Population pharmacokinetics of intravenous and oral ciprofloxacin in children to optimize dosing regimens.

PURPOSE: This study aimed to characterize pharmacokinetics of intravenous and oral ciprofloxacin in children to optimize dosing scheme. METHODS: Children treated with ciprofloxacin were included. Pharmacokinetics were described using non-linear mixed-effect modelling and validated with an external dataset. Monte Carlo simulations investigated dosing regimens to achieve a target AUC0-24 h/MIC ratio ≥ 125. RESULTS: A total of 189 children (492 concentrations) were included. A two-compartment model with first-order absorption and elimination best described the data. An allometric model was used to describe bodyweight (BW) influence, and effects of estimated glomerular filtration rate (eGFR) and age were significant on ciprofloxacin clearance. CONCLUSION: The recommended IV dose of 10 mg/kg q8h, not exceeding 400 mg q8h, would achieve AUC0-24 h to successfully treat bacteria with MICs ≤ 0.25 (e.g. Salmonella, Escherichia coli, Proteus, Haemophilus, Enterobacter, and Klebsiella). A dose increase to 600 mg q8h in children > 40 kg and to 15 mg/kg q8h (max 400 mg q8h, max 600 mg q8h if augmented renal clearance, i.e., eGFR > 200 mL/min/1.73 m2) in children < 40 kg would be needed for the strains with highest MIC (16% of Pseudomonas aeruginosa and 47% of Staphylococcus aureus). The oral recommended dose of 20 mg/kg q12h (not exceeding 750 mg) would cover bacteria with MICs ≤ 0.125 but may be insufficient for bacteria with higher MIC and a dose increase according bodyweight and eGFR would be needed. These doses should be prospectively confirmed, and a therapeutic drug monitoring could be used to refine them individually.

A meropenem pharmacokinetics model in patients with haematological malignancies.

BACKGROUND: Optimal dosing of antibiotics is critical in immunocompromised patients suspected to have an infection. Data on pharmacokinetics (PK) of meropenem in patients with haematological malignancies are scarce. OBJECTIVES: To optimize dosing regimens, we aimed to develop a PK population model for meropenem in this population. METHODS: Patients aged ≥18 years, hospitalized in the haematology department of our 1500 bed university hospital for a malignant haematological disease and who had received at least one dose of meropenem were eligible. Meropenem was quantified by HPLC. PK were described using a non-linear mixed-effect model and external validation performed on a distinct database. Monte Carlo simulations estimated the PTA, depending on renal function, duration of infusion and MIC. Target for free trough concentration was set at >4× MIC. RESULTS: Overall, 88 patients (181 samples) were included, 66 patients (75%) were in aplasia and median Modification of Diet in Renal Disease (MDRD) CLCR was 117 mL/min/1.73 m2 (range: 35-359). Initial meropenem dosing regimen ranged from 1 g q8h to 2 g q8h over 30 to 60 min. A one-compartment model with first-order elimination adequately described the data. Only MDRD CLCR was found to be significantly associated with CL. Only continuous infusion achieved a PTA of 100% whatever the MIC and MDRD CLCR. Short duration of infusion (<60 min) failed to reach an acceptable PTA, except for bacteria with MIC < 0.25 mg/L in patients with MDRD CLCR below 90 mL/min/1.73 m2. CONCLUSIONS: In patients with malignant haematological diseases, meropenem should be administered at high dose (6 g/day) and on continuous infusion to reach acceptable trough concentrations.

Assessment of cetirizine, an antihistamine, to prevent cutaneous reactions to nevirapine therapy: results of the viramune-zyrtec double-blind, placebo-controlled trial.

We conducted a 12-week, multicenter, randomized, double-blind, placebo-controlled trial of cetirizine to assess the ability of antihistamines to prevent nevirapine-associated rash in patients infected with human immunodeficiency virus type 1. Patients initiating treatment with nevirapine were randomized to receive either cetirizine, 10 mg q.d. (104 patients), or placebo (96 patients) during the first 6 weeks of therapy. Rash occurred in 22 (11%) of 200 patients; 10 (9.6%) were in the cetirizine group and 12 (12.5%) were in the placebo group (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.31-1.81; P=.5). Five of 22 rashes were cases of hypersensitivity syndrome. The rate of nevirapine discontinuation due to rash was similar in the 2 groups (7.7% and 6.25% in the cetirizine and placebo groups, respectively; P=.4). Multivariate analysis showed no treatment-group effect but indicated that age >40 years (OR, 3.83; 95% CI, 1.4-10.46; P=.008) was associated with an increased risk of rash. Cetirizine has no preventive effect on nevirapine-associated rash.

[What's new in pediatric pharmacology?]. / Quoi de neuf en pharmacologie pédiatrique?

Only a minority of the drugs administered to children and infants have a pediatric labeling and have been sufficiently tested for efficacy, safety and correct pediatric dosing, which cannot necessarily be extrapolated from adult data. This situation is scientifically and ethically unacceptable. To address this problem, the suggestion is being made in several countries that more formal legal requirements should be introduced. In the United States, in 1997, a new legislation encouraged pharmaceutical companies to study medicines in children (for example, by offering the financial incentive of a six-month extension to patent exclusivity). However, there are undeniable difficulties in pediatric and neonatal studies. To minimize the risks of clinical investigation in children, appropriate methodologies should be used. New in vitro and in vivo methods are now available, taking into account pediatric characteristics.