Citalopram and viloxazine in the treatment of depression by means of slow drop infusion. A double-blind comparative trial

Viloxazine in the Management of CNS Disorders: A Historical Overview and Current Status

Viloxazine has a long history of clinical use in Europe as an antidepressant, and has recently been repurposed into an extended-release form for the treatment of attention-deficit/hyperactivity disorder in the USA. An immediate-release formulation was approved for the treatment of depression in the UK in 1974, and was subsequently marketed there and in several European countries for 30 years with no major safety concerns. In contrast to first-generation antidepressants (e.g., tricyclic antidepressants, monoamine oxidase inhibitors), viloxazine was associated with a relatively low risk for cardiotoxicity. Gastrointestinal symptoms were the most commonly reported side effects. The therapeutic effects of viloxazine are thought to be primarily the result of its action as a norepinephrine reuptake inhibitor, although in vitro and preclinical in vivo animal data suggest that viloxazine may also impact the serotoninergic system. This review summarizes the evolving knowledge of viloxazine based on information from previously published preclinical and clinical investigations, and acquired unpublished historical study reports from both open-label and blinded controlled clinical trials. We review the chemical properties, mechanism of action, safety, and tolerability across these studies, and discuss the contemporary rationale for the development of this agent as an extended-release oral formulation for the treatment of attention-deficit/hyperactivity disorder.

Depression development: From lifestyle changes to motivational deficits

Until now, depression research has taken a surprisingly narrow approach to modelling the disease, mainly focusing on some form of psychomotor retardation within a mechanistic framework of depression etiology. However, depression has many symptoms and each is associated with a vast number of substrates. Thus, to deepen our insights, this SI ("Depression Symptoms") reviewed the behavioral and neurobiological sequelae of individual symptoms, specifically, psychomotor retardation, sadness, low motivation, fatigue, sleep/circadian disruption, weight/appetite changes, and cognitive affective biases. This manuscript aims to integrate the most central information provided by the individual reviews. As a result, a dynamic model of depression development is proposed, which views depression as a cumulative process, where different symptoms develop at different stages, referred to as early, intermediate, and advanced, that require treatment with different pharmaceutical agents, that is, selective serotonin reuptake inhibitors early on and dopamine-based antidepressants at the advanced stage. Furthermore, the model views hypothalamic disruption as the source of early symptoms and site of early intervention. Longitudinal animal models that are capable of modelling the different stages of depression, including transitions between the stages, may be helpful to uncover novel biomarkers and treatment approaches.

Citalopram versus other anti-depressive agents for depression

BACKGROUND

Recent US and UK clinical practice guidelines recommend that second-generation antidepressants should be considered amongst the best first-line options when drug therapy is indicated for a depressive episode. Systematic reviews have already highlighted some differences in efficacy between second-generation antidepressants. Citalopram, one of the first selective serotonin reuptake inhibitors (SSRI) introduced in the market, is one of these antidepressant drugs that clinicians use for routine depression care.

OBJECTIVES

To assess the evidence for the efficacy, acceptability and tolerability of citalopram in comparison with tricyclics, heterocyclics, other SSRIs and other conventional and non-conventional antidepressants in the acute-phase treatment of major depression.

SEARCH METHODS

We searched The Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to February 2012. No language restriction was applied. We contacted pharmaceutical companies and experts in this field for supplemental data.

SELECTION CRITERIA

Randomised controlled trials allocating patients with major depression to citalopram versus any other antidepressants.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data. Information extracted included study characteristics, participant characteristics, intervention details and outcome measures in terms of efficacy (the number of patients who responded or remitted), patient acceptability (the number of patients who failed to complete the study) and tolerability (side-effects).

MAIN RESULTS

Thirty-seven trials compared citalopram with other antidepressants (such as tricyclics, heterocyclics, SSRIs and other antidepressants, either conventional ones, such as mirtazapine, venlafaxine and reboxetine, or non-conventional, like hypericum). Citalopram was shown to be significantly less effective than escitalopram in achieving acute response (odds ratio (OR) 1.47, 95% confidence interval (CI) 1.08 to 2.02), but more effective than paroxetine (OR 0.65, 95% CI 0.44 to 0.96) and reboxetine (OR 0.63, 95% CI 0.43 to 0.91). Significantly fewer patients allocated to citalopram withdrew from trials due to adverse events compared with patients allocated to tricyclics (OR 0.54, 95% CI 0.38 to 0.78) and fewer patients allocated to citalopram reported at least one side effect than reboxetine or venlafaxine (OR 0.64, 95% CI 0.42 to 0.97 and OR 0.46, 95% CI 0.24 to 0.88, respectively).

AUTHORS' CONCLUSIONS

Some statistically significant differences between citalopram and other antidepressants for the acute phase treatment of major depression were found in terms of efficacy, tolerability and acceptability. Citalopram was more efficacious than paroxetine and reboxetine and more acceptable than tricyclics, reboxetine and venlafaxine, however, it seemed to be less efficacious than escitalopram. As with most systematic reviews in psychopharmacology, the potential for overestimation of treatment effect due to sponsorship bias and publication bias should be borne in mind when interpreting review findings. Economic analyses were not reported in the included studies, however, cost effectiveness information is needed in the field of antidepressant trials.

Intravenous anti-obsessive agents: a review

Oral antidepressants are currently the first-line pharmacotherapy for obsessive-compulsive disorder (OCD), but response rates can often be low and with delayed onset of therapeutic action. Some reports have suggested that intravenous (i.v.) anti-obsessive agents may have faster onset of action and greater efficacy. A Medline search was conducted for all reports pertaining to the use of i.v. antidepressants for OCD. Search terms included: 'intravenous', 'clomipramine', 'selective serotonin reuptake inhibitor', 'tricyclic', 'citalopram', 'sertraline', 'paroxetine', 'fluvoxamine', 'SSRIs' and 'intravenous antidepressants'. Relevant articles mainly investigated clomipramine (CMI) with one open trial examining citalopram. Intravenous agents appear to be well-tolerated, particularly in those who have failed oral agents, and may act more rapidly to produce initial clinical response, although this advantage is often lost over time. Preliminary evidence suggests subgroups of patients with severe treatment-refractory OCD may benefit from i.v. anti-obsessive agents, CMI and citalopram. Larger, controlled trials are needed for more definitive conclusions.

Antidepressive-drug-induced bodyweight gain is associated with polymorphisms in genes coding for COMT and TPH1

Bodyweight gain is a common side effect of treatment with antidepressive drugs; however, little is known about the mechanisms behind this weight gain. Genetic differences may contribute to the susceptibility for bodyweight gain during antidepressive treatment. The objective of this study was to examine the association of antidepressive-drug-induced bodyweight gain with polymorphisms in genes within the serotonin or catecholamine systems. Participants (N = 165) were selected from the Danish Psychiatric Central Research Register from June 2005 through May 2007 as patients with a diagnosis of a single depressive episode and who were under antidepressive treatment. Weight gainers were identified based on rating with the Udvalg for Kliniske Undersøgelser Side Effect Rating Scale. Polymorphisms in catechol-O-methyltransferase, tryptophan hydroxylase (TPH1), serotonin receptor 2C (HTR2C) and serotonin transporter (SLC6A4) genes were identified and associated with bodyweight gain during treatment. The AG genotype of catechol-O-methyltransferase rs4680 and the AA genotype of TPH1 rs18532 were significantly associated with bodyweight gain during antidepressive treatment, when adjusted for age and sex. These new findings may aid the understanding of susceptibility to side effects such as weight gain during clinical antidepressive treatment.

Safety and efficacy of oral escitalopram as continuation treatment of intravenous citalopram in patients with major depressive disorder

The objective of this open-label, multicentre study was to evaluate the safety and efficacy of treatment with escitalopram (10 or 20 mg/day) for 6 weeks following a switch from intravenous citalopram treatment (20 or 40 mg/day) in patients presenting with a major depressive episode. A total of 173 patients were included, 147 (85%) of whom completed the study. The mean Montgomery-Asberg Depression Rating Scale (MADRS) total score at inclusion (last citalopram dose) was 31.6 +/- 9.9. The MADRS score decreased to 23.4 +/- 10.5 after 3 days of oral treatment with escitalopram and was 12.7 +/- 9.3 at the end of the study. The scores on the Clinical Global Impression (CGI) and Patient Global Evaluation scales also improved: at the end of the study, the response rates were 67% on the MADRS (defined as >or=50% decrease from MADRS baseline score) and 68% on the CGI-I (defined as CGI-I <or=2). More than half of the patients were in remission (MADRS score <or=12). Overall, the switch from intravenous citalopram to escitalopram was well tolerated. In all, 57 patients (33%) reported at least 1 adverse event, and 7 patients (4%) were withdrawn due to an adverse event. The most frequently reported adverse events were probably linked to residual depressive symptoms (anxiety: 9%; insomnia: 5%). In conclusion, escitalopram was well tolerated as a continuation treatment after switching from intravenous citalopram and reduced depressive symptoms in patients with a moderate to severe major depressive episode.

Tolérance et efficacité de l’escitalopram per os, en relais de la forme intraveineuse du citalopram chez des patients présentant un épisode dépressif majeur

Intravenous (iv) administration of an antidepressant is a common practice in some European countries, particularly in France, Spain, and Italy in the initial treatment phase of hospitalised, severe depressed patients. After a beneficial response is observed, patients are switched to an oral formulation. The approved treatment period of the iv form of citalopram is limited to 8-10 days. The high bioavailability of citalopram permits the use of identical iv and oral doses. Citalopram is a racemate, consisting of a 1:1 mixture of the S- and R-enantiomers. The therapeutically active component is the S-enantiomer (escitalopram). Pharmacokinetic single dose administration studies in healthy subjects have demonstrated that daily oral administration of 20 mg of escitalopram or 40 mg citalopram results in similar plasma concentrations of the S-enantiomer of citalopram. This open-label multicentre French prospective study investigated the tolerability and efficacy of oral escitalopram 10 and 20 mg/day, administered for a 6-week period as continuation treatment of citalopram (20 mg or 40 mg daily) intravenous (iv), in patients with Major Depressive Disorder. A total of 171 patients were enrolled, of whom 147 (85%) completed the study. The mean MADRS score at inclusion (last citalopram dose) was 31.6 +/- 9.9. The total MADRS score decreased after 3 days of oral treatment with escitalopram. Escitalopram demonstrated a continuous effect in treating depressive symptoms throughout the study. The decrease in MADRS mean total score from baseline was statistically significant to each visit (day 3, 15; p < 0.0001). At final visit (J42), the decrease was - 18.9 +/- 11.7 (p < 0.0001) and the MADRS mean total score was 12.7 +/- 9.3. There were no differences seen in the patient response comparing gender, age, and the single or recurrent episodes. The changes of Clinical Global Impression scores (CGI-S, CGI-I, PGE-Patient Global Evaluation) were also indicative of an improvement of the patients' depression. The CGI-I and PGE scores were significantly correlated indicating good agreement between investigator and patient in rating the degree of improvement. At the end of the study, 67% of patients were classified as responders (decrease of MADRS score from baseline > or = 50%), and the majority of them were considered remitters (final MADRS score < or = 12). Overall, the switch from intravenous citalopram to oral escitalopram was well tolerated in the study population. In all, 57 patients (33%) reported at least one adverse event (AE) during the study (21 patients in the 10 mg group and 36 patients in the 20 mg group); of these, 7 patients (4%) withdrew from the study. The most frequently reported AEs were suggestive of residual symptoms of depression (anxiety, 9%; insomnia, 5% of patients). In conclusion, in this study oral escitalopram (10 mg or 20 mg) was well tolerated as continuation treatment after switching from intravenous citalopram (20 mg or 40 mg). From the efficacy and safety data of this study, it can be concluded that the switch from citalopram iv to oral escitalopram (10 and 20 mg/day) is effective in decreasing depressive symptoms, and could be safely proposed in patients with major depressive disorder.

Clinical effects of pharmacological variations in selective serotonin reuptake inhibitors: an overview

Although the selective serotonin reuptake inhibitor (SSRI) class of antidepressants shares a common primary pharmacology, namely the inhibition of serotonin reuptake, their secondary pharmacology is remarkably heterogeneous. Inhibition of serotonin reuptake and the consequent increase in serotonin availability are responsible for the relief of depressive symptoms and for some of the adverse effects of this class of drugs. Transsynaptic effects such as modulation of signalling cascades, gene expression processes and neuroplasticity are also important in the mechanism of action of antidepressants. However, this review shows that secondary properties of the SSRIs may contribute to the differences in efficacy and tolerability between members of the class. For example, fluvoxamine has affinity for sigma(1)-receptors -- a property likely to be responsible for its particular efficacy in delusional depression. By understanding the properties of SSRIs and employing careful selection of agents for individual patients, physicians are more able to tailor antidepressant treatments to their patients' particular circumstances.

Intravenous antidepressants: a review

Antidepressant medications have an onset of action of several weeks and have moderate efficacy. Their mode of administration is oral (p.o.). Some clinicians wondered whether intravenous (i.v.) administration would speed onset of action and increase efficacy. In this article we review controlled studies on i.v. administration of antidepressants. These include clomipramine, citalopram, and other antidepressants. Overall these studies do not support increased efficacy of i.v. over p.o.administration but there are suggestions of a faster onset of action. In one study i.v. citalopram showed superior response rates over p.o. citalopram (79% vs. 63%) in severely depressed patients at 8 weeks.

Efficacy of intravenous citalopram compared with oral citalopram for severe depression. Safety and efficacy data from a double-blind, double-dummy trial

BACKGROUND

Intravenous administration is often beneficial in the treatment of severely depressed patients. It is mainly the tri- and tetracyclic antidepressant drugs that can be administered intravenously. However, these drugs have a less favourable safety profile than newer antidepressants, such as the selective serotonin reuptake inhibitors (SSRIs). Citalopram is the only SSRI that is available in a formulation for infusion. This double-blind, randomised, multicentre trial was designed to compare the efficacy and tolerability of citalopram infusion (40 mg per day) and citalopram tablet (40 mg per day).

METHODS

Patients were randomised to receive either placebo tablet plus citalopram infusion (the infusion group; n=135) or citalopram tablet plus placebo infusion (the tablet group; n=119). After receiving randomised treatment for eight days, all patients entered an open treatment phase, during which they received oral citalopram 40 mg per day for five weeks.

RESULTS

Although there was no difference in Montgomery-Asberg Depression Rating Scale (MADRS) scores at the end of the randomised treatment period, by the end of the open treatment phase the reduction in MADRS scores was significantly greater in the infusion group than in the tablet group (p=0.015). The infusion group also showed superior efficacy in Clinical Global Impressions assessments. Citalopram was equally well tolerated in both treatment groups.

CONCLUSIONS

This trial confirmed the efficacy of citalopram 40 mg per day, and clearly supports the use of citalopram infusion in the treatment of severely depressed, hospitalised patients.

Neuropharmacology of paradoxic weight gain with selective serotonin reuptake inhibitors

It has been suggested that weight gain associated with tricyclic antidepressants (TCA) reflect actions on dopamine (DA) and histamine receptors. However, a definitive cause is purely assumptive given the nonselective pharmacology of these agents. The selective serotonin reuptake inhibitors (SSRIs), as well as agents like dexfenfluramine (DFF), have emphasized the pivotal role of serotonin (5HT) in reducing carbohydrate (CHO) intake, and have provided a more selective tool with which to study appetite regulation. It would be expected that all SSRIs should exert a similar anorectic action. However, recent reports provide evidence to the contrary. Despite their claimed selectivity, SSRIs still interact, either directly or indirectly, with various critical neurotransmitter systems. In addition, although the anorectic action of fluoxetine (FLX) is well recognized, long-term follow-up studies in depressed patients and in obese nondepressed patients reveal that its weight-reducing effects are transient, even leading to a gain in body weight. Similarly, paroxetine (PRX) and citalopram (CTP) have also been associated with weight gain. These latter observations are unexpected because PRX and CTP are highly potent and selective SSRIs. A neuropharmacologic rationale for the apparent paradoxic effects of SSRIs on appetite not a review of neuronal regulation of appetite is presented in this article. As with the regulation of feeding, paradoxic weight gain observed with SSRIs appears to rest on the interaction of 5HT with multiple mechanisms, with the extent of weight gain observed being dependent on subtle, yet important pharmacologic differences within the group. Finally, the neurobiology of depressive illness itself, and of recovery from it, is a major contributing factor to individual response to these drugs.

A double-blind double-dummy study of citalopram comparing infusion versus oral administration

BACKGROUND

This study compares antidepressant efficacy and tolerability of citalopram given either orally or as a slow drop infusion.

METHODS

Citalopram (40 mg/day) was administered double-blindly as tablets or slow-drop infusion during the first 10 days and then open, orally, up to treatment Day 42.

RESULTS

In 60 moderately to severely depressed patients, the Hamilton depression total score (17-items) at baseline was 23.9 and 23.6 in the active infusion (n = 30) and active tablet (n = 30) group, respectively. These scores dropped in both groups to 15.6 and 16.9 on Day 10, and to 10.3 and 10.2 on Day 42. Response rates (delta Hamilton > or = 50%) amounted to 33.3% and 17.9% on Day 10, and 66.2% and 63.3% on Day 42, without a relevant group difference in citalopram plasma concentration.

CONCLUSION

Slow-drop infusion with citalopram shows a similar risk/benefit relationship to oral citalopram. The design of this study allowed us to evaluate pharmacological but not psychological factors which may contribute to response to slow-drop infusion.