Third-generation antidepressants: do they offer advantages over the SSRIs?

Pluronic F-68 Montmorillonite As A Drug Delivery Vehicle For Extended Release Of Venlafaxine Hydrochloride

Short half-life and low bioavailability of Venlafaxine hydrochloride (VF), an antidepressant drug, necessitates the frequent administration of VF tablets in a day in order to maintain adequate drug concentration in blood plasma. This generates the need for the development of formulations which could prolong the release of VF and reduce the multiple dosages. The present work explores the combination of Montmorillonite (Mt) with Pluronic F-68 (PF-68) (OrganoMT) for oral delivery of VF. The effect of various parameters including pH of aqueous drug solution, contact time and initial drug concentration on drug loading capacity of OrganoMT has been studied. The synthesized OrganoMT-VF complexes were characterized by various suitable techniques. XRD studies indicated that the VF molecules were intercalated within the OrganoMT layers. In vitro release behavior of VF from OrganoMT-VF complexes shows an extended-release pattern for a period of 30 h and reaches upto 70% and 60% compared to pure VF having complete release time of 5.5 h and 3.5 h in simulated gastric and intestinal fluid respectively. Various kinetic models were employed to elucidate the drug release mechanism where the best fitting was obtained with Korsmeyer Peppas model. The results suggest the possibility of designing an oral extended controlled release formulation for VF to minimize its administration frequency thereby increasing the effectiveness of drug. This improves patient compliance by reducing the dose from 4 times in 24 h to once in 24 h.

Loganin ameliorates depression-like behaviors of mice via modulation of serotoninergic system

RATIONALE

Depression is a serious neuropsychiatric disorder, which is characterized by sustaining mood disorders. Loganin, a major iridoid glycoside from Corni fructus, has a variety of pharmacological activities, including neuroprotective effect and hypnotic effect. However, little is known about the effects of loganin on stress-induced depression.

OBJECTIVE

To investigate the effects of loganin on behavioral despair of mice, and whether serotonin (5-HT) and/or noradrenaline (NE) are involved in this process.

METHODS

We tested the effectiveness of loganin using tail suspension test (TST). The possible mechanism was explored using reserpine-induced ptosis and hypothermia, and 5-HTP-induced head-twitch response in mice. The changes of 5-HT and NE in the prefrontal cortex, hippocampus, and striatum were measured through high-performance liquid chromatography (HPLC) analysis. Then, we identified the effects of depleting 5-HT and NE by PCPA (p-chlorophenylalanine) and DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride) pretreatment, respectively.

RESULTS

Loganin (12.5/50 mg/kg) induced antidepressant-like effects in mice submitted to TST. Loganin (12.5/50 mg/kg) ameliorated the reserpine-induced hypothermia and ptosis, as well as increased 5-HTP-induced head-twitch responses in mice. Loganin (50 mg/kg) significantly increased the levels of 5-HT in the prefrontal cortex, hippocampus, and striatum. Furthermore, only PCPA treatment could eliminate loganin-induced antidepressant-like effects in TST.

CONCLUSION

Loganin exerts antidepressant-like effect in the TST depending on 5-HT levels in the central nervous system, which provide a potential agent for depression therapy.

New generation antidepressants for depression in children and adolescents: a network meta-analysis

BACKGROUND

Major depressive disorders have a significant impact on children and adolescents, including on educational and vocational outcomes, interpersonal relationships, and physical and mental health and well-being. There is an association between major depressive disorder and suicidal ideation, suicide attempts, and suicide. Antidepressant medication is used in moderate to severe depression; there is now a range of newer generations of these medications.

OBJECTIVES

To investigate, via network meta-analysis (NMA), the comparative effectiveness and safety of different newer generation antidepressants in children and adolescents with a diagnosed major depressive disorder (MDD) in terms of depression, functioning, suicide-related outcomes and other adverse outcomes. The impact of age, treatment duration, baseline severity, and pharmaceutical industry funding was investigated on clinician-rated depression (CDRS-R) and suicide-related outcomes.

SEARCH METHODS

We searched the Cochrane Common Mental Disorders Specialised Register, the Cochrane Library (Central Register of Controlled Trials (CENTRAL) and Cochrane Database of Systematic Reviews (CDSR)), together with Ovid Embase, MEDLINE and PsycINFO till March 2020.

SELECTION CRITERIA

Randomised trials of six to 18 year olds of either sex and any ethnicity with clinically diagnosed major depressive disorder were included. Trials that compared the effectiveness of newer generation antidepressants with each other or with a placebo were included. Newer generation antidepressants included: selective serotonin reuptake inhibitors; selective norepinephrine reuptake inhibitors (SNRIs); norepinephrine reuptake inhibitors; norepinephrine dopamine reuptake inhibitors; norepinephrine dopamine disinhibitors (NDDIs); and tetracyclic antidepressants (TeCAs).

DATA COLLECTION AND ANALYSIS

Two reviewers independently screened titles/abstracts and full texts, extracted data, and assessed risk of bias. We analysed dichotomous data as Odds Ratios (ORs), and continuous data as Mean Difference (MD) for the following outcomes: depression symptom severity (clinician rated), response or remission of depression symptoms, depression symptom severity (self-rated), functioning, suicide related outcomes and overall adverse outcomes. Random-effects network meta-analyses were conducted in a frequentist framework using multivariate meta-analysis. Certainty of evidence was assessed using Confidence in Network Meta-analysis (CINeMA). We used "informative statements" to standardise the interpretation and description of the results.

MAIN RESULTS

Twenty-six studies were included. There were no data for the two primary outcomes (depressive disorder established via clinical diagnostic interview and suicide), therefore, the results comprise only secondary outcomes. Most antidepressants may be associated with a "small and unimportant" reduction in depression symptoms on the CDRS-R scale (range 17 to 113) compared with placebo (high certainty evidence: paroxetine: MD -1.43, 95% CI -3.90, 1.04; vilazodone: MD -0.84, 95% CI -3.03, 1.35; desvenlafaxine MD -0.07, 95% CI -3.51, 3.36; moderate certainty evidence: sertraline: MD -3.51, 95% CI -6.99, -0.04; fluoxetine: MD -2.84, 95% CI -4.12, -1.56; escitalopram: MD -2.62, 95% CI -5.29, 0.04; low certainty evidence: duloxetine: MD -2.70, 95% CI -5.03, -0.37; vortioxetine: MD 0.60, 95% CI -2.52, 3.72; very low certainty evidence for comparisons between other antidepressants and placebo). There were "small and unimportant" differences between most antidepressants in reduction of depression symptoms (high- or moderate-certainty evidence). Results were similar across other outcomes of benefit. In most studies risk of self-harm or suicide was an exclusion criterion for the study. Proportions of suicide-related outcomes were low for most included studies and 95% confidence intervals were wide for all comparisons. The evidence is very uncertain about the effects of mirtazapine (OR 0.50, 95% CI 0.03, 8.04), duloxetine (OR 1.15, 95% CI 0.72, 1.82), vilazodone (OR 1.01, 95% CI 0.68, 1.48), desvenlafaxine (OR 0.94, 95% CI 0.59, 1.52), citalopram (OR 1.72, 95% CI 0.76, 3.87) or vortioxetine (OR 1.58, 95% CI 0.29, 8.60) on suicide-related outcomes compared with placebo. There is low certainty evidence that escitalopram may "at least slightly" reduce odds of suicide-related outcomes compared with placebo (OR 0.89, 95% CI 0.43, 1.84). There is low certainty evidence that fluoxetine (OR 1.27, 95% CI 0.87, 1.86), paroxetine (OR 1.81, 95% CI 0.85, 3.86), sertraline (OR 3.03, 95% CI 0.60, 15.22), and venlafaxine (OR 13.84, 95% CI 1.79, 106.90) may "at least slightly" increase odds of suicide-related outcomes compared with placebo. There is moderate certainty evidence that venlafaxine probably results in an "at least slightly" increased odds of suicide-related outcomes compared with desvenlafaxine (OR 0.07, 95% CI 0.01, 0.56) and escitalopram (OR 0.06, 95% CI 0.01, 0.56). There was very low certainty evidence regarding other comparisons between antidepressants.

AUTHORS' CONCLUSIONS

Overall, methodological shortcomings of the randomised trials make it difficult to interpret the findings with regard to the efficacy and safety of newer antidepressant medications. Findings suggest that most newer antidepressants may reduce depression symptoms in a small and unimportant way compared with placebo. Furthermore, there are likely to be small and unimportant differences in the reduction of depression symptoms between the majority of antidepressants. However, our findings reflect the average effects of the antidepressants, and given depression is a heterogeneous condition, some individuals may experience a greater response. Guideline developers and others making recommendations might therefore consider whether a recommendation for the use of newer generation antidepressants is warranted for some individuals in some circumstances. Our findings suggest sertraline, escitalopram, duloxetine, as well as fluoxetine (which is currently the only treatment recommended for first-line prescribing) could be considered as a first option. Children and adolescents considered at risk of suicide were frequently excluded from trials, so that we cannot be confident about the effects of these medications for these individuals. If an antidepressant is being considered for an individual, this should be done in consultation with the child/adolescent and their family/caregivers and it remains critical to ensure close monitoring of treatment effects and suicide-related outcomes (combined suicidal ideation and suicide attempt) in those treated with newer generation antidepressants, given findings that some of these medications may be associated with greater odds of these events. Consideration of psychotherapy, particularly cognitive behavioural therapy, as per guideline recommendations, remains important.

Hippocampal MicroRNAs Respond to Administration of Antidepressant Fluoxetine in Adult Mice

Current antidepressant treatments to anxiety and depression remain inadequate, burdened by a significant percentage of misuse and drug side-effects, due to unclear mechanisms of actions of antidepressants. To better understand the regulatory roles of antidepressant fluoxetine-related drug reactions, we here investigate changes of expression levels of hippocampal microRNAs (miRNAs) after administration of fluoxetine in normal adult mice. We find that 64 miRNAs showed significant changes between fluoxetine treatment and control groups by analyzing 626 mouse miRNAs. Many miRNAs in response to fluoxetine are involved in neural-related signaling pathways by analyzing miRNA-target gene pairs using the Kyoto encyclopedia of genes and genomes (KEGG) and Gene Ontology (GO). Moreover, miRNAs with altered expression are mainly associated with the repression of the dopaminergic synapse signals, which may affect hippocampal function after fluoxetine treatment. Our results demonstrate that a number of miRNAs respond to antidepressants even in normal mice and may affect target gene expression, which supports the safety consideration of inappropriate treatment and off-label use of antidepressant drugs.

Newer v. older antidepressants in long-term pharmacotherapy: Revisiting… Prevention of relapse and recurrence of depression

There is much evidence from clinical trials that antidepressants help prevent relapse and recurrence of major depression. However, this is unlikely to hold true for all patients with depression, particularly those treated in primary care. Individual antidepressants are equally efficacious, so choice (as first-line treatment in general or for individual patients) is largely determined by differences in side-effects, even though many of these disappear during long-term treatment, owing to adaptation. Specific effects that are considered in choosing a drug include those on cognition, psychomotor performance and sexual function; drug interactions, lethality in overdose and the potential for teratogenicity are also considered. There are insufficient entirely objective and generally accepted data on pharmaco-economics to allow for confident recommendations on drug choice for long-term treatment. Drug acquisition costs must be considered by those with restricted budgets, and especially patients in developing countries where difference in cost between newer and older drugs can be translated into more food for a hungry family.

Efficacy and safety of escitalopram versus desvenlafaxine in the treatment of major depression: A preliminary 1-year prospective randomized open label comparative trial

Aim and Objective:

To compare efficacy and safety of escitalopram with desvenlafaxine in the treatment of major depression.

Materials and Methods:

A total of 60 patients of depression were randomized into two groups after meeting inclusion criterion. In the first 3 weeks, escitalopram 10 mg/day was given and then 20 mg/day for the next 3 weeks in group 1 (n = 30). Desvenlafaxine in the first 3 weeks was given 50 mg/day and 100 mg/day for the next 3 weeks in group 2 (n = 30). The parameters evaluated during the study were efficacy assessments byHamilton Scale of Rating Depression (HAM-D), Hamilton Rating Scale of Anxiety (HAM-A), and Clinical Global Impression (CGI). Safety assessments were done by UKU-scale.

Results:

Escitalopram and desvenlafaxine significantly (P < 0.001), reduced HAM-D, HAM-A, and CGI scores from their respective base lines. However, on comparison failed show any statistical difference at 3 and 6 weeks of treatment. Escitalopram and desvenlafaxine were both found to be safe and well-tolerated and there was not much difference between the two groups as evident from UKU Scale and their effect on various biochemical parameters.

Conclusion:

The present study demonstrated similar efficacy and safety in reducing depression and anxiety with both escitalopram and desvenlafaxine, but clinical superiority of one drug over the other cannot be concluded due to limitations of the small sample size.

Interactions between an antidepressant reboxetine and four classic antiepileptic drugs in the mouse model of myoclonic seizures

BACKGROUND

The incidence rate of depression among patients with epilepsy is relatively high. The basis of proper therapy is knowledge of drug interactions, which may enable to maximize therapeutic effects and minimize undesired effects of the combined treatment. The purpose of this study was to evaluate the influence of reboxetine, a selective norepinephrine reuptake inhibitor, on the seizure threshold and anticonvulsant effects of four classic antiepileptic drugs: valproate, phenobarbital, ethosuximide, and clonazepam. Moreover, we assessed the adverse effects of reboxetine and combinations of reboxetine with antiepileptic drugs on motor coordination and long-term memory.

METHODS

The subcutaneous pentylenetetrazole (PTZ) test in mice was used to determine effects of anticonvulsant activity of antiepileptic drugs and reboxetine. Undesired effects of either reboxetine or and its combinations with antiepileptics were evaluated in the chimney test (motor coordination) and the step-through passive-avoidance task (long-term memory).

RESULTS

Analysis of obtained results revealed that reboxetine given at doses of 10 and 15 mg/kg doses exhibits anticonvulsant activity expressed by increasing the median convulsive dose (CD(50)) for pentylenetetrazole (p < 0.01). However, the antidepressant did not affect the anticonvulsant action of antiepileptic drugs studied in this seizure model. Moreover, no adverse reactions were found after administration of reboxetine alone or in combinations.

CONCLUSION

If further research confirms the obtained results, reboxetine may be categorized as an antidepressant which can be safely administered to epileptic patients treated with valproate, phenobarbital, ethosuximide or clonazepam.

Interventions for preventing relapse and recurrence of a depressive disorder in children and adolescents

BACKGROUND

Depressive disorders often begin during childhood or adolescence. There is a growing body of evidence supporting effective treatments during the acute phase of a depressive disorder. However, little is known about treatments for preventing relapse or recurrence of depression once an individual has achieved remission or recovery from their symptoms.

OBJECTIVES

To determine the efficacy of early interventions, including psychological and pharmacological interventions, to prevent relapse or recurrence of depressive disorders in children and adolescents.

SEARCH METHODS

We searched the Cochrane Depression, Anxiety and Neurosis Review Group's Specialised Register (CCDANCTR) (to 1 June 2011). The CCDANCTR contains reports of relevant randomised controlled trials from The Cochrane Library (all years), EMBASE (1974 to date), MEDLINE (1950 to date) and PsycINFO (1967 to date). In addition we handsearched the references of all included studies and review articles.

SELECTION CRITERIA

Randomised controlled trials using a psychological or pharmacological intervention, with the aim of preventing relapse or recurrence from an episode of major depressive disorder (MDD) or dysthymic disorder (DD) in children and adolescents were included. Participants were required to have been diagnosed with MDD or DD according to DSM or ICD criteria, using a standardised and validated assessment tool.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed all trials for inclusion in the review, extracted trial and outcome data, and assessed trial quality. Results for dichotomous outcomes are expressed as odds ratio and continuous measures as mean difference or standardised mean difference. We combined results using random-effects meta-analyses, with 95% confidence intervals. We contacted lead authors of included trials and requested additional data where possible.

MAIN RESULTS

Nine trials with 882 participants were included in the review. In five trials the outcome assessors were blind to the participants' intervention condition and in the remainder of trials it was unclear. In the majority of trials, participants were either not blind to their intervention condition, or it was unclear whether they were or not. Allocation concealment was also unclear in the majority of trials. Although all trials treated participants in an outpatient setting, the designs implemented in trials was diverse, which limits the generalisability of the results. Three trials indicated participants treated with antidepressant medication had lower relapse-recurrence rates (40.9%) compared to those treated with placebo (66.6%) during a relapse prevention phase (odds ratio (OR) 0.34; 95% confidence interval (CI) 0.18 to 0.64, P = 0.02). One trial that compared a combination of psychological therapy and medication to medication alone favoured a combination approach over medication alone, however this result did not reach statistical significance (OR 0.26; 95% CI 0.06 to 1.15). The majority of trials that involved antidepressant medication reported adverse events including suicide-related behaviours. However, there were not enough data to show which treatment approach results in the most favourable adverse event profile.

AUTHORS' CONCLUSIONS

Currently, there is little evidence to conclude which type of treatment approach is most effective in preventing relapse or recurrence of depressive episodes in children and adolescents. Limited trials found that antidepressant medication reduces the chance of relapse-recurrence in the future, however, there is considerable diversity in the design of trials, making it difficult to compare outcomes across studies. Some of the research involving psychological therapies is encouraging, however at present more trials with larger sample sizes need to be conducted in order to explore this treatment approach further.

Newer generation antidepressants for depressive disorders in children and adolescents

BACKGROUND

Depressive disorders are common in young people and are associated with significant negative impacts. Newer generation antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), are often used, however evidence of their effectiveness in children and adolescents is not clear. Furthermore, there have been warnings against their use in this population due to concerns about increased risk of suicidal ideation and behaviour.

OBJECTIVES

To determine the efficacy and adverse outcomes, including definitive suicidal behaviour and suicidal ideation, of newer generation antidepressants compared with placebo in the treatment of depressive disorders in children and adolescents.

SEARCH METHODS

For this update of the review, we searched the Cochrane Depression, Anxiety and Neurosis Review Group's Specialised Register (CCDANCTR) to October 2011. The CCDANCTR includes relevant randomised controlled trials from the following bibliographic databases: CENTRAL (the Cochrane Central Register of Controlled Trials) (all years), EMBASE (1974 -), MEDLINE (1950 -) and PsycINFO (1967 -). We searched clinical trial registries and pharmaceutical company websites. We checked reference lists of included trials and other reviews, and sent letters to key researchers and the pharmaceutical companies of included trials from January to August 2011.

SELECTION CRITERIA

Published and unpublished randomised controlled trials (RCTs), cross-over trials and cluster trials comparing a newer generation antidepressant with a placebo in children and adolescents aged 6 to 18 years old and diagnosed with a depressive disorder were eligible for inclusion. In this update, we amended the selection criteria to include newer generation antidepressants rather than SSRIs only.

DATA COLLECTION AND ANALYSIS

Two or three review authors selected the trials, assessed their quality, and extracted trial and outcome data. We used a random-effects meta-analysis. We used risk ratio (RR) to summarise dichotomous outcomes and mean difference (MD) to summarise continuous measures.

MAIN RESULTS

Nineteen trials of a range of newer antidepressants compared with placebo, containing 3335 participants, were included. The trials excluded young people at high risk of suicide and many co-morbid conditions and the participants are likely to be less unwell than those seen in clinical practice. We judged none of these trials to be at low risk of bias, with limited information about many aspects of risk of bias, high drop out rates and issues regarding measurement instruments and the clinical usefulness of outcomes, which were often variously defined across trials. Overall, there was evidence that those treated with an antidepressant had lower depression severity scores and higher rates of response/remission than those on placebo. However, the size of these effects was small with a reduction in depression symptoms of 3.51 on a scale from 17 to 113 (14 trials; N = 2490; MD -3.51; 95% confidence interval (CI) -4.55 to -2.47). Remission rates increased from 380 per 1000 to 448 per 1000 for those treated with an antidepressant. There was evidence of an increased risk (58%) of suicide-related outcome for those on antidepressants compared with a placebo (17 trials; N = 3229; RR 1.58; 95% CI 1.02 to 2.45). This equates to an increased risk in a group with a median baseline risk from 25 in 1000 to 40 in 1000. Where rates of adverse events were reported, this was higher for those prescribed an antidepressant. There was no evidence that the magnitude of intervention effects (compared with placebo) were modified by individual drug class.

AUTHORS' CONCLUSIONS

Caution is required in interpreting the results given the methodological limitations of the included trials in terms of internal and external validity. Further, the size and clinical meaningfulness of statistically significant results are uncertain. However, given the risks of untreated depression in terms of completed suicide and impacts on functioning, if a decision to use medication is agreed, then fluoxetine might be the medication of first choice given guideline recommendations. Clinicians need to keep in mind that there is evidence of an increased risk of suicide-related outcomes in those treated with antidepressant medications.

Agomelatine suppresses locomotor hyperactivity in olfactory bulbectomised rats: a comparison to melatonin and to the 5-HT(2c) antagonist, S32006

The novel melatonergic agonist/5-HT(2C) antagonist agomelatine displays robust antidepressant properties in humans and is active in pre-clinical models predictive of antidepressant effects. In this study, we investigated its potential influence on the locomotor hyperactivity displayed by olfactory bulbectomised rats, a putative measure of potential antidepressant activity. In addition, we compared the actions of agomelatine to those of melatonin and S32006, a selective antagonist at 5-HT(2C) receptors. Vehicle, agomelatine (10 and 50mg/kg), melatonin (10 and 50mg/kg), S32006 (0.16mg/kg to 10mg/kg) and the prototypical tricyclic antidepressant, imipramine (10mg/kg), were administered by intraperitoneal injection for 14days to male, Sprague-Dawley sham-operated and bulbectomised rats. In agreement with previous studies, imipramine was active in the model and both the lower and higher doses of agomelatine also significantly and markedly reversed the bulbectomy-induced hyperactivity to a level comparable to that seen in sham operated animals, in which agomelatine exerted no effect. Similarly the 5-HT(2C) antagonist, S32006, dose-dependently and significantly attenuated hyperactivity of bulbectomised animals, albeit with a maximal effect somewhat less marked than that of agomelatine. On the other hand, melatonin did not affect the locomotor behaviour of bulbectomised rats. The activity of agomelatine in the model is consistent with its known antidepressant properties in the clinic.

Ameliorating effects of mirtazapine on visceral hypersensitivity in rats with neonatal colon sensitivity

BACKGROUND

The aim was to investigate the effects of mirtazapine on visceral hypersensitivity and gastric emptying in an established rodent model of colonic sensitization.

METHODS

Twenty colonic sensitized rats and 20 matched controls were used. Visceral sensitivity during colorectal distension (CRD) was assessed by the measurement of abdominal electromyogram (EMG) with the pressures of 20, 40, and 60 mmHg. Mirtazapine with doses of 1, 5, and 10 mg kg(-1) were administered orally. Gastric emptying and small intestinal transit were performed in a separated experiment after gavage of 1.5 mL of phenol red solution.

KEY RESULTS

(i) Visceral hypersensitivity after neonatal colonic sensitization was confirmed. (ii) Mirtazapine dose-dependently reduced visceral hypersensitivity in the colonic sensitized rats. The increases in EMG during CRD at 40, 60 mmHg were, 17.59 +/- 6.49 and 26.04 +/- 8.30, respectively, with saline session, and substantially reduced to 10.0 +/- 5.95 (P = 0.02 vs corresponding saline) and 12.58 +/- 7.43 (P < 0.001 vs saline) with mirtazapine at 10 mg kg(-1). Similar findings were noted at doses of 5 and 1 mg kg(-1) at a lesser degree. In the control rats, mirtazapine-reduced visceral sensitivity only during CRD at 60 mmHg. (iii) Mirtazapine 10 mg kg(-1) significantly accelerated gastric emptying (P = 0.045) but slightly and marginally delayed intestinal transit (P = 0.058) the colonic sensitized rats.

CONCLUSIONS & INFERENCES

Mirtazapine dose-dependently ameliorates visceral hypersensitivity in colonic sensitized rats. Mirtazapine at a high dose improves delayed gastric emptying in colonic sensitized rats but slightly and marginally delays small intestinal transit. Its roles in altering gastrointestinal motility need further investigation.

Comparison of the antidepressant effects of venlafaxine and dosulepin in a naturalistic setting

The relative efficacy of the various classes of antidepressants has not been established. Observational studies in naturalistic settings are important in evaluating treatment outcomes with antidepressants, since controlled clinical trials include only a minority of patients present in clinical practice. This study sought to evaluate in a naturalistic setting the treatment outcomes of dosulepin and venlafaxine for patients with depressive episodes. At the university hospital in Copenhagen, Denmark, between 1998 and early 2001, the first-line treatment for psychiatric inpatients with depression was dosulepin; after that time, venlafaxine was the first-line medication. We compared the treatment outcomes among inpatients during the respective periods. There was no significant difference in the primary outcome parameters between the two groups. A tendency in favour of dosulepin confirmed by a post-hoc analysis suggested that the failure to achieve significant difference was related to a type 2 error. However, missing data and possible confounders related to the different treatment periods weaken the results. This naturalistic study showed a non-significant trend for poorer treatment outcomes (probably because of an underpowered design) after replacing dosulepin with venlafaxine as first-line drug for depression in a naturalistic inpatient setting.

Limitations of current medical treatments for depression: disturbed circadian rhythms as a possible therapeutic target

The proportion of diagnosed depressives prescribed antidepressants has increased markedly over the last 20 years, mainly following the introduction of the selective serotonin reuptake inhibitors. However, currently available antidepressants have notable limitations, relating to their only moderate efficacy relative to placebo, relatively slow onset of action, possible withdrawal symptoms, and problems of compliance. Sleep disturbances are often used to identify newly presenting depressive patients, and may be part of a more general alteration of bodily rhythms. There are links between pharmacological treatments and circadian rhythms in depression, which might represent another, new option for the development of a therapeutic approach to depression treatment. Many antidepressants affect sleep, some are sedative, and others have been used specifically in severely insomniac depressives. Disturbances in circadian rhythms may be an integral part of depressive mechanisms, and normalising them via an innovative mechanism of antidepressant action may be a fruitful avenue in the search for improved antidepressant agents.

Validation and application of a stability-indicating HPLC method for the in vitro determination of gastric and intestinal stability of venlafaxine

Gastrointestinal stability of venlafaxine was evaluated in vitro in simulated gastric (SGF) and intestinal (SIF) fluids using a stability indicating HPLC method. The method was validated using a 5 microm Ascentis C18 column (150 mm x 4.6 mm) and mobile phase consisting of 30% acetonitrile in 20 mM potassium phosphate buffer (pH 6.5) delivered isocratically at a flow rate of 1 mL/min with UV detection at 228 nm. Venlafaxine in USP simulated gastric and intestinal fluids (0.4 mg/mL) was incubated at 37 degrees C in a shaking water bath. The gastric stability study samples were assayed at 0, 15, 30 and 60 min intervals while sampling for the intestinal stability study was at 0, 1, 2 and 3 h. System suitability determinations gave R.S.D.s of 0.68, 0.5 and 3.9% for retention factor (k'), peak area and tailing factor, respectively. The method was shown to be accurate, precise, specific, and linear over the analytical range. Intra- and inter-day precision was <5.3%. Forced degradation studies of drug substance in basic media at 70 degrees C as well as in H2O2 for 1 h and ultra-violet photostability studies at 255 and 365 nm for 24 h did not produce any detectable degradation products. Forced degradation studies of drug substance in acidic media at 70 degrees C for 1 h produced the dehydro-venlafaxine degradant. Venlafaxine was stable in SGF (pH approximately 1.2) for the 1-h incubation period and in SIF (pH 6.8) up to 3 h with <1.5% relative difference (RD) between the amount of drug added and that found for all time points. This stability experiment in simulated gastric and intestinal fluids suggests that drug loss in the gastrointestinal tract takes place by membrane permeation rather than a degradation process.

Duloxetine treatment of pediatric chronic pain and co-morbid major depressive disorder

In the United States, the novel compound duloxetine has been approved for the treatment of major depressive disorder (MDD) and diabetic peripheral neuropathic pain in the adult population. There are currently no published data on the use of duloxetine in children and adolescents. This report describes the successful treatment of 2 adolescent females with chronic pain and co-morbid MDD. Both patients required admission to a tertiary-care pediatric hospital due to the chronicity, severity, and treatment resistance of their pain syndromes. In both cases, duloxetine provided rapid improvement in the experience of pain, as well as mood symptoms, at minimum dosages. Pain symptom reduction and restoration of a euthymic state was maintained at 4- and 3-month follow-up visits, respectively, with minimal to no adverse effects being reported. These cases present preliminary evidence of promising uses for duloxetine in the pediatric population.

Emerging treatments for major depression

Antidepressant drugs were introduced into clinical practice in the mid-20th Century. While for the most part they have proven effective for the amelioration of depressive symptoms, they are associated with significant deficiencies. These well-recognized shortcomings have given impetus to the pursuit of new molecules that seek to improve on the efficacy, tolerability and safety of existing medications. The following article reviews several new compounds that may have antidepressant potential. Some are more advanced in development, having undergone clinical trials, whereas the clinical potential of others is yet to be explored. For this latter group of compounds, the antidepressant potential relies on their activity in validated animal models. Agomelatine and duloxetine are in the first category, having shown antidepressant efficacy in clinical trials. The blockade of cortisol secretion continues to be a focus of attention for the development of new antidepressants. Thus, synthesis inhibitors, nonpeptide antagonists of corticotropin-releasing factor and glucocorticoid receptor antagonists show some promise in clinical and preclinical tests. Antagonists of the neuropeptide substance P, vasopressin and neuropeptide Y represent a departure of approach from traditional monoamine receptor-based mechanisms. While the clinical results with one substance P antagonist have led to the cessation of further trials, other molecules are in development. Approaches to treatment based on glutamatergic transmission arose from observations in animal models. The clinical evaluation of such compounds awaits further development. The extent to which new agents can be judged to have met the goals of efficacy, tolerability and safety rely not only acute treatment trials but also on longer-term outcomes and postmarketing surveillance. Whether any of the new agents canvassed here prove to be significantly better than existing agents is clearly a judgement for the future.

Calcium-dependent interactions of the human norepinephrine transporter with syntaxin 1A

The norepinephrine (NE) transporter (NET) terminates noradrenergic signaling by clearing released NE at synapses. The activity of NET can be rapidly regulated by depolarization and receptor activation via Ca2+ and kinase/phosphatase-linked pathways. The SNARE protein syntaxin 1A (SYN1A) interacts with NET and influences transporter surface trafficking and catalytic activity. In this study, we establish a link between changes in intracellular Ca2+ and SYN1A/NET interactions. SYN1A influenced NE transport only in the presence of Ca2+ in brain cortical synaptosomes. Although NET/SYN1A associations were sensitive to manipulations of Ca2+ in CHO cells, in vitro binding experiments using purified NET and SYN1A fusion proteins demonstrated a lack of direct Ca2+ sensitivity. Disruption of NET/SYN1A interaction abolished inhibition of NE transport by phorbol ester (PMA) to activate protein kinase C (PKC), but had no effect on transport inhibition by the Ca2+ calmodulin kinase (CaMK) inhibitor KN93. Furthermore, PMA enhanced Ca2+-dependent modulation of NE transport in synaptosomes. Our data reveal roles for SYN1A in the Ca2+-dependent regulation of NET, likely reliant on regulation by PKC signaling, but independent of CaMK.

Escitalopram versus venlafaxine XR in the treatment of depression

This article reanalyses and reviews data from the two published randomized clinical trials comparing escitalopram and venlafaxine XR in the treatment of patients with major depressive disorder. The aim was to further compare the efficacy and tolerability of escitalopram and venlafaxine XR and to assess the impact of the two treatments on the patient's quality of life, as well as the benefit/risk of treatment. A total of 243 escitalopram-treated patients and 240 venlafaxine XR-treated patients were included in this analysis. Comparable treatment efficacy was achieved with respect to the prospectively defined primary efficacy endpoint (mean change from baseline in Montgomery Asberg Depression Rating Scale (MADRS) total score at week 8). An analysis of the outcome at the end of study by baseline severity showed that the treatment difference became greater the more severely depressed the patients were at baseline. At the highest permitted doses, in the subgroup of patients who were severely depressed (baseline MADRS > or =30), patients treated with escitalopram had a statistically significantly greater improvement (P<0.05) in mean MADRS total scores than patients treated with venlafaxine XR at endpoint. For these patients, treatment with 20 mg/day escitalopram resulted in a statistically significantly (P<0.05) higher remission rate at week 8 (47%) than treatment with venlafaxine XR (29%). This difference was confirmed by the analysis of the pooled data, which showed that patients in the escitalopram group had a significantly (P<0.05) higher mean number of depression-free days (30.4 days) than those in the venlafaxine XR group (26.2 days) over the 8-week period. The relative benefit of escitalopram versus venlafaxine XR was 1.46, indicating that a patient was more likely to benefit from treatment with escitalopram. The proportions of patients who withdrew owing to adverse events were 7.5% in the escitalopram group and 11.2% in the venlafaxine XR group. The mean number of discontinuation emergent signs and symptoms in the venlafaxine XR group (mean: 5.0) was significantly (P<0.001) higher than for the escitalopram group (mean: 2.4).

The pharmacological management of depression

Depressive disorders are common, recurrent, and chronic, and require treatment A review of the symptom picture and current drug targets demonstrates the need for accument of depression severity, including suicidaliltial focus of treatment is rapid resolution of: during an acute phase, followed by continuation. Maintenance treatment is indicated if the risk of recurrence is high. The range of available medications is considerable and the benefit/risk ratio is acceptable. Depression is diagnosable across the life span and treatable at every age (although recent disagreement has arisen with regard to young patients). Comorbidity, both psychiatric and medical, need to be assessed, as does the possible presence of two subtypes of depression (psychotic and bipolar) often requiring different interventions. It is expected that the next generation of antidepressants would be associated with more specific disease and outcome biomarkers.

The AGNP-TDM Expert Group Consensus Guidelines: focus on therapeutic monitoring of antidepressants

Therapeutic drug monitoring (TDM) of psychotropic drugs such as antidepressants has been widely introduced for optimization of pharmacotherapy in psychiatric patients. The interdisciplinary TDM group of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) has worked out consensus guidelines with the aim of providing psychiatrists and TDM laboratories with a tool to optimize the use of TDM. Five research-based levels of recommendation were defined with regard to routine monitoring of drug plasma concentrations: (i) strongly recommended; (ii) recommended; (iii) useful; (iv) probably useful; and (v) not recommended. In addition, a list of indications that justify the use of TDM is presented, eg, control of compliance, lack of clinical response or adverse effects at recommended doses, drug interactions, pharmacovigilance programs, presence of a genetic particularity concerning drug metabolism, and children, adolescents, and elderly patients. For some drugs, studies on therapeutic ranges are lacking, but target ranges for clinically relevant plasma concentrations are presented for most drugs, based on pharmacokinetic studies reported in the literature. For many antidepressants, a thorough analysis of the literature on studies dealing with the plasma concentration-clinical effectiveness relationship allowed inclusion of therapeutic ranges of plasma concentrations. In addition, recommendations are made with regard to the combination of pharmacogenetic (phenotyping or genotyping) tests with TDM. Finally, practical instructions are given for the laboratory practitioners and the treating physicians how to use TDM: preparation of TDM, drug analysis, reporting and interpretation of results, and adequate use of information for patient treatment TDM is a complex process that needs optimal interdisciplinary coordination of a procedure implicating patients, treating physicians, clinical pharmacologists, and clinical laboratory specialists. These consensus guidelines should be helpful for optimizing TDM of antidepressants.

L’escitalopram dans le traitement des épisodes dépressifs majeurs de l’adulte

Escitalopram is a selective serotonin reuptake inhibitor (SSRI); it is the therapeutically active S-enantiomer of the racemic mixture, citalopram. This review aimed to compare the efficacy and tolerability of escitalopram versus citalopram and several other SSRIs (citalopram, fluoxetine, paroxetine, sertraline), and a selective reuptake inhibitor of noradrenaline and serotonin, venlafaxine XR, for treatment of DSM IV (Diagnostic and Statistical Manual of mental disorders - fourth edition) major depressive disorder, based on the studies evaluated by the Commission de la Transparence de la R6publique Frangaise, and data from a pooled analysis presented in 2005 at the 158th annual congress of the American Psychiatric Association. Change from baseline to end-point on total MADRS (Montgomery-Asberg Depression Rating Scale--10 items, score range: 0-60) was the primary efficacy parameter; changes on HAM-D17 (Hamilton rating scale for depression--17 items), CGI-S and CGI-I (Clinical global Impression-Severity and-Improvement), and response rates (> or = 50% MADRS score reduction) and remissions (< 12 MADRS score) were the secondary efficacy parameters. Tolerability assessment was based on the numbers and rates of adverse events observed with treatment, and the DESS (Discontinuation Emergent Signs and Symptoms-43 items) scale was used for assessment of adverse events observed with treatment withdrawal. Analyses were based on intention to treat using the LOCF (last observation carried forward) method. Efficacy of escitalopram appeared to be at least equivalent to that of the active comparators in all cases. The difference between active compounds was more marked when depressive symptoms were more severe. From the point of view of tolerability, frequency of adverse effects occurring on treatment and the frequency of treatment discontinuations due to adverse effects were comparable with both escitalopram and the active comparators; however, the comparisons were mostly favourable to escitalopram, though differences were generally not statistically significant. In both studies of escitalopram versus venlafaxine XR, treatment discontinuations due to adverse events were less frequent on escitalopram than on venlafaxine XR (7.5% vs 11.2%, and 4.1% vs 16.0% respectively). With regard to adverse events associated with the withdrawal period, the signs and symptoms occurring on treatment discontinuation assessed after 1 week using the DESS scale were less frequent on escitalopram than on venlafaxine XR at 8 weeks and paroxetine at 24 weeks. Concerning suicide risk, a review of clinical trials involving 2277 patients on escitalopram and 1814 patients on placebo showed that this risk was minimal, and similar in both groups; moreover, no evidence was found suggesting that escitalopram might promote suicidal behaviour compared with placebo. These results suggest that escitalopram is suitable to be considered as a first-line drug treatment for major depressive disorder.

Safety and tolerability of duloxetine in the treatment of major depressive disorder: analysis of pooled data from eight placebo-controlled clinical trials

OBJECTIVE

To examine the safety and tolerability of the antidepressant duloxetine across multiple studies for major depressive disorder (MDD).

METHOD

Safety data were integrated from the acute phases of eight double-blind, placebo-controlled trials in which patients were randomized to duloxetine (40-120 mg/d; n = 1139) or placebo (n = 777) for up to 9 weeks. This data set included all acute-phase clinical trials that formed the basis of the New Drug Application (United States) or European Union submission package for duloxetine in the treatment of MDD. Two studies included continuation phases in which acute treatment responders received duloxetine or placebo for an additional 26 weeks. Safety assessments included serious adverse event reports, rates of discontinuation, spontaneously reported treatment-emergent adverse events, changes in vital signs and laboratory values, and electrocardiograms.

RESULTS

The rates of serious adverse events for duloxetine- and placebo-treated patients were 0.3% and 0.6%, respectively (p = 0.282). Adverse events led to discontinuation in 9.7% of duloxetine-treated patients, compared with 4.2% of patients receiving placebo (p < 0.001). Treatment-emergent adverse events with an incidence for duloxetine > or = 5.0% and significantly greater than placebo were nausea, dry mouth, constipation, insomnia, dizziness, fatigue, somnolence, increased sweating and decreased appetite. Mean changes in blood pressure and heart rate were small, and the incidence of increases above normal ranges was low. Duloxetine-treated patients had a mean decrease in weight of 0.5 kg compared with an increase of 0.2 kg for patients receiving placebo (p < 0.001). No significant differences were found between duloxetine and placebo in the incidence of potentially clinically significant laboratory values at anytime while on treatment.

CONCLUSION

These results are consistent with those obtained previously from smaller pooled data sets, and suggest that duloxetine is safe and well tolerated in patients with MDD.

A comparison of the direct costs and cost effectiveness of serotonin reuptake inhibitors and associated adverse drug reactions

BACKGROUND

The economic burden of depression is known to be high and was estimated to be USD 83.1 billion in 2000. Serotonin reuptake inhibitors (SRIs), including both selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs), have a superior adverse effect and safety profile relative to traditional agents (e.g. TCAs), and as a result have demonstrated superior cost effectiveness. Although efficacy across the SRIs is similar, the incidence of adverse drug reactions (ADRs) within SRIs remains significant and varies by agent. Patients who experience ADRs from SRIs may seek medical care, require additional treatment, and even discontinue treatment altogether, leading to increased utilisation and cost of therapy.

OBJECTIVE

This study estimates the direct cost and cost effectiveness, taking into account the impact of treatment-related ADRs, of eight currently marketed SRIs (citalopram, escitalopram, generic fluoxetine, paroxetine, paroxetine controlled release [CR], sertraline, venlafaxine and venlafaxine extended release [XR]) used as initial treatment for depression.

METHODS

A decision analytic model with a 6-month treatment goal was used to estimate the direct cost and cost effectiveness of treatment from the managed care/payer perspective. Estimates of SRI-related ADRs, associated treatments and costs were derived from the US FDA-approved prescribing information and published literature. Efficacy was assumed to be similar across all SRIs. Effectiveness was measured using quality-adjusted life years (QALY) based on EuroQol EQ-5D scores derived from the 2000 Medical Expenditure Panel Survey (MEPS). Censored least absolute deviations (CLAD) regression analysis was used to derive age-adjusted estimates of utility for all health states. Univariate and Bayesian second-order multivariate probabilistic sensitivity analyses were conducted to examine the impact of uncertainty in the parameter estimates.

RESULTS

The expected direct cost and cost effectiveness of treatment from least to most expensive were: escitalopram (USD 3891; 0.341), citalopram (USD 3938; 0.340), generic fluoxetine (USD 4034; 0.335), venlafaxine XR (USD 4226; 0.336), sertraline (USD 4250; 0.335), generic paroxetine (USD 4385; 0.332), paroxetine CR (USD 4440; 0.332) and venlafaxine (USD 4613; 0.326). Monte Carlo simulation results suggested that escitalopram was the most likely (77%) to be cost effective for a willingness to pay < or = USD 50,000 per QALY, followed by citalopram (22%), generic fluoxetine (0.3%) and all other SRIs (0%). Sensitivity analyses indicated that the results of the study were robust to the assumptions underpinning the model.

CONCLUSIONS

SRI-related ADRs have a significant impact on the direct cost and cost effectiveness of treatment. Escitalopram, with the lowest ADR rate of the SRIs, had the lowest expected treatment cost and greatest effectiveness when compared with citalopram, generic fluoxetine, generic paroxetine, paroxetine CR, sertraline, venlafaxine and venlafaxine XR.

Economic considerations in the prescribing of third-generation antidepressants

A comprehensive, multinational literature search was conducted of all articles published from 1993 to 2003 regarding the cost effectiveness of antidepressant drugs, with special emphasis on comparing third-generation antidepressants (TGAs) with tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). Information from the collected articles was entered into a database and then analysed to assess the different approaches to cost effectiveness comparisons for the various classes of antidepressants. Factors examined included direct and indirect costs, treatment endpoints, healthcare cost burden and productivity gains for patients successfully treated for depression. Most model-based studies published between 1993 and 2003 supported the cost effectiveness of TGAs compared with TCAs or SSRIs. While the purchase price of TGAs may be greater, cost savings in terms of direct and indirect costs were realised because of the reduced adverse effects of TGAs and subsequent improved patient compliance. Studies based on patient level cost data, however, were less conclusive about the economic benefits of TGAs compared with SSRIs or TCAs. While it may be premature to conclude that TGAs have a significant net economic benefit compared with other antidepressant classes, prescribers and payers may find it helpful when choosing antidepressants for depressed patients to consider that the higher drug prices for TGAs may be offset by savings, in terms of their greater compliance and resultant therapeutic success rates compared with TCAs or SSRIs. Additional research is needed to clarify how cost effectiveness is assessed in different patient populations, such as geriatric patients--who commonly have more co-morbidities and higher total healthcare costs than other patient populations.

Comparaison de deux outils de mesure des effets indésirables d’un traitement antidépresseur : la notification spontanée et l’échelle UKU

BACKGROUND AND AIM OF THE STUDY

Overall, the efficacy of the newer antidepressants: serotonin selective reuptake inhibitors (SSRI), selective serotonin/norepinephrine reuptake inhibitor (SNRI), noradrenergic and specific serotonergic antidepressant (NaSSA) and tianeptine is similar to that of the tricyclics, and so their acceptability/safety becomes a selection criterion for the clinician. However, side-effect assessment comes up against several difficulties: distinguishing between somatic symptoms caused by the depression and those caused by the treatment -- which assessment tool to use (spontaneous notification, standardized scales that are not specific for the side effects caused by psychotropic drugs, standardised scales specific for the side effects caused by psychotropic drugs, meta-analysis, etc.) -- which data sources to consult (anecdotal reports, reviews, prospective studies), and which data set to use, etc. As a result, the question of the exhaustiveness and reliability of the data consulted by the clinician can arise. We therefore conducted a comparative study in patients treated with these newer antidepressants, of 2 antidepressants side-effect assessment tools: spontaneous notification (SN) versus the UKU scale, a standardised scale specific for the side effects of psychotropic drugs.

METHODOLOGY

The depressed outpatients were selected from a psychiatric unit in a French psychiatric hospital and from a non-hospital consulting room. The main inclusion criteria were: male or female subjects, suffering from major depression without melancholia or psychotic features or suffering from mood disorders (according to DSM IV criteria), who had been treated for at least 4 weeks with one of the newer antidepressants. The main exclusion criteria were: any other psychiatric disorder, a serious physical disorder, treatment with neuroleptics, mood-changing drugs or other antidepressants, and patients who were not able to understand the questionnaire. The investigation was carried out by a clinical pharmacist.

RESULTS

Fifty patients were included in the study. There were 18 men and 32 women. The mean age was 53.5 15.9 years [22 - 77], the mean period of treatment was 24 30.5 months [1 - 127] and 52% of the patients received concomitant medication with anxiolitic or hypnotic drug(s). The percentage of patients who reported at least one side effect was significantly higher for the UKU scale than for SN (84% vs 58%, p<0.01). The ratio between SN and UKU scale scores was 2/3. A similar pattern was found for the total number of side effects (n=177 vs n=47, p<0.001). The ratio between the total number of side effects for the SN and UKU scale was 1/4. The side effects were divided into five subgroups: psychiatric, neurovegetative, sexual, neurological and others. In all these subgroups, the number of side effects reported was significantly higher when the UKU scale was used than when SN was used. The values were as follows: psychiatric (n=44 vs n=15, p<0.001), neurovegetative (n=59 vs n=15, p<0.001), sexual (n=36 vs n=10, p<0.001), neurological (n=11 vs n=2, p<0.001) and other side effects (n=27 vs n=5, p<0.001). Nineteen side effects were only reported when SN was used (for example: dry eyes, incompatibility with alcohol, euphoria...). Twenty-four side effects were only reported when the UKU scale was used (for example: increased libido, loss of bodyweight...). The side effects had no impact on daily life in most of 80% of the patients; there was no significant difference between the patient's assessment of the discomfort caused by side effects and the clinician's assessment. In 90% of cases, the side effects did not lead to any change in the treatment.

DISCUSSION

The findings of this study show that the collection of data regarding side effects depends on the assessment tool used: the number of side effects reported was significantly higher when the UKU scale was used than when SN was used. However, this finding must viewed with caution, because it has been showed that checklists can induce symptoms in suggestible patients. Neurovegetative troubles are the most commonly reported side effects, and neurological troubles the least often reported. This matches the tolerability profile of these antidepressants. The disorders that were least frequently spontaneously reported were the neurological, sexual and "other" side effects. These emerged only when the clinician asked the patient about them. The 19 side effects that were only reported when SN was used were side effects that were not included in the UKU scale or that had not been present during the three days before we started the investigation. The 34 side effects that were only reported when the UKU scale was used were either side effects with no apparent link with the treatment (for example: micturition troubles) or embarrassing effects (such as increased libido).

CONCLUSION

Our findings show that the collection of data on side effects depends on the assessment tool used. These findings need to be confirmed by large-scale comparative studies, and the standardization of the assessment of side effects is a question that needs to be raised.

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.

Extended release of a novel antidepressant, venlafaxine, based on anionic polyamidoamine dendrimers and poly(ethylene glycol)-containing semi-interpenetrating networks

The multiple daily administration of venlafaxine, a novel third-generation antidepressant, was reduced based on polyamidoamine and polyethylene glycol (PEG)-containing semi-interpenetrating network (IPN), respectively. Venlafaxine was covalently linked to water-soluble G2.5 anionic polyamidoamine dendrimer via a hydrolyzable ester bond. Semi-IPN hydrogels were prepared by crosslinking acrylamide in the presence of PEG, and venlafaxine with predetermined amounts was loaded in situ. Dendrimer-venlafaxine conjugate and semi-IPNs were characterized by proton nuclear magnetic resonance and Fourier transform infrared, respectively. The effect of PEG concentration and molecular weight was studied and discussed for an optimal controlled release.

The treatment of depression with different formulations of venlafaxine: a comparative analysis

Venlafaxine is the first of a group of antidepressants that show dual reuptake inhibition of serotonin and noradrenaline (SNRIs). Originally marketed in an immediate release (IR) formulation a microencapsulated, extended release (XR) formulation is now available. Significant differences exist between these two formulations with respect to pharmacokinetic parameters which have an impact on clinical use. The XR has lower maximum plasma concentrations (Cmax) and achieves these at a later time (higher Tmax). The longer apparent elimination half-life of the drug after single XR doses suggests that it is suitable for once daily dosing compared with the twice daily dosing regimen required by the IR formulation. With respect to antidepressant efficacy the XR formulation is equivalent to other marketed antidepressants and to the IR formulation. Consistent with its pharmacokinetic properties the use of the XR formulation is associated with less nausea and dizziness at the initiation of therapy. While in clinical usage XR might be expected to increase compliance with medication and to reduce discontinuation syndromes there are few comparative studies for which this has been evaluated. The XR formulation of venlafaxine is no worse than the IR form with respect to tolerability and offers some benefits to patients in terms of ease of use. On the other hand there does not appear to be any increase in the efficacy of the active agent.

New formulations of existing antidepressants: advantages in the management of depression

For nearly 50 years, antidepressant drugs have been the first-line treatment for various forms of depression. Despite their widespread use, these medications have significant shortcomings, in particular problems of patient compliance due to adverse effects. The introduction of new formulations of existing antidepressant medications may provide patients with benefits in terms of convenience of use. As a consequence, improvements in compliance may lead to better antidepressant efficiency.An orally disintegrating formulation of mirtazapine (mirtazapine SolTab), a once-weekly formulation of fluoxetine, an enantiomer-specific formulation of citalopram (escitalopram), an extended-release formulation of venlafaxine (venlafaxine XR), a controlled-release formulation of paroxetine (paroxetine CR) and intravenous formulations of some of the newer antidepressants have all been evaluated in limited clinical trials. In this article, a review of the pharmacokinetics and clinical evaluations of these formulations is presented. While there do not appear to be major clinical advantages for the new formulations in terms of antidepressant efficacy, none of them is less efficacious than their older counterpart. Indeed, some of the new formulations are more acceptable to patients (fluoxetine once-weekly, paroxetine CR), others have pharmacokinetic advantages (venlafaxine XR, paroxetine CR), while others may have a faster onset of effect (mirtazapine SolTab, intravenous formulations). Further evaluation of some formulations is still required (mirtazapine SolTab, fluoxetine once-weekly), while others (venlafaxine XR, escitalopram) are finding widespread acceptance in clinical practice.

Metabolic drug interactions with new psychotropic agents

New psychotropic drugs introduced in clinical practice in recent years include new antidepressants, such as selective serotonin reuptake inhibitors (SSRI) and 'third generation' antidepressants, and atypical antipsychotics, i.e. clozapine, risperidone, olanzapine, quetiapine, ziprasidone and amisulpride. These agents are extensively metabolized in the liver by cytochrome P450 (CYP) enzymes and are therefore susceptible to metabolically based drug interactions with other psychotropic medications or with compounds used for the treatment of concomitant somatic illnesses. New antidepressants differ in their potential for metabolic drug interactions. Fluoxetine and paroxetine are potent inhibitors of CYP2D6, fluvoxamine markedly inhibits CYP1A2 and CYP2C19, while nefazodone is a potent inhibitor of CYP3A4. These antidepressants may be involved in clinically significant interactions when coadministered with substrates of these isoforms, especially those with a narrow therapeutic index. Other new antidepressants including sertraline, citalopram, venlafaxine, mirtazapine and reboxetine are weak in vitro inhibitors of the different CYP isoforms and appear to have less propensity for important metabolic interactions. The new atypical antipsychotics do not affect significantly the activity of CYP isoenzymes and are not expected to impair the elimination of other medications. Conversely, coadministration of inhibitors or inducers of the CYP isoenzymes involved in metabolism of the various antipsychotic compounds may alter their plasma concentrations, possibly leading to clinically significant effects. The potential for metabolically based drug interactions of any new psychotropic agent may be anticipated on the basis of knowledge about the CYP enzymes responsible for its metabolism and about its effect on the activity of these enzymes. This information is essential for rational prescribing and may guide selection of an appropriate compound which is less likely to interact with already taken medication(s).

Neuropeptide Y (NPY) and depression: from animal studies to the human condition

Neuropeptide Y (NPY) is widely distributed throughout the central nervous system (CNS) and is one of the most conserved peptides in evolution, suggesting an important role in the regulation of basic physiological functions. In addition, both pre-clinical and clinical evidence have suggested that NPY, together with its receptors, may have a direct implication in several psychiatric disorders, including depression and related illnesses. NPY-like immunoreactivity and NPY receptors are expressed throughout the brain, with varying concentrations being found throughout the limbic system. Such brain structures have been repeatedly implicated in the modulation of emotional processing, as well as in the pathogenesis of depressive disorders. This review will concentrate on the distribution of NPY, its receptors, and the putative role played by this peptide in depressive illness based on both pre-clinical and clinical evidence.