Rifampin levels in daily practice: the accuracy of a single measurement.

BACKGROUND: Measurement of rifampin levels is not part of routine practice. However, low levels are associated with failure of tuberculosis treatment. The clinical relevance of serum levels in daily practice is unclear. The objective was to evaluate rifampin serum concentrations and factors associated with insufficient concentrations. METHODS: Patients with at least one rifampin concentration drawn 3 hours after intake (C3) between 2005 and 2014 were included. Data on demographic and clinical characteristics were collected, including side effects and dose adjustments. Two different criteria were used to define adequate concentrations (criterion 1: C3 a nd C 6 ≥ 3 mg/l; criterion 2: C3 or C6 ≥ 5 mg/l). RESULTS: Of 63 patients, 66% and 76% had a sufficient level according to criterion 1 or 2, respectively. C3 exceeded C6 in most patients, while a late maximum was significantly associated with diabetes mellitus (p = 0.003). A dose adjustment was made in 19% of cases, more frequently in patients with insufficient levels (p = 0.02) or with ≥ 2 side effects (p = 0.03). CONCLUSION: Rifampin levels varied but were mostly adequate and a single measurement at 3 hours after intake provided the required information in most cases, indicating that full AUC0-24 measurements could be limited to specific situations.

Everolimus pharmacokinetics and its exposure-toxicity relationship in patients with thyroid cancer.

BACKGROUND: Everolimus is a mTOR inhibitor used for the treatment of different solid malignancies. Many patients treated with the registered fixed 10 mg dose once daily are in need of dose interruptions, reductions or treatment discontinuation due to severe adverse events. This study determined the correlation between systemic everolimus exposure and toxicity. Additionally, the effect of different covariates on everolimus pharmacokinetics (PK) was explored. METHODS: Forty-two patients with advanced thyroid carcinoma were treated with 10 mg everolimus once daily. Serial pharmacokinetic sampling was performed on days 1 and 15. Subsequently, a population PK model was developed using NONMEM to estimate individual PK values used for analysis of an exposure-toxicity relationship. Furthermore, this model was used to investigate the influence of patient characteristics and genetic polymorphisms in genes coding for enzymes relevant in everolimus PK. RESULTS: Patients who required a dose reduction (n = 18) due to toxicity at any time during treatment had significant higher everolimus exposures [mean AUC0-24 (SD) 600 (274) vs. 395 (129) µg h/L, P = 0.008] than patients without a dose reduction (n = 22). A significant association between everolimus exposure and stomatitis was found in the four-level ordered logistic regression analysis (P = 0.047). The presence of at least one TTT haplotype in the ABCB1 gene was associated with a 21 % decrease in everolimus exposure. CONCLUSION: The current study showed that dose reductions and everolimus-induced stomatitis were strongly associated with systemic everolimus drug exposure in patients with cancer. Our findings confirm observations from another study in patients with cancer and show us that everolimus is a good candidate for individualized dosing in patients with cancer. CLINICALTRIAL. GOV NUMBER: NCT01118065.

Population pharmacokinetics and pharmacogenetics of once daily tacrolimus formulation in stable liver transplant recipients.

PURPOSE: The once daily formulation of tacrolimus is an important immunosuppressive drug. Interpatient variability in metabolism has been related to genetic variation in CYP3A4 and CYP3A5. However, in liver transplantation, both donor and recipient genotypes may affect pharmacokinetics. The primary objective of this study was to investigate the effect of CYP3A4*22 and CYP3A5*3 of both donor and recipient on once daily tacrolimus pharmacokinetics. The secondary objective was to develop a limited sampling model able to accurately predict exposure. METHODS: Stable liver transplant patients receiving once daily tacrolimus (N = 66) were included. Population pharmacokinetic analysis was performed with patients of whom DNA was available (N = 49), and demographic factors, CYP3A4*22 and CYP3A5*3, were tested as covariates. Moreover, a limited sampling model was developed using data of 66 patients. RESULTS: Pharmacokinetics was best described by a two-compartment model with delayed absorption. CYP3A5*1 carrying recipients engrafted with a CYP3A5*1 carrying liver had an average 1.7-fold higher clearance compared to non-carriers. CYP3A5*1 carrying recipients engrafted with a CYP3A5*1 non-carrying liver or vice versa showed an average 1.3-fold higher clearance compared with non-carriers. CYP3A4*22 was not significantly associated with once daily tacrolimus pharmacokinetics. Using 0, 2, and 3 h postdose as limited sampling model resulted in significantly improved prediction of tacrolimus exposure compared with trough concentration. CONCLUSIONS: Both donor and recipient CYP3A5 genotype significantly influences tacrolimus once daily pharmacokinetics. In contrast, CYP3A4*22 appears not suitable as biomarker. The developed limited sampling model can be used to accurately estimate tacrolimus once daily exposure.

Population Pharmacokinetic Model Characterizing 24-Hour Variation in the Pharmacokinetics of Oral and Intravenous Midazolam in Healthy Volunteers.

Daily rhythms in physiology may affect the pharmacokinetics of a drug. The aim of this study was to evaluate 24-hour variation in the pharmacokinetics of the CYP3A substrate midazolam. Oral (2 mg) and intravenous (1 mg) midazolam was administered at six timepoints throughout the 24-hour period in 12 healthy volunteers. Oral bioavailability (population mean value [RSE%] of 0.28 (7.1%)) showed 24-hour variation that was best parameterized as a cosine function with an amplitude of 0.04 (17.3%) and a peak at 12:14 in the afternoon. The absorption rate constant was 1.41 (4.7%) times increased after drug administration at 14:00. Clearance (0.38 L/min (4.8%)) showed a minor 24-hour variation with an amplitude of 0.03 (14.8%) L/min and a peak at 18:50. Simulations show that dosing time minimally affects the concentration time profiles after intravenous administration, while concentrations are higher during the day compared to the night after oral dosing, reflecting considerable variation in intestinal processes.

Short-term variation in plasma mitotane levels confirms the importance of trough level monitoring.

OBJECTIVE: Mitotane is the drug of choice in patients with adrenocortical carcinoma. The anti-neoplastic effect is correlated with mitotane plasma levels, which render it crucial to reach and maintain the concentration above 14 mg/l. However, mitotane pharmacokinetics is poorly understood. The aim of this study was to investigate the variation in plasma mitotane levels during the day and the influence of a single morning dose. DESIGN: A prospective case-control study was conducted to investigate the variation in plasma mitotane levels. METHODS: Patients who had been treated for at least 24 weeks and had reached the therapeutic plasma level (14 mg/l) at least once were eligible. In the first group, mitotane levels were determined hourly for the duration of 8 h after administration of a single morning dose. In the second group, mitotane levels were assessed similarly without administration of a morning dose. RESULTS: Ten patients were included in this study, and three patients participated in both groups. Median plasma level at baseline was 16.2 mg/l (range 11.3-23.3 mg/l) in the first group (n=7) and 17.0 mg/l (13.7-23.8) in the second group (n=6). Plasma levels displayed a median increase compared with baseline of 24% (range 6-42%) at t=4 after morning dose and a change of 13% (range -14 to 33%) at t=4 without morning dose (P=0.02). CONCLUSION: A substantial increase in mitotane plasma levels was observed in steady-state patients within a period of 8 h after morning dosing. Without morning dose, mitotane curves showed a variable profile throughout the day. This implies that random sampling could yield incidentally high levels. For this reason, we recommend early-morning trough sampling as standard management in monitoring mitotane treatment.

Isolated hepatic perfusion with oxaliplatin combined with 100 mg melphalan in patients with metastases confined to the liver: A phase I study.

AIM: To improve isolated hepatic perfusion (IHP), we performed a phase I dose-escalation study to determine the optimal oxaliplatin dose in combination with a fixed melphalan dose. METHODS: Between June 2007 and July 2008, 11 patients, comprising of 8 colorectal cancer and 3 uveal melanoma patients and all with isolated liver metastases, were treated with a one hour IHP with escalating doses of oxaliplatin combined with 100 mg melphalan. Samples of blood and perfusate were taken during IHP treatment for pharmacokinetic analysis of both drugs and patients were monitored for toxicity, response and survival. RESULTS: Dose limiting sinusoidal obstruction syndrome (SOS) occurred at 150 mg oxaliplatin. The areas under the concentration-time curves (AUC) of oxaliplatin at the maximal tolerated dose (MTD) of 100 mg oxaliplatin ranged from 11.9 mg/L h to 16.5 mg/L h. All 4 patients treated at the MTD showed progressive disease 3 months after IHP. CONCLUSIONS: In view of similar and even higher doses of oxaliplatin applied in both systemic treatment and hepatic artery infusion (HAI), applying this dose in IHP is not expected to improve treatment results in patients with isolated hepatic metastases.

Effect of CYP3A4*22, CYP3A5*3, and CYP3A Combined Genotypes on Cyclosporine, Everolimus, and Tacrolimus Pharmacokinetics in Renal Transplantation.

Cyclosporine, everolimus, and tacrolimus are the cornerstone of immunosuppressive therapy in renal transplantation. These drugs are characterized by narrow therapeutic windows, highly variable pharmacokinetics (PK), and metabolism by CYP3A enzymes. Recently, the decreased activity allele, CYP3A4*22, was described as a potential predictive marker for CYP3A4 activity. This study investigated the effect of CYP3A4*22, CYP3A5*3, and CYP3A combined genotypes on cyclosporine, everolimus, and tacrolimus PK in renal transplant patients. CYP3A4*22 carriers showed a significant lower clearance for cyclosporine (-15%), and a trend was observed for everolimus (-7%) and tacrolimus (-16%). Patients carrying at least one CYP3A5*1 allele had 1.5-fold higher tacrolimus clearance compared with noncarriers; however, CYP3A5*3 appeared to be nonpredictive for everolimus and cyclosporine. CYP3A combined genotype did not significantly improve prediction of clearance compared with CYP3A5*3 or CYP3A4*22 alone. These data suggest that dose individualization of cyclosporine, everolimus, or tacrolimus therapy based on CYP3A4*22 is not indicated.CPT: Pharmacometrics Systems Pharmacology (2014); 3, e100; doi:10.1038/psp.2013.78; published online 12 February 2014.

Midazolam as a phenotyping probe to predict sunitinib exposure in patients with cancer.

PURPOSE: Patients treated with sunitinib show substantial inter-patient variability in drug exposure (~30-40 %), which is largely unexplained. Since sunitinib is metabolized by cytochrome P450(CYP)3A4, variability in the activity of this enzyme may explain a considerable proportion of this inter-patient variability. Midazolam is widely used as a phenotyping probe to assess CYP3A4-activity. The objective of this study was to prospectively evaluate the relationship between midazolam and sunitinib exposure. Additionally, the correlation between sunitinib trough levels and exposure and the influence of sunitinib on midazolam exposure was determined. METHODS: Thirteen patients treated with sunitinib in a 4 weeks "on"-2 weeks "off" regimen received twice 7.5 mg midazolam; once with and once without sunitinib. Steady-state sunitinib, its active metabolite SU12662 and midazolam exposures were determined. RESULTS: A significant correlation between midazolam exposure (AUC(0-7h)) and steady-state sunitinib and sunitinib + SU12662 exposure (AUC(0-24h)) was found (p = 0.006 and p = 0.0018, respectively); midazolam exposure explained 51 and 41 % of the inter-patient variability in sunitinib and sunitinib + SU12622 exposure. Furthermore, C trough was highly correlated (r(2) = 0.94) with sunitinib AUC(0-24h). Sunitinib decreased midazolam exposure with 24 % (p = 0.034). CONCLUSION: Midazolam exposure is highly correlated with sunitinib exposure and explains a large proportion of the observed inter-patient variability in sunitinib pharmacokinetics. Consequently, midazolam could be used to identify patients that are at risk of under- or overtreatment, respectively, at the start of sunitinib therapy. Moreover, sunitinib and sunitinib + SU12662 trough levels are highly correlated with drug exposure and can thus be used in clinical practice to individualize sunitinib therapy. The decrease in midazolam exposure by sunitinib needs further investigation.

Concentration-controlled treatment of lupus nephritis with mycophenolate mofetil.

BACKGROUND: Mycophenolate mofetil (MMF) has recently been established as a potent drug in maintenance treatment for lupus nephritis. However, there is no consensus on the optimal dosing regimen because of a high inter-individual variability of mycophenolic acid (MPA), the active metabolite of MMF. This retrospective study aimed to investigate the effect of an individualized dosing regimen through concentration-controlled treatment on MPA exposure and renal outcome in patients with lupus nephritis. METHODS: Sixteen patients with lupus nephritis and treatment with low-dose intravenous cyclophosphamide followed by MMF were included. MPA area under the plasma concentration-time curve from 0 to 12 hours (MPA-AUC(0-12)) was assessed within a month after MMF initiation. After determination of MPA-AUC(0-12), MMF doses were titrated to achieve a target MPA-AUC(0-12) of 60-90 mg*h/l. After on average six months, MPA-AUC(0-12) measures were repeated to assess the effect of dose adjustment. RESULTS: One month after introducing MMF, MPA-AUC(0-12) was low and showed a high inter-individual variability. Dose adjustment with a target MPA-AUC(0-12) of 60-90 mg*h/l resulted in individualized MMF dosing, significantly higher MPA-AUC(0-12) levels, and a non-significant reduction in variability of MPA-AUC(0-12). Adverse effects were reported by 37.5% of patients, which resulted in a switch to azathioprine in two patients. There was no significant relationship between the occurrence of adverse effects and MPA-AUC(0-12). At 12 months of follow-up 87.5% of patients had achieved either partial (18.7%) or complete (68.8%) remission. CONCLUSION: Concentration-controlled dose adjustments with a target MPA-AUC(0-12) of 60-90 mg*h/l was associated with optimized MPA exposure and an excellent renal outcome at 12 months of follow-up in a small sample of SLE patients with lupus nephritis.

The use of the 13C-dextromethorphan breath test for phenotyping CYP2D6 in breast cancer patients using tamoxifen: association with CYP2D6 genotype and serum endoxifen levels.

PURPOSE: Adjuvant therapy with tamoxifen significantly reduces breast cancer recurrence and mortality in estrogen receptor positive disease. CYP2D6 is the main enzyme involved in the activation of the prodrug tamoxifen into the anti-estrogen endoxifen. Endoxifen is thought to be a main determinant for clinical efficacy in breast cancer patients using tamoxifen. As the large interindividual variation in endoxifen levels is only partly explained by CYP2D6 genotype, we explored the use of the (13)C-dextromethorphan breath test (DM-BT) for phenotyping CYP2D6 and to predict serum steady-state endoxifen levels as a marker for clinical outcome in breast cancer patients using tamoxifen. METHODS: In 65 patients with early breast cancer using tamoxifen, CYP2D6 phenotype was assessed by DM-BT. CYP2D6 genotype using Amplichip and serum steady-state levels of endoxifen were determined. Genotype was translated into the gene activity score and into ultrarapid, extensive, heterozygous extensive, intermediate or poor metabolizer CYP2D6 predicted phenotype. RESULTS: CYP2D6 phenotype determined by the DM-BT explained variation in serum steady-state endoxifen levels for 47.5% (R(2) = 0.475, p < 0.001). Positive and negative predictive values for a recently suggested threshold serum level of endoxifen (5.97 ng/mL) for breast cancer recurrence rate were 100 and 90%, respectively, for both CYP2D6 phenotype by DM-BT (delta-over-baseline at t = 50 min (DOB(50)) values of 0.7-0.9) and genotype (CYP2D6 gene activity score of 1.0). CONCLUSION: DM-BT might be, along with CYP2D6 genotyping, of value in selection of individualized endocrine therapy in patients with early breast cancer, especially when concomitant use of CYP2D6 inhibiting medication alters the phenotype.

Effect of genetic polymorphisms in genes encoding GST isoenzymes on BU pharmacokinetics in adult patients undergoing hematopoietic SCT.

BU is used in conditioning regimens before hemopoietic SCT. High BU exposure is associated with toxicity, whereas low BU exposure leads to higher rates of therapy failure. The pharmacokinetics of BU show large interpatient variability, hypothesized to be caused by variability in BU metabolism. In this report, the effect of genetic polymorphisms in three gluthatione S-transferase genes involved in BU metabolism (hGSTA1), GSTM1 (deletion-mutation) and GSTP1 (313A/G) on the pharmacokinetics of BU in Caucasian adult patients was investigated. In all, 66 adult patients received BU as part of their conditioning regimen. After the first infusion, two serum samples were collected and measured using a HPLC assay. A one-compartment population model was used to estimate individual pharmacokinetic parameters. The genetic variants of the three glutathione S-transferase (GST) genes were determined by pyrosequencing and PCR. A reduction of 14% in BU clearance was seen for the GSTA1*B allele and an increase in BU exposure was found. No relationship was found between polymorphisms in GSTM1 and GSTP1 and BU pharmacokinetics. This study shows that an increasing number of copies of GSTA1*B allele results in a significant decrease of BU clearance.

Intravesical gentamicin for recurrent urinary tract infection in patients with intermittent bladder catheterisation.

Clean intermittent catheterisation (CIC) of the bladder is used to imitate normal bladder emptying in patients with bladder dysfunction. CIC is associated with urinary tract infection (UTI) that may be difficult to treat in the case of antimicrobial resistance. The aim of this study was to establish the effect and safety of intravesical gentamicin treatment in such settings. In 2009, intravesical gentamicin treatment was started in selected patients. Here we describe our experience with two patients treated until March 2010. Two patients using CIC suffering recurrent UTI with multiresistant Escherichia coli were treated with daily administration of 80 mg intravesical gentamicin. On treatment they appeared asymptomatic. During 8- and 9-month follow-up they were free of UTI, urine cultures were negative and there were no side effects. A systematic review was conducted through searches of PubMed and other databases. Clinical trials that met the eligibility criteria and displayed the efficacy or safety of intravesical aminoglycoside treatment in patients using CIC were studied. Study selection was performed by two independent reviewers. Eight studies were included for review. Owing to study heterogeneity, a meta-analysis could not be performed. Of four controlled studies using neomycin or kanamycin, two demonstrated a significant reduction in bacteriuria, whilst two other trials did not. One case series on neomycin/polymyxin showed that the majority of patients still developed bacteriuria. Three case series using gentamicin all pointed towards a significant reduction in bacteriuria and UTIs. There were no clinically relevant side effects reported but follow-up in all studies was limited. Although data are limited, intravesical treatment with gentamicin might be a reasonable treatment option in selected patients practicing CIC who suffer recurrent UTIs with highly resistant microorganisms.

CsA exposure is associated with acute GVHD and relapse in children after SCT.

CsA is commonly used after haematological SCT (HSCT) as GVHD prophylaxis. In solid organ transplantation, area under the blood concentration vs time curve (AUC) correlates with clinical outcome. However, in HSCT, it has not been determined whether the AUC is superior to trough level monitoring to optimize clinical efficacy of CsA therapy. Therefore, the aim of this study was to investigate the relationships between CsA trough levels and/or AUC early after HSCT with clinical outcome. A total of 91 children (1.1-17.3 years) were treated consecutively with HSCT for a haematological malignancy. CsA trough levels were obtained and were used to estimate the AUC, retrospectively, with a NONMEM (Non-Linear Mixed Effects Modelling) method. Subsequently, these exposure parameters were correlated to the occurrence of acute GVHD, relapse risk (RR) and OS. Low CsA trough levels were found to correlate with the occurrence of acute GVHD. In addition, a CsA AUC over 3000 mcg h/l in AML patients was associated with a higher RR and a reduced OS. This was not the case for ALL patients. Thus, monitoring CsA exposure early after HSCT and adjusting the CsA dose to a predefined target trough level and AUC may provide a tool to influence GVHD/GVL balance.

Efficacy of 3,4-diaminopyridine and pyridostigmine in the treatment of Lambert-Eaton myasthenic syndrome: a randomized, double-blind, placebo-controlled, crossover study.

3,4-Diaminopyridine and pyridostigmine are widely used to treat Lambert-Eaton myasthenic syndrome (LEMS), either alone or in combination. 3,4-Diaminopyridine enhances the release of acetylcholine at the neuromuscular synapse, and pyridostigmine inhibits the degradation of this neurotransmitter. Although this could lead to a synergistic effect on neuromuscular transmission, no studies have compared the effects of these drugs in patients with LEMS. Therefore, we performed a placebo-controlled, double-dummy, double-blind, randomized, crossover study in nine patients with LEMS.

Effect of intrapulmonary tetrahydrocannabinol administration in humans.

This randomised, double-blind, placebo-controlled, cross-over study was designed to identify which pharmacodynamic parameters most accurately quantify the effects of delta-9-Tetrahydrocannabinol (THC), the predominantly psychoactive component of cannabis. In addition, we investigated the acceptability and usefulness of a novel mode of intrapulmonary THC administration using a Volcano vaporizer and pure THC instead of cannabis. Rising doses of THC (2, 4, 6 and 8 mg) or vehicle were administered with 90 minutes intervals to twelve healthy males using a Volcano vaporizer. Very low between-subject variability was observed in THC plasma concentrations, characterising the Volcano vaporizer as a suitable method for the administration of THC. Heart rate showed a sharp increase and rapid decline after each THC administration (8 mg: 19.4 bpm: 95% CI 13.2, 25.5). By contrast, dose dependent effects of body sway (8 mg: 108.5%: 95% CI 72.2%, 152.4%) and different subjective parameters did not return to baseline between doses (Visual Analogue Scales of 'alertness' (8 mg: -33.6 mm: 95% CI -41.6, -25.7), 'feeling high' (8 mg: 1.09 U: 95% CI 0.85, 1.33), 'external perception' (8 mg: 0.62 U: 95% CI 0.37, 0.86)). PK/PD-modeling of heart rate displayed a relatively short equilibration half-life of 7.68 min. CNS parameters showed equilibration half-lives ranging between 39.4 - 84.2 min. Some EEG-frequency bands, and pupil size showed small changes following the highest dose of THC. No changes were seen in saccadic eye movements, smooth pursuit and adaptive tracking performance. These results may be applicable in the development of novel cannabinoid agonists and antagonists, and in studies of the pharmacology and physiology of cannabinoid systems in humans.

Ciclosporin kinetics in children after stem cell transplantation.

AIMS: To develop a limited sampling strategy to determine ciclosporin systemic exposure [area-under-the-curve(AUC)]. This is meant to be the first step in a future study of the relationship between AUC and the biological effects of ciclosporin. METHODS: The pharmacokinetics of ciclosporin was investigated prospectively following stem cell transplantation (SCT) in 17 children, aged 1.8-16.1 years. Ciclosporin was given twice daily, intravenously over a short infusion of 2 h duration during the early post-SCT period, or orally later on, when oral medication was well tolerated. Parameter estimation was performed using nonlinear mixed effect modelling as implemented in the NONMEM program. Individual empirical Bayes estimates of clearance and distribution volume were correlated with the demographic variables. RESULTS: Pharmacokinetics was described adequately with a two-compartment model with lag time (population estimates: CL = 11.3 l h(-1); V(c) = 16.5 l; V(p) = 59.9 l; t(1/2) absorption = 0.78 h, t(lag) = 0.6 h). The AUCs, determined for the combination of trough level with one time point between 2 and 3 h after dosing, correlated very well with the reference AUC (r(2) = 0.97). No correlation was found between clearance and distribution volume, and the demographic patient variables length, body weight, age and glomerular filtration rate. CONCLUSION: A two-point limited sampling strategy, in combination with a Bayesian fitting procedure using the pharmacokinetic population model described, can adequately determine the AUC of ciclosporin. Since no correlation between clearance and body weight was found, dosing ciclosporin per kg bodyweight is not supported by the results of this study. We suggest starting with a fixed dose, followed by AUC determination and dose adjustment.

Once-daily intravenous busulfan with therapeutic drug monitoring compared to conventional oral busulfan improves survival and engraftment in children undergoing allogeneic stem cell transplantation.

Because of intra- and interindividual variability, bioavailability, and pharmacokinetics of busulfan (Bu) in children, oral busulfan without therapeutic drug monitoring (TDM) is assumed to be associated with higher graft failure rates as well as higher toxicity (eg, veno-occlusive disease [VOD]). This study compares the outcome of hematopoietic stem cell transplantation (HSCT) of 2 groups: 1) 30 patients who received myeloablation with once-daily intravenous (i.v.) dose-targeted busulfan (BUdtIV) based on TDM and 2) 30 patients who received the current practice of untargeted oral busulfan (BUPO). Patients received a 3-hour infusion of Bu at a first dose of 120 mg/m(2) (age >or=1 year) or 80 mg/m(2) (<1 year), or BUPO 1 mg/kg 4 times daily. Both regimens were continued for 4 days. The target area under the curve (AUC) was defined as 17,500 microg *h/l. BUdtIV resulted in higher event-free survival (EFS) and survival rates compared to BUPO (EFS: 30% versus 83%, P < .001, survival: 53% versus 83%, P = .016). BUdtIV was associated with more cases of VOD. TDM was feasible in routine clinical practice. The results show that i.v. Bu using TDM is preferable over oral Bu in children undergoing allogeneic stem cell transplantation, especially in those at high risk for graft failure/relapse.

[Treatment of falciparum malaria with artemether-lumefantrine according to a 5-day schedule: results of a study in 21 patients and recommendations]. / Behandeling van malaria tropica met artemether-lumefantrine volgens een 5-daags schema: resultaten van onderzoek bij 21 patiënten en aanbevelingen.

OBJECTIVE: To describe the outcome of 21 successive patients with falciparum malaria treated with artemether-lumefantrine in 6 oral doses of 80-480 mg in 96 hrs (5-day schedule). DESIGN: Retrospective cohort study. METHOD: The data on all successive patients with falciparum malaria that were treated with artemether-lumefantrine in the Leiden University Medical Centre (n = 15) and the Bronovo Hospital (n = 6), the Netherlands, during the period from August 2003 to February 2006 were evaluated. RESULTS: Ten patients with uncomplicated falciparum malaria were treated exclusively with artemether-lumefantrine; time to parasitological clearance was less than 48 hrs in 5 out of 6 tested patients. The mean admission time was 1.3 days (95% CI: 0.7-1.9). 6 patients with non-severe falciparum malaria were initially treated with intravenous quinine because of vomiting; artemether-lumefantrine was started after an average of 0.9 days. Parasite clearance required more than 48 hrs in all patients. The mean admission time was 3.8 days (95% CI: 2.7-4.9). 5 patients had severe falciparum malaria. They received artemether-lumefantrine 4-24 hrs after starting quinine therapy. The parasite count was < 0.1% after an average of 1.5 days (95% CI: 0.3-2.7). The mean admission time was 4.2 days (95% CI: 2.2-5.2). The serum level of lumefantrine was > or = 500 microg/l (target value) in 9 out of 10 tested patients. CONCLUSION: Treatment of falciparum malaria with artemether-lumefantrine according to a 5-day schedule resulted in a swift recovery and short admissions. No relapses were reported.