Pharmacokinetic study of memantine in healthy and renally impaired subjects.

OBJECTIVE: Our objective was to evaluate the pharmacokinetics of the Alzheimer's disease treatment memantine in subjects with normal and impaired renal function. METHODS: This was a single-center, single-dose, open-label study. Thirty-two subjects aged 18 to 80 years were assigned to 1 of 4 groups (8 subjects each) based on baseline creatinine clearance: normal renal function (>80 mL/min), mild renal impairment (50-80 mL/min), moderate renal impairment (30-49 mL/min), and severe renal impairment (5-29 mL/min). A single 20-mg memantine dose was administered under fasting conditions. Assessments included pharmacokinetic and safety measures. RESULTS: Thirty-one subjects completed the study. There were no relevant differences in maximum memantine plasma concentration between subjects with normal and impaired renal function of any severity. The mean area under the plasma concentration versus time curve extrapolated to infinity was similar between subjects with normal and mildly impaired renal function but increased by 60% (95% confidence interval [CI], 24%-97%) and 115% (95% CI, 77%-152%) in subjects with moderate and severe renal impairment, respectively. Simulations predicted steady-state maximum concentration values of 82 ng/mL (95% CI, 70-95 ng/mL), 85 ng/mL (95% CI, 70-101 ng/mL), and 128 ng/mL (95% CI, 109-147 ng/mL) in healthy subjects, those with mild renal impairment, and those with moderate renal impairment, respectively, for the recommended dosing regimen of 10 mg twice daily; for subjects with severe renal impairment, a steady-state maximum concentration value of 84 ng/mL (95% CI, 68-101 ng/mL) was predicted for a dosing regimen of 5 mg twice daily. CONCLUSION: On the basis of the predicted steady-state plasma concentrations with the use of the current dosing regimen of 10 mg twice daily, no dosage adjustments are needed for patients with mild or moderate renal impairment. A target dose of 5 mg twice daily is recommended in patients with severe renal impairment.

A double-blind, randomized, placebo-controlled trial of escitalopram in the treatment of pediatric depression.

OBJECTIVE: Escitalopram is a selective serotonin reuptake inhibitor antidepressant indicated for use in adults. This trial examined the efficacy and safety of escitalopram in pediatric depression. METHOD: Patients (6-17 years old) with major depressive disorder were randomized to receive 8 weeks of double-blind flexibly dosed treatment with escitalopram (10-20 mg/day; n = 131) or placebo (n = 133). Randomization was not stratified by age. The primary efficacy measure was the mean change from baseline to endpoint in Children's Depression Rating Scale-Revised (CDRS-R) scores, using the last observation carried forward approach. RESULTS: A total of 82% of patients completed treatment. Escitalopram did not significantly improve CDRS-R scores compared to placebo at endpoint (least squares mean difference = -1.7, p = .31; last observation carried forward). In a post hoc analysis of adolescent (ages 12-17 years) completers, escitalopram significantly improved CDRS-R scores compared with placebo (least squares mean difference = -4.6, p = .047). Headache and abdominal pain were the only adverse events in >10% of patients in the escitalopram group. Discontinuation rates caused by adverse events were 1.5% for both groups. Potential suicide-related events were observed in one escitalopram- and two placebo-treated patients. There were no completed suicides. CONCLUSIONS: Although there were no significant differences between escitalopram and placebo in the total population, the data suggest that escitalopram may have beneficial effects in adolescent patients. Escitalopram appeared to be well tolerated.

Investigation of the pharmacokinetic and pharmacodynamic interactions between memantine and glyburide/metformin in healthy young subjects: a single-center, multiple-dose, open-label study.

BACKGROUND: The high prevalence rates of both Alzheimer's disease (AD) and type 2 diabetes mellitus in the elderly population suggest that concomitant pharmacotherapy is likely. Given the renal tubular transport and extensive urinary excretion of memantine and metformin, it was of interest to assess the pharmacokinetic and pharmacodynamic interaction with glyburide/metformin. OBJECTIVE: The primary goal of this study was to determine whether an in vivo pharmacokinetic or pharmacodynamic interaction exists between memantine (an uncompetitive, moderate-affinity, N-methyl-D-aspartate receptor antagonist with fast blocking/unblocking kinetics that is available in the United States for moderate to severe AD) and glyburide/metformin (a combination pharmacotherapy formulation approved for glycemic control in patients with type 2 diabetes mellitus). METHODS: In this single-center, multiple-dose, open-label study, healthy adult subjects received a single oral dose of memantine hydrochloride (20 mg) on day 1. After a 14-day washout period, subjects were orally administered 1.25-mg glyburide/250-mg metformin BID with food for 6 days. On day 21, subjects were coadministered memantine (20 mg) and glyburide/metformin with food. Assessments included determination of pharmacokinetic parameters for memantine and the antidiabetic agents when administered alone and in combination, pharmacodynamic measurements of blood glucose levels, and analyses of tolerability. RESULTS: The study population consisted of 24 subjects (13 women, 11 men; 79.2% white) with a mean (SD) age of 26.1 (5.6) years and a mean (SD) weight of 69.5 (11.3) kg. Twenty-one subjects completed the study: 2 discontinued due to adverse events judged unrelated to study medication, and 1 withdrew consent. No significant pharmacokinetic or pharmacodynamic interactions were observed between memantine and glyburide/metformin. Adverse events included dizziness (41.7% of patients) with memantine administration and gastrointestinal effects (nausea, 9.1 %; vomiting, 9.1%; abdominal cramps, 13.6%) with glyburide/metformin administration. CONCLUSIONS: No pharmacokinetic interactions between memantine and glyburide/metformin were detected in this study of healthy young volunteers. Memantine had no effect on the pharmacodynamic activities of glyburide and metformin, and the drug combination was well tolerated in this population.

A double-blind comparison of escitalopram and venlafaxine extended release in the treatment of major depressive disorder.

BACKGROUND: Escitalopram is the most selective serotonin reuptake inhibitor (SRI) antidepressant available. Venlafaxine is a non-selective SRI that also inhibits noradrenergic re-uptake. This study compared escitalopram and venlafaxine extended release (XR) in depressed outpatients at the highest doses recommended in the United States. METHOD: In this randomized trial, patients (diagnosis of DSM-IV-defined major depressive disorder; baseline Hamilton Rating Scale for Depression score of >/= 20) received 1 week of single-blind placebo treatment, followed by 8 weeks of double-blind, fixed-dose treatment with either escitalopram or venlafaxine XR (rapidly titrated to 20 mg/day and 225 mg/day, respectively, in accordance with prescribing information). The primary efficacy variable was change from baseline to week 8 in Montgomery-Asberg Depression Rating Scale (MADRS) total score. Data were collected from May to December 2002. RESULTS: Mean baseline MADRS scores for the escitalopram (N = 97) and venlafaxine XR (N = 98) groups were 30.7 and 30.0, respectively. There were no significant differences in measures of efficacy between the 2 antidepressants. Mean changes from baseline to endpoint in MADRS total score for escitalopram and venlafaxine XR were -15.9 and -13.6, respectively. Remission (MADRS score of /= 50% reduction from baseline MADRS score) rates for the escitalopram and venlafaxine XR groups were 58.8% and 48.0%, respectively. Tolerability measures favored escitalopram over venlafaxine XR treatment. The venlafaxine XR group had a higher incidence than the escitalopram group of treatment-emergent adverse events (85.0% vs. 68.4%) and discontinuation due to adverse events (16.0% vs. 4.1%; p <.01). CONCLUSION: Results of this study indicate that, when titrated rapidly to their maximum recommended doses, escitalopram is at least as effective as venlafaxine XR and significantly better tolerated. These results do not support the hypothesis that nonselective SRIs have greater efficacy than selective SRIs.

Alien seed beetles (Coleoptera: Chrysomelidae: Bruchinae) in Europe.

Under the framework of the DAISIE consortium, whose main mission is to make an inventory of the alien invasive species of Europe and its islands, we review the current state of knowledge and provide an up-to-date catalogue and distributional status for alien seed beetles (Coleoptera: Chrysomelidae: Bruchinae) in Europe. This work is based on studies of the species detected from the last century to the present, but with greater emphasis on the beginning of the 21st century, during which new biological studies have been carried out and findings made in European countries. The main objective of this paper is to focus on this last fact, which has promoted new views on the existing and potential threat of exotic bruchids in relation to climate change. This must now be regarded as a matter of concern for European agricultural and environmental policies. Only species of exotic origin introduced in European regions outside their native range were considered. Therefore, species of European origin spreading to new countries within Europe are not treated. Also, we provide a new approach to classifying alien seed beetle species according to their ability to become established, distinguishing between the well-established and those that may appear in seed stores but are not capable of invading natural and agricultural ecosystems. We present a taxonomic characterization of the alien bruchids found in Europe, providing an illustrated key based on external morphological characters of adults. The key facilitates the identification of the sixteen most frequently recorded genera, which represent 37 of the 42 species of exotic species recorded in Europe up to the present, whether established, not established or occasional. Finally, we provide a summary of the state of knowledge of the taxonomy and biology of the 20 most worrying species as pests, both established and non-established. This includes, where appropriate, an illustrated key for the identification of species. The study reveals that the majority of exotic bruchid species in Europe originate in Asia and Africa, from host plant species imported for ornamental or forestry purposes, and that a greater effort in European customs control is advisable.

Escitalopram in the treatment of adolescent depression: a randomized placebo-controlled multisite trial.

OBJECTIVE: This article presents the results from a prospective, randomized, double-blind, placebo-controlled trial of escitalopram in adolescent patients with major depressive disorder. METHOD: Male and female adolescents (aged 12-17 years) with DSM-IV-defined major depressive disorder were randomly assigned to 8 weeks of double-blind treatment with escitalopram 10 to 20 mg/day (n = 155) or placebo (n = 157). The primary efficacy parameter was change from baseline to week 8 in Children's Depression Rating Scale-Revised (CDRS-R) score using the last observation carried forward approach. RESULTS: A total of 83% patients (259/312) completed 8 weeks of double-blind treatment. Mean CDRS-R score at baseline was 57.6 for escitalopram and 56.0 for placebo. Significant improvement was seen in the escitalopram group relative to the placebo group at endpoint in CDRS-R score (-22.1 versus -18.8, p =.022; last observation carried forward). Adverse events occurring in at least 10% of escitalopram patients were headache, menstrual cramps, insomnia, and nausea; only influenza-like symptoms occurred in at least 5% of escitalopram patients and at least twice the incidence of placebo (7.1% versus 3.2%). Discontinuation rates due to adverse events were 2.6% for escitalopram and 0.6% for placebo. Serious adverse events were reported by 2.6% and 1.3% of escitalopram and placebo patients, respectively, and incidence of suicidality was similar for both groups. CONCLUSIONS: In this study, escitalopram was effective and well tolerated in the treatment of depressed adolescents.

Escitalopram versus sertraline in the treatment of major depressive disorder: a randomized clinical trial.

OBJECTIVE: This trial was conducted to compare the efficacy and tolerability of a fixed dose of escitalopram 10 mg/day with sertraline optimally dosed within its recommended dose range (50-200 mg/day) for the treatment of major depressive disorder. METHODS: In this multicenter trial, depressed patients (DSM-IV defined; baseline Montgomery-Asberg Depression Rating Scale [MADRS] 22) aged 18-80 years were randomly assigned to 8 weeks of double-blind treatment with escitalopram (10 mg/day) or sertraline (50-200 mg/day) following a 1-week single-blind placebo lead-in period. There was no placebo comparison arm. Sertraline was initiated at 50 mg/day, and could be increased by 50 mg/day at weekly intervals based on clinical need and tolerability at the lower dose level. The blind was maintained with matching double-blind placebo capsules for the escitalopram group. Change from baseline to endpoint in MADRS total score (last observation carried forward) was the primary efficacy measure. RESULTS: A total of 212 patients received double-blind medication. At week 8, the mean sertraline dosage was 144 mg/day (median = 150 mg/day). Mean changes from baseline to endpoint in MADRS scores were -19.1 and -18.4 for the escitalopram and sertraline groups, respectively. At endpoint, 75% and 70% of escitalopram- and sertraline-treated patients, respectively, were responders (> or =50% improvement from baseline in mean MADRS scores). Both treatments were generally well tolerated; only 2% and 4% of patients prematurely discontinued escitalopram and sertraline treatment, respectively, due to adverse events. CONCLUSION: No differences in efficacy were observed for fixed-dose escitalopram 10 mg/day and sertraline flexibly dosed from 50-200 mg/day. At these doses, both escitalopram and sertraline were generally well tolerated.

Lack of pharmacokinetic or pharmacodynamic interaction between memantine and donepezil.

BACKGROUND: Memantine, a low- to moderate-affinity, uncompetitive N-methyl-D-aspartate receptor antagonist, was approved in the US for treatment of moderate to severe Alzheimer's disease in October 2003. OBJECTIVE: To determine whether an in vivo pharmacokinetic interaction exists between memantine and the acetylcholinesterase (AChE) inhibitor donepezil. METHODS: In this open-label, multiple-dose study, 24 healthy subjects (aged 18-35 y) received oral administration of memantine 10 mg on day 1. Following a 14-day washout period, subjects were orally administered donepezil 5 mg once daily for 7 days on an outpatient basis. Beginning on day 22, the donepezil dosage was doubled for 22 days to the target dose of 10 mg once daily, with the last donepezil dose concomitantly administered with memantine 10 mg on day 43. Assessments included pharmacokinetic as well as safety parameters. In addition, AChE inhibition was measured in red blood cells by radiolabeled-enzyme assay following administration of donepezil alone and after a single memantine dose. RESULTS: Data from 19 subjects who completed the study indicated no significant pharmacokinetic interactions between a single dose of memantine and multiple doses of donepezil. Percent maximum inhibition of AChE activity (mean +/- SD) by donepezil was 77.8 +/- 7.3% and not significantly different upon coadministration of a single dose of memantine (81.1 +/- 5.7%). Two subjects withdrew due to adverse events while taking donepezil alone. Single memantine doses administered with multiple donepezil doses were well tolerated. CONCLUSIONS: The pharmacokinetic and pharmacodynamic data from this study indicated a lack of interaction between memantine and donepezil, suggesting that memantine and donepezil may be safely and effectively used in combination.