Therapeutic Drug Monitoring And Intervention Study Of Voriconazole In ICU Patients

Objective:To establish a method for determining the concentration of voriconazole in human plasma by HPLC.To do the therapeutic drug monitoring of voriconazole inintensive care unit and evaluate the pharmacokinetic characteristics of ICU patients with the treatment of antifungal infection;To explore the factors assicoated with the plasma concentration of voriconazole via multivariate stepwise regression analysis;Patients were classified into three subgroups（fast,middle and slow）by the polymorphism of CYP2C19 gene,and the relationship between the concentration and CYP2C19 gene polymorphism was identified;Recording the symptoms,signs,laboratory tests and bacterial culture of the patients,and the adverse reactions induced by voriconazole to evaluate the efficacy and safety of voriconazole in the treatment of fungal infection.Intervention study of Voriconazole was conducted on ICU patients.It was effective to improve clinical respond and reduce the occurrence of adverse reaction of voriconazole.Method:1.Determining the concentration of voriconazole in human plasma concentration:The internal standard method was used,the separation was performed on a HC-C₁₈（4.6 mm×250 mm,5μm）,the mobile phase consisted of acetonitrile:water（37:63）with a flow rate of 1.0 mL·min^-1,the UV detection wavelength was 254 nm.2.Therapeutic drug monitoring of voriconazole and factor analysis of plasma concentraton in patients of intesive care unit:a prospective observation study was performed between January 2017 and January 2018.44 cases of application of voriconazole were included,5 patients receiving oral administration,others nasal feeding.Blood specimens were collected after dosing at day 3,6,10 and 14.If not,±2 days were available.All samples were centrifugaled,and plasma samples were cryopreserved in-20℃.Otherwise,1ml of blood was collected in EDTA anticoagulants for DNA extraction.Patients’plasma were analyzed by HPLC.Direct sequencing was performed to determine the patients’CYP2C19 genotype.The experimental data was statistical analysis by SPSS 23.0 statistical analysis software package.3.The effect of CYP2C19 gene polymorphism on the voriconazole pharmacokinetics of ICU patients:50 cases of application of voriconazole were included.Blood specimens were collected after dosing at day 6.Direct sequencing was performed to determine the patients’CYP2C19 genotype.Pharmacokinetic characteristics of ICU patients and CYP2C19 genotype of patients were indentified.4.Intervention study on therapeutic drug monitoring in ICU patients:a prospective observation study was performed between October 2017 and January2018.9 cases of application of voriconazole were included.All patients were taken measures to get target concentration.all patients were receiving administration by nasal feeding.Blood specimens were collected after dosing at day 6,and repeated blood specimens were collected after dose adjustment.Results:1.Determining the concentration of voriconazole in human plasma concentration:the calibration curves of voriconazole showed good linear regression in the range of0.2048-32 mg/L,the limits of detection was 0.2048 mg/L,Intra and inter-day variations were all less than 5.84%,the method absolute recovery was in 97-132%and RSD was 11.3%.2.Therapeutic drug monitoring of voriconazole andfactor analysis of plasma concentraton in patients of intesive care unit:44 cases of application of voriconazole were included 27 of 44 were male.129 trough concentrations（C₀）of voriconazole were determined（C₀ range:0-8.56 mg/L）.8 C₀ of voriconazole were lower than 1.0mg/L and 33 were higher than 5.5 mg/L.88 of 144 were in target window.Multivariate stepwise regression analysis showed ALP、HF、CYP2C19 genotype、GGT、Age、Weight and hs-CRP significantly influence the C₀ of voriconazole（P<0.001）.The effective rate was 68.2%in 44 patients treated with voriconazole.A total of 11 people had adverse reactions,including hallucination and ataxia and elevating level of liver enzymes.According to the concentration range,only one person was less than 1.0 mg/L,and the treatment failed.There were 31patients in the range of 1-5.5 mg/L,of which 21 were effective,with an effective rate of 67.8%.5 patients had increasing liver enzymes and the incidence of adverse reactions was 16.1%.Another 12 trough concentrations were higher than 5.5 mg/L,9patients had effective responds,but there were 6 patients had adverse reactions,including 5 elevated liver enzymes and 1illusion,ataxia.Adverse reaction rates were 50%.3.The effect of CYP2C19 gene polymorphism on the voriconazole pharmacokinetics of ICU patients:Totally fifty patients was detected by CYP2C19genotype.There are four phenotypes among these patients.18 of 50 patients were CYP2C19*1*1 who were extensive metabolizers（EM）;27 were CYP2C19*1*2,1was CYP2C19*1*3,both of them are intermediate metabolizers（IM）;4 patients were CYP2C19*2*2,who were poor metabolizers（PM）.The incidence of CYP2C19*2allele was 35%and CYP2C19*3 was 1%among the fifty ICU patients.To compare trough concentrations between EM group and（IM+EM）group,the result indicated there was significant difference between two groups.The C₀ of voriconazole in（IM+EM）group was higher than that of EM group.4.Intervention study on therapeutic drug monitoring in ICU patients:9 cases of application of voriconazole were included.8 of 9 were male.During the treatment of voriconazole,3 patients’trough plasma concentration were higher than 5.5 mg/L.Their maintenance doses were halved.Trough plasma concentration of 1 patient was too high to stop twice administrating and his maintenance doses were also halved.11patient’maintenance dose was increased by 50%because of his big weight.But the trough concentration was high,so decreasing the dose.But repeated concentration wasn’t optimal.Then increasing the maintentance dose to 300 mg,the result was normal.Otherwise,there was a patient achieving target concentration by adjusting dose twice.According to this experience,target trough concentration was obtained timely during next treatment of voriconazole in the same patient.The last patient was different from those.Trough concentration was lower than 1 mg/L and maintenance dose was increased by 50%.But the trough concentration was still low.8 of 9 patients got a good intervention to increase the efficacy.Conclusions:1.The established method is accurate,easy,reproducible,stable and reliable,can be used in biological samples analysis,to provide a reliable laboratory data for further therapeutic drug monitoring of voriconazole.2.A wide variability amongst patients was observed in Chinese intensive care unit patients.There were many factors influencing trough plasma concentrations of voriconazole,such as ALP、HDF、CYP2C19 genotype、GGT、Age、Weight and hs-CRP.3.The relationship between C0 and efficacy/safety.It was necessary to do the TDM of ICU patients to improve the efficacy and safety.4.CYP2C19 polymorphisms affect the PK of voriconazole,C₀ between EM and（IM+PM）was significantly differert.5.（IM+EM）group has 53.1%higher C₀,and the determination of genotype and TDM could help adjust the treatment plan.6.The standardized administration of VRC in ICU patients is not applicable to all patients,and the clinical pharmacists are required to determine the initial dose according to the patient’s own condition,and adjust the dosage by TDM.7.Intervention study on voriconazole via therapeutic drug monitoring can decrease the doses.If low concentration was found,increasing dose by 25%-50%may be appropriate.If C₀ was high,decreasing dose by 50%-75%may be suggested.