable antifungal activity determined by microbiological assay (zone of inhibition).

Application of different pharmacokinetic models to describe and predict pharmacokinetics of voriconazole in magellanic penguins following oral administration.

Aspergillosis is a condition causing serious morbidity and mortality in captive penguins and other bird species. It can be treated with antifungal drugs, such as voriconazole. However, the pharmacokinetics of voriconazole are variable between different animal and bird species. Therefore, the pharmacokinetics of voriconazole were investigated in this study in Magellanic penguins. Pharmacokinetic models were constructed and applied to predict the pharmacokinetics of voriconazole during long‐term treatment in Magellanic penguins, since the voriconazole treatment duration in chronic aspergillosis cases can last up to several months. Plasma voriconazole concentration–time data from adult Magellanic penguins (Spheniscus magellanicus; n = 15) following a single oral (PO) dose of either 2.5 mg/kg or 5 mg/kg in a herring in three separate study periods 7–12 months apart were collected. Mean plasma voriconazole concentrations were above the targeted MIC for Aspergillus fumigatus for 2 hr following a single 2.5 mg/kg voriconazole dose while the plasma concentrations exceeded the MIC for least 24 hr following a 5 mg/kg dose. Nonlinear mixed‐effects modeling was used to fit two pharmacokinetic models, one with first‐order and another with saturable elimination, to the single‐dose data. Fits were good for both, as long as dose was included as a covariate for the first‐order model so that clearance was lower and the half‐life longer for animals receiving the 5 mg/kg dose. Although the single‐dose data suggested saturated elimination at higher concentrations, the model with saturable elimination did not predict plasma voriconazole concentrations well for a clinical aspergillosis case receiving long‐term treatment, possibly because of induction of metabolizing enzymes with chronic exposure. Pharmacokinetic models should accurately predict plasma drug concentrations for different dosage regimens in order to be applicable in the field. Future studies should focus on determining clearance at steady‐state to be able to refine the pharmacokinetic models presented here and improve model performance for long‐term oral voriconazole administration in Magellanic penguins.

Therapeutic drug monitoring and safety of voriconazole therapy in patients with Child–Pugh class B and C cirrhosis: A multicenter study

ObjectivesThe purpose of this study was to investigate the pharmacokinetic profile and safety of voriconazole treatment in patients with Child–Pugh class B and C cirrhosis. MethodsLiver cirrhosis patients who had received the recommended voriconazole maintenance dose (group A) or halved maintenance dose (group B), orally or intravenously, were included. Voriconazole-related adverse events (AEs) were defined according to the Common Terminology Criteria for Adverse Events. ResultsA total of 110 trough plasma concentrations of voriconazole (Cmin) were measured in 78 patients. There was a significant difference in voriconazole Cmin between group A and group B (Cmin, 6.95±3.42mg/l vs. 4.02±2.00mg/l; p<0.001). No significant difference in voriconazole Cmin between Child–Pugh class B and C cirrhosis patients was observed in either of the two groups. The international normalized ratio and co-medication with a CYP2C19 inhibitor had a significant effect on voriconazole Cmin in group B. The incidence of AEs in group A was 26.5% and in group B was 15.9%, and 87.5% of AEs developed within 7days after starting voriconazole treatment. ConclusionsThese results suggest that the recommended dose and halved maintenance dose may be inappropriate in patients with Child–Pugh class B and C cirrhosis due to the high Cmin, and that voriconazole Cmin should be monitored earlier to avoid AEs.

Manual punch versus automated flow-through sample desorption for dried blood spot LC-MS/MS analysis of voriconazole

Dried blood spot (DBS) sampling is a patient-friendly alternative for plasma sampling for the purpose of therapeutic drug monitoring (TDM). To speed up the analysis time, an automated flow-through desorption method of DBS samples may be beneficial. This article describes the cross-validation of a manual punch DBS method with an automated desorption (DBS autosampler, DBSA) method for the DBS analysis of the antifungal drug voriconazole, followed by cross-validation of both DBS methods with a plasma-based method, and an assessment of agreement between DBS/DBSA and regular plasma concentration measurements (gold standard) in samples from patients on voriconazole treatment.DBS and DBSA LC-MS/MS assays for voriconazole were validated according to the latest guidelines on bioanalytical method validation (FDA, EMA). Additional DBS-specific validation parameters included hematocrit effect and the influence of spot volume. Passing-Bablok regression and Bland-Altman plots were used to cross-validate the punch DBS, DBSA and plasma methods. The assessment of agreement between DBS/DBSA and plasma concentration measurements involved the performance of DBS/DBSA measurements to predict voriconazole plasma concentrations in patient samples.Both DBS methods complied with all validation parameters. Sample pre-processing time was reduced from 1.5 h to 3 min when using the DBSA. Cross-validation of both DBS methods showed a proportional bias and a correction factor was needed to interchange voriconazole concentrations of both DBS methods. Similarly, the punch DBS method required a factor to correct for proportional bias compared to the plasma method, but the DBSA and plasma assays showed no bias. Limits of agreement of the DBS/DBSA and plasma assays in Bland-Altman analysis were relatively wide, i.e. 0.75–1.28 for the DBS punch method versus plasma method and 0.57–1.38 for the DBSA versus plasma assay. Interpretation of DBS, DBSA and plasma samples in terms of concentrations in or outside of the voriconazole therapeutic range agreed in 82–86% of the cases.The variability in paired DBS/DBSA and plasma concentration measurements is considered high for TDM purposes and this limitation should be balanced against the advantages of DBS sampling of voriconazole and the speed of flow through desorption.

CYP2C19 genetic polymorphism and monitoring voriconazole plasma concentrations in the treatment and prevention of invasive fungal disease for hematological patients

目的研究CYP2C19基因型对血液病患者伏立康唑血药浓度的影响，并探讨伏立康唑血药浓度监测在侵袭性真菌病（IFD）防治中的价值。方法回顾性分析2016年1月至12月接受伏立康唑静脉注射的65例血液病合并IFD患者临床资料。应用焦磷酸测序检测患者CYP2C19基因型，超高效液相色谱-串联质谱法监测患者伏立康唑血清谷浓度。结果65例患者中，CYP2C19基因型伏立康唑快代谢型30例，中代谢型33例，慢代谢型2例，将中代谢型与慢代谢型归于非快代谢型组。共检测伏立康唑血药浓度169次，快代谢型组患者伏立康唑血清谷浓度明显低于非快代谢型组[0.98（0.38~2.08）mg/L对2.19（1.53~4.27）mg/L，z=10.286，P<0.001]。26例伏立康唑平均血清谷浓度<1.5 mg/L患者，其治疗失败率（50.0%）明显高于伏立康唑平均血清谷浓度≥1.5 mg/L患者（20.5%）（P=0.052）。5例伏立康唑平均血清谷浓度>5.5 mg/L患者中，4例出现视觉障碍；60例伏立康唑平均血清谷浓度≤5.5 mg/L患者中，4例（6.1%）出现视觉障碍，1例（1.5%）出现中枢神经系统毒性，不良反应发生率差异有统计学意义（χ2=11.689，P=0.020）。结论CYP2C19基因快代谢型患者伏立康唑血清谷浓度明显低于CYP2C19基因非快代谢型，恰当的伏立康唑血清谷浓度能减少药物不良反应，并降低抗真菌治疗的失败率。

Improving survival of acute-on-chronic liver failure patients complicated with invasive pulmonary aspergillosis

The mortality of acute-on-chronic liver failure (ACLF) patients complicated with invasive pulmonary aspergillosis (IPA) was extremely high. We aimed to explore prognostic value of the Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) lung score and to establish an optimal voriconazole regimen for ACLF patients complicated with IPA. We retrospectively screened hospitalized ACLF patients in our hospital from July 2011 to April 2016, from which 20 probable IPA cases were diagnosed. Along with onsets of IPA, deteriorated diseases severity, especially lung conditions were found in those 20 ACLF patients. It was found that IPA patients with CLIF-SOFA lung score <2 had better 28-day survival than those with lung score >1 (11/13 vs 0/7, p < 0.001). Based on plasma voriconazole concentration measurement, an optimal voriconazole regimen (loading doses: 0.2 g twice daily; maintenance doses, 0.1 g once daily) was established, which resulted in rational trough plasma drug concentrations (1–5 μg/mL), good clinical outcomes (90-day survival rate of 6/8) and no observed adverse events. In conclusion, CLIF-SOFA lung score >1 was able to identify ACLF patients complicated with IPA encountering much higher 28-day mortality. An optimal voriconazole regimen was safe and effective in our ACLF patients complicated with IPA.

PP-46 Voriconazole dosing strategies in young children: challenges and recommendations

Background Voriconazole pharmacokinetics (PK) have been studied in paediatric studies and described by popu-lation pharmacokinetic modelling.1 Using the currently approved intravenous (IV) dosing regimen,2 ,3 paediatric patients provided 30 trough samples resulting in a ob-served median (range) of 1.2 (0.11–17.4) mg/L.1 This illustrates the highly variable pharmacokinetic (PK) pro-file of voriconazole in children. The aim of this case series is to evaluate the effectiveness of dosing guidelines in combination with routine therapeutic drug monitoring (TDM) to achieve therapeutic serum concentrations of voriconazole in young cancer patients (age 0–6 years old). Methods At the VUmc, paediatric patients are treated using TDM. Voriconazole plasma concentrations are monitored and dosing regimens are individualised, aiming at trough levels of 1–6 mg/L depending on the location of the Asper-gillus. A case series of 4 children (age 0–6 years) is presented. Results Highly variable voriconazole exposure (n=4) were observed. Case 1 Boy, 13 months, acute myeloid leukaemia: Loading dose 9 mg/kg tid (IV), maintenance 8 mg/kg tid (IV) [2] resulted in supratherapeutic levels, hepatic toxicity and circulatory insufficiency. Root cause: CYP2C inhibition by previous prophylactic Itraconazole treatment. Itraconazole has a half-life time up to two days. Therapeutic voriconazole levels achieved at 6 mg/kg tid (IV); Case 2 Boy, 5 years, acute lymphatic leukaemia: Doses varying between 7 mg/kg tid IV and 11 mg/kg tid IV during 4 months of IV therapy. Highly variable trough concentrations varying from 0.10–13.3 mg/L; 65% within the target range of 2–6 mg/L for cerebral Aspergillus: Case 3 Girl, 7 months, mixed phenotype acute leukaemia: Load-ing dose 6 mg/kgbid (IV), maintenance 9 mg/kgbid (PO) resulted in subtherapeutic trough levels (0.1–0.2 mg/L), possibly due to high first pass metabolism. Case 4 Girl, 5 years, acute lymphatic leukaemia: Loading dose 10 mg/kgbid (PO), high maintenance dose of 23 mg/kgbid (PO) re-sulted in therapeutic levels. Higher doses of 30 mg/kgbid resulted in a more than dose-proportional increase of ex-posure (trough level 22 mg/L), suggesting non-linear PK. Conclusion Voriconazole PK is highly variable in pedi-atric cancer patients, which can only partly be attributed to drug interactions and co-morbidities. A starting dose of 18 mg/kg (IV) is recommended and could be adminis-tered as 6 mg/kg tid (IV).2 Intensive TDM (at least twice weekly) and daily in-depth status reviews are recom-mended to achieve therapeutic drug levels.

In vivo evaluation of voriconazole eye drops efficacy in a rat Acanthamoeba polyphaga keratitis model

PurposeAcanthamoeba keratitis is a sight‐threatening infectious disease. Its effective and safe medical therapy remains highly debated. The aim of this study is to test in vitro and in vivo voriconazole as a potential antiamoebic treatment for Acanthamoeba keratitis.MethodsIn vitro sensitivity of Acanthamoeba polyphaga to voriconazole was assessed using a commercially available viability assay. In vivo, Sprague‐Dawley male rats were injected in the left cornea stromal layer with trophozoites. Forty rats were divided into 3 groups, topically treated with 1% voriconazole eyedrop (hourly administrations for 3 days followed by every two hours for 11 days and followed every four hours for 7 days), orally treated with voriconazole (60 mg/kg/day), and control. At day 28, cornea and blood samples were collected and corneal scrapings were performed for bacterial and parasitological cultures and real‐time PCR analyses. Paraffin‐embedded corneas were analyzed. The plasma and corneal concentration of voriconazole was determined by high‐performance liquid chromatography.ResultsIn vitro, voriconazole inhibited Acanthamoeba polyphaga trophozoites proliferation with IC90 value of 6 μg/ml, however no cystical activity was found. Mean intracorneal concentration of voriconazole eyedrops after three days treatment was 5.6 +/‐ 4.4 ng / mg; after seven days treatment was 2.38 + /1.6 ng/mg; and after twenty one days treatment was 0.32 +/‐ 0.15 ng / mg. Clinical infection worsened in fewer rats between the 7th and the14th day post infection in the voriconazole eye drops group (1/10 rats) and the control group (9/10 rats) (p = 0.001).ConclusionsOur findings support the potential use of voriconazole as anti‐amoebic agents.

Flucloxacillin Results in Suboptimal Plasma Voriconazole Concentrations.

Combining voriconazole and flucloxacillin is indicated in patient cohorts experiencing both invasive aspergillosis and Gram-positive infections (e.g., patients with chronic granulomatous disease or postinfluenza pulmonary aspergillosis). We report a highly relevant interaction between voriconazole and flucloxacillin, resulting in subtherapeutic plasma voriconazole concentrations in more than 50% of patients, that poses a severe threat if not managed properly.

Impact of CYP2C19 Genotype and Liver Function on Voriconazole Pharmacokinetics in Renal Transplant Recipients.

Background:Invasive fungal infection (IFI) is one of the leading causes of early death after renal transplantation. Voriconazole (VRC) is the first-line drug of IFI. Because of the large inter- and intraindividual variability in VRC plasma concentrations and the narrow therapeutic window for treating patients with IFIs, it is crucial to study the factors which could influence pharmacokinetic variability. We performed a population pharmacokinetics (PPK) study of VRC for personalized medicine.Methods:A total of 125 trough concentrations (Cmin) from 56 patients were evaluated, retrospectively. Nonlinear mixed effect model was used to describe a PPK model that was internally validated by bootstrap method. Potential covariates included demographic characteristics, physiological and pathological data, concomitant medications, and CYP2C19 genotype.Results:A 1-compartment model with first-order absorption and elimination was fit to characterize the VRC pharmacokinetics in renal transplant recipients (RTRs). Aspartate aminotransferase (AST) had a significant influence on clearance (CL) while CYP2C19 genotype had a major impact on the volume of distribution (V). The parameters of CL and V were 4.76 L/h and 22.47 L, respectively. The final model was V (L) = 22.47 × [1 + 2.21 × (EM = 1)] × [1 + 4.67 × (IM = 1)] × [1 + 3.30 × (PM = 1)] × exp (0.96); CL (L/h) = 4.76 × (AST/33)^(−0.23) × exp (0.14). VRC Cmin in intermediate metabolizers was significantly higher than in extensive metabolizers.Conclusions:Liver function and CYP2C19 polymorphism are major determinants of VRC pharmacokinetic variability in RTRs. Genotypes and clinical biomarkers can determine the initial scheme. Subsequently, therapeutic drug monitoring can optimize clinical efficacy and minimize toxicity. Hence, this is a feasible way to facilitate personalized medicine in RTRs. In addition, it is the first report about PPK of VRC in RTRs.

Plasma Concentrations of Itraconazole, Voriconazole, and Terbinafine When Delivered by an Impregnated, Subcutaneous Implant in Japanese Quail (Coturnix japonica)

Aspergillosis is a common fungal infection in both wild and pet birds. Although effective antifungal medications are available, treatment of aspergillosis can require months of medication administration, which entails stressful handling one or more times per day. This study examined the delivery of the antifungal drugs itraconazole, voriconazole, and terbinafine to Japanese quail ( Coturnix japonica ) via an impregnated implant. Implants contained 0.5, 3, 8, or 24 mg of itraconazole, voriconazole, or terbinafine. The implants were administered subcutaneously over the dorsum and between the scapulae. Blood was collected from birds before and 2, 7, 21, 42, and 56 days after implant placement. Plasma was analyzed by high-performance liquid chromatography for concentrations of itraconazole, voriconazole, or terbinafine, as appropriate. During the course of the study, targeted terbinafine concentrations were achieved in some birds at various time points, but concentrations were inconsistent. Itraconazole and voriconazole concentrations were also inconsistent and did not reach targeted concentrations. Currently, the implant examined in this study cannot be recommended for treatment of aspergillosis in avian species.