Integrated clinical pharmacy activities into the pediatric kidney graft pathway / Activités de pharmacie clinique intégrées dans le parcours du patient de greffe rénale pédiatrique

The pediatric renal graft pathway is at risk of care discontinuation, even though therapeutic adherence is essential. The objective is to evaluate the integration of clinical pharmacy activities into this care pathway. This feasibility study is divided into three stages: structuring, implementing and evaluation. In pre-transplant, immediate and remote post-transplant, interviews were proposed as well as the pharmaceutical analysis of medication prescriptions. In 8 months duration, 32 patients were included. All patients included in pre-transplant and immediate post-transplant benefited from the activities. At M0, all the prescriptions analyzed resulted in at least one problem detected. Half of the transplanted patients benefited from M1 maintenance, one patient from M3 maintenance and no M6 follow-up could be carried out. This work concludes with the good feasibility and integration of clinical pharmacy activities within the care pathway.

Le parcours de greffe rénale pédiatrique est à risque de rupture de soins car les patients sont polymédiqués alors même que l'adhésion thérapeutique est essentielle. L'objectif est d'évaluer l'intégration d'activités de pharmacie clinique dans ce parcours de soins. Cette étude de faisabilité se décline en trois étapes : structuration, mise en œuvre et évaluation. En pré-greffe, post-greffe immédiate et post-greffe à distance, des entretiens ont été proposés ainsi que l'analyse pharmaceutique des prescriptions médicamenteuses. En huit mois, 32 patients ont été inclus. Tous les patients inclus en pré-greffe et en post-greffe immédiate ont bénéficié des activités. À M0, toutes les prescriptions analysées ont abouti à au moins un problème détecté. La moitié des patients greffés ont bénéficié de l'entretien à M1, un patient de l'entretien à M3 et aucun suivi à M6 n'a pu être réalisé. Ce travail conclut à la bonne faisabilité et intégration des activités de pharmacie clinique au sein du parcours de soins.

Monitoring of azathioprine metabolites in pediatric patients with autoimmune hepatitis.

Azathioprine is commonly used in the treatment of autoimmune hepatitis (AIH). Few data are available on drug monitoring of azathioprine metabolites in patients with AIH, especially in pediatric patients. The purpose of this study was to investigate intracellular thiopurine metabolites in children with AIH and to assess the relevance of drug monitoring compared with the efficacy and toxicity. Data from 28 patients with AIH treated by azathioprine for at least 3 months were recorded. 6-Thioguanine nucleotides (6-TGN) and 6-methyl mercaptopurine nucleotides (6-MeMPN) concentrations and TPMT activity were determined by high-performance liquid chromatography. Blood cell counts and liver function tests were also collected and the clinical outcome was documented. A wide interindividual variability in 6-TGN and 6-MeMPN concentrations was observed with values ranging from 51 to 1966 pmol/8 x 10(8) red blood cells (RBCs) for 6-TGN and from 42 to 8189 pmol/8 x 10(8) RBCs for 6-MeMPN. A total of 61.4% of the patients achieved remission and only 32.6% of these children had 6-TGN values within the target range proposed for inflammatory bowel disease (250-450 pmol/8 x 10(8) red blood cells). No difference in metabolite concentrations was observed between children in remission and those with active disease. Azathioprine dosage was significantly related to 6-TGN and 6-MeMPN levels (r = 0.308, P < 0.001 and r = 0.405, P < 0.001, respectively). A significant negative correlation was observed between 6-TGN concentrations and erythrocyte and lymphocyte counts, whereas 6-MeMPN was not related to blood cell counts. Although leukocyte counts were not related to 6-TGN concentrations, patients with leucopenia exhibited higher 6-TGN values than those without leucopenia (median values 438 pmol/8 x 10(8) RBCs versus 405 pmol/8 x 10(8) RBCs, respectively). Thiopurine metabolite monitoring appears useful in identifying the myelotoxicity and the hepatotoxicity as a result of azathioprine with disease recurrence and to assess adherence to therapy. A further larger study will be required to confirm the optimal recommended target for thiopurine metabolites to achieve remission in patients with AIH.

Relationship between MPA free fraction and free MPAG concentrations in heart transplant recipients based on simultaneous HPLC quantification of the target compounds in human plasma.

A simple and sensitive HPLC method for the simultaneous analysis of free MPA and free MPAG was developed. Separation was achieved on a X-Terra RP18 column with acetonitrile-40 mM orthophosphoric acid as eluents using a gradient elution mode over 35 min at a flow rate of 1.5 ml/min. The assay was linear in the range 0.005 mg/L (LOQ) to 5mg/L for free MPA and 0.05 mg/L (LOQ) to 200 mg/L for free MPAG. Isolation of free MPA and free MPAG was done by ultrafiltration and the ultrafiltrate was directly injected. A positive correlation between MPA free fractions and free MPAG concentrations was found. Likewise, free MPAG was related to total MPAG concentrations in the seven heart transplant patients.

A rapid and simple HPLC method for the analysis of propofol in biological fluids.

A selective and sensitive high-performance liquid chromatographic method for the analysis of propofol in biological samples was developed. Propofol and thymol (internal standard) were analysed on a Purospher RP-18 endcapped (75 mmx4 mm, 3 microm) stationary phase using acetonitrile and water (65:35, v/v) as eluents at a flow rate of 0.6 mL/min. The excitation and emission wavelengths were 276 and 310 nm, respectively. Sample treatment consisted of deproteinization by acetonitrile containing the internal standard and direct injection of the supernatant. Mean analytical recovery were 105% (CV 2.0%) at concentrations ranging from 0.05 to 10 mg/L. The quantification limit was 3 ng/mL for a 500 microL sample plasma volume and 5 ng/mL for a 500 microL blood sample. The intra-day and inter-day precisions were lower than 5.5% for three concentrations assessed (0.05, 1.0 and 10.0 mg/L). Considering the column size and the flow rate, the separation was achieved with an analysis time less than 6 min with a reduced consumption of solvent. This rapid HPLC method using a simple treatment procedure is sensitive enough for monitoring propofol in human biological samples.

Evaluation of MPA and MPAG removal by continuous venovenous hemodiafiltration and continuous venovenous hemofiltration.

The study assessed the removal of mycophenolic acid (MPA) and its major glucuronide metabolite (MPAG) during continuous venovenous hemofiltration (CVVHF) and continuous venovenous hemodiafiltration (CVVHDF) in 4 heart transplant recipients treated for at least 6 days with mycophenolate mofetil (MMF) in addition to cyclosporine and corticosteroids. The sieving coefficient ranged from 0.02 to 0.04 for MPA and from 0.15 to 0.33 for MPAG. The clearance of MPAG by CVVHDF or CVVHF ranged from 7.52 mL/min to 19.45 mL/min, and that of MPA was lower than 2.28 mL/min, with no significant difference between the two continuous replacement therapies. Whereas MPA percentage recovered by hour following CVVHDF or CVVHF was negligible, the percentage of MPAG represents up to 12.9% of the administered dose. A relevant decrease in the free fraction of MPA and MPAG was observed after continuous renal replacement therapy (CRRT). These preliminary results demonstrate that MPAG is able to permeate the filter. In light of the alteration in protein binding following CRRT and the competition between MPA and MPAG to albumin site, drug monitoring of MPA and MPAG in patients undergoing CVVHDF or CVVHF may be suggested. Moreover, monitoring of free MPA may be of interest for these patients.

A limited sampling strategy for estimating individual pharmacokinetic parameters of coagulation factor VIII in patients with hemophilia A.

Therapeutic drug monitoring of factor VIII is well established in the treatment of patients with hemophilia attributable to important interindividual variability. The individual initial factor VIII dosage is usually calculated according to individual pharmacokinetic parameters obtained after a dose test administered before the surgery, using at least five-concentration data. The authors proposed a limited sampling strategy to estimate individual pharmacokinetic parameters from one- or two-concentration data in patients with hemophilia A before surgery. The mean population pharmacokinetic parameters and the interindividual variability (CV) were obtained from a group of 33 patients according to a two-compartment model using NONMEM. Eighteen additional patients were used to estimate the predictive performances of the population parameters and to evaluate the limited sampling strategies. Population parameters were clearance 2.6 mL/h per kilogram (CV 45.4%), initial volume of distribution 2.8 L (CV 21.1%). From two sampling times (0.5 and 6 hours or 0.5 and 8 hours after the end of infusion), the estimation of pharmacokinetic parameters was precise and not biased. Until now, in the hemophilic center of Lyon, the factor VIII dosage before surgery was based on the determination of the clearance, estimated from five- to nine-concentration data and on the target concentration (infusion rate = clearance x target). Ruffo et al proposed a limited sampling strategy (two-stage method) to estimate pharmacokinetic parameters from two concentration measurements drawn 3 and 9 hours after the dose. No information was given on the bias and precision of the estimation. This paper reports a one-stage method for a population pharmacokinetic study of factor VIII. The Bayesian estimation of individual pharmacokinetic parameters based on only two sampling times (0.5 and 6 hours or 0.5 and 8 hours after the end of infusion) is useful to define the best factor VIII dosage in hemophilic patients before surgery.