Spotlight on paroxetine in psychiatric disorders in adults

Paroxetine is a selective serotonin reuptake inhibitor (SSRI), with antidepressant and anxiolytic activity. In 6- to 24-week well designed trials, oral paroxetine 10 to 50 mg/day was significantly more effective than placebo, at least as effective as tricyclic antidepressants (TCAs) and as effective as other SSRIs and other antidepressants in the treatment of major depressive disorder. Relapse or recurrence over 1 year after the initial response was significantly lower with paroxetine 10 to 50 mg/day than with placebo and similar to that with imipramine 50 to 275 mg/day. The efficacy of paroxetine 10 to 40 mg/day was similar to that of TCAs and fluoxetine 20 to 60 mg/day in 6- to 12-week trials in patients aged > or = 60 years with major depression. Paroxetine 10 to 40 mg/day improved depressive symptoms to an extent similar to that of TCAs in patients with comorbid illness, and was more effective than placebo in the treatment of dysthymia and minor depression. Paroxetine 20 to 60 mg/day was more effective than placebo after 8 to 12 weeks' treatment of obsessive-compulsive disorder (OCD), panic disorder, social anxiety disorder (social phobia), generalised anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Improvement was maintained or relapse was prevented for 24 weeks to 1 year in patients with OCD, panic disorder, social anxiety disorder or GAD. The efficacy of paroxetine was similar to that of other SSRIs in patients with OCD and panic disorder and similar to that of imipramine but greater than that of 2'chlordesmethyldiazepam in patients with GAD. Paroxetine is generally well tolerated in adults, elderly individuals and patients with comorbid illness, with a tolerability profile similar to that of other SSRIs. The most common adverse events with paroxetine were nausea, sexual dysfunction, somnolence, asthenia, headache, constipation, dizziness, sweating, tremor and decreased appetite. In conclusion, paroxetine, in common with other SSRIs, is generally better tolerated than TCAs and is a first-line treatment option for major depressive disorder, dysthymia or minor depression. Like other SSRIs, paroxetine is also an appropriate first-line therapy for OCD, panic disorder, social anxiety disorder, GAD and PTSD. Notably, paroxetine is the only SSRI currently approved for the treatment of social anxiety disorder and GAD, which makes it the only drug of its class indicated for all five anxiety disorders in addition to major depressive disorder. Thus, given the high degree of psychiatric comorbidity of depression and anxiety, paroxetine is an important first-line option for the treatment of major depressive disorder, OCD, panic disorder, social anxiety disorder, GAD and PTSD.     

Paroxetine: an update of its use in psychiatric disorders in adults

Paroxetine is a selective serotonin reuptake inhibitor (SSRI), with antidepressant and anxiolytic activity. In 6- to 24-week well designed trials, oral paroxetine 10 to 50 mg/day was significantly more effective than placebo, at least as effective as tricyclic antidepressants (TCAs) and as effective as other SSRIs and other antidepressants in the treatment of major depressive disorder. Relapse or recurrence over 1 year after the initial response was significantly lower with paroxetine 10 to 50 mg/day than with placebo and similar to that with imipramine 50 to 275 mg/day. The efficacy of paroxetine 10 to 40 mg/day was similar to that of TCAs and fluoxetine 20 to 60 mg/day in 6- to 12-week trials in patients aged > or =60 years with major depression. Paroxetine 10 to 40 mg/day improved depressive symptoms to an extent similar to that of TCAs in patients with comorbid illness, and was more effective than placebo in the treatment of dysthymia and minor depression. Paroxetine 20 to 60 mg/day was more effective than placebo after 8 to 12 weeks' treatment of obsessive-compulsive disorder (OCD), panic disorder, social anxiety disorder (social phobia), generalised anxiety disorder (GAD) and post-traumatic stress disorder (PTSD). Improvement was maintained or relapse was prevented for 24 weeks to 1 year in patients with OCD, panic disorder, social anxiety disorder or GAD. The efficacy of paroxetine was similar to that of other SSRIs in patients with OCD and panic disorder and similar to that of imipramine but greater than that of 2'chlordesmethyldiazepam in patients with GAD. Paroxetine is generally well tolerated in adults, elderly individuals and patients with comorbid illness, with a tolerability profile similar to that of other SSRIs. The most common adverse events with paroxetine were nausea, sexual dysfunction, somnolence, asthenia, headache, constipation, dizziness, sweating, tremor and decreased appetite. In conclusion, paroxetine, in common with other SSRIs, is generally better tolerated than TCAs and is a first-line treatment option for major depressive disorder, dysthymia or minor depression. Like other SSRIs, paroxetine is also an appropriate first-line therapy for OCD, panic disorder, social anxiety disorder, GAD and PTSD. Notably, paroxetine is the only SSRI currently approved for the treatment of social anxiety disorder and GAD, which makes it the only drug of its class indicated for all five anxiety disorders in addition to major depressive disorder. Thus, given the high degree of psychiatric comorbidity of depression and anxiety, paroxetine is an important first-line option for the treatment of major depressive disorder, OCD, panic disorder, social anxiety disorder, GAD and PTSD.     

Treatment of generalized anxiety disorder with citalopram

Serotonin reuptake inhibitors (SSRI), such as venalafaxine and paroxetine, are used in the treatment of generalized anxiety disorder (GAD). Patients with GAD frequently have comorbid psychiatric disorders, such as depression. SSRIs are effective in the treatment of a variety of anxiety disorders and depression. Citalopram, a newer SSRI used in the treatment of depression, has not been studied for GAD. This is the first report of the use of citalopram, the most selective SSRI, for the treatment of GAD in a retrospective case observation study. Thirteen patients diagnosed with GAD were treated with citalopram at an academic outpatient clinic. The main outcome measures were the Hamilton Rating Scale for Anxiety (HAM-A), Hamilton Depression Rating Scale (HAM-D) and Clinical Global Impressions of Severity (CGI-S; at baseline) and Improvement (CGI-I). The mean age of the patients was 38 years. The mean dose of citalopram at endpoint was 33 mg/day (range 10-60 mg/day). After 12 weeks of treatment with citalopram, all 13 patients experienced full or partial improvement in GAD and depressive symptoms leading to meaningful improvement in social and occupational functioning. Mean baseline HAM-A scores (mean+/-SEM) decreased from 22.2+/-1.3 to 6.2+/-0.9 after citalopram treatment. The mean CGI-I score was 1.8+/-0.2 with 11 of the 13 patients responding (CGI-I of 1 or 2). These data suggest that citalopram may be an effective treatment for GAD. Several patients who had failed previous treatment with other SSRIs responded to citalopram, suggesting that a second SSRI, such as citalopram, may be beneficial in this population. A larger placebo-controlled study of citalopram is warranted in GAD.     

Escitalopram: a review of its use in the management of anxiety disorders

Escitalopram (Cipralex, Lexapro, Seroplex, Sipralexa), the therapeutically active S-enantiomer of racemic citalopram (RS-citalopram), is a potent and highly selective serotonin reuptake inhibitor. It is effective and generally well tolerated in the treatment of moderate to severe generalised anxiety disorder (GAD) or social anxiety disorder (SAD), panic disorder (with or without agoraphobia) as well as obsessive-compulsive disorder (OCD). Moreover, escitalopram is at least as effective as paroxetine for the treatment of GAD, SAD or OCD and appears to achieve a more rapid response than racemic citalopram in the management of panic disorder. Generally, it has a more favourable tolerability profile than paroxetine in terms of fewer discontinuation symptoms. In addition, a favourable pharmacokinetic profile permits once-daily administration of the drug. Additional comparative studies are required to definitively position escitalopram with respect to other SSRIs and venlafaxine. Nevertheless, available clinical data indicate that escitalopram is an effective first-line treatment option for the management of GAD, SAD, panic disorder and OCD.     

Clinical experience with paroxetine in social anxiety disorder

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) with proven efficacy in the treatment of depression, panic disorder and obsessive-compulsive disorder. Evidence that paroxetine may be effective in social anxiety disorder (social phobia) first arose from open-label studies. More recently, three multicentre, randomized, placebo-controlled trials have been performed, each lasting 12 weeks, to assess the efficacy and tolerability of paroxetine in the treatment of social anxiety disorder, and these studies are reviewed here. The data from all three studies consistently demonstrated that paroxetine was effective in reducing both the symptoms of anxiety and the disability and impairment of social anxiety disorder. Paroxetine performed significantly better than placebo on all primary (Liebowitz Social Anxiety Scale, Clinical Global Impression) and secondary (Social Avoidance and Distress Scale, Sheehan Disability Scale) outcome measures. Adverse events were restricted to those already known to be associated with SSRIs, no serious adverse events associated with medication were experienced, and the numbers withdrawing from the studies were not significantly different in the paroxetine and control groups. Taken together, these studies confirm that paroxetine is an effective and well tolerated treatment for patients with social anxiety disorder.     

Paroxetine: safety and tolerability issues

Paroxetine is a selective serotonin re-uptake inhibitor (SSRI) available in immediate release and controlled release (CR) formulations. Paroxetine is the most potent inhibitor of serotonin re-uptake among the now available SSRIs. Paroxetine has been approved for the treatment of major depressive disorder (MDD), obsessive–compulsive disorder, panic disorder (PD), generalised anxiety disorder, post traumatic stress disorder (PTSD), and social anxiety disorder (SAD) in adults, whereas paroxetine CR is approved for the treatment of MDD, SAD, PD and premenstrual dysphoric disorder in adults. The overall efficacy of paroxetine seems to be comparable to other SSRIs in the treatment of approved indications, although paroxetine treatment induces more sedation, constipation, sexual dysfunction, discontinuation syndrome and weight gain than other SSRIs. Recent data suggest that paroxetine treatment leads to increased rates of congenital malformations, although this evidence is not conclusive. Paroxetine and paroxetine CR are not indicated for use in the paediatric population and are categorised as Pregnancy Class D. In conclusion, whether the tolerability profile of paroxetine differs substantially from other new antidepressants (including other SSRIs) needs to be determined in adequately powered well-designed randomised controlled comparative clinical trials.     

Effect of short-term SSRI treatment on cognitive bias in generalised anxiety disorder

RATIONALE: There is considerable evidence showing that individuals with generalised anxiety disorder (GAD) selectively process threat-related information, e.g. they have a bias to interpret ambiguous information in a threat-related manner. Cognitive theories of anxiety, which provide the basis of cognitive-behaviour therapy, propose that such processing biases play an important role in causing and maintaining anxiety. OBJECTIVES: Given that treatment with selective serotonin re-uptake inhibitors (SSRIs) appears to be effective for GAD, we examined whether it is successful in removing cognitive bias. METHODS: The clinical group included 19 patients with a diagnosis of GAD, and the control group consisted of a non-clinical sample of volunteers, matched for age, gender and years in education. The patients were assessed on measures of interpretative bias (homophone task), anxiety and depression before being prescribed an SSRI (paroxetine or citalopram). After 4 weeks, the cognitive task and mood measures were repeated in the patient group. RESULTS: Prior to treatment, the GAD group showed a significantly greater level of threat-related interpretive bias than controls. Following SSRI treatment, there were significant reductions in both interpretive bias and in anxiety levels in the GAD group. Furthermore, individuals who showed greater clinical improvement (e.g. reflected by reduced anxiety scores) showed a correspondingly greater reduction in their cognitive bias. CONCLUSION: The results suggest that SSRIs are effective in modifying both subjective anxiety levels and threat-related interpretive bias.     

Paroxetine: safety and tolerability issues

Paroxetine is a selective serotonin re-uptake inhibitor (SSRI) available in immediate release and controlled release (CR) formulations. Paroxetine is the most potent inhibitor of serotonin re-uptake among the now available SSRIs. Paroxetine has been approved for the treatment of major depressive disorder (MDD), obsessive-compulsive disorder, panic disorder (PD), generalised anxiety disorder, post traumatic stress disorder (PTSD), and social anxiety disorder (SAD) in adults, whereas paroxetine CR is approved for the treatment of MDD, SAD, PD and premenstrual dysphoric disorder in adults. The overall efficacy of paroxetine seems to be comparable to other SSRIs in the treatment of approved indications, although paroxetine treatment induces more sedation, constipation, sexual dysfunction, discontinuation syndrome and weight gain than other SSRIs. Recent data suggest that paroxetine treatment leads to increased rates of congenital malformations, although this evidence is not conclusive. Paroxetine and paroxetine CR are not indicated for use in the paediatric population and are categorised as Pregnancy Class D. In conclusion, whether the tolerability profile of paroxetine differs substantially from other new antidepressants (including other SSRIs) needs to be determined in adequately powered well-designed randomised controlled comparative clinical trials.     

An evaluation of paroxetine in generalised social anxiety disorder

It is estimated that social anxiety disorder affects approximately 13.3% individuals within the community at some point in their lifetime and is associated with significant functional impairment. A variety of drug groups have demonstrated efficacy in treating social anxiety disorder, including selective serotonin reuptake inhibitors (SSRIs). Paroxetine is an SSRI approved by the FDA and Health Canada for the treatment of a variety of psychiatric conditions. Paroxetine has been the most studied agent in social anxiety disorder and has been shown to be effective in short-term, fixed- and flexible-dose placebo-controlled trials, as well as in long-term treatment. The pharmacotherapy of social phobia will be reviewed, with a special focus on investigations with paroxetine.     

The selective serotonin reuptake inhibitor paroxetine is effective in more generalized and in less generalized social anxiety disorder

RATIONALE: The DSM-IV includes the specifier "generalized" to refer to social anxiety disorder (social phobia) patients if the fears include "most social situations". The focus on interventions such as the selective serotonin reuptake inhibitors (SSRIs) for generalized social anxiety disorder arguably runs the risk that inadequate treatment will be provided to patients with the non-generalized or discrete subtypes. There are, however, few data to address whether more generalized and less generalized subgroups of social anxiety disorder differ in response to medication. OBJECTIVE: To compare response of more generalized and less generalized social anxiety disorder to pharmacotherapy. METHODS: Data from three randomized placebo-controlled double-blind multicenter trials of the SSRI paroxetine in social anxiety disorder were pooled. Response on the Clinical Global Impression Global Improvement item was analyzed using logistic regression, and change in total Liebowitz Social Anxiety Score was analyzed using analysis of variance, with both models incorporating treatment (paroxetine vs placebo), subgroup (more generalized vs less generalized), demographic, and clinical variables. RESULTS: The prevalence of more generalized social anxiety disorder was higher in females than in males. However, there was no significant difference in terms of age or clinical characteristics (duration of condition, baseline pulse, mean arterial blood pressure). At treatment endpoint there were significant treatment effects (for paroxetine vs placebo), but no significant subgroup effects (for more generalized vs less generalized). CONCLUSIONS: Although the current database is limited insofar as few patients with discrete social anxiety disorder would have been included, it is helpful in addressing the value of medication for patients lying on the spectrum from generalized to non-generalized and discrete social anxiety disorder. Paroxetine was effective in both more generalized and in less generalized social anxiety disorder.     

Biological basis of anxiety disorders and serotonergic anxiolytics]

Selective serotonin reuptake inhibitors (SSRIs) have wide indications for the treatment of anxiety disorders, including panic disorder, generalized anxiety disorder, posttraumatic stress disorder, obsessive-compulsive disorder and social anxiety disorder in addition to depression. Until recently, no animal model has been available for screening the anxiolytic effect of SSRIs and studying its mechanism of action. We have investigated the relationship between serotonin neurotransmission and anxiety using conditioned fear stress (CFS), an animal model of anxiety. CFS increased serotonin neurotransmission in the medial prefrontal cortex and amygdala. In behavioral pharmacological studies, SSRIs, serotonin1A agonists and monoamine oxidase inhibitors, which are assumed to facilitate serotonin neurotransmission, decreased conditioned freezing, an index of anxiety or fear, in CFS. In vivo microdialysis studies showed that serotonin neurotransmission in the medial prefrontal cortex increased after recovery from the freezing behavior. Microinjection of SSRI to the basolateral nucleus of the amygdala reduced conditioned freezing, indicating that the amygdala is one of target brain sites of anxiolytic action of SSRIs. Furthermore, CFS-induced c-Fos expression in the basolateral nucleus of the amygdala was reduced by SSRI pretreatment. Taken together, recent studies indicate that facilitation of brain serotonin neurotransmission decreases anxiety in agreement with the clinical evidence.     

Serotonergic drugs in the treatment of depressive and anxiety disorders

Serotonergic dysfunction has been implicated in the aetiology of several psychiatric conditions, including depressive and anxiety disorders. Much of the evidence for the role of serotonin (5-HT) in these disorders comes from treatment studies with serotonergic drugs, including selective serotonin reuptake inhibitors (SSRIs), 5-HT(1A) agonists and 5-HT antagonists. This review considers the place of these drugs in the treatment of panic disorder, obsessive-compulsive disorder (OCD), social phobia, and generalized anxiety disorder (GAD). Among these agents, the SSRIs stand out with proven efficacy in the treatment of a spectrum of disorders, such as depression, panic disorder, OCD and social phobia. They may also be a suitable treatment for GAD. 5-HT(1A) agonists have been used extensively for the treatment of depression and GAD but evidence of their efficacy in other anxiety disorders is equivocal. 5-HT antagonists are the least well studied of these agents: while they may have activity in depression, their efficacy has not been fully investigated in anxiety disorders. However, preliminary reports suggest that they may be useful as adjuvants to SSRIs in treatment-refractory OCD. The high incidence of comorbidity amongst psychiatric disorders means that pharmacotherapy that is effective against a range of disorders, such as the SSRIs, is of considerable use to clinicians. Future research into the biological mechanisms underlying such disorders is likely to further enhance pharmacotherapy. Copyright 2000 John Wiley & Sons, Ltd.     

Paroxetine controlled release

A controlled-release (CR) formulation of the SSRI paroxetine has been developed. This CR formulation delays the release of paroxetine until the tablet has passed through the stomach; the drug is then released over 4-5 hours. In well designed placebo-controlled trials in patients with major depressive disorder (including a study in the elderly), social anxiety disorder or premenstrual dysphoric disorder (PMDD), paroxetine CR was consistently superior to placebo with regards to primary endpoints (i.e. mean Hamilton Rating Scale for Depression total score [major depressive disorder], Liebowitz social anxiety scale total score and Clinical Global Impressions-Global Improvement score [social anxiety disorder] and Visual Analogue Scale-Mood score [PMDD]). The duration of treatment was 12 weeks or, in PMDD, over three menstrual cycles (intermittent or continuous administration). Paroxetine CR also demonstrated efficacy in three well designed studies in patients with panic disorder with or without agoraphobia. Paroxetine CR was generally well tolerated in clinical trials, with an adverse-event profile typical of SSRIs, although recipients of paroxetine CR experienced significantly less nausea than recipients of immediate-release paroxetine in the first week of treatment.     

Defining an appropriate management strategy for social anxiety disorder

Social anxiety disorder is a chronic and disabling, yet treatable, condition. Effective treatment should alleviate the core domains of fear, anxiety and physiological symptoms, as well as reduce overall disability and improve social functioning. Response to treatment can, therefore, be assessed at a global level where overall improvement is considered, and at the level of individual symptoms. In considering the way in which response to treatment can be measured, this review also identifies several factors that may worsen the prognosis of social anxiety disorder. Clinical studies of monoamine oxidase inhibitors, selective serotonin reuptake inhibitors (SSRIs), and benzodiazepines for the treatment of social anxiety disorder are presented and discussed. The accumulation of evidence supports the use of SSRIs as first line therapy for social anxiety disorder, and the majority of data come from well controlled studies of paroxetine. In line with the recommendations of the International Consensus Group on Depression and Anxiety, a strategy for the management of social anxiety disorder is provided.     

Role of the serotonergic nervous system in anxiety disorders and the anxiolytic mechanism of selective serotonin reuptake inhibitors]

Some selective serotonin reuptake inhibitors (SSRIs) have recently been approved for the treatment of anxiety disorders such as obsessive-compulsive disorder, panic disorder and social anxiety disorder, and they are considered first-line treatment for anxiety disorders in Japan as well as in other countries. Previous clinical studies have suggested that the 5-HT2C receptors in subjects with anxiety disorders are hypersensitive. We recently reported that chronic treatment with fluvoxamine or paroxetine desensitized 5-HT2C receptor function. The desensitization of 5-H T2C receptor function has also been reported with other SSRIs and is considered to be a common mechanism of action of SSRIs in the treatment of anxiety disorders. In addition, some studies have suggested that 5-HT2A receptors and 5-HTIA receptors participate in anxiety disorders and the therapeutic mechanism. Both clinical studies and animal studies have indicated that the amygdala plays an essential role in anxiety and fear response. Thus, it may be important to elucidate functional changes in these 5-HT receptor subtypes in brain regions including the amygdala under the chronic administration of SSRIs to understand the anxiolytic mechanism of SSRIs.     

Differences in compliance patterns across the selective serotonin reuptake inhibitors (SSRIs)

OBJECTIVE: To evaluate differential compliance rates between immediate-release (IR) selective serotonin reuptake inhibitors (SSRI) and a controlled-release (CR) SSRI in patients initiating SSRI therapy. METHODS: A retrospective analysis of patients initiating treatment with SSRIs identified in the IHCIS National Managed Care Database between July 2001 and December 2002 was conducted. Logistic regression models were used to assess differences in 6-month compliance rates, controlling for age, gender, utilization of mental health specialty care services, titration rates, diagnoses, and comorbidities. Compliance was defined as having a minimum medication possession ratio of 80% over a 180-day period without evidence of a 15-day gap prior to 90 days of therapy. RESULTS: There were 116 090 patients included in the study, with approximately 4% receiving a CR SSRI and 96% receiving IR SSRIs. Approximately 25% of patients had a diagnosis for depression, 16% had a diagnosis for anxiety, and 13% had a 16% had a diagnosis for anxiety, and 13% had a diagnosis for both anxiety and depression. Overall, diagnosis for both anxiety and depression. Overall, 54.2% were noncompliant with therapy, while 30.2% of patients were compliant with therapy, and 15.7% had evidence of a therapy change. After controlling for baseline covariates, patients initiating IR SSRIs were 14% less likely to be compliant compared to those initiating paroxetine CR (p < 0.0001). Patients initiating on paroxetine IR were least likely to be compliant (odds ratio [OR] 0.788; p < 0.0001), followed by escitalopram (OR 0.850; p = 0.0179), sertraline (OR 0.877; p = 0.0005), citalopram (0.909; p = 0.0114), and fluoxetine (OR 0.916; p = 0.0250). CONCLUSIONS: Approximately 54% of patients initiating SSRI therapy were noncompliant with SSRI therapy over a 6-month period, with the lowest level of compliance found in patients receiving IR SSRI agents. Future studies should assess the effect of compliance on economic measures and determine if reductions in resource utilization are found across specific SSRI agents.     

Selective serotonin reuptake inhibitors for premenstrual dysphoric disorder: the emerging gold standard?

There have been a large number of studies conducted investigating the use of selective serotonin reuptake inhibitors (SSRIs) in the treatment of patients with premenstrual dysphoric disorder (PMDD). The 12 randomised, controlled trials with continuous dose administration of SSRIs and the eight randomised, controlled trials with luteal phase dose administration (from ovulation to menses) are reviewed. All the treatment studies on fluoxetine, sertraline, paroxetine and citalopram have reported positive efficacy. Fluoxetine and sertraline have the largest literature, with a smaller number of studies endorsing paroxetine and citalopram. Mixed efficacy results have been reported with fluvoxamine. In general, adverse effects from the use of SSRIs in women with PMDD are the usual mild and transient adverse effects from SSRIs including anxiety, dizziness, insomnia, sedation, nausea and headache. Sexual dysfunction and weight gain can be problematic long-term adverse effects of SSRIs, but these effects have not been systematically evaluated with long-term SSRI use in women with PMDD. Serotonergic antidepressants have differential superiority over nonserotonergic antidepressants in the treatment of PMDD. Treatments that enhance serotonergic action improve premenstrual irritability and dysphoria with a rapid onset of action, suggesting a different mechanism of action than in the treatment of depression. It is possible that neurosteroids, such as progesterone metabolites, are involved in the rapid action of serotonergic antidepressants in PMDD. Future research needs to address less frequent dose administration regimens, such as 'symptom-onset' dose administration, and the recommended length of treatment.     

Influence of fluoxetine and paroxetine in behavioral sensitization induced by ethanol in mice

The serotonergic system is involved in depression, anxiety and alcoholism. The rewarding properties of ethanol, mainly its anxiolytic and stimulant effects, as well as the development of dependence on ethanol have been related to the serotonergic system. Consequently, the use of selective serotonergic reuptake inhibitors (SSRI) has been proposed in the treatment of alcoholism. In this study we investigated whether acute administration of the SSRIs fluoxetine or paroxetine is able to (i) reverse the behavioral effects induced by chronic ethanol consumption, and conversely, (ii) to determine whether acute ethanol is able to substitute for the chronically induced behavioral effects of fluoxetine or paroxetine. Four groups of male Swiss mice (n=60/group) received daily i.p. saline, ethanol (2 g/kg), fluoxetine (10 mg/kg) or paroxetine (5 mg/kg) for 27 days. On the 28th day, each group was challenged with saline, ethanol, fluoxetine or paroxetine. The 14 groups (SS, SE, SP, SF, EE, ES, EP, EF, PP, PE, PS, FF, FE, and FS) were then tested in open field, activity cage and plus-maze. EP and EF groups were able to reverse the behavioral sensitization to the psychomotor stimulant effects of chronic ethanol administration. In contrast, a sensitized stimulatory effect was observed in chronically fluoxetine- or paroxetine treated mice challenged with ethanol (PE and FE). An anxiolytic effect was observed whether ethanol was substituted for SSRI or, conversely, SSRI was substituted for ethanol. SSRIs facilitated ethanol-induced locomotor sensitization, although SSRIs by themselves are unable to produce the locomotor stimulation similar to that induced by ethanol. Finally, SSRIs are unable to interfere in the ethanol anxiolytic effect.     

Utility of selective serotonin reuptake inhibitors in premature ejaculation

The introduction of selective serotonin reuptake inhibitors (SSRIs) has revolutionized our understanding of the treatment of premature ejaculation. Lifelong premature ejaculation may be a neurobiological phenomenon, namely part of a biological variability of the intravaginal ejaculation latency time in men. Animal studies support this view, and an animal model for premature and delayed ejaculation has recently been developed. It is proposed that drug treatment of premature ejaculation should consist of 5-hydroxytryptamine (5-HT)2c receptor stimulation and/or 5-HT1A receptor inhibition. A meta-analysis of 35 daily treatment studies with selective serotonin reuptake inhibitors (SSRIs) and clomipramine demonstrated comparable efficacy of clomipramine with the SSRIs sertraline and fluoxetine in delaying ejaculation, whereas the efficacy of the SSRI paroxetine was greater than all other SSRIs and clomipramine. It is postulated that acute treatment with SSRIs, including those with short half-lives, will not produce an ejaculation delay equivalent to that induced by daily treatment of SSRIs.     

Occupancy of brain serotonin transporters during treatment with paroxetine in patients with social phobia: a positron emission tomography study with 11C McN 5652

Abstract Rationale. Although selective serotonin reuptake inhibitors (SSRIs) are widely used in the treatment of anxiety and depressive disorders, the occupancy of the serotonin reuptake transporter (SERT) achieved in humans at typical clinical doses by these agents remains poorly characterized. Objective. The purpose of this study was to determine the occupancy of the SERT achieved in vivo by the SSRI paroxetine in social phobia patients at typical antianxiety doses. Methods. Measures of SERT availability were obtained with positron emission tomography and the SERT radiotracer [¹¹C](+)-McN 5652 in five patients with social phobia before and during treatment with paroxetine at usual therapeutic doses (20–40 mg per day). Results. Occupancy of the SERT by paroxetine was high in all subjects and in all regions measured after 3–6 months of continuous treatment. Conclusions. The results of this study in an anxiety disorder sample are consistent with previously reported results in a depressed sample and suggest that paroxetine at therapeutic doses achieves very high occupancy levels of the SERT. Electronic Publication