The efficacy of reboxetine in the treatment-refractory patients with panic disorder: an open label study

Manipulation of vocal communication and anxiety through pharmacologic modulation of norepinephrine in the Pink1-/- rat model of Parkinson disease

Vocal deficits and anxiety are common, co-occurring, and interacting signs of Parkinson Disease (PD) that have a devastating impact on quality of life. Both manifest early in the disease process. Unlike hallmark motor signs of PD, neither respond adequately to dopamine replacement therapies, suggesting that their disease-specific mechanisms are at least partially extra-dopaminergic. Because noradrenergic dysfunction is also a defining feature of PD, especially early in the disease progression, drug therapies targeting norepinephrine are being trialed for treatment of motor and non-motor impairments in PD. Research assessing the effects of noradrenergic manipulation on anxiety and vocal impairment in PD, however, is sparse. In this pre-clinical study, we quantified the influence of pharmacologic manipulation of norepinephrine on vocal impairment and anxiety in Pink1-/- rats, a translational model of PD that demonstrates both vocal deficits and anxiety. Ultrasonic vocalization acoustics, anxiety behavior, and limb motor activity were tested twice for each rat: after injection of saline and after one of three drugs. We hypothesized that norepinephrine reuptake inhibitors (atomoxetine and reboxetine) and a β receptor antagonist (propranolol) would decrease vocal impairment and anxiety compared to saline, without affecting spontaneous motor activity. Our results demonstrated that atomoxetine and reboxetine decreased anxiety behavior. Atomoxetine also modulated ultrasonic vocalization acoustics, including an increase in vocal intensity, which is almost always reduced in animal models and patients with PD. Propranolol did not affect anxiety or vocalization. Drug condition did not influence spontaneous motor activity. These studies demonstrate relationships among vocal impairment, anxiety, and noradrenergic systems in the Pink1-/- rat model of PD.

A case of social phobia and avoidant personality disorder with erectile dysfunction successfully treated with venlafaxine and add-on reboxetine

A 25-year-old man with DSM-IV-TR Axis I social phobia and Axis II avoidant personality disorder and erectile dysfunction, presenting with depression, anxiety and insomnia, responded partially to extended release oral venlafaxine (75 mg/die for 6 weeks), but developed side effects and worsening symptoms when dose was increased to 150 mg/die; he responded to a combination of 75 mg/die venlafaxine and 4 mg/die reboxetine and improved on most of his symptoms.

Pharmacological Therapy in Panic Disorder: Current Guidelines and Novel Drugs Discovery for Treatment-resistant Patient

Panic disorder (PD) being one of the most intensively investigated anxiety disorders is considered a heterogeneous psychiatric disease which has difficulties with early diagnosis. The disorder is recurrent and usually associated with low remission rates and high rates of relapse which may exacerbated social and quality of life, causes unnecessary cost and increased risk for complication and suicide. Current pharmacotherapy for PD are available but these drugs have slow therapeutic onset, several side effects and most patients do not fully respond to these standard pharmacological treatments. Ongoing investigations indicate the need for new and promising agents for the treatment of PD. This article will cover the importance of immediate and proper treatment, the gap in the current management of PD with special emphasis on pharmacotherapy, and evidence regarding the novel anti-panic drugs including the drugs in developments such as metabotropic glutamate (mGlu 2/3) agonist and levetiracetam. Preliminary results suggest the anti-panic properties and the efficacy of duloxetine, reboxetine, mirtazapine, nefazodone, risperidone and inositol as a monotherapy drug. Apart for their effectiveness, the aforementioned compounds were generally well tolerated compared to the standard available pharmacotherapy drugs, indicating their potential therapeutic usefulness for ambivalent and hypervigilance patient. Further strong clinical trials will provide an ample support to these novel compounds as an alternative monotherapy for PD treatment-resistant patient.

Management of Treatment-Resistant Panic Disorder

PURPOSE OF REVIEW

Purpose of Review Management of treatment-resistant (TR) panic disorder (PD) is an unresolved issue. In this paper, we provide a brief summary of previous findings, an updated (2015-2017) systematic review of pharmacological/non-pharmacological studies, and our personal perspective on this topic.

RECENT FINDINGS

Recent Findings We found a very limited number of recent findings. Quetiapine extended-release augmentation has not been found to be beneficial, in comparison to placebo, in non-responders to previously recommended pharmacotherapy. In non-responders to cognitive behavioral therapy (CBT), switching to paroxetine/citalopram has been found to be more effective than continuing CBT. Acceptance and commitment therapy (ACT) has shown some improvement in patients' resistance to previous psychological/pharmacological interventions compared with a waiting-list condition.

SUMMARY

Summary Previous and recent findings regarding the treatment of TR PD suffer from several methodological limitations. Available studies provide insufficient evidence to support the use of medications alternative to the recommended medications; the efficacy of ACT needs confirmation with more rigorous methodology. Prolonged pharmacotherapy may produce significant improvement in patients with unsatisfactory response to short-term pharmacotherapy, while switching to pharmacotherapy may help non-responders to CBT. We discuss our personal perspective on the definition of "treatment resistance" as it relates to PD and provide personalized intervention strategies to increase favorable clinical outcomes based on our clinical expertise and review of experimental studies on the pathophysiology of PD.

Evidence-based pharmacotherapy of panic disorder: an update

The evidence-based pharmacotherapy of panic disorder continues to evolve. This paper reviews data on first-line pharmacotherapy, evidence for maintenance treatment, and management options for treatment-refractory patients. A Medline search of research on pharmacotherapy was undertaken, and a previous systematic review on the evidence-based pharmacotherapy of panic disorder was updated. Selective serotonin reuptake inhibitors remain a first-line pharmacotherapy of panic disorder, with the serotonin noradrenaline reuptake inhibitor venlafaxine also an acceptable early option. Temporary co-administration of benzodiazepines can be considered. Maintenance treatment reduces relapse rates, but further research to determine optimal duration is needed. For patients not responding to first-line agents several pharmacotherapy options are available, but there is a notable paucity of data on the optimal choice.

The role of central noradrenergic dysregulation in anxiety disorders: evidence from clinical studies

The nature of the noradrenergic dysregulation in clinical anxiety disorders remains unclear. In panic disorder, the predominant view has been that central noradrenergic neuronal networks and/or the sympathetic nervous system was normal in patients at rest, but hyper-reactive to specific stimuli, for example carbon dioxide. These ideas have been extended to other anxiety disorders, which share with panic disorder characteristic subjective anxiety and physiological symptoms of excess sympathetic activity. For example, Generalized Anxiety Disorder is characterized by chronic free-floating anxiety, muscle tension, palpitation and insomnia. It has been proposed that there is chronic central hypersecretion of noradrenaline in Generalized Anxiety Disorder, with consequent hyporesponsiveness of central post-synaptic receptors. With regards to other disorders, it has been suggested that there is noradrenergic involvement or derangement, but a more specific hypothesis has not been enunciated. This paper reviews the evidence for noradrenergic dysfunction in anxiety disorders, derived from indirect measures of noradrenergic function in clinical populations.

Pharmacologic treatment of panic disorder

Comprehensive management of panic disorder involves a wide array treatments and interventions to reduce symptoms and increase functionality. This chapter provides an overview of the pharmacologic treatment of panic disorder including aspects of assessment, treatment selection and the biologic mechanisms of the illness.

Design, synthesis, and pharmacological evaluation of phenoxy pyridyl derivatives as dual norepinephrine reuptake inhibitors and 5-HT1A partial agonists

Preclinical studies suggest that compounds with dual norepinephrine reuptake inhibitor (NRI) and 5-HT(1A) partial agonist properties may provide an important new therapeutic approach to ADHD, depression, and anxiety. Reported herein is the discovery of a novel chemical series with a favorable NRI and 5-HT(1A) partial agonist pharmacological profile as well as excellent selectivity for the norepinephrine transporter over the dopamine transporter.

A randomized controlled trial of venlafaxine ER and paroxetine in the treatment of outpatients with panic disorder

RATIONALE

Few randomized, placebo-controlled trials have evaluated the comparative efficacy and tolerability of more than one pharmacological agent for panic disorder.

OBJECTIVES

The primary objective of this study was to compare the efficacy and tolerability of venlafaxine extended release (ER) with placebo in treating panic disorder. Secondary objectives included comparing paroxetine with venlafaxine ER and placebo.

METHODS

Outpatients aged > or =18 years (placebo, n = 157; venlafaxine ER 75 mg, n = 156; venlafaxine ER 225 mg, n = 160; paroxetine, n = 151), with a primary diagnosis of panic disorder (+/-agoraphobia) based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) criteria for > or =3 months were randomly assigned to receive venlafaxine ER (titrated to 75 mg/day or 225 mg/day), paroxetine (titrated to 40 mg/day), or placebo for 12 weeks. The primary efficacy measure was the percentage of patients free of full-symptom panic attacks (> or = four symptoms) at endpoint. Key secondary outcomes included the Panic Disorder Severity Scale (PDSS) mean score change and response.

RESULTS

At endpoint, all active treatment groups showed a significantly (P < 0.01) greater proportion of patients free of full-symptom panic attacks, compared with placebo, and were superior (P < 0.05) on most secondary measures. The venlafaxine ER 225 mg group had significantly (P < 0.05) greater mean PDSS score improvement than the paroxetine group (-12.58 vs -11.87) and a significantly higher proportion of patients free of full symptom panic attacks (70.0 vs 58.3%). Both drugs were generally well tolerated.

CONCLUSION

Venlafaxine ER 75 mg/days and 225 mg/days and paroxetine 40 mg/day were both well tolerated and effective for short-term treatment of panic disorder.

Resistência ao tratamento nos transtornos de ansiedade: fobia social, transtorno de ansiedade generalizada e transtorno do pânico

OBJETIVOS: Os transtornos de ansiedade são condições psiquiátricas prevalentes que determinam importante prejuízo funcional, piora na qualidade de vida do indivíduo e um enorme custo social. Embora diversas medicações eficazes para os transtornos de ansiedade encontrem-se disponíveis, um número significativo de pacientes não responde adequadamente ao tratamento e muitos permanecem com sintomas residuais clinicamente significativos. O objetivo deste estudo é rever aspectos relacionados à resistência ao tratamento e estratégias farmacológicas no manejo dos transtornos de ansiedade resistentes ao tratamento. MÉTODO: Revisão narrativa. RESULTADOS: São discutidos os diversos aspectos conceituais relacionados à resistência ao tratamento, os possíveis preditores de resistência e, finalmente, algumas estratégias a serem utilizadas no manejo dos transtornos de ansiedade (incluindo transtorno de ansiedade social, transtorno de ansiedade generalizada e transtorno do pânico) que não respondem às abordagens terapêuticas convencionais. CONCLUSÃO: A resistência ao tratamento ainda é um desafio para a prática clínica que começa em conceitos não operacionalizados de resposta e resistência e termina na escassez de estudos controlados sobre estratégias de tratamento nesse último cenário clínico.

Olanzapine augmentation in treatment-resistant panic disorder: a 12-week, fixed-dose, open-label trial

The purpose of our study was to evaluate the efficacy and tolerability of low-dose olanzapine augmentation in selective serotonin reuptake inhibitor (SSRI)-resistant panic disorder (PD) with or without agoraphobia. In this 12-week, open-label study, 31 adult outpatients with treatment-resistant PD who had previously failed to respond to SSRI treatment were treated with fixed dose of olanzapine (5 mg/d) in addition to SSRI. Efficacy was assessed using the Panic Attack and Anticipatory Anxiety Scale (PAAAS), the Agoraphobic Cognitions Questionnaire (ACQ), the Hamilton Rating Scale for Anxiety (HAM-A), the Hamilton Rating Scale for Depression (HAM-D), the Global Assessment of Functioning Scale (GAF), and the Clinical Global Impression of Improvement (CGI-I). Twenty-six patients completed the trial period with a dropout rate of 16.1%. At week 12, 21 patients were responders (81.8%), and an overall improvement on all rating scales was observed in all patients both with or without agoraphobia. Fifteen patients (57.7%) achieved remission. Olanzapine was well tolerated and the most frequent adverse effects were mild-to-moderate weight gain and drowsiness. No extrapyramidal symptoms were reported. Olanzapine appears to be effective as augmentation strategy in the treatment of SSRI-resistant PD, but study limitations must be considered and placebo-controlled studies are needed.

Lack of hypo/hyperglycemic effects of Reboxetine in diabetic and non-diabetic rats

Depression occurs frequently with diabetes affecting the quality of life. All major classes of antidepressants have been shown to have a direct pharmacologic effect on metabolic function, which further worsens glycemic control. There were no reports of effects of reboxetine on glucose and insulin levels. We observed that 21 days administration of reboxetine (2.5 mg/kg, i.p.) in streptozotocin (55 mg/kg, i.p.) induced diabetic and non-diabetic rats produced no significant alteration in glucose levels in diabetic and non-diabetic rats. Serum insulin levels were also not significantly changed by reboxetine (2.5 mg/kg, i.p.). Selective inhibition of noradrenaline reuptake by reboxetine has been suggested to be responsible for lack of effects on glucose and insulin levels.

Screening antidepressants in the chick separation-stress paradigm

RATIONALE

Clinical research has indicated that antidepressants are efficacious in the treatment of anxiety disorders, especially when repeatedly administered. However, few animal models of anxiety are sensitive to antidepressants, a finding that may be due to procedures limited to acute administrations.

OBJECTIVES

The purpose of the present research was to further validate the chick separation-stress paradigm as an animal model of anxiety by examining its sensitivity to the monoamine oxidase inhibitor (MAOI) phenelzine (6.25, 12.5, 25.0 mg/kg), the tricyclic antidepressant (TCA) imipramine (5.0, 10.0, 20.0 mg/kg), the selective serotonin reuptake inhibitor (SSRI) citalopram (1.0, 2.5, 5.0 mg/kg), and the norepinephrine reuptake inhibitor (NRI) maprotiline (5.0, 10.0, 20.0 mg/kg) under acute (no pretreatment) or repeated (3 or 6 days pretreatment) administration procedures.

METHODS

Following any pretreatment, 8-day-old chicks received their respective vehicle or drug probe injection 15 min before tests in either a "mirror" (low stress) or "no mirror" (high stress) condition for a 180-s isolation period. The dependent measures were distress vocalizations to index separation stress and sleep onset latency to index sedation.

RESULTS

The model was sensitive to acutely administered phenelzine (MAOI), imipramine (TCA), and maprotiline (NRI), but not citalopram (SSRI) and retained its sensitivity to these drug probes across both repeated administration procedures. None of the drug probes possessed any sedative properties.

CONCLUSIONS

These results help extend the validity and utility of the chick separation-stress paradigm as an animal model of anxiety by demonstrating its sensitivity to antidepressants under both acute and repeated administration procedures.

The selective norepinephrine reuptake inhibitor antidepressant reboxetine: pharmacological and clinical profile

Reboxetine is the first commercially available norepinephrine reuptake inhibitor developed specifically as a first line therapy for major depressive disorder. In vitro and in vivo pharmacological studies indicated that reboxetine methanesulphonate has high affinity and selectivity for the human norepinephrine transporter over the serotonin and dopamine transporters. Pharmacological specificity is further demonstrated by the absence of affinity for 45 transmitter receptors and CNS targets. Pharmacokinetic studies demonstrated that reboxetine is suitable for twice daily administration (8-10 mg/day) and that it exhibits minimal drug-drug interactions. The starting dose of reboxetine should be reduced in the elderly, in patients with renal or hepatic impairment, or in patients receiving potent CYP3A inhibitors. A total of 20 phase II/III clinical studies comprising placebo-controlled, active comparator-controlled and open-label uncontrolled studies in both short-term and long-term treatment of major depression have been conducted. In the treatment of major depression, reboxetine was superior to placebo in 5 of 12 short- or long-term placebo-controlled studies and was comparable in efficacy to active comparators in 3 out of 3 active-controlled studies. Unlike conventional tricyclic antidepressants (TCAs), reboxetine had only minimal sedative and cardiovascular liabilities, probably due to increased pharmacological specificity of reboxetine as compared with TCAs. Unlike serotonin reuptake inhibitors, this selective and specific norepinephrine reuptake inhibitor demonstrated a distinct side-effect profile with diminishing sexual dysfunction and GI side effects. The availability of this agent has afforded patients suffering from major depressive disorder a new class of agents to combat the debilitating consequence of this psychiatric disease. The demonstrated pharmacological specificity of this compound has provided the psychopharmacology community with a tool to elucidate the role of norepinephrine in brain functions. Testing this agent in different animal models has enabled the exploration of the role of modulation of norepinephrine tone in the therapy of CNS disorders beyond depression.

The promises and pitfalls of reboxetine

The antidepressant compound, morpholine, 2-[(2-ethoxyphenoxy)phenylmethyl]-,methanesulfonate, or reboxetine, is a selective noradrenergic reuptake inhibitor that acts by binding to the norepinephrine (NE) transporter and blocking reuptake of extracellular NE back into terminals. This compound has low affinity for other transporters and receptors. The development of reboxetine as a potential antidepressant stems from the prior demonstration that blockade of the NE transporter imparts antidepressant activity. Desipramine, lofepramine, and nortryptiline are examples of tricyclic antidepressant (TCA) compounds from the first generation of antidepressants that exert their effects by blockade of NE reuptake. Maprotiline, a non-tricyclic compound, is also a NE selective reuptake inhibitor. Unfortunately, these antidepressants are also associated with interactions with muscarinic, histaminergic, and adrenergic receptors, which are known to contribute to a variety of untoward side effects. Despite the positive pharmacological profile of reboxetine, i.e., selectivity and specificity, with relatively fewer side effects, its use as an antidepressant is currently limited to Europe. Reboxetine is marketed as Edronax in the UK, Norebox in Italy, and as Irenor in Spain. It is registered in Germany, Sweden, Denmark, Ireland, Austria and Finland. Based on studies conducted primarily outside the US, the FDA granted a preliminary letter of approval in 1999. However, more recent clinical studies conducted in the US and Canada, prompted by the FDA, resulted in a letter of non-approval. To date, it is unclear why the further development of reboxetine as an antidepressant in the US has been halted. Despite this setback, reboxetine has been a valuable pharmacological tool to assess the role of the noradrenergic system in preclinical studies of depressive disorder.

Reboxetine and citalopram in panic disorder: a single-blind, cross-over, flexible-dose pilot study

Both noradrenergic and serotonergic systems have been implicated in the pathophysiology of panic disorder. The advent of selective serotonin (5-HT) reuptake inhibitors (SSRIs) (e.g. citalopram) and, more recently, selective noradrenergic (NA) reuptake inhibitors (NRIs) (e.g. reboxetine) has provided potentially important avenues of treatment for the disorder. To date, the comparative efficacy of selective NA and 5-HT reuptake inhibitors for panic disorder remains unresolved. Nineteen patients with panic disorder were randomized in a single-blind, cross-over design to either citalopram or reboxetine for 8 weeks and after a 2-week washout were switched to the other study drug. At week 18, seven of 13 patients (54%) in the intent-to-treat sample responded to reboxetine and nine of 11 patients responded to citalopram (82%). Both citalopram and reboxetine led to significant improvements in panic attack severity with no apparent between-drug differences in efficacy. However, citalopram demonstrated superior efficacy in treating depressive symptoms. One non-responder to citalopram responded to reboxetine and three non-responders to reboxetine responded to citalopram. Although SSRIs are viewed as a first-line treatment for panic disorder, these results suggest that a NA agent such as reboxetine may also have a role. These data also suggest an advantage for citalopram in treating comorbid depressive symptoms, although some patients may respond preferentially to an SSRI and other patients to an NRI.