Effects Of Reboxetine Research Articles

Monoaminergic mediation of hyperalgesic and analgesic descending control of nociception in mice.

Descending control of nociception (DCN; also known as conditioned pain modulation [CPM], the behavioral correlate of diffuse noxious inhibitory controls) is the phenomenon whereby pain inhibits pain in another part of the body and is the subject of increasing study because it may represent a biomarker of chronic pain. We recently discovered that pain modulation on the application of a DCN paradigm involving low-intensity test stimuli occurs in the direction of hyperalgesia in healthy mice and rats, whereas the use of high-intensity stimuli produces analgesia. To elucidate the physiological mechanisms underlying hyperalgesic DCN, we administered agonists and antagonists of norepinephrine (NE) and serotonin (5-HT) receptors, key neurochemical players in the production of analgesic DCN. We find that 3 different monoamine reuptake inhibitors-the NE-selective reboxetine, the 5-HT-selective fluoxetine, and the dual NE/5-HT agonist duloxetine-all abolish hyperalgesic DCN when administered into the spinal cord (but not systemically), with no effect on heat or mechanical pain sensitivity. The reversal by reboxetine of hyperalgesic DCN is mediated by α 2 -adrenergic receptors (ie, blocked by atipamezole), and the fluoxetine reversal is mediated by 5-HT 7 receptors (ie, blocked by SB269970). By contrast, analgesic DCN was found to be reversed by atipamezole and SB269970 themselves, with no effect of reboxetine or fluoxetine. Thus, hyperalgesic DCN seems to be the neurochemical opposite to analgesic DCN. These data further validate and help elucidate a preclinical paradigm that mimics dysfunctional CPM and thus may form the basis of translational experiments that aim to reveal preventative pharmacological strategies for individuals predisposed to persistent pain.

O001 Reboxetine reduces obstructive sleep apnea severity: a randomized trial

Abstract Introduction Noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. Selective norepinephrine reuptake inhibitors (SNRIs) such as reboxetine combined with an antimuscarinic reduce obstructive sleep apnea (OSA) severity. The effects of reboxetine alone on OSA severity are unknown. Methods Double-blind, placebo-controlled, three-way crossover trial in 16 people with OSA. Each participant completed three overnight polysomnograms (~1-week washout). Single doses of reboxetine 4mg, placebo, or reboxetine+oxybutynin 5mg were administered before sleep (randomized order). The primary outcome was apnea-hypopnea index (AHI). Secondary outcomes included other polysomnography parameters, next day sleepiness and alertness. Endotyping analysis was performed to determine the medications’ effects on OSA pathophysiological mechanisms. Results Reboxetine reduced the AHI by 5.4 [95% CI -10.4 to -0.3] events/h, P=0.03 (men: -24±27%; women: -0.7±32%). The addition of oxybutynin did not further reduce AHI. Reboxetine alone and reboxetine+oxybutynin reduced overnight hypoxemia versus placebo (e.g. 4% oxygen desaturation index 10.4±12.8 vs. 10.6±12.8 vs. 15.7±14.7 events/h, P=0.02). Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control stability. Men had higher baseline loop gain. Larger reductions in AHI with reboxetine occurred in those with high loop gain. Neither drug intervention changed next day sleepiness or alertness. Discussion A single 4mg dose of reboxetine modestly reduces OSA severity without further improvement with the addition of an antimuscarinic. Reboxetine increases breathing stability via improvements in pharyngeal collapsibility and respiratory control. These findings provide new insight into the role of SNRIs on upper airway stability during sleep and have important implications for pharmacotherapy development for OSA.

Acute administration of reboxetine reduces alcohol self-administration but, after a subchronic treatment with this drug, alcohol self-administration is enhanced

IntroductionComorbidity between alcoholism and depression has long been acknowledged, and the possibility that similar brain mechanisms, involving both serotonergic (5-HT) and noradrenergic systems (NE), underlie both pathologies has been suggested. Thus, inhibitors of NE and 5HT uptake have been proposed for the treatment of alcoholism, as they have shown to reduce alcohol intake in various animal models. However, most of the studies mentioned were carried out acutely and there is a lack of knowledge of the possible long-term effects. Clinical studies report an overall low efficacy of antidepressant treatment on alcohol consumption, or even a worsened prognosis. In addition, several cases of alcohol dependence following antidepressant treatment have been reported in the literature.ObjectivesWe aimed at comparing the acute and chronic effects of the treatment with the antidepressant drug reboxetine on alcohol consumption.MethodsWe used a rat model of alcohol self-administration, and two different schedules of reboxetine administration (acute and chronic).ResultsOur results confirm the acute suppressant effects of reboxetine on alcohol consumption but indicate that, when this drug is administered chronically in a period of abstinence from alcohol, it can significantly increase the rate of alcohol self-administration.ConclusionsThese results are important for the understanding of the clinical reports describing cases of increased alcohol consumption after antidepressant treatment, and suggest that much more research is needed to fully understand the long term effects of antidepressants, which remain the most widely prescribed class of drugs.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Effect of reboxetine on activity of carboxypeptidase E in the nerve tissue of rats

Depression is one of the most common mental disorders, but its etiology is not completely understood. It is assumed that peptidergic system components are involved in the formation of this pathology. Neuropeptides play an important role in the regulation of mental and emotional states. Сarboxypeptidase E is a key enzyme of peptide processing; it regulates neuropeptide levels in the various structures of the nervous system. We have studied effects of a single dose of reboxetine on the activity of carboxypeptidase E in various brain regions and the adrenal glands of rats. The reboxetine injection decreased carboxypeptidase E activity in the pituitary gland (12 h after injection), in the pituitary gland, the quadrigeminal bodies, the medulla oblongata, the hypothalamus, the hippocampus and the amygdala (24 h after injection), in the pituitary gland and striatum (72 h after injection). The enzyme activity in adrenal glands remained basically unchanged. Apparently, the decrease of carboxypeptidase E activity may influence the level of regulatory peptides involved in the pathogenesis of depression.

Current pharmacological interventions in panic disorder.

The aim of this review was to summarize the recent evidences regarding the pharmacological treatment of panic disorder (PD). The authors performed a review of the literature regarding the pharmacological treatment of PD since the year 2000. The research done in the last decade brought strong evidences of effectiveness for paroxetine, venlafaxine, sertraline, fluvoxamine, citalopram, fluoxetine, clonazepam, and the relatively novel agent escitalopram. There are evidences indicating that the other new compounds inositol, duloxetine, mirtazapine, milnacipran, and nefazodone have antipanic properties and may be effective compounds in the treatment of PD. The effectiveness of reboxetine and anticonvulsants is a subject of controversy. In addition to selective serotonin reuptake inhibitors and serotonin and noradrenaline reuptake inhibitors, tricyclic antidepressants, monoamine oxidase inhibitors, benzodiazepines and atypical antipsychotics may be valid alternatives in the treatment of PD. Recent data indicate that augmentation strategies with aripiprazole, olanzapine, pindolol or clonazepam may be effective. D-cycloserine is a promising agent in the augmentation of cognitive behavioral therapy.

A Case of Profound Weight Loss Secondary to use of Reboxetine

Reboxetine is a selective norepinephrine re-uptake inhibitor used in the treatment of depression. The studies testing the effects of reboxetine on body weight have demonstrated that reboxetine reduces body weight and reboxetine found to be superior to placebo in reducing antipsychotic-induced weight gain. To date there are only a few cases in the literature of reboxetine use in adults resulting in profound weight loss. We present an unusual case report of a patient who experienced a marked weight loss with reboxetine treatment, regained weight after its withdrawal and experienced marked weight loss after re-challenge with reboxetine.

Intermittent swim stress causes Morris water maze performance deficits in a massed-learning trial procedure that are exacerbated by reboxetine

Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for research in this area, as many unanswered questions remain. Therefore, we sought to employ a novel animal model of depression known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already shown subsequent immobility in the forced swim test (FST), deficits in instrumental and spatial (spaced-trial procedure), and responsiveness to norepinephrine. We are now examining how this will translate in the Morris water maze for rats in a massed-learning trial procedure, and further assessing ISS sensitivity toward norepinephrine selective anti-depressant drugs. The results indicated no difference in cued learning when the platform was visible in the water maze, but a hidden platform task revealed poorer spatial learning for ISS-exposed rats versus controls. In terms of spatial memory, there was a notable ISS-induced deficit 1h after the learning trials, regardless of performance on the previous platform task. Interestingly, the administration of reboxetine interfered with the spatial learning and memory trials for both ISS and CC groups. As a result, ISS exposure compromised spatial learning and memory in the Morris water maze, and norepinephrine does not appear to be a mediator of this deficit. The results demonstrate a key difference in the effects of reboxetine in a massed- vs. spaced-learning trial procedure in the Morris water maze following ISS exposure.

Acute antidepressant drug administration and autobiographical memory recall: A functional magnetic resonance imaging study.

Antidepressants affect memory and neural responses to emotionally valenced stimuli in healthy volunteers. However, it is unclear whether this extends to autobiographical memory for personally experienced events. The current study investigated the effects of acute administration of the antidepressant reboxetine on emotional autobiographical retrieval in healthy volunteers (14 men, 10 women). Functional magnetic resonance imaging was used in a double-blind between-groups investigation with reboxetine (4 mg) and placebo. Consistent with previous reports using lab-based stimuli, neural activation in the processing of positive versus negative memories was reduced following reboxetine compared with placebo in the left frontal lobe (extending into the insula) and the right superior temporal gyrus. This was paired with increased memory speed in volunteers given reboxetine versus placebo. The effect of reboxetine on emotional memory extends to recall of personally experienced events. Such effects may be relevant to the cognitive improvements found with recovery from depression and with the mechanism of action of contemporary antidepressant drugs.

Effects of reboxetine and citalopram on appraisal of infant facial expressions and attentional biases.

Difficulties in mother–child interaction are commonly observed in the context of postnatal depression. These difficulties may result in part from the negative cognitive bias present in depression, which may in turn lead to biased negative perceptions of the infant: in particular, these biases encompass the negative appraisal of facial expressions. Given the important role of early mother–child interactions in child development it is vital to investigate potential interventions that might be beneficial in ameliorating the negative cognitive bias. This study aimed to examine the effects of two different antidepressants (reboxetine and citalopram) on the appraisal of infant facial expressions of emotion using a faces rating task, and on attention to infant emotion using an attentional probe. Thirty-nine volunteers were randomly assigned to a double-blind 7-day intervention with either placebo, citalopram or reboxetine. There were significant positive effects on the appraisal of facial expressions; participants assigned to the placebo group rated positive faces less positively than those either in the citalopram or in the reboxetine groups. However, there was no evidence that these drugs had an effect on attentional vigilance. If antidepressants are able to help a mother to perceive her infant’s facial expressions as more positive, this may lead to more positive interactions, thereby potentially mitigating the negative effects of depression on infant development. These findings should be treated with caution until replicated in larger and clinical samples.

Publishing negative clinical trials results: the case of reboxetine

The recent publication of a systematic review and meta-analysis of published and unpublished data from controlled trials on the effects of reboxetine in the acute treatment of major depression (Eyding et al, 2010) has reignited the debate surrounding the publication of negative trials by pharmaceutical companies.

Effects of reboxetine and citalopram pretreatment on changes in cocaine and amphetamine regulated transcript (CART) expression in rat brain induced by the forced swimming test

Cocaine and amphetamine regulated transcript (CART) has been implicated in the regulation of the stress response. Although the forced swimming test (FST), in which rats are forced to swim for 15 min (pretest swim) and then again for 5 min (test swim) 24 h later, has been used to study the effects of antidepressants, there have been few studies examining the effects of antidepressants on FST-induced changes in CART mRNA levels in the brain. To answer this question, we injected reboxetine and citalopram into male Sprague-Dawley rats 1, 5, and 23.5 h before the test swim and then sacrificed rats 2 h after the test swim, at the peak of the FST-induced increase in CART expression. The FST significantly increased CART mRNA levels in the nucleus accumbens, central nucleus of the amygdala, and locus ceruleus 2 h after the test session. Both reboxetine and citalopram pretreatment blocked FST-induced increases in CART mRNA levels in the nucleus accumbens, central nucleus of the amygdala, and locus ceruleus, despite the fact these antidepressants exert their therapeutic effect by different mechanisms. In addition, the FST significantly increased plasma corticosterone levels, and this effect was also blocked by reboxetine and citalopram pretreatment. These results suggest that inhibition of FST-induced increases in CART expression in the nucleus accumbens, central nucleus of the amygdala, and locus ceruleus may be a common mechanism of antidepressant effects during the FST.

Reboxetine for ADHD in children non-responders or with poor tolerance to methylphenidate: a prospective long-term open-label study

Up to 30% of patients with attention-deficit hyperactivity disorder (ADHD) treated with psychostimulants discontinue the treatment because of intolerance or lack of therapeutic response. Therapeutic alternatives are needed for such patients. In the present case series, we study the effectiveness of reboxetine over a period of 6 months in a sample of 14 children diagnosed with ADHD according to DSM-IV-TR criteria, who had responded only partially or had presented poor tolerance to conventional treatment with methylphenidate. Clinical efficacy was evaluated through the application of the 18-item Attention-Deficit Hyperactivity Disorder Rating Scale (ADHD-RS-IV) and the Clinical Global Impressions-Global Improvement Scale (CGI-I). Percentages of responders (ADHD-RS ≥ 25%) and improvers (CGI-I absolute value < 4) were 90.9 and 72.7%, respectively. No serious side-effects were observed during treatment, the most frequent effects being headaches and insomnia. The initial findings of our study show that reboxetine may constitute an effective tool for long-term treatment of children with ADHD who present poor response or poor tolerance to initial treatment with methylphenidate.

Pharmacological validation of a chronic social stress model of depression in rats: effects of reboxetine, haloperidol and diazepam

Chronic social stress is one of the most important factors responsible for precipitation of depressive disorder in humans. In recent years, the impact of social stress on the development of psychopathologies has been thoroughly investigated in preclinical animal studies. We have shown recently that behavioural effects of chronic social stress in rats can be reversed by citalopram and fluoxetine. This study has been designed for further pharmacological validation of the chronic social stress paradigm as a model of depressive symptoms in rats. For this, rats were subjected to 5 weeks of daily social defeat and were in parallel treatment for a clinically relevant period of 4 weeks with the antidepressant drug reboxetine (40 mg/kg/day) and the neuroleptic drug haloperidol (2 mg/kg/day). The anxiolytic diazepam (1 mg/kg) was administered acutely at the end of the stress period. Stress caused decreased locomotor and exploratory behaviours, decreased sucrose preference and increased immobility in the forced swim test, but did not affect behaviour in the elevated plus maze. Four weeks of oral treatment with reboxetine ameliorated the adverse effects of social stress and normalized behaviours related to motivation and reward sensitivity. The treatment with haloperidol worsened the adverse effects of chronic social stress having effects similar to stress on reward and motivation-related behaviours. Diazepam reduced anxiety-related behaviours as measured in elevated plus maze in control animals having no effects on socially stressed individuals. Neither sucrose preference nor performance in forced swim test was affected by diazepam. The effectiveness and selectivity of the treatment with the antidepressant reboxetine in ameliorating socially induced behavioural disturbances supports the validity of the chronic social stress as a model of depressive-like symptoms in rats.

The effects of reboxetine on emotional processing in healthy volunteers: an fMRI study

Recent neuropsychological studies in healthy volunteers suggest that antidepressants enhance the processing of positive emotional information. However, the neural substrates underpinning these changes have not been fully elucidated. The current study, therefore, used functional magnetic resonance imaging (fMRI) to map brain systems activated during successful categorization and subsequent recognition of self-referent positive and negative personality characteristics in healthy volunteers following short-term (7 days) repeated administration of the selective noradrenergic reuptake inhibitor reboxetine. Twenty-four healthy volunteers were randomly assigned to 7-day double-blind intervention with reboxetine or placebo. On day 7, neural responses during the categorization and subsequent recognition of positive and negative characteristics were assessed using fMRI. Questionnaires monitoring mood, hostility and anxiety were given before and during this intervention. During categorization, reboxetine was associated with greater activation to positive words, relative to negative words, in left precuneus and right inferior frontal gyrus. By contrast, at subsequent recognition reboxetine was associated with reduced response to positive words, relative to negative words, in left precuneus, anterior cingulate and medial frontal gyrus. These changes in the neural processing of positive and negative words occurred in the absence of significant differences in ratings of mood and anxiety. Such adaptations in the neural processing of emotional information support the hypothesis that antidepressants have early effects on emotional processing in a manner which would be expected to reverse negative biases in depression.

No effects of enhanced central norepinephrine on finger-sequence learning and attention

When paired with training, substances that increase monoaminergic transmission in the brain support motor and language learning in healthy subjects and in rehabilitation after brain lesions. To test the hypotheses that enhancement of central norepinephrine by the selective norepinephrine reuptake inhibitor reboxetine (1) improves skilled motor performance, (2) promotes skilled motor learning, and (3) does not exert these effects by modulation of attention. In a double blind, placebo-controlled, crossover study in healthy, adult subjects (n=16), finger-sequence performance and learning was measured after the stimulation of the central noradrenergic system with a single dose (8 mg) of reboxetine and placebo. Effects on attention were assessed by the standardized continuous performance test "CPT-M". No differential effects of reboxetine or placebo on finger-sequence performance, learning and parameters of attention were found. Selective stimulation of the central noradrenergic system did not promote skilled motor learning or performance as assessed by finger-sequences. The plasticity-enhancing effect of reboxetine, documented in other studies, appears to be dependent on specific neurophysiological and neuropsychological characteristics of the task, and cannot be generalized to other behavioral paradigms.

Differential α2‐mediated inhibition of dopamine and noradrenaline release in the parietal and occipital cortex following noradrenaline transporter blockade

Parietal and occipital cortices, while densely innervated by noradrenalin 2 (NA) projections, possess a comparatively sparse dopamine 2 (DA) innervation, even sparser than the prefrontal cortex. We previously reported that reboxetine and desipramine, two selective norepinephrine transporter (NET) blockers, at doses that maximally increase DA in the prefrontal cortex, do not increase DA in the parietal and occipital cortices. In the present study, we performed a full dose-response study of the effect of systemic reboxetine and desipramine on DA and NA in dialysates from the parietal and occipital cortices. Seven doses of reboxetine (0.1, 0.25, 0.5, 1.0, 2.5, 5.0 and 10 mg/kg) and four doses of desipramine (0.25, 1.0, 2.5 and 5.0 mg/kg) were tested. Reboxetine and desipramine differentially affected dialysate DA as compared with NA. Reboxetine increased DA maximally by about 100% after doses of 0.25-0.5 mg/kg and showed a bell-shaped dose-response function in both areas; desipramine did not affect DA in the parietal cortex and increased it in the occipital cortex only at 2.5 mg/kg. NA was maximally increased by 275% by 0.5-2.5 mg/kg reboxetine and by about 300% by 5.0 mg/kg desipramine with a more linear dose-response curve. The mechanism of peculiar dose-response function of dialysate DA after reboxetine and desipramine was further investigated by testing the effect of drugs on dialysate DA and NA under alpha(2) receptor blockade. Under local perfusion of the occipital cortex with idazoxan, an otherwise ineffective dose of reboxetine and desipramine (5 mg/kg) became effective in raising extracellular DA. In contrast, the effect of reboxetine on NA was potentiated, while that of desipramine was not affected. These results suggest that, in the parietal and occipital cortices, extracellular NA, raised by NET blockade, exerts a preferential inhibitory influence on DA release by acting on local alpha(2) receptors, thus accounting for the bell-shaped feature of the dose-response function of drugs on dialysate DA in these areas.

Reboxetine may cause amenorrhea in female patients

Objective. Reboxetine is a selective noradrenaline reuptake inhibitor (NaRI), a study on the effects of reboxetine on amenorrhea has not been reported in the literature up to now. This report describes a patient with symptoms of amenorrhea which is thought to be caused by reboxetine. Case. A female patient with major depressive disorder was given reboxetine 8 mg/day. She had experienced secondary amenorrhea for 3 months. The patient had no periodic irregularity before reboxetine use, and after reboxetine was discontinued menstruation resumed. After another trial with reboxetine at the optimal dose (8 mg/day, increased gradually), the patient reported amenorrhea again for 2 months. On discontinuing reboxetine, her menstrual cycle became regular again. Discussion. FSH, LH, E2 and prolactin levels were normal in our patient. Because amenorrhea was temporally related with reboxetine trials, we posit that this phenomenon may be due to side effects of reboxetine. This may be due to noraderenergic effects on hormonal function.

Resolution of sexual dysfunction during double-blind treatment of major depression with reboxetine or paroxetine

The selective noradrenaline re-uptake inhibitor reboxetine may have advantages over the selective serotonin re-uptake inhibitors fluoxetine and citalopram, in effects on sexual function and satisfaction. The effects of reboxetine and paroxetine on sexual function were compared by examining data from the UK centres in an international double-blind flexible-dose parallel-group multi-centre randomized controlled trial of acute treatment of patients with DSM-IV major depression. Patients were randomly assigned to receive reboxetine (4 mg b.d.) or paroxetine (20 mg mane) using a double-dummy technique to preserve the blind. The dosage could be increased at day 28 (to reboxetine 4 mg mane, 6 mg nocte; or paroxetine 20 mg b.d.). Antidepressant efficacy was assessed by the 21-item Hamilton Rating Scale for Depression (HAM-D) and Clinical Global Impression Scale for Severity (CGI-S) at all study visits, and the Clinical Global Impression of Improvement (CGI-I) at each visit after randomization. Sexual function and satisfaction was assessed by visual analogue scale (VAS) items of the Rush Sexual Inventory completed at baseline and days 28 and 56. There were no significant differences between groups in demographic or clinical features at baseline. There was a gradual reduction in severity of depressive symptoms (reboxetine, 14.3; paroxetine, 12.0: observed case analysis), with no significant differences between groups. There were significant differences (p 0.05), with advantages for reboxetine, at Week 4 and Week 8 on the VAS item assessing ability to become sexually excited, and non-significant trends with advantages for reboxetine, in frequency of sexual thoughts at Week 4 (p 0.05) and Week 8 (p 0.08); and in desire to initiate sexual activity at Week 4 (p 0.09). Exclusion of patients who had ever experienced sexual dysfunction with any medication prior to participation in this study (n 10) reduced the statistical significance of the findings, although there were still numerical advantages for reboxetine. Sexual function and satisfaction in depressed patients improves during double-blind acute treatment with reboxetine or paroxetine, but this improvement is greater and more rapid with reboxetine.

Efficacy and Tolerability of Reboxetine in Depressive Patients Treated in Routine Clinical Practice

Reboxetine, a potent and selective noradrenaline reuptake inhibitor, has been approved for treatment of major depression. The aim of this study was to investigate the efficacy and tolerability of reboxetine in depressive outpatients undergoing treatment in routine clinical practice. This post-marketing surveillance study was conducted to evaluate the therapeutic efficacy and tolerability of standard therapeutic doses of reboxetine in patients with depressive symptoms, particularly when administered in routine clinical practice. The 1835 patients (mean 54 years of age) evaluated showed demographic characteristics representative of the general depressive population. The majority of patients received the recommended dose of reboxetine 8 mg/day. Measures of efficacy showed improvement in depressive symptoms with reboxetine therapy over the mean observational period of 9.6 weeks. Response to therapy, defined as Hamilton depression scale 21-item version score reduction of > or =50%, was reported in 83% of patients. The effects of reboxetine were rated by physicians as 'good' or 'very good' in 86% of patients at the last visit. The tolerability of reboxetine was rated by physicians as 'good' or 'very good' in 92% of patients at all evaluations. No adverse events that were possibly related to reboxetine therapy occurred in >1% of patients. The results of this study suggest that reboxetine is safe and well tolerated and may improve symptoms in depressive patients treated in routine clinical practice.

Chronic Dose effects of Reboxetine on Motor Skill Acquisition and Cortical Excitability

Background: Enhancement of cortical excitability is thought to be potentially beneficial for synaptic plasticity as, e.g., associated with motor skill acquisition. The selective norepinephrine re-uptake inhibitor reboxetine (RBX) might therefore be able to facilitate functional recovery after brain lesions. Considering patient administration in the future we studied the effects of a chronic dose regimen on motor skill acquisition and cortical excitability. Methods: The study was randomized, double blind and placebo-controlled. 12 healthy subjects received 4mg RBX twice a day for 4 full days preceded by 2mg RBX twice a day for 2 days. Each subject served as its own control. There were at least 16 days between the verum and the placebo session. Measurement of cortical excitability by means of paired pulse transcranial magnetic stimulation (ppTMS) was conducted before and after the motor skill acquisition task for each session. The task was to lift two fingers of the right hand at once while the hand positioned sprawled out on the table. The movements were self-paced and subjects had to perform as many moves as possible in 60 seconds. Between 7 blocks of self-paced movements 6 blocks with 60 single trials at a fixed interstimulus interval were presented. Two equally difficult versions of the task using different finger combinations were established in order to avoid carryover effects in performance. The finger movements were recorded with a three-dimensional ultrasound movement analysis system (Zebris). Results: All subjects had a substantial gain in performance over the self-paced blocks. Average increase in number of correct moves was 87% (from 27.8 to 51.9). There was no significant difference either between the versions of the task or between placebo vs. verum. Also, there was no significant difference between first and second session, indicating that there was no carryover effect in performance. ppTMS revealed no significant differences in cortical excitability between groups. Conclusion: The newly developed skill acquisition task yields a robust single session gain of performance. As the two versions of the task do not interact, it is suitable to be used in cross-over designs. In contrast to studies using single doses of RBX, motor cortex excitability seems to be unaffected in a chronic dose steady-state. This could explain why motor behavior was not modulated by the study medication.