Effects of the addition of high-dose vitamin C to polyethylene glycol solution for colonic cleansing: A pilot study in healthy volunteers.

BACKGROUND: Polyethylene glycol (PEG) solutions, with or without osmotic agents, are used to empty the large intestine before procedures such as colonoscopy or colonic surgery. Data concerning the effectiveness of vitamin C as an ingredient in colonic preparations are scant. OBJECTIVE: The aim of this article was to assess the effectiveness, acceptability, and tolerability of 6 preparations of a standard PEG electrolyte solution containing different doses of PEG, vitamin C (as an osmotic agent), and sodium sulfate in colonic cleansing. METHODS: This double-blind, randomized, 2-period crossover study was conducted at the Lariboisière Hospital, Paris, France. Healthy adult volunteers were randomly assigned to receive 2 of 6 colonic cleansing preparations, each containing different doses of PEG (100 or 125 g/L), vitamin C (0, 5, or 10 g/L, in the form of sodium ascorbate, ascorbic acid, or a mixture of both), and sodium sulfate (5 or 7.5 g/L), diluted in water to a volume of 2 L. Study drug administration was separated by a washout period of 7 to 15 days, after which the volunteers received an alternate preparation. Stools were collected for 10 hours after the start of solution ingestion. The primary efficacy end point was stool volume. Secondary end points included acceptability of taste, assessed using a 100-mm visual analog scale (VAS) (0 = excellent to 100 = execrable), taste criteria (saltiness, acidity, and sweetness, assessed on a 4-point Likert-type scale [0 = very pleasant to 3 = intolerable]) and tolerability (clinical effects [changes in body weight, blood pressure, heart rate, and nausea and vomiting] and biologic effects [changes in serum electrolytes, creatinine, hematocrit, and ascorbic acid]). RESULTS: Thirty volunteers (15 men, 15 women; mean [SD] age, 29.8 [8.2] years [range, 20-45 years]) were enrolled and completed the study. Mean (SD) stool volume obtained with preparations containing 10 g/L of vitamin C did not differ significantly from the volume obtained without vitamin C (2.54 [0.54] L vs 1.93 [0.62] L; 95% CI, -0.13 to 1.47). Mean (SD) VAS scores for acceptability of taste ranged from 54.4 (25.0) (preparation E) to 74.4 (20.1) (preparation C) (P = 0.03 preparation E vs all other preparations). The only significant difference in taste criteria was in acidity, with preparation A being the least acidic according to patients' ratings on the VAS (1.4 [0.7] vs 1.8 [0.4] [mean of the other 5 preparations combined]; P = 0.04 preparation A vs all other preparations). Mild dehydration occurred in 6 subjects (1 for each preparation). No clinical or biological adverse effects were found. CONCLUSIONS: In this study of 6 colonic cleansing preparations in healthy volunteers, the use of high-dose vitamin C as an osmotic agent in addition to PEG did not significantly increase stool output. All 6 preparations were well tolerated.

Aspirin alters arterial function in patients with chronic heart failure treated with ACE inhibitors: a dose-mediated deleterious effect.

BACKGROUND: By inhibiting prostaglandin synthesis, aspirin can interfere with both arterial functional and angiotensin-converting enzyme inhibitor (ACEI) properties and be deleterious in chronic heart failure (CHF). AIM: Our aim was to prospectively evaluate the effect of aspirin on arterial functional properties in CHF patients treated with ACEIs. METHODS AND RESULTS: Over three consecutive treatment periods of 7 days, 18 patients received placebo, followed by aspirin 100 mg/day, and then aspirin 325 mg/day. Single blind prospective assessment of reflected wave and time reflection by radial applanation tonometry; pulse wave velocity; blood pressure; thromboxane B2 (TxB2) and prostaglandins in plasma and urine was performed. Aspirin 325 mg/day induced a significant increase in augmentation index of reflected wave (P<0.0001 and P=0.0013 vs. placebo and aspirin 100 mg, respectively) and a significant decrease in reflected wave traveling times (P=0.0007 vs. placebo). Aspirin 100 mg/day produced a similar, though non-significant, trend in these parameters compared with placebo. Both aspirin treatments produced a statistically significant decrease in serum TxB2 (P<0.0001) but did not have an effect on the metabolite of prostaglandin I2 (P=0.136). CONCLUSION: This study demonstrates the existence of a dose-mediated deleterious effect of aspirin upon arterial functional properties in CHF patients treated with ACEI.

The [14C-N-methyl]-erythromycin breath test dosimetry complies with the French regulations for radiation safety.

The [14C-N-methyl]-erythromycin breath test (14C-ERMBT) is one of the most valuable probes for liver cytochrome P450-3A4 activity in humans. In order to extend the use of this test in France, we herein provide safety data regarding either patient dosimetry or worker exposure to [14C-N-methyl]-erythromycin. In order to determine the maximum radiation exposure for patient and nuclear medicine technician following one intravenous 14C-ERMBT [111 kiloBequerel (kBq)], we have used the dosimetric data gathered in animal studies and extrapolated to humans using a weight-based method, approximate data provided by the French Society of Radioprotection and erythromycin pharmacokinetics in humans, considering always the worst conditions for the patient and worker exposure determination. The radioactivity administered to a patient after one 14C-ERMBT was equal to 108.8 kBq (i.e. 98% of the total radioactivity in the 14C-erythromycin vial) leading to a patient effective dose of 20 microsievert (microSv) and a maximum effective dose after 14CO2 inhalation by the exposed worker of 16 microSv compared with a mean individual annual effective dose from natural and artificial radioactivity exposure of 3500 microSv in France. The 14C-ERMBT is safe and complies with the European regulations regarding the administration of 14C-labelled compounds in humans. It can therefore be used in clinical research in France without any particular safety requirement.

Framework conditions facilitating paediatric clinical research.

The use of unlicensed and "off-label" medicines in children is widespread. Between 50-80% of the medicines currently administered to children have neither been tested nor authorized for their use in the paediatric population which represents approximately 25% of the whole European population. On 26 January 2007, entered into force the European Regulation of Paediatric Medicines. It aims at the quality of research into medicines for children but without subjecting the paediatric population to unnecessary clinical trial. This article addresses ethical and legal issues arising from the regulation and makes recommendations for the framework conditions facilitating the development of clinical research with children.

Prevalence and patterns of methylphenidate use in French children and adolescents.

OBJECTIVE: The aim of the study was to describe the prevalence and utilization patterns of methylphenidate (MPH) in children and adolescents in France. METHODS: This was a population-based retrospective study in which the cohort consisted of patients for whom data were extracted from the dispensation drug claims database of the national health insurance (NHI) fund for self-employed workers. Annual prevalence of MPH use was evaluated on patients aged 6-18 years who were reimbursed for at least one MPH prescription a year. Between January 2004 and June 2005, features of MPH medication and user profile were described for the "new starters" having a screening period of 1 year without receiving a MPH prescription and a follow-up >or=12 months. Time to interruption of MPH regular use was analysed by Kaplan-Meier survival analysis. Mean duration of exposure to MPH treatment was computed with the 95% confidence interval (CI). RESULTS: Annual prevalence of MPH per 1000 persons was 1.1 in 2003, 1.5 in 2004 and 1.8 in 2005 (relative increase of 63.5%). New starters (n = 447) received their first MPH prescription through the hospital (65.1%) or through private practitioners (34.9%). The user profiles were: short (16.6%), occasional (33.8%) and regular (49.6%). Among the new starters, the median time to interruption of MPH regular use was 10.2 months (95% CI: 7.9-12.4). The mean duration of exposure to MPH treatment was: occasional (4.9 months, 95% CI: 4.3-5.5) and regular (25.7 months, 95% CI: 24.6-26.8). CONCLUSION: Although there is a low prevalence of MPH use in France, this survey revealed a wide profile of users and heterogeneous use patterns.

Enhanced saquinavir exposure in human immunodeficiency virus type 1-infected patients with diarrhea and/or wasting syndrome.

The protease inhibitor saquinavir was administered to 100 human immunodeficiency virus type 1 (HIV-1)-infected patients as a single 600-mg oral dose (hard gelatin capsules) with a standard breakfast, including 200 ml of grapefruit juice, during an open-label trial to assess whether diarrhea and/or wasting syndrome has consequences on its pharmacokinetics. Three groups of patients were enrolled: group 1, asymptomatic patients (n = 30); group 2, AIDS symptomatic patients without body weight loss or diarrhea (n = 37); and group 3, AIDS symptomatic patients with severe body weight loss and/or diarrhea (n = 33). Clinical and biological data (covariates) were collected. A population approach was performed with three blood samples per patient to estimate the mean population pharmacokinetic parameters (clearance [CL]/oral bioavailability [F], V/F, k(a), and lag time) and the derived ones (k(el), C(max), T(max), and area under the curve [AUC]). The relationships between groups, exposure (i.e., estimated individual post hoc AUCs), and covariates were explored by using multiple linear regressions. A significant increase in median AUCs (165, 349, and 705 ng. h. ml(-1) for groups 1, 2, and 3, respectively [P < 0.0001]) was observed. The enhancement in saquinavir exposure could be due to the destruction of the transporters in enterocytes and/or to the enlargement of their tight junctions, allowing a paracellular crossing of saquinavir as the illness spreads. Because of grapefruit juice intake by every patient, no implication of CYP3A4 could be assessed. These results strongly suggest that, despite its low intrinsic oral bioavailability, saquinavir can be considered as a relevant treatment for HIV-1-infected patients with diarrhea and/or wasting syndrome. This must be evaluated in a long-term period.