SNaRIs, NaSSAs, and NaRIs: new agents for the treatment of depression

Modeling a negative response bias in the human amygdala by noradrenergic-glucocorticoid interactions

An emerging theme in the neuroscience of emotion is the question of how acute stress shapes, and distorts, social-emotional behavior. The prevailing neurocircuitry models of social-emotional behavior emphasize the central role of the amygdala. Acute stress leads to increased central levels of norepinephrine (NE) and cortisol (CORT), and evidence suggests that these endogenous neuromodulators synergistically influence amygdala responses to social-emotional stimuli. We therefore hypothesized that amygdala responses to emotional facial expressions would be susceptible to pharmacologically induced increases in central NE and CORT levels. To specifically test this hypothesis, we measured amygdala activation to emotional faces using functional magnetic resonance imaging in 62 healthy subjects under four pharmacological conditions: (1) single oral dose of placebo, (2) 4 mg of the selective NE-reuptake inhibitor reboxetine (RBX), (3) 30 mg of hydrocortisone, or (4) both drugs in combination. We found that a decrease in amygdala activation to positive facial emotion was coupled with an increase in amygdala activation to negative facial emotion in the RBX-CORT combined challenge condition. In conclusion, a pharmacologically induced elevation of central NE and CORT levels in healthy subjects created a negative response bias in the amygdala that did not exist at baseline. Our results implicate a causative role of NE-CORT interactions in the emergence of a negative bias of cognitive and emotional functions which is germane in stress-related affective spectrum disorders.

Delusional disorder, somatic type treated with aripiprazole--mirtazapine combination

Delusional disorder, somatic type (DDST) is a rare psychiatric disorder and the treatment is mostly based on observations, due to the lack of well-organized studies. Initially, antipsychotics and especially pimozide were considered to be the pharmacological approach of choice but, subsequently, tryciclic anti-depressants and selective serotonin re-uptake inhibitors (SSRIs) were also suggested to be effective, implicating the serotonergic system in the pathophysiology of the disorder. We present the case of a female with DDST, who responded to aripiprazole-mirtazapine combination, a finding that is in accordance with the initial approach of this disorder as a part of the schizophrenic spectrum, but also supports the hypothesis of serotonin dysfunction in DDST.

Treatment of depression as part of end-of-life care

We present a case report of a severe treatment resistant major depressive episode in a patient with advanced cancer and limited life expectancy which resolved completely within 10 days of commencing combination therapy involving mirtazepine and paroxetine. Aggressive treatment of clinical depression even in the context of short life expectancy (that is, a short number of weeks) can dramatically reduce patient and family distress and improve quality of life.

Comparison of electron and chemical ionization modes by validation of a quantitative gas chromatographic-mass spectrometric assay of new generation antidepressants and their active metabolites in plasma

A gas chromatographic-mass spectrometric method (GC-MS) for the simultaneous determination of the 'new' antidepressants (mirtazapine, viloxazine, venlafaxine, trazodone, citalopram, mianserin, reboxetine, fluoxetine, fluvoxamine, sertraline, maprotiline, melitracen, paroxetine) and their active metabolites (desmethylmirtazapine, O-desmethylvenlafaxine, m-chlorophenylpiperazine, desmethylcitalopram, didesmethylcitalopram, desmethylmianserin, desmethylfluoxetine, desmethylsertraline, desmethylmaprotiline) in plasma using different ionization modes was developed and validated. Sample preparation consisted of a strong cation exchange mechanism and derivatisation with heptafluorobutyrylimidazole. The GC separation was performed in 24.8 min. Identification and quantification were based on selected ion monitoring in electron (EI) and chemical ionization (CI) modes. Calibration by linear and quadratic regression for electron and chemical ionization, respectively, utilized deuterated internal standards and a weighing factor 1/x(2). Limits of quantitation were established between 5 and 12.5 ng/ml in EI and positive ionization CI (PICI), and 1 and 6.25 ng/ml in negative ionization CI (NICI). During validation stability, sensitivity, precision, accuracy, recovery, and selectivity were evaluated for each ionization mode and were demonstrated to be acceptable for most compounds. While it is clear that not all compounds can be quantitated either due to chromatographic (trazodone) or derivatisation problems (O-desmethylvenlafaxine), this method can quantitate most new antidepressants (ADs) in the therapeutic range using EI. PICI and NICI lead to higher selectivity. Moreover, NICI is of interest for small sample volumes and high sensitivity requirements. This paper draws the attention to the pros and cons of the different ionization modes in the GC-MS analysis of these antidepressants in plasma.

Selegiline transdermal system in the treatment of depressive disorders

Selegiline is a selective irreversible inhibitor of monoamine oxidase (MAO)-B during low-dose oral treatment. Additional MAO-A inhibition occurs in higher dose ranges. Selegiline transdermal system (STS) shows a more potent MAO inhibition in comparison with orally administered selegiline, and at minimum doses of 20 mg/20 cm2 patch delivering 6 mg/24 h, no dietary restrictions, including low-tyramine food, are necessary. While oral selegiline has been used for years in the treatment of Parkinson’s disease, the US FDA recently approved the STS for use in treating major depression. Data from three randomized controlled trials showed a significantly better efficacy of STS in the treatment of unipolar major depression in comparison with placebo during 6–8 weeks of treatment. In addition, one long-term randomized controlled trial demonstrated the efficacy of the STS in relapse prevention of unipolar depression over 1 year. A total number of 515 depressed patients received STS during these studies. The tolerability profile of STS without dietary restrictions was excellent. The only side effects that were more frequent than with placebo were application-site reactions. No change in vital parameters and no hypertensive crisis have been recorded. Comparative studies including treatment with established antidepressants and the investigation of bipolar depressed patients and of specific patient subgroups (e.g., anergic and atypical depression) have to follow. The combination of the well-known effectiveness of irreversible MAO inhibitors with a good tolerability profile and a new pharmaceutical form, possibly enhancing compliance, represents a promising further expansion of the pharmacotherapeutic repertoire in the treatment of depression.

Receptor occupancy of mirtazapine determined by PET in healthy volunteers

RATIONALE

Molecular tools are needed for assessing anti-depressant actions by positron emission tomography (PET) in the living human brain.

OBJECTIVES

This study determined whether [(11)C]mirtazapine is an appropriate molecular tool for use with PET to estimate the magnitude of neuroreceptor occupancy produced by daily intake of mirtazapine.

METHODS

This study used a randomised, double-blind, placebo-controlled, parallel-group, within-subject design. Eighteen healthy volunteers were PET-scanned twice with [(11)C]mirtazapine; once under baseline condition and again after receiving either placebo or mirtazapine (7.5 or 15 mg) for 5 days. We determined kinetic parameters of [(11)C]mirtazapine in brain regions by the simplified reference region method and used binding potential values to calculate receptor occupancy produced by mirtazapine.

RESULTS

Serum concentrations of mirtazapine ranged from 33 to 56 nmol/l after five daily doses of 7.5 mg mirtazapine and were between 41 and 74 nmol/l after 15 mg mirtazapine. Placebo treatment failed to alter the binding potential of [(11)C]mirtazapine from baseline values, whereas daily intake of mirtazapine markedly decreased the binding potential in cortex, amygdala and hippocampus. Receptor occupancy ranged from 74 to 96% in high-binding regions of the brain after five daily doses of 7.5 mg or 15 mg mirtazapine, whereas 17-48% occupancy occurred in low-binding regions.

CONCLUSIONS

[(11)C]Mirtazapine together with PET can determine the degree of receptor occupancy produced by daily doses of mirtazapine in regions of the living human brain.

Duloxetine: a review of its use in the treatment of major depressive disorder

Duloxetine (Cymbalta) is an orally administered, selective serotonin and noradrenaline reuptake inhibitor (SNRI) that has been approved for the treatment of major depressive disorder (MDD). Based on a considerable body of evidence, duloxetine at dosages ranging from 40 to 120 mg/day was effective in the short- and long-term treatment of MDD. Significant improvements versus placebo in core emotional symptoms as well as painful physical symptoms associated with depression, were seen in most, but not all, appropriately designed studies; results of meta-analyses suggested that improvements in these efficacy measures were apparent after 1-2 weeks' treatment with the highest recommended dosage of 60 mg once daily. Short-term (< or =15 weeks) administration of duloxetine at fixed or flexible dosages between 60 and 120 mg/day was noninferior to paroxetine 20 mg once daily, noninferior or inferior to escitalopram 10-20mg once daily, and had a similar global benefit-risk (GBR) profile to that of venlafaxine extended-release (XR) 150-225 mg/day in the treatment of MDD. Longer-term (6-8 months) treatment with duloxetine was similar in efficacy to paroxetine and escitalopram. Duloxetine is generally well tolerated, although it may be appropriate to avoid initiating treatment with the 60 mg/day dosage, as this has been associated with a higher discontinuation rate due to adverse events in some (but not all) comparative studies with escitalopram and venlafaxine XR. Definitive comparisons are awaited, although duloxetine seemingly provides a useful alternative to SSRIs and other SNRIs for the treatment of MDD. It also appears to be an attractive option for MDD patients presenting with painful physical symptoms.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Unipolar Depressive Disorders in Primary Care

These practical guidelines for the biological treatment of unipolar depressive disorders in primary care settings were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP). They embody the results of a systematic review of all available clinical and scientific evidence pertaining to the treatment of unipolar depressive disorders and offer practical recommendations for general practitioners encountering patients with these conditions. The guidelines cover disease definition, classification, epidemiology and course of unipolar depressive disorders, and the principles of management in the acute, continuation and maintenance phase. They deal primarily with biological treatment (including antidepressants, other psychopharmacological and hormonal medications, electroconvulsive therapy, light therapy).

Reliable HPLC method for therapeutic drug monitoring of frequently prescribed tricyclic and nontricyclic antidepressants

A new high-performance liquid chromatography method is presented for the determination of 10 frequently prescribed tricyclic and nontricyclic antidepressants: imipramine, amitriptyline, clomipramine, fluoxetine, sertraline, paroxetine, citalopram, mirtazapine, moclobemide and duloxetine. The simple and accurate sample preparation step, consisted of liquid:liquid extraction with recoveries ranging between 72% and 86%, except for moclobemide (59%). Separation was obtained using a reverse phase Select B column under isocratic conditions with UV detection (230 nm). The mobile phase consisted of 35% of a mixture of acetonitrile/methanol (92:8, v/v) and 65% of 0.25 mol L(-1) sodium acetate buffer, pH 4.5. The standard curves were linear over a working range of 2.5-1000 ng mL(-1) for moclobemide, 5-2000 ng mL(-1) for citalopram, duloxetine, fluoxetine, 10-2000 ng mL(-1) for sertraline, imipramine, paroxetine, mirtazapine and clomipramine. The intra-assay and inter-assay precision and accuracy were studied at three concentrations (50, 200, and 500 ng mL(-1)). The intra-assay coefficients of variation (CVs) for all compounds were less than 8.8%, and all inter-CVs were less than 10%. Limits of quantification were 2.5 ng mL(-1) for moclobemide, 5 ng mL(-1) for citalopram, duloxetine and amitriptyline, and 10 ng mL(-1) for mirtazapine, paroxetine, imipramine, fluoxetine, sertraline, and clomipramine. No interference of the drugs normally associated with antidepressants was observed. The method has been successfully applied to the analysis of real samples, for the drug monitoring of ten frequently prescribed tricyclic and non-tricyclic antidepressant drugs.

High-throughput on-line solid-phase extraction–liquid chromatography–tandem mass spectrometry method for the simultaneous analysis of 14 antidepressants and their metabolites in plasma

A rapid, sensitive and fully automated on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method was developed and validated for the direct analysis of 14 antidepressants and their metabolites in plasma. Integration of the sample extraction and LC separation into a single system permitted direct injection of the plasma without prior sample pre-treatment. The applied gradient ensured the elution of all the examined drugs within 14 min and produced chromatographic peaks of acceptable symmetry. The total process time was 20 min and only 50 microL of plasma was required. Selectivity of the method was achieved by a combination of retention time and two precursor-product ion transitions for the non-deuterated compounds. The use of SPE was demonstrated to be highly effective and led to significant decreases in the interferences present in the matrix. Extraction was found to be both reproducible and efficient with recoveries >99% for all the analytes. The method showed excellent intra-assay and inter-assay precision (relative standard deviation (RSD) and bias <20%) for quality control (QC) samples spiked at a concentration of 40, 200 and 800 microg/L and the r2>0.99 over the range investigated (10-1000 microg/L). Limits of quantification (LOQs) were estimated to be 10 microg/L. Furthermore, the processed samples were demonstrated to be stable for at least 48 h, except for clomipramine and norclomipramine, where a slight negative trend was observed, but did not compromise the quantification. The method was subsequently applied to authentic samples previously screened by a routine HPLC method with diode array detection (DAD).

Antidepressant pharmacotherapy: considerations for the pain clinician

Antidepressant pharmacotherapy presents many challenges to clinicians dealing with patients suffering from chronic pain. Co-existent depression and pain continues to present clinicians with a plethora of difficult treatment selections. Treated in isolation, each of these disease states can prove difficult to treat. Collectively, depression and pain often present significantly more difficult challenges to the clinician. Antidepressants may be used as a primary treatment modality for depression in a patient dealing with chronic pain. At other times these agents may be used to treat certain specific chronic pain syndromes, possibly in the face of concomitant depression. Clinicians should be aware of the many peculiarities associated with this broad class of medications. Included in this review are considerations for drug selection, dose escalation, and common drug related problems (eg, adverse drug reactions). In addition, attention is paid to the appropriate selection of an agent for use in either the primary management of pain or depression.

Novel pharmacotherapy for fibromyalgia

Fibromyalgia is a common disorder that is characterized by chronic widespread pain, tenderness to light palpation, fatigue and sleep disturbances. The present lack of a well-accepted model of the disorder has hampered progress towards adequate treatment. A review of potential models to explain the pathophysiology underlying its primary symptom (i.e., chronic widespread pain) lends insight on the therapeutic potential of novel therapies. Following this, a mechanistic evaluation of those medications that are under consideration for the treatment of the disorder is offered. Adequate treatment will be likely to involve the identification of biologic subgroups within the greater fibromyalgia construct. Key insights from basic research are the basis for increased optimism for effective relief among patients and clinicians.

Metabotropic glutamate receptor ligands as possible anxiolytic and antidepressant drugs

Depression and anxiety represent a major problem. However, the current treatment of both groups of diseases is not satisfactory. As the glutamatergic system may play an important role in pathophysiology of both depression and anxiety, we decided to discuss the recent data on possible anxiolytic and/or antidepressant effects of metabotropic glutamate (mGlu) receptor ligands. Preclinical data indicated that antagonists of group I mGlu receptors, particularly antagonists of mGlu5 receptors, produced both anxiolytic-like and antidepressant-like effects. Clinical data also demonstrated that mGlu5 receptor antagonist, fenobam, was an active anxiolytic drug. The anxiolytic effects exerted by mGlu5 receptor antagonists are profound, comparable with or stronger than those of benzodiazepines. However, the problem with the psychotomimetic activity of mGlu5 receptor antagonists and their possible influence on memory has to be further investigated. Among all mGlu receptor ligands, group II mGlu receptor agonists seem to be the drugs with the most promising therapeutic potential and a good safety profile. Animal studies showed anxiolytic-like effects of group II mGlu receptor agonists. Currently, group II mGlu receptor agonists are in phase III clinical trials for potential treatment of anxiety disorders. On the other hand, data has been accumulated, indicating that antagonists of group II mGlu receptors have an antidepressant potential. Group III mGlu receptor ligands represent the least investigated group of mGlu receptors. However, preclinical data also indicates that ligands of these receptors, both agonists and antagonists, may have an anxiolytic-like and antidepressant-like potential.

The MAOA T941G polymorphism and short-term treatment response to mirtazapine and paroxetine in major depression

This study investigated the possible association of the MAOA T941G gene variant with differential antidepressant response to mirtazapine and/or paroxetine in 102 patients with major depression (DSM-IV criteria) participating in a randomized double-blind controlled clinical trial. Female mirtazapine-treated patients homozygous for the T-allele had a significantly faster and better treatment response than TG/GG-patients. In males, we failed to show an association between MAOA T941G gene variant and mirtazapine response. In the paroxetine-treated group, there were no significant differences in treatment response between MAOA T941G genotype groups. Time course of response and antidepressant efficacy of mirtazapine, but not paroxetine, seem to be influenced in a clinically relevant manner by this allelic variation within the MAOA gene, at least in female patients. An independent replication of our finding is needed. If replicated, genotyping of this locus could become a promising tool to predict response to mirtazapine treatment in females suffering from major depression.

Pharmacokinetics of mirtazapine: enantioselective effects of the CYP2D6 ultra rapid metabolizer genotype and correlation with adverse effects

Enantiomerically pure drugs and genotyping are promising approaches to achieve optimization in antidepressant therapy. Mirtazapine is a mixed noradrenergic serotoninergic antidepressant used as a racemate. We analyzed pharmacokinetics of its enantiomers in relation to CYP2D6 genotype and in relation to its adverse effects. Mirtazapine was enantioselectively absorbed from the gut with a rate constant of 0.2 min-1 for S+, but 0.08 min-1 for R- mirtazapine. Kinetics of R- mirtazapine was only marginally dependent on CYP2D6 genotype, but total clearance of the S+ enantiomer were 1.3, 2.3, and 3.4 L min-1 in poor, extensive, and ultrarapid metabolizers of CYP2D6 substrates with apparent substantial first-pass metabolism in rapid and ultrarapid metabolizers. Mirtazapine effects on heart rate and blood pressure correlated much more strongly with R- then with S+ concentrations, whereas sedation correlated similarly with both enantiomers. At least concerning some adverse effects, it might be worthwhile to study further mirtazapine enantiospecifically.

Role of atypical opiates in OCD. Experimental approach through the study of 5-HT(2A/C) receptor-mediated behavior

RATIONALE

The selective serotonin (5-HT) reuptake inhibitors (SSRIs) represent the first-line pharmacotherapy for obsessive-compulsive disorder (OCD), and atypical antipsychotic drugs, which block 5-HT2A receptors, are used in augmentation strategies. Opiate drugs are also effective in treatment-refractory OCD and Tourette syndrome. The 5-HT2A-related behavior (i.e., head twitch) has been related with tics, stereotypes, and compulsive symptoms observed in Tourette syndrome and OCD.

OBJECTIVES

The aim of this study was to explore whether 5-HT2A-related behavior is affected by atypical opiate drugs.

MATERIALS AND METHODS

Head-twitch response was induced in mice by administration of either 5-hydroxytryptophan (5-HTP) or the 5-HT2A/C agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Dose-effect curves of atypical opiate drugs [(+/-)-tramadol, (-)-methadone and levorphanol], morphine, and other psychoactive drugs (fluvoxamine, desipramine, nefazodone, and clozapine) were performed. Opioid mechanisms were investigated by administration of naloxone.

RESULTS

All the opiates tested reduced both 5-HTP and DOI-induced behavior in a naloxone-reversible fashion, atypical opiates being more effective. The effects of the other drugs depended on the protocol, clozapine being the most effective.

CONCLUSIONS

Combined 5-HT and opioid properties result in a greater efficacy in antagonizing 5-HT2A-related behavior. These results provide behavioral evidence to support convergent effects of the 5-HT and opioid systems in discrete brain areas, offering the potential for therapeutic advances in the management of refractory stereotypes and compulsive behaviors.

Characterization of the trace-level impurities in the bulk drug citalopram by high-performance liquid chromatography/tandem multistage mass spectrometry

Five trace impurities were detected in the bulk drug citalopram using high-performance liquid chromatography with UV detection. A simple and sensitive method suitable for liquid chromatography tandem multistage mass spectrometry (HPLC/MS(n)) analysis was developed. Using this method, the fragmentation behavior of citalopram and the impurities was investigated. Four impurities were rapidly characterized, and an unknown impurity was elucidated as 3-(3-dimethylaminopropyl)-N-(1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-yl)-3-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carboxamide on the basis of the MS(n) and exact mass evidence, and the proposed structure was further confirmed by nuclear magnetic resonance (NMR) experiments after preparative isolation.

Antidepressants and sexual dysfunction

OBJECTIVE

Many patients with depression suffer from sexual dysfunction and sexual dysfunction is a recognized side-effect of antidepressants. The aim of this review was to examine the prevalence of psychosexual dysfunction associated with antidepressants, and to review treatment options which are specific to the affected component of sexual functioning and antidepressants.

METHOD

Comprehensive literature review using Medline and Cochrane databases.

RESULTS

Up to 70% of patients with depression may have sexual dysfunction. Tricyclic antidepressants, selective-serotonin reuptake inhibitors and venlafaxine are most and the non-serotonergic antidepressants and duloxetine least likely to produce sexual dysfunction. Pharmacological treatment options include antidepressants less likely associated or 'antidotes' to reverse sexual dysfunction.

CONCLUSION

Sexual dysfunction may be a preventable or treatable side-effect of antidepressants. Patients need routinely to be asked about sexual function to identify problems early. If sexual dysfunction is ignored it may maintain the depression, compromise treatment outcome and lead to non-compliance.

A role for serotonin (5-HT) in hepatic stellate cell function and liver fibrosis

Hepatic stellate cells (HSCs) are key cellular components of hepatic wound healing and fibrosis. There is emerging evidence that the fibrogenic function of HSCs may be influenced by neurochemical and neurotrophic factors. This study addresses the potential for the serotonin (5-HT) system to influence HSC biology. Rat and human HSCs express the 5-HT1B, 5-HT1F 5-HT2A 5-HT2B, and 5-HT7 receptors, with expression of 5-HT1B 5-HT2A and 5-HT2B being induced on HSC activation. Induction of 5-HT2A and 5-HT2B was 106+/-39- and 52+/-8.5-fold that of quiescent cells, respectively. 5-HT2B was strongly associated with fibrotic tissue in diseased rat liver. Treatment of HSCs with 5-HT2 antagonists suppressed proliferation and elevated their rate of apoptosis; by contrast 5-HT was protective against nerve growth factor-induced apoptosis. 5-HT synergized with platelet-derived growth factor to stimulate increased HSC proliferation. HSCs were shown to express a functional serotonin transporter and to participate in both active uptake and release of 5-HT. We conclude that HSCs express key regulatory components of the 5-HT system enabling them to store and release 5-HT and to respond to the neurotransmitter in a profibrogenic manner. Antagonists that selectively target the 5-HT class of receptors may be exploited as antifibrotic drugs.

PET neuroimaging of [11C]mirtazapine enantiomers in pigs

Previously, we used positron emission tomography (PET) for studying the pharmacokinetics of rac-[11C]mirtazapine in living brain. Our findings showed that rac-[11C]mirtazapine has suitable properties for PET neuroimaging. However, separate studies of enantiomers are typically required for characterizing the pharmacokinetics of a racemic drug. Therefore, we have determined the whole-body distribution and brain pharmacokinetics of S- and R-[11C]mirtazapine in pigs. The enantiomers of [11C]mirtazapine produced similar effective doses of radioactivity in most body organs, except for the brain, in which the dose was approximately 40% higher after injection of S-[11C]mirtazapine than the antipode. Kinetic analyses of dynamic brain PET recordings showed that values for regional accumulation of compound (k3) were significantly higher for S-[11C]mirtazapine than for the antipode, while the values for clearance of compounds from tissue to circulation (k2) were consistently lower for S-[11C]mirtazapine than for the R-form. No reliable difference occurred in the rate of metabolism of S- and R-[11C]mirtazapine in the bloodstream of the pigs. The present findings indicate that enantioselective processes affect the cerebral pharmacokinetics of rac-mirtazapine.

Multi-target strategies for the improved treatment of depressive states: Conceptual foundations and neuronal substrates, drug discovery and therapeutic application

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a high social cost. Depressed patients generally display co-morbid symptoms, and depression frequently accompanies other serious disorders. Currently available drugs display limited efficacy and a pronounced delay to onset of action, and all provoke distressing side effects. Cloning of the human genome has fuelled expectations that symptomatic treatment may soon become more rapid and effective, and that depressive states may ultimately be "prevented" or "cured". In pursuing these objectives, in particular for genome-derived, non-monoaminergic targets, "specificity" of drug actions is often emphasized. That is, priority is afforded to agents that interact exclusively with a single site hypothesized as critically involved in the pathogenesis and/or control of depression. Certain highly selective drugs may prove effective, and they remain indispensable in the experimental (and clinical) evaluation of the significance of novel mechanisms. However, by analogy to other multifactorial disorders, "multi-target" agents may be better adapted to the improved treatment of depressive states. Support for this contention is garnered from a broad palette of observations, ranging from mechanisms of action of adjunctive drug combinations and electroconvulsive therapy to "network theory" analysis of the etiology and management of depressive states. The review also outlines opportunities to be exploited, and challenges to be addressed, in the discovery and characterization of drugs recognizing multiple targets. Finally, a diversity of multi-target strategies is proposed for the more efficacious and rapid control of core and co-morbid symptoms of depression, together with improved tolerance relative to currently available agents.

Mirtazapine orally disintegrating tablets versus venlafaxine extended release: a double-blind, randomized multicenter trial comparing the onset of antidepressant response in patients with major depressive disorder

This randomized, multicenter, double-blind study was designed to compare specifically the onset of antidepressant action of mirtazapine orally disintegrating tablets (ODT) with venlafaxine extended-release (XR) formulation in outpatients with major depression. Both treatments were administered in a rapidly escalating dosing regimen. Target doses (mirtazapine ODT, 45 mg OD; venlafaxine XR, 225 mg OD) were reached by day 6 of treatment. On the primary efficacy parameter [the average of the change in HAM-D (17-item) total score on days 5, 8, 11, and 15], mirtazapine ODT was significantly superior to venlafaxine XR (P = 0.008). In addition, calculating the HAM-D score without the sleep items resulted in significant reductions in favor of mirtazapine ODT on days 8 (P = 0.006) and 11 (P = 0.037). The proportion of responders (HAM-D decrease of > or =50% from baseline) was higher in the mirtazapine ODT group on all assessment days, being significant on days 8 (P = 0.002), 11 (P = 0.004), and 22 (P = 0.027). More patients in the mirtazapine ODT group achieved remission (HAM-D total score of < or =7) up to day 29, and the difference was statistically significant on day 15 (P = 0.016). Significant differences in favor of mirtazapine ODT were evident in the CGI of change on days 8 (P = 0.019), 11 (P = 0.004), and 15 (P = 0.031), and the CGI of severity on days 8 (P = 0.014) and 11 (P = 0.033). Both treatments were well tolerated. These results indicate that mirtazapine ODT has a faster onset of antidepressant efficacy than venlafaxine XR in patients with major depressive disorder, and that this effect is independent of its sleep-improving properties.

Inhibition of [11C]mirtazapine binding by α2-adrenoceptor antagonists studied by positron emission tomography in living porcine brain

We have developed [(11)C]mirtazapine as a ligand for PET studies of antidepressant binding in living brain. However, previous studies have determined neither optimal methods for quantification of [(11)C]mirtazapine binding nor the pharmacological identity of this binding. To obtain that information, we have now mapped the distribution volume (V(d)) of [(11)C]mirtazapine relative to the arterial input in the brain of three pigs, in a baseline condition and after pretreatment with excess cold mirtazapine (3 mg/kg). Baseline V(d) ranged from 6 ml/ml in cerebellum to 18 ml/ml in frontal cortex, with some evidence for a small self-displaceable binding component in the cerebellum. Regional binding potentials (pBs) obtained by a constrained two-compartment model, using the V(d) observation in cerebellum, were consistently higher than pBs obtained by other arterial input or reference tissue methods. We found that adequate quantification of pB was obtained using the simplified reference tissue method. Concomitant PET studies with [(15)O]-water indicated that mirtazapine challenge increased CBF uniformly in cerebellum and other brain regions, supporting the use of this reference tissue for calculation of [(11)C]mirtazapine pB. Displacement by mirtazapine was complete in the cerebral cortex, but only 50% in diencephalon, suggesting the presence of multiple binding sites of differing affinities in that tissue. Competition studies with yohimbine and RX 821002 showed decreases in [(11)C]mirtazapine pB throughout the forebrain; use of the multireceptor version of the Michaelis-Menten equation indicated that 42% of [(11)C]mirtazapine binding in cortical regions is displaceable by yohimbine. Thus, PET studies confirm that [(11)C]mirtazapine affects alpha(2)-adrenoceptor binding sites in living brain.

Chiral resolution and binding study of 1,3,4,14b-tetrahydro-2,10-dimethyl-2H,10H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzotriazepine (10-methyl-10-azaaptazepine) and 2-methyl-1,3,4,14b-tetrahydro-2H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzothiadiazepine 10,10-dioxide (tiaaptazepine)

The affinities of the enantiomers of 1,3,4,14b-tetrahydro-2,10-dimethyl-2H,10H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzotriazepine (10-methyl-10-azaaptazepine, 5) and 2-methyl-1,3,4,14b-tetrahydro-2H-pyrazino[2,1-d]pyrrolo[1,2-b] [1,2,5]benzothiadiazepine 10,10-dioxide (tiaaptazepine, 6) were evaluated in receptor binding assays. Compound (+)-(S)-5, the most significant tested enantiomer, showed good affinities for 5-HT1A, 5-HT2A 5-HT2C and alpha2NA receptors, moderate affinities for DA1, DA3r and 5-HT3 receptors and it was devoid of affinity for DA2, alpha(1NA) and muscarinic receptors. Compound (+)-(S)-5 showed an interesting pharmacological profile different from those of the reference compounds mirtazepine, mianserin and 6-methoxymianserin.

Development of a solid phase extraction for 13 'new' generation antidepressants and their active metabolites for gas chromatographic-mass spectrometric analysis

A solid phase extraction procedure (SPE) for 13 'new' antidepressants (venlafaxine, fluoxetine, viloxazine, fluvoxamine, mianserin, mirtazapine, melitracen, reboxetine, citalopram, maprotiline, sertraline, paroxetine and trazodone) together with eight of their metabolites (O-desmethylvenlafaxine, norfluoxetine, desmethylmianserine, desmethylmirtazapine, desmethylcitalopram, didesmethylcitalopram, desmethylsertraline and m-chlorophenylpiperazine) from plasma is optimized using HPLC-DAD as monitoring system. Special attention has been paid to the choice of washing and eluting solvent, resulting in a highly concentrated, clean and moisture free extract, also suitable for GC-MS. A total number of 10 sorbents (apolar, polymeric, ion-exchange and mixed mode) was evaluated. Based on recovery, reproducibility and absence of interfering substances the strong cation exchanger gave the best results. Recoveries were determined at low and high therapeutic and toxic levels and ranged between 70 and 109% for all compounds, except for trazodone (39%).

Evaluation of low-dose venlafaxine hydrochloride for the therapy of hot flushes in breast cancer survivors

OBJECTIVE

To evaluate the efficacy and tolerability of long-term treatment with venlafaxine at low dose for the reduction of vasomotor symptoms in breast cancer survivors.

DESIGN

Forty consecutive breast cancer patients suffering troublesome hot flushes have been treated for 8 weeks with venlafaxine XR 37.5 mg/day in an open-label study. Vasomotor symptoms have been evaluated before starting treatment and every 4 weeks with a hot flushes diary pointing out the number and the severity of vasomotor symptoms. A Beck Depression Inventory (BDI) was completed at baseline and at the end of the treatment.

RESULTS

Thirty patients had completed the first 4 weeks of treatment, reporting a reduction of hot flushes frequency of 39% as compared to baseline (p<0.001). After 8 weeks of treatment, a further significant reduction was observed both for the hot flushes frequency (-53%; p<0.001) and for the hot flushes score (-59%; p<0.001), a measure which reflects both the number and the severity of hot flushes. Very few side effects were reported, mostly nausea in the first 2 weeks of assumption and mouth dryness. Only 23 women had completed BDI at week 8; a reduction of 23% was observed (p=0.000).

CONCLUSION

Venlafaxine is an effective treatment for the relief of vasomotor symptoms in patients previously treated for breast cancer. A favourable effect is maintained also in those patients using tamoxifen as adjuvant therapy. The use of the low dose (37.5 mg/day) is associated with minimal side effects and produces a good improvement in hot flushes if pursued over 8 weeks.

Effect of mirtazapine treatment on serotonin transporter in blood peripheral lymphocytes of major depression patients

Lymphocytes from human peripheral blood exhibit a series of markers of neurotransmitters, such as specific receptors and transporters. A reduction of serotonin transporters and an increase of them has been reported after treatment with fluoxetine in depressed patients. The aim of this study was to determine if the administration of an antidepressant with a different mechanism of action, such as mirtazapine, could produce a similar effect. Twenty eight patients (age 41.40+/-2.45) were diagnosed following the criteria for major depression by the Structured Clinical Interview for Disorders of Axis I of the American Psychiatric Association. Severity was measured by Hamilton Scale and by Beck Inventory for Depression, scores of 30.88+/-7.48 and 30.24+/-10.88, respectively, prior to treatment. Samples from control subjects were obtained alternating with patients before and after the administration of the antidepressant: twenty eight and twenty four, respectively (age 38.80+/-2.95). Mirtazapine was given in a dose of 30 mg/day for 6 weeks. Blood lymphocytes were isolated by density gradient from patients and controls before and after treatment. There was a partial response according to clinical evaluation and scores of the Scale and the Inventory. Serotonin transporters were labeled with [3H] paroxetine. Number of sites (B(max)) were 10.86+/-2.60 and 12.58+/-2.71 fmol/10(6) cells for both groups of controls. The depressed patients had a significant reduction of serotonin transporters in their lymphocytes before treatment and an increase after it, with B(max) values of 6.52+/-0.49 and 15.61+/-0.49 fmol/10(6) cells, respectively. There were no significant differences in the affinity for the ligand. Concentrations of serotonin or noradrenaline in lymphocytes were not modified before the treatment, although there was a significant decrease after taking 30 mg/day of the antidepressant for 6 weeks. Mirtazapine, not being a serotonin reuptake inhibitor, did increase the number of transporters in lymphocytes of major depression patients, indicating a complex mechanism, not only directly related to the transporter, but involved in the therapeutic response.

A possible antienuretic effect of reboxetine in children and adolescents with attention deficit/hyperactivity disorder: case series

Reboxetine is a selective norepinephrine reuptake inhibitor.

OBJECTIVES

To evaluate the antienuretic effect of reboxetine in children with attention deficit and mood disorders.

METHODS

Six children aged 12-15 years with primary nocturnal enuresis and with attention deficit/hyperactivity disorder with or without other comorbid disorders were treated with reboxetine (4-8 mg/day). Monitoring of enuretic frequency was recorded at baseline and once a week for 6 weeks.

RESULTS

A statistically significant decrease in bedwetting was noted along the assessment points (p < 0.001), with the maximal change noted in the first week of treatment (p = 0.004). Reboxetine was well tolerated with minimal and transient side effects.

CONCLUSIONS

reboxetine may possess an antienuretic effect in some children with the attention deficit/hyperactivity disorder.

Implication of 5-HT2 receptor subtypes in the mechanism of action of antidepressants in the four plates test

RATIONALE

The selective serotonin reuptake inhibitors (SSRIs) and the serotonin and noradrenaline reuptake inhibitors (SNRIs) increase synaptic levels of serotonin, leading to an increased activation of a multitude of specific postsynaptic 5-HT receptors. However, it is not yet known which 5-HT receptor subtypes mediate the therapeutic effects of antidepressants.

METHODS

The effects of the SSRI, paroxetine and the SNRI, venlafaxine were evaluated in the mouse four plates test (FPT).

RESULTS

Paroxetine administered intraperitoneally (IP) (0.5, 2-8 mg/kg) potently augmented the number of punished passages accepted by mice in this paradigm. The effects of paroxetine (8 mg/kg) were not reversed by the selective 5-HT2C receptor antagonist, RS 10-2221 (0.1 mg/kg and 1 mg/kg) or the selective 5-HT2B/2C receptor antagonist SB 206553 (0.1 mg/kg and 1 mg/kg), at doses which lack an effect when administered alone. In contrast, the selective 5-HT2A receptor antagonist, SR 46349B (0.1 mg/kg and 1 mg/kg) completely abolished the paroxetine-induced increase in punished passages. The acute administration of venlafaxine induced an anxiolytic-like effect in the FPT at the doses of 2-16 mg/kg. This effect was reversed by the 5-HT2B/2C receptor antagonist as did SR 46349B, for both doses administered. Our results strongly suggest that activation of 5-HT2A receptors is critically involved in the anxiolytic activity of paroxetine, whereas the 5-HT2A and 5-HT2B receptors are involved in the anti-punishment action of venlafaxine in the FPT. The co-administration of selective 5-HT2A, 2B, 2C receptor agonists (DOI, 0.06 mg/kg and 0.25 mg/kg; BW 723C86, 0.5 mg/kg and 2 mg/kg and RO 60-0175, 0.06 mg/kg and 0.25 mg/kg), respectively, was subsequently investigated. The effects of sub-active doses of paroxetine (0.25 mg/kg and 1 mg/kg) were augmented by BW 723C86 and RO 60-0175 receptor agonist challenge. The anti-punishment effects of venlafaxine (0.25 mg/kg and 1 mg/kg) were potentialised only by DOI co-administration.

CONCLUSION

These results indicate that the co-administration of 5-HT2 receptor agonists with paroxetine and venlafaxine may provide a powerful tool for enhancing the clinical efficacy of these antidepressants.

Six-week open-label reboxetine treatment in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

This open-label study assessed the effectiveness of reboxetine, a selective norepinephrine reuptake inhibitor, in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) resistant to a previous methylphenidate trial.

METHOD

Thirty-one child and adolescent outpatients, aged 8 to 18 (mean age, 11.7; SD = 2.87) years, diagnosed with ADHD were enrolled in a 6-week open-label study. Assessments included rater-administered scales (DSM-IV ADHD Scale; Clinical Global Impressions Scale), parent-administered scales (the Abbreviated Conners Rating Scale), and self-administered-scales for the evaluation of depressive (Children's Depression Inventory) and anxiety (the Revised Children's Manifest Anxiety Scale) symptoms. Reboxetine was initiated and maintained at a dose of 4 mg/day.

RESULTS

A significant decrease in ADHD symptoms, on all scales measured, was noted. Adverse effects were relatively mild and transient. The most common adverse effects were drowsiness/sedation and gastrointestinal complaints.

CONCLUSIONS

The results of the current open-label study suggest the effectiveness of reboxetine in the treatment of ADHD in methylphenidate-resistant children and adolescents. Double-blind, placebo-, and active comparator-controlled studies are indicated to rigorously test the efficacy of reboxetine in ADHD.

DOV 216,303, a "triple" reuptake inhibitor: safety, tolerability, and pharmacokinetic profile

This report describes the first evaluation in humans of DOV 216,303, a putative antidepressive that inhibits the reuptake of norepinephrine, serotonin, and dopamine. Subjects received single oral doses of 5 to 150 mg of DOV 216,303 or placebo. At 150 mg, 4 of 7 subjects reported gastrointestinal disturbances. In the multiple-dose phase of the evaluation, subjects received total daily doses of 50, 75, or 100 mg of DOV 216,303 or placebo for 10 days. At a total daily dose of 100 mg, gastrointestinal disturbances were reported in 4 of 6 volunteers. In both the single- and multiple-dose evaluations, no significant changes were noted in vital signs, electrocardiogram, hematology, or clinical chemistry. DOV 216,303 was rapidly absorbed (plasma t(max) of 0.7-1.2 hours and t(1/2) of 3.3-4.4 hours), with dose-proportional C(max) and AUC values. Furthermore, no remarkable difference was apparent in either the C(max) or AUC(tau) of DOV 216,303 following 1 and 10 days of dosing. The present results demonstrate that DOV 216,303 is safe and well tolerated both at single doses of up to 100 mg and multiple doses of up to 100 mg/day for 10 days. Plasma concentrations of DOV 216,303 after doses > 10 mg exceed its reported IC(50) values for inhibition of biogenic amine reuptake.

Remission from depression : a review of venlafaxine clinical and economic evidence

Worldwide, major depression is the leading cause of years lived with a disability, and the fourth cause of disability-adjusted life years. Depression is second only to hypertension as the most common chronic condition encountered in general medical practice. Unfortunately, despite the high prevalence of depression, under-recognition and under-treatment are common.Historically, clinicians have assessed the short-term effectiveness of antidepressants by response rates, often defined as a 50% reduction in depressive symptoms. However, this usually does not reflect true clinical remission, and residual symptoms are common. Persistence of residual symptoms appears to be a common link to relapse, chronic disability and suicide. The burden of not treating depression effectively to remission is significant, as the disease is an important contributor to the disability levels of the general population. Disability, in turn, has a profound impact on lost productivity and medical expenses. In 2000, depression cost the US more than US 83 billion dollars annually in lost productivity, medical expenses and premature death.Venlafaxine, a dual-acting serotonin norepinephrine (noradrenaline) reuptake inhibitor, may improve a patient's response to treatment and their chances of achieving complete remission compared with conventional antidepressant therapies, with the evidence for this being the strongest for comparisons with the selective serotonin receptor inhibitors (SSRIs). To date, there are only a small number of economic studies of venlafaxine, and most are cost or resource utilisation analyses with significant limitations. Nevertheless, two cost-effectiveness analyses of venlafaxine are available. They found venlafaxine had a lower average cost per patient achieving remission or per symptom-free day compared with SSRIs; one reported an incremental cost-effectiveness ratio for venlafaxine of US 586 dollars (year 2002 values) per additional patient achieving remission over 8 weeks, and the other found venlafaxine to be a dominant treatment choice over SSRIs over 6 months (year 2001 values). Although requiring further confirmation, these initial data suggest that venlafaxine is a cost-effective strategy for the treatment of depression. The availability of an effective armamentarium of antidepressant strategies, including venlafaxine, to achieve and sustain remission offers both clinical and economic value to all those touched by the burden of depression.

Determination of fluvoxamine in rat plasma by HPLC with pre-column derivatization and fluorescence detection using 4-fluoro-7-nitro-2,1,3-benzoxadiazole

A sensitive, simple and reliable method using high-performance liquid chromatographic (HPLC) assay of fluvoxamine (FLU), a selective serotonin reuptake inhibitor (SSRI), in rat plasma after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed in this study. Extracted plasma samples were mixed with NBD-F at 60 degrees C for 5 min and injected into HPLC. Retention times of FLU and an internal standard (propafenone) derivative were 15.5 and 13.5 min, respectively. The calibration curve was linear over the range 0.015-1.5 microg/mL (r2 = 0.9985) and the lower limits of detection and quantification of FLU were 0.008 and 0.015 microg/mL, respectively, in 100 microL of plasma. The derivative sample was stable at 4 degrees C for 1 day. The coefficients of variation for intra-day and inter-day assay of FLU were less than 8.3 and 9.6%, respectively. Other SSRIs and centrally acting drugs did not interfere with the peak of the FLU derivative. The method was applied for analysis of the plasma samples from rats treated with FLU. These results indicate that the method presented is useful to determine the FLU levels in rat plasma of volumes as small as 100 microL and can be applied to pharmacokinetic studies.

The catechol-O-methyltransferase Val108/158Met polymorphism affects short-term treatment response to mirtazapine, but not to paroxetine in major depression

The catechol-O-methyltransferase (COMT) is a major degrading enzyme in the metabolic pathways of catecholaminergic neurotransmitters such as dopamine and norepinephrine. This study investigated whether the functionally relevant Val(108/158)Met gene variant is associated with differential antidepressant response to mirtazapine and/or paroxetine in 102 patients with major depression (DSM-IV criteria) participating in a randomized clinical trial with both drugs. In patients treated with mirtazapine, but not paroxetine, allelic variations in the COMT gene were associated with differential response. COMT(VAL/VAL) and COMT(VAL/MET) genotype carriers showed a better response than COMT(MET/MET)-bearing patients in the mirtazapine group. Moreover, carriers of the COMT(VAL/VAL) or COMT(VAL/MET) genotype had significantly greater HAMD-17 (Hamilton Rating Scale for Depression 17 item version) score reductions than COMT(MET/MET) homozygotes from week 2 to 6, respectively, in the mirtazapine group. Time course of response and antidepressant efficacy of mirtazapine, but not paroxetine, seem to be influenced in a clinically relevant manner by this allelic variation within the COMT gene.

Early-Life Blockade of the 5-HT Transporter Alters Emotional Behavior in Adult Mice

Reduced serotonin transporter (5-HTT) expression is associated with abnormal affective and anxiety-like symptoms in humans and rodents, but the mechanism of this effect is unknown. Transient inhibition of 5-HTT during early development with fluoxetine, a commonly used serotonin selective reuptake inhibitor, produced abnormal emotional behaviors in adult mice. This effect mimicked the behavioral phenotype of mice genetically deficient in 5-HTT expression. These findings indicate a critical role of serotonin in the maturation of brain systems that modulate emotional function in the adult and suggest a developmental mechanism to explain how low-expressing 5-HTT promoter alleles increase vulnerability to psychiatric disorders.

Oligomer formation by Na+-Cl--coupled neurotransmitter transporters

Na+-Cl--dependent neurotransmitter transporters (or neurotransmitter:Na+ symporters, NSS) share many structural and functional features, e.g. a conserved topology of 12 transmembrane spanning alpha-helices, the capacity to operate in two directions and in an electrogenic manner. Biochemical and biophysical experiments indicate that these transporters interact in oligomeric quaternary structures. Fluorescence resonance energy transfer (FRET) microscopy has provided evidence for a constitutive physical interaction of NSS at the cell surface and throughout the biosynthetic pathway. Two interfaces for protein-protein interaction have been shown to be important in NSS; these comprise a glycophorin-like motif and a leucine heptad repeat. Upon mutational modification of the latter, surface targeting is considerably impaired without concomitant loss in uptake activity. This supports a role of oligomer formation in the passage of the quality control mechanisms of the endoplasmic reticulum and/or Golgi. In contrast, oligomerisation is dispensable for substrate binding and translocation.

Reboxetine adjunct for partial or nonresponders to antidepressant treatment

BACKGROUND

To investigate the usefulness of the combination therapy with two antidepressants from different pharmacological families in treatment-resistant depressive patients.

METHODS

In this prospective 6 weeks open-label study, we assessed the effectiveness of the addition of reboxetine to 61 depressive patients that had previously not responded, or had done so only in a partial way, to conventional treatment, in monotherapy, with selective serotonin reuptake inhibitors (SSRIs), venlafaxine or mirtazapine. Data were analyzed on an intent-to-treat basis, using the last-observation-carried-forward (LOCF) method.

RESULTS

Mean decrease on the 21-item Hamilton Depression Rating Scale (HDRS) score was 48.9% and on the Clinical Global Impressions Scale (CGI), 38.9%. At the end of the treatment, 62.3% of the patients were evaluated as improvement (CGI < 4), 54.1% as responders (HDRS < or = 50%) and 45.9% in remission (HDRS < or = 10). No serious side effects were observed during combination therapy, being more frequent increased sweating (8.2%) and dry mouth (6.6%).

CONCLUSIONS

These findings suggest that the strategy of combination with reboxetine may be an effective and well-tolerated tool in treatment-resistant patients who have failed to adequately respond to monotherapy with SSRIs, venlafaxine or mirtazapine.

Use of antidepressant medications: are there differences in psychiatric visits among patient treatments in the Veterans Administration?

BACKGROUND

Information on the effectiveness of newer antidepressants like serotonin-norepinephrine reuptake inhibitors in terms of healthcare utilization is limited. Treatment guidelines affect evaluation. Second-line medications are usually prescribed to patients with higher utilization.

OBJECTIVES

The objective of this study was to compare antidepressants within the Veterans Affairs (VA) healthcare system on the basis of the number of outpatient psychiatric visits for each class of antidepressants.

RESEARCH DESIGN AND SUBJECTS

We conducted a retrospective cohort design using precollected information from VA national databases from 1999 and 2000. The study identified 92,537 patients on serotonin specific reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), or tricyclic antidepressants (TCAs).

MEASURES

We stratified individual patients by the number of visits in the baseline year for each medication class. For each stratum, we created a dichotomized variable YK: Yk = 1 if there is a reduction of K visits or more and 0 if there is no reduction. We calculated the odds of reduction of psychiatric visits among the 3 classes of antidepressants.

RESULTS

TCAs and SSRIs were associated with greater odds of reduction compared with SNRIs at the level of 1 through 10 or 11 visits, respectively. SNRIs were associated with greater odds of reduction in visits at the level of 14, 16, or more visits compared with SSRIs and TCAs, respectively (P <0.05). SSRIs were associated with greater odds of reduction compared with TCAs at the level of 1 to 11 visits (P <0.05); there were no significant differences between the 2 classes above 11 visits.

CONCLUSION

Effectiveness research using databases should consider how medications are prescribed within systems. Treatment guidelines result in differences in severity and utilization among users of different medications.

Structural Effects and Neurofunctional Sequelae of Developmental Exposure to Psychotherapeutic Drugs: Experimental and Clinical Aspects

The advent of psychotherapeutic drugs has enabled management of mental illness and other neurological problems such as epilepsy in the general population, without requiring hospitalization. The success of these drugs in controlling symptoms has led to their widespread use in the vulnerable population of pregnant women as well, where the potential embryotoxicity of the drugs has to be weighed against the potential problems of the maternal neurological state. This review focuses on the developmental toxicity and neurotoxicity of five broad categories of widely available psychotherapeutic drugs: the neuroleptics, the antiepileptics, the antidepressants, the anxiolytics and mood stabilizers, and a newly emerging class of nonprescription drugs, the herbal remedies. A brief review of nervous system development during gestation and following parturition in mammals is provided, with a description of the development of neurochemical pathways that may be involved in the action of the psychotherapeutic agents. A thorough discussion of animal research and human clinical studies is used to determine the risk associated with the use of each drug category. The potential risks to the fetus, as demonstrated in well described neurotoxicity studies in animals, are contrasted with the often negative findings in the still limited human studies. The potential risk fo the human fetus in the continued use of these chemicals without more adequate research is also addressed. The direction of future research using psychotherapeutic drugs should more closely parallel the methodology developed in the animal laboratories, especially since these models have already been used extremely successfully in specific instances in the investigation of neurotoxic agents.

Pharmacological and electrophysiological properties of the naturally occurring Pro391Arg variant of the human 5-HT3A receptor

The 5-HT3A receptor, a ligand-gated ion channel, is involved in pain pathways, nausea and emesis, and irritable bowel syndrome, and may play a role in the pathogenesis of psychiatric diseases such as schizophrenia and depression. Recently, a naturally occurring variation (ProArg) in the second intracellular loop of the human (h) 5-HT3A receptor was identified in a schizophrenic patient. Because the substitution of proline, an alpha-imino acid, by arginine may affect the conformation of the whole receptor, the aim of the present study was to determine the pharmacological and functional properties of this variant compared to the wild-type receptor in stably transfected HEK293 cells. Studies of binding of [H]GR65630, a 5-HT3 receptor antagonist, to membranes (saturation and competition experiments with 5-HT3 receptor ligands) and patch-clamp studies of agonist-induced currents in outside-out patches were carried out. In comparison to the wild-type, the variant receptor exhibited no changes in the receptor density and the affinities for nine representative ligands (five agonists and four antagonists). The potencies and efficacies of three 5-HT3 receptor agonists in inducing currents through the ion channel and the potencies of two 5-HT3 receptor antagonists in blocking 5-HT-evoked currents did not differ between wild-type and variant receptors. In addition, there were no differences in the desensitization kinetics of both receptor isoforms. In conclusion, the ArgPro variation of the h5-HT3A receptor does not change ligand binding to the h5-HT3A receptor, nor does it modify current through the receptor channel.