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Biomedical subjects

M Klausner

Publications and source records attributed to M Klausner.

5 recordsLinked to original sources
PubMed1998

Effect of current density on pharmacokinetics following continuous or intermittent input from a fentanyl electrotransport system.

The pharmacokinetics of fentanyl were determined in two open-label crossover studies following 24-h periods of delivery by an electrotransport transdermal system (E-TRANS [fentanyl] system) in young healthy male volunteers. A direct current was applied continuously in study 1 (at 50, 100, and 200 microA; surface area = 5 cm2; n = 8), but in study 2 it was limited to the first 20 min of each hour (at 150, 200, and 250 microA; surface area = 2 cm2; n = 12). The opioid effects of fentanyl were blocked with naltrexone administered every 12 h. With increasing electrical current, the increase in serum fentanyl concentration, amount absorbed, and AUC values were proportional in study 2 but not in study 1. It is hypothesized that the lack of proportionality in study 1 is due to lower current density (microA/cm2) in this study. It appears that for fentanyl, the current density should be about 75 microA/cm2 or greater for a linear relation between current and amount absorbed as seen in study 2. Compared with intravenously infused fentanyl, the serum concentrations resulting from E-TRANS (fentanyl) system application revealed a slightly dampened rate of increase (stratum-corneum barrier effect) and decrease in serum concentrations, and a similar intersubject variability in fentanyl AUC values. Fentanyl pharmacokinetics with either E-TRANS (fentanyl) or intravenous infusion were time-invariant over a 24-h application period, with similar mean half-life values (about 15-18 h). E-TRANS (fentanyl) administration (either continuous or intermittent input) was safe and well tolerated. Adverse effects were mild to moderate; they consisted mainly of local erythema and pruritus (which resolved in most patients within 24 h after system removal) and occasional opioid effects.

Adult↗
PubMed1997

Effect of a cola beverage on the bioavailability of itraconazole in the presence of H2 blockers.

Thirty-three healthy individuals participated in an open-label, randomized, three-way crossover study designed to compared the bioavailability of a single 200-mg oral dose of itraconazole when administered alone or after treatment with ranitidine, both with and without coadministration of a cola beverage. Each treatment phase was separated by a 2-week washout period. Participants pretreated with ranitidine were required to have a gastric pH of at least 6.0 before receiving itraconazole. An analysis of the area under the curve (AUC) and peak plasma concentration (Cmax) data indicated that the bioavailability of itraconazole was significantly reduced when the gastric pH was increased by pretreatment with ranitidine but showed that this effect was counteracted by the coadministration of an acidic solution (e.g., a cola beverage) that transiently reduced the gastric pH. These findings suggest that the coadministration of an acidic beverage with itraconazole may be an effective approach in improving the bioavailability of itraconazole in patients who are hypochlorhydric or who are taking gastric acid suppressants.

Adult↗
PubMed1997

A clinical evaluation of risperidone in the treatment of schizophrenia: a 10-week, open-label, multicenter trial. ARCS Study Group. Assessment of Risperdal in a Clinical Setting.

The efficacy and safety of risperidone have previously been demonstrated in controlled clinical trials in hospitalized chronic schizophrenia patients who met strict research criteria. The present study was designed to evaluate the efficacy and safety of risperidone in a heterogeneous patient population. Patients were enrolled in the study if they had a diagnosis of schizophrenia (DSM-III-R) with or without acute exacerbation. Of the 945 patients from 158 psychiatric centers who entered this phase IV study, 558 completed the 10-week trial. During week 1, the dose of risperidone was titrated to 6 mg/day, maintained there for 1 week, and then adjusted over a 4-week period as clinically necessary; the dose was then fixed for the final 4-week period. The mean dose of risperidone at endpoint was 5.9 mg/day. Patients were evaluated at baseline and at weeks 2, 6, and 10, using Clinical Global Impression scale, Psychotic Symptoms Assessment scale, and Global Assessment of Functioning scale. Significant improvement in mean scores was found on each of these measures at endpoint. Comparable results were obtained at week 10 in treatment-resistant and non-treatment-resistant patients. Risperidone was generally well tolerated and the severity of extrapyramidal symptoms was significantly reduced at endpoint.

Adult↗
PubMedDate not supplied

Retrospective analysis of yeast colonization and infections in paediatric bone marrow transplant recipients.

Sixty-four paediatric patients who underwent allogeneic (n = 35), autologous (n = 28) or syngeneic (n = 1) bone marrow transplantation (BMT) between 1992 and 1994 were evaluated retrospectively. As antifungal prophylaxis, all patients received amphotericin B tablets and 62 of 64 (96.9%) received oral fluconazole. Weekly surveillance cultures revealed fungal colonization in 35 patients (54.7%). Six patients (9.4%) were colonized before BMT only, 17 (26.6%) after BMT only and 12 (18.8%) both before and after BMT. Candida albicans was the most frequently isolated fungus [21 of 46 fungal isolates (45.7%)], followed by C. glabrata [14 isolates (30.4%)]. Non-albicans species of Candida were most frequently isolated after BMT from the faeces, often in high numbers. Autologous marrow recipients had a higher fungal colonization rate both before and after BMT than allogeneic marrow recipients. One patient suffered from invasive pulmonary aspergillosis after BMT. No fungaemias or deep-seated yeast infections were observed. Six of the seven patients who had to be treated with intravenous amphotericin B because of antibiotic-refractory fever had undergone autologous BMT. Multivariate analysis of various parameters showed only pre-BMT yeast colonization to be independently associated with post-BMT colonization. Thus, systemic mycoses occurred only rarely in this study population; however yeast colonization after BMT (especially with non-albicans species) was a frequent event in spite of double prophylaxis with oral amphotericin B and fluconazole.

Adolescent↗