Ceftazidime dosage regimen in intensive care unit patients: from a population pharmacokinetic approach to clinical practice via Monte Carlo simulations.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The large variability in drug pharmacokinetic disposition has already been described in ICU patients leading to important variations in drugs concentrations. The usual recommended dosage of ceftazidime is not adapted for all ICU situations and ceftazidime should be monitored closely. New recommendations have to be given for some specific cases. WHAT THIS STUDY ADDS: Our results propose individual therapeutic drug monitoring taking into account: For the patient: the reason of admission in the ICU, the mechanical ventilation status and the creatinine clearance calculated by the modified diet in renal disease (MDRD). • For the antibiotics: the lung distribution, the minimal inhibitory concentration (MIC) of the strain to eradicate and the potential toxicity. AIM To predict the ceftazidime dosage regimen as a function of the glomerular filtration rate expressed by the modification of the diet in renal disease (MDRD), reason for admission and mechanical ventilation in intensive care unit (ICU) patients to treat Pseudomonas aeruginosa pneumonia. METHOD: A published and qualified population pharmacokinetic model was used to perform Monte Carlo simulations of ceftazidime concentrations. The serum target of 40-100 mg l(-1) was defined based on the minimal inhibitory concentration (MIC), the European break point (EBP), the pulmonary drug diffusion and toxicity. The recommended dosage regimens were based on the maximum percentile of the patients with simulated steady state concentrations reaching the target. RESULTS: Steady-state was reached at 72 h whatever the MDRD. The simulations of serum concentrations generated higher percentiles of the population reaching the target after continuous administration. We recommend a 4 g continuous dose after the usual 2 g loading dose for patients with MDRD from 10 to 30 ml min(-1) , 6 g for MDRD between 40 and 80 ml min(-1) , 8 g for MDRD from 90 to 110 ml min(-1) , 10 g for MDRD from 120 to 190 ml min(-1) and 12 g day(-1) for patients with MDRD higher than 200 ml min(-1) . CONCLUSION: Our study demonstrated that in ICU patients for a given MDRD, steady-state takes longer to reach in polytrauma patients than in patients with medical or post surgery reasons for admission. Continuous infusion ensures that a higher percentage of patients reaches the target than the same dose given by discontinuous administration and this only depends on MDRD.

Cost-effectiveness analysis of individualized mycophenolate mofetil dosing in kidney transplant patients in the APOMYGRE trial.

BACKGROUND: In the prospective, randomized, multicenter APOMYGRE trial conducted in France, concentration-controlled mycophenolate mofetil (MMF) dosing based on mycophenolic acid (MPA) exposure significantly reduced the treatment failure and acute rejection during the first posttransplantation year compared with fixed-dose MMF. This analysis investigated the cost effectiveness of dose individualization. METHOD: The study included 65 patients per group (intent-to-treat population). Treatment failure (primary efficacy endpoint) was defined as death, graft loss, acute rejection, or MMF discontinuation because of adverse effects. Data on hospitalizations, drugs prescribed, physicians' fees, laboratory expenses, ambulatory visits, and transportation were retrieved. Costs were calculated from the French National Health System perspective. RESULTS: The mean (95% confidence interval) total yearly cost per patient was Euro 47,477 (Euro 43,933; Euro 51,020) in the concentration-controlled group and Euro 46,783 ( Euro 44,152; Euro 49,414) in the fixed-dose group (P=0.7). The observed incremental cost-effectiveness ratio was Euro 3757 per treatment failure (Purchasing Power Parities United States/France: $4129). Hospitalization and drug costs accounted for approximately 50% and 25% of total costs, respectively. The cost for MPA area under the concentration-time curve and dose calculation was Euro 452 per patient, less than 1% of the total cost. CONCLUSION: In the APOMYGRE trial, therapeutic MPA monitoring using a limited sampling strategy reduced the risk of treatment failure and acute rejection in renal allograft recipients during the first 12 months posttransplantation, at neutral cost.

Blood concentrations of hydroxychloroquine and its desethyl derivative correlate negatively with the percentage of CD45RO+ cells among CD4+ lymphocytes in hydroxychloroquine-treated lupus patients.

The objective of the study was to investigate the influence of the blood concentrations of hydroxychloroquine ([HCQ]) and its derivative desethylhydroxychloroquine ([DHCQ]) on lymphocyte activation or differentiation in HCQ-treated lupus patients. We studied the correlations between [HCQ], [DHCQ], and the frequency of various lymphocyte subsets in 58 HCQ-treated lupus patients (mean HCQ dose: 4.93 +/- 1.58 mg/kg/day; mean duration of the disease: 122 +/- 64 months). [HCQ] and [DHCQ] were determined by high-performance liquid chromatography (HPLC). Lymphocyte markers were studied by flow cytometry using monoclonal anti-CD3, -CD4, -CD8, -CD25, -DR, -CD45RA, -CD45RO, -CD19, -CD38, and -CD86 antibodies. sIL2-R serum concentrations were measured by enzyme-linked immunosorbent assay (ELISA). [HCQ] and [DHCQ] were 599.9 ng/mL (median: 529.5; range: 55-1935) and 353.43 (median: 286 ng/mL; range: 118-1090). In a multiple regression analysis, [HCQ] and [DHCQ] were associated with the HCQ prescribed dose in mg/kg/day (P = 0.0002 and P = 0.03) and with compliance to the treatment (P = 0.004 and P = 0.03). We found a negative correlation between [HCQ], [DHCQ], and the CD45RO+ cell frequency among CD3+CD4+ cells (P = 0.03 and P = 0.007, respectively). Other lymphocyte subset markers (LSMs) and sIL2-R concentrations were not significantly associated with [HCQ] or [DHCQ]. In the multiple regression analysis, CD45RO+ expression was negatively influenced by [HCQ] (P = 0.005), and positively influenced by smoking habits (P = 0.005) and age (P = 0.005). Similar results were found in the multivariate model including [DHCQ]. Disease activity and taking more than 10 mg/day of corticosteroids or an immunosuppressive drug did not influence CD45RO+ expression. Lupus patients had less CD3+CD4+CD45RO+ cells than controls (P = 0.03). In lupus patients, HCQ and DHCQ may alter the generation or the blood circulation of CD4+CD45RO+ lymphocytes in a concentration-dependent pattern.