OPTIMAL PLASMA CONCENTRATION OF THROMBOMODULIN ALFA TO TREAT SEPSIS-INDUCED DISSEMINATED INTRAVASCULAR COAGULATION.

ABSTRACT: Thrombomodulin alfa (TM alfa) has been shown effective for treatment of disseminated intravascular coagulation (DIC) associated with sepsis, although the optimal therapeutic plasma concentration has not been clarified. In the present study, the plasma trough concentration of TM alfa in septic patients with DIC was determined, then the cutoff value for that concentration showing influence on treatment outcome was calculated using a receiver operating characteristic curve. With a cutoff value of 1,010, the area under the curve of the receiver operating characteristic was 0.669 (95% confidence interval, 0.530-0.808), with sensitivity of 0.458 and specificity of 0.882. To evaluate its accuracy, patients were divided into those above or below the cutoff value, and 90-day survival rates were compared. The above-cutoff group showed a significantly higher 90-day survival rate (91.7%) as compared with the below-cutoff group (63.4%) ( P = 0.017), with a hazard ratio of 0.199 (95% confidence interval, 0.045-0.871). Interestingly, the incidence of hemorrhagic adverse effects was not significantly different between the groups. Based on these results, the recommended plasma trough concentration of TM alfa for treatment of septic DIC is 1,010 ng/mL, which should minimize the risk of severe bleeding while maximizing the therapeutic effect.

Basic Verification of ß-D Glucan in Leukocyte-Rich Plasma for the Diagnosis of Deep Mycosis.

BACKGROUND: Currently, supplementary serological testing for ß-D glucan (BDG) is often selected to diagnose deep mycosis in care covered by the health insurance in Japan. The Wako method used by our center has low sensitivity, and different studies have used different cut-off values due to factors that cause false positives and false negatives. One possible cause of false negatives is the use of platelet-rich plasma (PRP) as the sample material. Because phagocytic white blood cells (WBC) are precipitated by centrifugation and only plasma is measured, it seems unlikely that the actual amount of BDG is being measured when using PRP. Further, a frequent cause of false positives is contamination from blood products and gauze containing BDG. To resolve these issues, the blood cell separator, hydroxyethyl starch, is used to precipitate only the red blood cells to obtain leukocyte-rich plasma (LRP). We hypothesized that it might be possible to improve the diagnostic rate of deep mycosis by measuring the BDG content of plasma containing WBC and fungal components and by comparing the BDG content of PRP and LRP measured simultaneously. MATERIALS AND METHODS: Healthy human blood, albumin-added blood, wrung-out gauze fluid-added blood, and fungal solution-added blood were prepared, and PRP and LRP were prepared using hydroxyethyl starch. The BDG content of each sample was measured using the Wako method and compared. In addition, PRP and LRP of fungal-added blood were Gram-stained and examined under a microscope, and the number of WBCs and phagocytosed fungi was counted visually and compared. RESULTS: Measuring the BDG content of LRP confirmed that there were no false positives with LRP, and in vitro experiments comparing albumin-added false-positive blood to fungal-added blood showed significant differences between PRP and LRP only in the fungal-added blood. CONCLUSION: Calculating the BDG-ratio (LRP/PRP) by measuring both LRP and PRP may eliminate false positives and false negatives of true deep mycosis and improve the diagnostic rate.

Prediction of treatment failure during infliximab induction therapy in inflammatory bowel disease patients based on pharmacokinetic and pharmacodynamic modeling.

BACKGROUND: In infliximab (IFX) treatment for Crohn's disease (CD) and ulcerative colitis (UC), it is difficult to predict treatment failure during the induction phase. In the present study for optimal IFX treatment, we attempted to estimate serum IFX concentration and clinical response in individual patients during the induction phase to predict the indication of therapeutic effect and the possibility of treatment failure in the maintenance phase. METHODS: We estimated pharmacokinetic and pharmacodynamic (PK/PD) parameters and predicted the serum IFX concentration and clinical response using a PK/PD model and Markov chain Monte Carlo Bayesian analysis method during the induction phase. Then, we determined whether the indication of therapeutic effect between predicted and observed clinical response were matched during the maintenance phase. RESULTS: Data obtained from 15 patients were analyzed. The correlation between predicted and observed values of serum IFX concentration (Pearson product-moment correlation coefficient, 0.700; P < 0.0001, n = 68) and clinical response of CD patients (0.790; P < 0.0001, n = 25) and UC patients (0.702; P = 0.0004, n = 21) were significantly high. The indication of therapeutic effect at the final time point of each patient (from day 115 to day 203) were successfully predicted in 14 of 15 patients (93.3%). CONCLUSIONS: This study presents prediction of serum IFX concentration and clinical response in individual patients during induction therapy, with presumption of the indication of therapeutic effect and the treatment failure in the maintenance phase. Our results show the possibility of optimizing IFX therapy during the induction phase.

Therapeutic and Adverse Effects of Thrombomodulin Alfa to Treat Sepsis-Induced Disseminated Intravascular Coagulation.

In the treatment of disseminated intravascular coagulation (DIC), which is a complication of underlying diseases such as infections and malignant tumors, effective plasma concentrations of thrombomodulin (TM) alfa range from 300 to 900 ng/mL; however, appropriate concentrations when treating sepsis-induced DIC are unknown. Thus, our aim was to determine the relationship between plasma concentrations of TM alfa and its therapeutic effects, and hemorrhagic adverse events. First, we calculated the plasma trough concentrations of TM alfa in septic DIC patients. Next, we divided patients into two groups according to their plasma concentrations into a low- and high-concentration group based on a cut-off value of 600 ng/mL. Fourteen and 35 patients were included in the low- and high-concentration groups, respectively. The Japanese Association for Acute Medicine DIC diagnostic criteria score 4 days after TM alfa administration decreased significantly by 2.06 points from baseline in the high-concentration group compared with 0.71 points in the low-concentration group. The 90-day survival rate was significantly higher in the high-concentration group (85.4%) than in the low-concentration group (49.0%) (hazard ratio, 0.27; 95% confidence interval: 0.09-0.86). In contrast, the incidence of serious hemorrhage was not significantly different between the groups. The recommended plasma concentration of TM alfa in the treatment of septic DIC was determined to be higher than 600 ng/mL, and a dose of 380 U/kg (0.06 mg/kg) was necessary to achieve this concentration.

Prediction of clinical effects of infliximab administered for inflammatory bowel disease based on pharmacokinetic and pharmacodynamic modeling.

Infliximab (IFX) is used as a therapeutic agent for ulcerative colitis (UC) and Crohn's disease (CD). Although the dosage regimen has been established through clinical trial experience, it has yet to be assessed with a pharmacokinetic and pharmacodynamic model. The present study analysed sequential changes of clinical response in patients with ulcerative colitis and Crohn's disease following repeated administrations of infliximab using the pharmacokinetic/pharmacodynamic model. In addition, the dosage regimen presently used for patients with ulcerative colitis was evaluated, as well as the potential efficacy gained by increasing the dose and/or reducing the interval of administration for patients with Crohn's disease. Furthermore, the possibility of evaluating the difference between both diseases with regard to the efficacy of infliximab was investigated. Sequential changes in the clinical response values obtained with our model were in good agreement with the observed values following administration of infliximab in patients with ulcerative colitis and Crohn's disease. The results showed the importance of a loading dose for patients with ulcerative colitis, as well as the efficacy of increasing the dose and reducing the interval for patients with Crohn's disease. Also, the efficacy of infliximab for both diseases is suggested to be similar. In conclusion, our results show a possible modeling scenario that can accommodate the clinical response to infliximab administered for ulcerative colitis and Crohn's disease. Furthermore, it provides confirmation for the present dosage regimens given for these diseases.

Comparisons of Usual Dose of Pharmaceutical Products Used in Japan and United States: Can Differences Be Explained by Pharmacokinetics Alone?

BACKGROUND: It is important to examine how a usual drug dose is established in Japan and other countries, and to evaluate that on the basis of pharmacokinetic and pharmacodynamic properties. In the present study, we examined the contributions of area under the curve (AUC) ratio and other factors on differences of usual dose between Japan and the United States. METHODS: We examined drugs approved from January 2008 to January 2011 in Japan and collected related information. For the usual dose set for the same indication in both countries, we compared the maintenance dose values between the countries. We also examined the relationships of AUC ratio and difference of usual dose in both countries. RESULTS: Our results clarified that the usual dose for the same indication is comparable between Japan and the United States for 68.75% of the examined drugs, while that for 31.25% is different. Moreover, among products with different approved doses, the dosage was set higher in the United States for 18.75% and higher in Japan for 12.50%. Our findings indicate that the difference in dose between the countries is associated with AUC ratio for 82.1% and by factors other than AUC ratio for 17.9% of the examined medications. CONCLUSIONS: The approved dose varies between the countries for about one-third of products commonly used. Additionally, it was clarified that not only AUC ratio but also other factors are involved in dosage differences. The present results provide useful information for analysis of factors related to the different usual doses between countries.

Pharmacokinetic and pharmacodynamic model for analysis of adalimumab administered for Crohn's disease.

Adalimumab (ADA) is used as a therapeutic agent for Crohn's disease (CD). Although the dosage regimen has been established through clinical trial experience, it has not been analysed theoretically. The present study analysed of sequential changes in the Crohn's disease activity index (CDAI) after repeated administrations of adalimumab using a pharmacokinetic and pharmacodynamic model. In addition, we analysed the validity of the dosage regimen, and the potential efficacy gained by increasing the dose and reducing the interval of administration. The sequential changes in CDAI values obtained with our model were in good agreement with observed CDAI values, which is considered to show the validity of our analysis. We consider that our results showed the importance of a loading dose of adalimumab to obtain remission in an early stage of active CD. In addition, we showed that patients who have an incomplete response to adalimumab can obtain similar efficacy from increasing the dose and reducing the dose interval. In conclusion, our results showed that the present model may be applied to predict the CDAI values of adalimumab for CD. They indicate the validity of the dosage regimen, as well as the efficacy of increasing the dose and reducing the dose interval.

Method for Prediction of Efficacy of Sugammadex Administered to Recover from Rocuronium-Induced Neuromuscular Blockade in Gynecological Laparoscopic Surgery Cases.

Sugammadex (SDX), a neuromuscular blocking-reversal agent, quickly reverses neuromuscular blockade induced by rocuronium (RCR). SDX dosage is set according to the state of neuromuscular blockade determined with a neuromuscular monitoring device. However, in clinical situations, such a devise is not frequently used. Here, we report construction of a method for theoretically setting SDX dose by which the optimum reverse time (RT) can be obtained for individual patients even when the device is not available. The subjects were 42 adult female patients who underwent laparoscopic surgery from 1 August 2015 to 31 March 2016, during which RCR and SDX were administered. We formulated an equation for theoretically calculating the RCR residual ratio (RR) in blood after SDX administration. Furthermore, we examined the relationship between RR and RT. Based on the results obtained, we developed a method for predicting RT using RR. We excluded 1 subject as the RT value was detected as an outlier in our analysis. Multiple regression analysis was performed using standard body weight, serum creatinine, total bilirubin, and RR as explanatory variables. The number of subjects with a prediction error of RT within ±1 min was 36 (87.8%) of 41 in multiple regression analysis. We could predict RT following SDX administration by using the RT prediction expression with RR obtained for subjects administered RCR during the surgery. Furthermore, our results suggest that the SDX dose able to achieve optimum RT may be set prior to surgery on the basis of the present methodology.

Evaluation of Drug Efficacy of GLP-1 Receptor Agonists and DPP-4 Inhibitors Based on Target Molecular Binding Occupancy.

Glucagon-like peptide-1 (GLP-1) receptor agonists (liraglutide, exenatide, lixisenatide) have recently been used as anti-diabetes drugs. We examined relationships of the binding occupancy of GLP-1 receptors (Φ) and their clinical efficacy after administration of GLP-1 receptor agonists. Next, by focusing on changes of GLP-1 concentration after administration of dipeptidyl peptidase-4 (DPP-4) inhibitors (vildagliptin, alogliptin, sitagliptin, linagliptin), we analyzed the relationship between Φ and clinical efficacy. Furthermore, using Φ as a common parameter, we compared the clinical efficacy elicited by GLP-1 receptor agonists and DPP-4 inhibitors using a theoretical analysis method. The present results showed that GLP-1 receptor agonists produced their clinical effect at a relatively low level of Φ (1.1-10.7%) at a usual dose. Furthermore, it was suggested that the drugs might achieve their full effect at an extraordinarily low level of Φ. It was also revealed that the Φ value of DPP-4 inhibitors (0.83-1.3%) was at the lower end or lower than that of GLP-1 receptor agonists at a usual dose. Accordingly, the predicted value for hemoglobin A1c (HbA1c) reduction after administration of the GLP-1 receptor agonists was higher than that of DPP-4 inhibitors. We clarified the differences between the therapeutic effects associated with GLP-1 receptor agonists and DPP-4 inhibitors theoretically. Together, the present findings provide a useful methodology for proper usage of GLP-1 receptor agonists and DPP-4 inhibitors.

Theoretical method for evaluation of therapeutic effects and adverse effects of epidermal growth factor receptor tyrosine kinase inhibitors in clinical treatment.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are used for non-small cell lung cancer patients with an EGFR gene mutation. However, skin disorders are known as adverse events. In the present study, we investigated whether EGFR-TK occupancy is useful as an index for assessing clinical efficacy and adverse events for the proper use and development of EGFR-TKIs. Average binding occupancies (Φ ss) of EGFR-TKIs, gefitinib and erlotinib, for the EGFR-TK of cancer or skin cells were calculated. The relationships of Φ ss with response rate (RR) or frequency of rash were analyzed using the ternary complex model. Then, the relationships between the dose of EGFR-TKIs and RR or frequency of rash were examined. Gefitinib showed a greater difference for Φ ss value for both wild-type and mutant EGFR as compared to erlotinib at usual dose. The RR increased in a nonlinear manner rapidly rising when Φ ss exceeded 95%. It was thought that a very high Φ ss value might be needed to obtain the therapeutic effect of EGFR-TKIs. Meanwhile, the frequency of rash increased in a linear manner along with elevation of Φ ss. It was shown that the K d ratio (K d for mutant/K d for wild type) was less than 0.001, when the high RR and low frequency of rash were obtained simultaneously. The results showed that the therapeutic effects and skin disorder can be assessed by using Φ ss. Furthermore, it is likely that a proper choice of drug and dose can be made by using Φ ss in EGFR-TKI therapy.

Effects of FCGRIIIa-158V/F polymorphism on antibody-dependent cellular cytotoxicity activity of adalimumab.

The associations between the efficacy of IgG reagents and the FCGRIIIa-158V/F polymorphism (rs396991) have been investigated. Although the genotype frequencies in healthy Japanese have been reported, those have varied, as one study reported that the proportions of V/V, V/F, and F/F were 59.1%, 38.6%, and 2.3%, respectively, while another study found that they were 4%, 44%, and 52%, respectively. However, there are no known investigations of the association between the antibody-dependent cellular cytotoxicity (ADCC) activity of adalimumab (ADA), an IgG reagent, in combination with FcγRIIIa and the polymorphism. In this study, we analyzed healthy Japanese to clarify genotype frequency using a direct sequence method. In addition, we examined the association between the ADA-mediated ADCC activity and the polymorphism. Our results showed that the frequencies of the V/V, V/F, and F/F genotypes in healthy Japanese were 9.2%, 39.8%, and 51.0%, respectively. The average activity of ADA-mediated ADCC was 25.0%, 19.0%, and 13.3% in the V/V, V/F, and F/F genotypes, respectively. Then, the ADCC activity of V/V was significantly higher than that of F/F (p < 0.05) in therapeutic concentration. The differences in therapeutic effect of ADA among individuals can be explained, in part, by ADCC activity via the FCGRIIIa-158V/F polymorphism.

Evaluation of the Effects of Pharmacist Intervention for Adverse Drug Reaction Detection and Exacerbation Avoidance.

We evaluated the effects of pharmacist intervention for adverse drug reaction detection and exacerbation avoidance, as well as the severity and outcome of reactions based on analyses of pharmacist involvement in a collaborative approach to medicine. Of 5436 cases with pharmacist involvement, adverse drug reaction prevention was seen in 440, accounting for 8.1%, and exacerbation avoidance in 213, accounting for 3.9%. We concluded that pharmacist involvement contributes to detect adverse drug reactions and avoid exacerbation, and improves pharmacotherapy safety. We also analyzed 131 cases in which the course after intervention was followed. When categorized by adverse drug reaction severity, Grade 1 and 2 were the same at 45.8%, Grade 3 at 8.4%, respectively. Those findings suggested that pharmacist intervention contributes to early detection of an adverse drug reaction. Also, the relationship between clues for detecting adverse drug reactions by a pharmacist and their severity showed that objective evaluations such as clinical laboratory test results, physical assessments and medication history were important for detecting reactions that became more serious. Patients recovered or recovering from an adverse reaction comprised 76.4%, indicating that pharmacist intervention contributed to exacerbation avoidance and improvement. Our findings revealed the effects of pharmacist intervention for adverse drug reaction detection and exacerbation avoidance, and for safety improvement of pharmacotherapy. Additionally, we considered it necessary for the future pharmacist intervention to improve skills of assessing an adverse drug reaction objectively.

Analysis of Clinical Efficacy and Adverse Effects of ß-Blocking Agents Used Clinically for Chronic Heart Failure.

Clinical efficacy and adverse effects of the ß-blocking agents, carvedilol, bisoprolol, and metoprolol were analyzed theoretically, and then compared quantitatively, for the purpose of determining their proper use for chronic heart failure. Initially, we evaluated occupancy binding to the ß1 and ß2 receptors (Фssß1 and Фssß2) by these drugs. Thereafter, we examined the relationship between Фssß1 values and left ventricular ejection fraction (LVEF) increase rate to determine efficacy. The result showed that the efficacy with carvedilol could be attained with a lower Фssß1 value than the others. Therefore, we constructed a model under the assumption that ß-blocking agents exert both indirect action of LVEF increase through the ß1 receptor and direct action on ryanodine receptor 2. Using the model, it was suggested that these drugs have no differences in regard to the efficacy, while it was clarified theoretically that only carvedilol produces an effect that directly involves ryanodine receptor 2 at clinical doses. We also investigated decreases in heart rate and forced expiratory volume in 1 s as adverse effects of ß-blocking agents using a ternary complex model. It was indicated that carvedilol is less likely to induce a heart rate decrease. Meanwhile, it was also suggested that the risk of an asthmatic attack was higher for carvedilol at clinical doses. Our results are considered useful for selection of a proper ß-blocking agent and its administration at a reasonable dose for successful heart failure therapy.

Study of Safety Evaluation in Dispensing of Medicines-Analysis of Relationship between Dispensing Error Rate, Inspecting Error Rate, and Malpractice Rate.

In this study, we established a methodology to calculate the rate of overlooking a dispensing error (inspecting error rate) as a new index for the purpose of determining dispensing error and malpractice rates. Using data obtained from analyses of these error rates at our and two other hospitals, an inspecting error rate was calculated for each institution. Our results showed that inspecting errors occurred at a frequency 3-5 times greater as compared to dispensing errors at each of the examined hospitals. We concluded that construction of a higher quality safety management system would be enabled by incorporation of an inspecting error rate as a new index to evaluate medical safety in regard to dispensing of medicines and managing inspection accuracy.

Evaluation of drug efficacy of DPP-4 inhibitors based on theoretical analysis with pharmacokinetics and pharmacodynamics.

Dipeptidyl peptidase-4 (DPP-4) inhibitors are used clinically as therapeutic agents for the treatment of diabetes. To determine the rate of DPP-4 inhibition induced by these inhibitors, pharmacokinetic and pharmacodynamic parameters were used to theoretically examine the relationship between the rate of DPP-4 inhibition and clinical efficacy following the administration of four different DPP-4 inhibitors (sitagliptin, vildagliptin, alogliptin, linagliptin) by focusing on the increase in the level of glucagon-like peptide-1 (GLP-1) induced by their administration. On the basis of the relationship shown, changes in clinical efficacy in association with dose change were examined in order to discuss clinical dosage from the standpoint of proper usage. The results indicate that a high rate of DPP-4 inhibition is necessary for the onset of the effect of an administered the DPP-4 inhibitor and that the average value for the DPP-4 inhibition rate can be utilized as a common parameter of clinical efficacy. Furthermore, the efficacy profiles of the present DPP-4 inhibitors could be demonstrated on the basis of an increase in the GLP-1 level. It is considered that the present findings provide useful information for promoting the proper clinical use of DPP-4 inhibitors. Copyright © 2016 John Wiley & Sons, Ltd.

Impact of holding position during inhalation on drug release from a reservoir-, blister- and capsule-type dry powder inhaler.

OBJECTIVE: To determine whether drug release may be impaired by tilting some dry powder inhalers (DPIs). METHODS: Using an inhalation simulator, we measured drug release from Turbuhaler® (TBH), Diskus® (DKS) and Breezhaler® (BZH) at several peak inhaled flow rates (PIFs) while the DPIs were held at level and tilted (80°). Drug release was then measured from all three DPIs at 0, 30, 60 and 90° of tilt, and capsule rotation was also recorded. RESULTS: Drug release from TBH was flow-dependent while that from DKS and BZH was flow-independent. With TBH, the plot of drug release vs. PIF either at level or at tilted position scattered along approximately the same regression lines. With DKS and BZH, drug release at tilted position was significantly lower than that while at level. With DKS the decrease was almost 20%, while with BZH, drug release frequently failed. With BZH, significant reductions in drug release were observed while the device was tilted by 30-90°. CONCLUSION: The position in which the DPI is held may affect drug delivery, especially when using BZH.

Investigation of Appropriate Inhalation Technique for Mometasone Furoate Dry Powder Inhaler.

The aim of this study was to establish an appropriate inhalation method with a mometasone furoate dry powder inhaler (MF-DPI). Utilizing a tone-based inhalation training device, we investigated the maximum peak inspiratory flow rate time (Tmax PIFR) and peak inspiratory flow rate (PIFR) to determine whether either had an influence on lung deposition with use of an MF-DPI. A low tone indicated a PIFR of 28 L/min and a high tone that of 40 L/min, while 60 L/min was considered to be the standard. We established an inhalation profile in consideration of a human inhalation pattern, in which Tmax PIFR was set at 0.5 s (Tmax PIFR 0.5 s) and 2.5 s (Tmax PIFR 2.5 s). The reference cut-off value derived with a cascade impactor test was used for evaluation of the rate of delivered dose in the lung, which was the amount of drug from stage 3 to 7 at all PIFRs. We then investigated the relationship of the fine particle fraction (FPF) with the claimed dose at Tmax PIFR of 0.5 s and PIFR. There were no differences among the Tmax PIFR values for the doses emitted from the device or for the rate of delivered doses in stages 3-7. However, FPF for the claimed dose at 40 L/min was significantly lower than that at 60 L/min, which was dependent on PIFR. Our results showed that PIFR but not Tmax PIFR has an effect on lung deposition after inhalation with an MF-DPI.

Effects of tumor necrosis factor α-857C/T polymorphism on the expression of tumor necrosis factor α.

It was reported that homozygosity for a lymphotoxin α (LTA) 1-1-1-1 haplotype (LTA NcoI-TNFc-aa13L-aa26) may identify subgroups with a poor response to infliximab in Crohn's disease patients. Previously, we found a genetic polymorphism that linked with the LTA 1-1-1-1 haplotype and noted that it was a tumor necrosis factor (TNF) α-857 T allele. To investigate the effects of the -857C/T (rs1799724) polymorphism on the expression of TNFα, we compared levels of transcriptional activity of the gene, mRNA, and protein of the TNFα. The change in transcriptional activity of the -857T allele was higher than that of the -857C allele. Furthermore, the accumulated transcriptional activity of the -857T allele was 1.3-fold higher than that of the -857C allele up to 48 h. The levels of mRNA and protein of the TNFα after stimulation were also shown to be significantly higher in -857C/T as compared to the -857C/C genotype. Our results suggested that TNFα promoter -857T is higher than -857C in the levels of transcriptional activity of the gene, mRNA, and protein of the TNFα. The differences in therapeutic effect of TNF inhibitors among individuals can be explained in part by the induction ability of TNFα via the -857C/T polymorphism.

Prediction of Therapeutic Effect of Rasburicase on Hyperuricemia Associated with Chemotherapy Based on Theoretical Model.

Rasburicase has a strong and fast effect for reducing blood levels of uric acid. However, there have been no reports of theoretical analysis for the rational dose and interval of administration. Thus we constructed a pharmacokinetic and pharmacodynamic model to determine changes in uric acid level after rasburicase administration at various doses and regimens. The time courses of uric acid level predicted using our model were in good agreement with observed data, indicating adequate performance for our model. The therapeutic effects after a single infusion at various rates of generation of uric acid were predicted. The maximum effect was not a large difference, in spite of the generation rate. Then, the therapeutic effects of repeated administrations were predicted. The effect did not change when rasburicase was administered at more than the usual dose. Besides, as the administration interval increased, the difference between minimum and maximum level of uric acid became greater. However, in all doses and regimens, adequate therapeutic effects were obtained. In conclusion, the model was found useful for predicting therapeutic effect of rasburicase and individually determining rational dosage regimen of rasburicase.

Initial dosing regimen of vancomycin to achieve early therapeutic plasma concentration in critically ill patients with MRSA infection based on APACHE II score.

It is essential to assure the efficacy of antimicrobials at the initial phase of therapy. However, increasing the volume of distribution (Vd) of hydrophilic antimicrobials in critically ill patients leads to reduced antimicrobial concentration in plasma and tissue, which may adversely affect the efficacy of that therapy. The aim of the present study was to establish a theoretical methodology for setting an appropriate level for initial vancomycin therapy in individual patients based on Acute Physiology and Chronic Health Evaluation (APACHE) II score. We obtained data from patients who received intravenous vancomycin for a suspected or definitively diagnosed Gram-positive bacterial infection within 72 h after admission to the intensive care unit. The Vd and elimination half-life (t 1/2) of vancomycin values were calculated using the Bayesian method, and we investigated the relationship between them and APACHE II score. There were significant correlations between APACHE II scores and Vd/actual body weight (ABW), as well as t 1/2 (r = 0.58, p < 0.05 and r = 0.74, p < 0.01, respectively). Our results suggested that the Vd and t 1/2 of vancomycin could be estimated using the following regression equations using APACHE II score.[Formula: see text] [Formula: see text]We found that APACHE II score was a useful index for predicting the Vd and t 1/2 of vancomycin, and used that to establish an initial vancomycin dosing regimen comprised of initial dose and administration interval for individual patients.