[Pharmacogenetic analysis of the absorption kinetics of cyclosporine in a population of Spanish cardiac transplant patients]. / Análisis farmacogenético de la cinética de absorción de ciclosporina en una población española de pacientes trasplantados cardíacos.

OBJECTIVE: To determine how single nucleotide polymorphisms located on genes MDR1, CYP3A4 and CYP3A5 affect the absorption kinetics of cyclosporine in cardiac transplant patients. METHOD: We selected a sample of 30 adult patients having previously undergone a primary cardiac transplant and who had received cyclosporine as an immunosuppressant. During the first month after the transplant, we performed a pharmacokinetic study of each patient to determine values in the cyclosporine concentration area under the 12-hour curve, steady-state cyclosporine concentration, maximum cyclosporine concentration, and time to reach that concentration. Single nucleotide polymorphisms were genotyped in all patients: MDR1 3435C > T, CYP3A4-390A > G and CYP3A5 6986A > G. RESULTS: Being a carrier of the T-allele for polymorphism MDR1 3435C > T is associated with higher values in the cyclosporine concentration area under the 12-hour curve (p = 0.01) and in steady-state cyclosporine concentration (p = 0.05), compared with those from patients who do not carry that allele. DISCUSSION: Our results show that genotype differences in MDR1 3435C > T can explain part of the variability in cyclosporine absorption among individuals in the population of Spanish cardiac transplant recipients.

[Stability and in vitro activity of voriconazole eyedrops at a concentration of 3 microg/mL]. / La estabilidad y actividad in vitro de voriconazol en colirio a una concentración de 3 microg/mL.

OBJECTIVE: To assess the stability and activity of voriconazole 3 microg/mL eyedrops as prepared for use against amphotericin B- and fluconazole-resistant fungal endophthalmitis. METHOD: Stability (concentration using UV-spectrophotometry; pH, osmolarity, and particle formation) and sterility were analyzed under various preservation conditions--room temperature (22-24 degrees C) or refrigerated (2-8 degrees C). The preparation's in vitro efficacy was analyzed using the standard National Committee for Clinical Laboratory Standards method for 30 days. RESULTS: Voriconazole concentrations were found to be within limits allowed by the United Stated Pharmacopeia (90-115%). pH (room temperature: 6.96-7.60; refrigerated: 6.84-7.21) and osmolarity (room temperature: 265-284 mOsm/l; refrigerated: 270-285 mOsm/l) remained within eye physiological ranges throughout the study under the analyzed conditions. The preparation s antifungal activity remained stable during the first three weeks. CONCLUSIONS: The voriconazole 3 microg/mL eyewash preparation remained stable, sterile and with full antifungal activity for 21 days when stored both at room temperature and under refrigeration conditions.

[Tacrolimus blood levels and incidence of graft rejection in heart transplantation]. / Relación entre los niveles de tacrolimus en sangre y la incidencia de rechazo en enfermos trasplantados de corazón.

OBJECTIVE: To determine the relationship between pharmacokinetic parameters and clinical outcomes after heart transplantation and to determine the range of tacrolimus blood levels which provides the most effective protection against graft rejection. To study other factors that predict graft rejection. METHOD: We retrospectively analyzed the clinical outcomes of all adult patients who received a heart transplant between January 2000 and October 2003 and had routine monitoring of tacrolimus trough levels at the time of scheduled endomyocardial biopsy. Rejection was defined as Grade = 3, based on the International Society for Heart and Lung Transplantation (ISHLT) criteria. The follow-up period was 1 year. All patients were on a triple therapy regimen of Tacrolimus (TAC), Corticosteroids and Azatioprine/Micophenolate Mofetil. Data were analyzed by Student s t-test, univariate logistic regression and ROC curve. RESULTS: Tacrolimus blood levels measured at day +5 postransplant were the strongest predictor of acute graft rejection over a 1-year follow-up period (rejection 5.76 +/- 3.4 ng/ml vs no rejection 9.66 +/- 2.73 ng/ml, p = 0.016). A decrease of one unit in TAC trough level values at day +5 postransplant implied a 1.58 greater risk of rejection (p = 0.05). Overall incidence of treated acute rejection was lower for patients with trough levels higher than 8 ng/ml on day +5 postransplant (33 vs 80%, p = 0.055, Fisher s exact test). CONCLUSIONS: Data suggest that in heart transplant patients it may be crucial to achieve tacrolimus levels of at least 8 ng/ml during the first days postsurgery to avoid rejection.

New strategies of cyclosporine monitoring in heart transplantation: initial results.

The aim of this study was to evaluate cyclosporine (CyA) absorption profiles in heart transplantation to establish the most adequate monitoring strategy and determine the optimal therapeutic range for AUC(0-4) or C2 levels. A total of 22 full pharmacokinetic studies were performed at steady-state in 22 adult heart transplant recipients (18 men, 4 women). Twelve studies were performed during the first month posttransplant (group I), and 10 studies were done after 1 month (group II). In 9 outpatients we performed an abbreviated AUC(0-4). The mean age of the patients was 49+/-15 years (range, 15-72 years), and the mean weight was 70.4+/-10.8 kg (mean, 54-98 kg). The CyA dosage had been adjusted to maintain trough levels (C0) in the putative target ranges of 200 to 400 ng/mL in group I and between 100 to 300 ng/mL in group II. Blood samples were drawn prior to and at 0.5, 1, 2, 4, 6, 8, and 12 hours after the morning dose. The CyA blood levels were measured by the AxSYM cyclosporine assay. The AUC was calculated by the trapezoidal rule. Multiple linear regression was done to evaluate the predictive ability of various limited sampling strategies. The C0 correlated poorly, either with the full AUC (r2=0.64) or the AUC(0-4) (r2=0.43), while C2 seemed to be the most accurate single predictor of drug exposure (r2=0.92 for AUC(0-12); r2=0.74 for AUC(0-4)). For both AUC(0-4) and AUC(0-12), all 2- or 3-point strategies had r2 values approaching that of the C2 value. In conclusion, C2 is a simple, fast, and accurate value to predict AUC(0-4) in routine clinical practice. Its implementation must focus on ensuring the commitment of all unit staff, thus ensuring that patients are sampled on time and minimizing the impact on workload.

Clinical pharmacokinetics of tacrolimus in heart transplantation: new strategies of monitoring.

The aim of this study was to investigate the absorption profile of tacrolimus (TAC) in heart transplant patients in order to find the best sampling time to predict the total exposure and to explore the target range for optimal clinical immunosuppression. Twenty-five full pharmacokinetic studies were performed in 22 heart transplant patients (11 men and 7 women) at less than 1 year posttransplant. The immunosuppressive treatment was steroids plus azathioprine or mycophenolate mofetil and TAC. The mean age was 55 years (36-64 years) and the mean weight 70.49 kg (50-111 kg). After three days of receiving the same dose, eight blood samples were collected at 0.5, 1, 2, 4, 6, 8, and 12 hours postmorning dose. TAC concentrations were measured by microparticle enzyme immunoassay (IMx). Area under the concentration-time curve(AUC(0-12)) was calculated by the trapezoidal rule. Using 0-4 hours TAC blood concentrations, a projected 12 hours AUC (extrapolated AUC(0-4)) was calculated assuming C0 and C12 were comparable. A high interpatient TAC pharmacokinetics variability that was greater during the absorption phase was observed. A Cmax (30.5+/-13.8 ng/mL) was reached at 2.3+/-1.5 h. When target trough levels were achieved (10-20 ng/mL), the mean tacrolimus exposure was 230.6+/-59.2 ng h/mL (120.14-327.7) (n=19). Correlation between AUC(0-12) and C0 was relatively good (r2=0.74). Between individual time points, C4 showed the best correlation (r2=0.88). In any case the best strategy to monitor is to obtain the extrapolated AUC(0-4) (r2=0.98), as a good approach to patients with a poor response to treatment.

[Aluminum contamination of pediatric parenteral nutrition solutions]. / Contaminación por aluminio de las soluciones de nutrición parenteral pediátrica.

The main clinical manifestations of aluminum toxicity include progressive encephalopathy, osteomalacia, microcytic hypochromic anemia, and cholestasis. The premature newborn receiving IV therapy are at high risk of such aluminium intoxication: two conditions predispose them to an aluminum overdose-parenteral exposure and their reduced kidney function. The amount of aluminum present as contaminant was calculated for each of the i.v. solutions used in the preparation of the parenteral nutrition units in pediatrics, along with that for three prepared nutritions. This was done using atomic absorption spectrophotometry. The calcium salts (5.18 +/- 2.88(5)ppm), phosphorus salts (3.96 +/- 3.52(5)ppm) and trace elements (1.52 +/- 0.92(4) ppm) were the most contaminated components, the amount of aluminum being similar to that found by other authors showing bone and liver accumulations. The great variability between the solutions of different manufacturers and of different batches suggests that the contamination takes place during manufacture, so that it could in many cases be prevented by establishing adequate controls.