Duloxetine for major depressive episodes in the course of psychotic disorders: an observational clinical trial

Inhibitory effects of fluoxetine and duloxetine on the pharmacokinetics of metoprolol in vivo and in vitro

Depression is common among people with cardiovascular diseases. Therefore, the combined use of antidepressants and cardiovascular drugs is very common, which increases the possibility of drug interaction. Simultaneously compare the effects of duloxetine and fluoxetine on metoprolol metabolism, and provide evidence-based guidance for medication safety. Sprague-Dawley rats were randomly divided into three groups: group A (10.3 mg/kg metoprolol alone), group B (10.3 mg/kg metoprolol + 6.2 mg/kg fluoxetine), and group C (10.3 mg/kg metoprolol + 6.2 mg/kg duloxetine). Tail vein blood was collected and subjected to the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. Moreover, in vitro inhibition of fluoxetine and duloxetine were assessed by incubating liver microsomes and CYP2D6.1 with metoprolol. In in vivo study, the administration of fluoxetine or duloxetine significantly increased the AUC_(0-𝑡) and AUC_(0-∞) of metoprolol (P < 0.05). Differences between fluoxetine and duloxetine in plasma concentration were also investigated, and their pharmacokinetic parameters such as AUC_(0-𝑡) and AUC_(0-∞) were significantly distinct (P < 0.05). In vitro, fluoxetine and duloxetine inhibited the metabolism of metoprolol via mixed competitive mechanism of cytochrome P450. IC₅₀ values of fluoxetine and duloxetine were 12.86 and 2.51 μM, respectively. Moreover, the metabolism rate of metoprolol was inhibited to 19.62% and 17.14% in recombinant human CYP2D6.1 by fluoxetine and duloxetine, respectively. Duloxetine showed a more significant inhibitory potential compared to fluoxetine in vitro, but the main pharmacokinetic parameters of fluoxetine and duloxetine revealed differences in inhibiting metoprolol metabolism in vivo.

Modeling postpartum depression in rats: theoretic and methodological issues

The postpartum period is when a host of changes occur at molecular, cellular, physiological and behavioral levels to prepare female humans for the challenge of maternity. Alteration or prevention of these normal adaptions is thought to contribute to disruptions of emotion regulation, motivation and cognitive abilities that underlie postpartum mental disorders, such as postpartum depression. Despite the high incidence of this disorder, and the detrimental consequences for both mother and child, its etiology and related neurobiological mechanisms remain poorly understood, partially due to the lack of appropriate animal models. In recent decades, there have been a number of attempts to model postpartum depression disorder in rats. In the present review, we first describe clinical symptoms of postpartum depression and discuss known risk factors, including both genetic and environmental factors. Thereafter, we discuss various rat models that have been developed to capture various aspects of this disorder and knowledge gained from such attempts. In doing so, we focus on the theories behind each attempt and the methods used to achieve their goals. Finally, we point out several understudied areas in this field and make suggestions for future directions.

Psychotropics and Male Reproduction

Psychotropic drugs, including antidepressants, antipsychotics, and anticonvulsants, all have negative effects on sexual function and semen quality. These adverse events vary among men and are less pronounced for some medications, allowing their effects to be managed to some extent. Use of specific serotonin reuptake inhibitors (SSRIs) is prevalent in men of reproductive age; and application to treat premature ejaculation increases the number of young men on SSRI therapy. Oxidative damage to sperm can result from prolonged residence in the male reproductive tract. The increase in ejaculatory latency seen with SSRIs likely underlies some of their negative effects on semen quality, including higher sperm DNA fragmentation, seen in all SSRIs evaluated thus far. These medications increase prolactin (PRL) levels in some men, and this is often credited with inhibitory effects on male reproduction; however, testosterone levels are generally normal, reducing the likelihood of direct HPG axis inhibition by PRL. The tricyclic antidepressants have also been shown to increase PRL levels in some studies but not in others. The exception is the tricyclic antidepressant clomipramine, which profoundly increases PRL levels and may depress semen quality. Other antidepressants modulating synaptic levels of serotonin, norepinephrine, and/or dopamine may have toxicity similar to SSRIs, but most have not been evaluated. In limited studies, norepinephrine-dopamine reuptake inhibitors (NDRIs) and serotonin agonist/reuptake inhibitors (SARIs) have had minimal effects on PRL levels and on sexual side effects. Antipsychotic medications increase PRL, decrease testosterone, and increase sexual side effects, including ejaculatory dysfunction. The greatest evidence is for chlorpromazine, haloperidol, reserpine, risperidone, and thioridazine, with less effects seen with aripiprazole and clozapine. Remarkably few studies have looked at antipsychotic effects on semen quality, and this is an important knowledge gap in reproductive pharmacology. Lithium increases PRL and LH levels and decreases testosterone although this is informed by few studies. The anticonvulsants, many used for other indications, generally decrease free or bioavailable testosterone with variable effects on the other reproductive hormones. Valproate, carbamazepine, oxcarbazepine, and levetiracetam decrease semen quality; other anticonvulsants have not been investigated for this adverse reaction. Studies are required evaluating endpoints of pregnancy and offspring health for psychotropic medications.

Agomelatine for the Treatment of Major Depressive Episodes in Schizophrenia-Spectrum Disorders: An Open-Prospective Proof-of-Concept Study

BACKGROUND

Depressive episodes in schizophrenia constitute a major clinical problem, and treatment success is often limited by treatment-emergent side effects. Agomelatine, an agonist at melatonergic MT1/MT2 receptors and 5-HT2C receptor antagonist, is a new antidepressant with a novel mode of action which constitutes a potential therapeutic option for depression in schizophrenia.

METHODS

Twenty-seven patients with lifetime diagnoses within the schizophrenia spectrum and comorbid depression were treated with agomelatine in addition to stable doses of antipsychotic agents. Severity of depression and other psychopathological domains (positive/negative symptoms, general psychopathology, psychosocial performance) was assessed regularly by means of standardized rating scales during a 6-week acute treatment phase as well as after a 6-week extension phase. Moreover, safety measures (electrocardiograms, laboratory counts, neurological and non-neurological side effects, sleep quality, sexual functioning) were monitored on a regular basis.

RESULTS

Depressive symptoms improved significantly during the 6-week acute treatment phase. In parallel, a significant improvement of negative symptoms, global psychopathology, and psychosocial performance was observed, whereas positive symptoms remained stable. Agomelatine was mostly well tolerated with predominantly mild and self-limiting side effects. However, pharmacokinetic interactions with antipsychotic agents were observed. Interestingly, the quality of sleep did not improve significantly, pointing toward mechanisms that do not depend on resynchronization of circadian rhythms.

CONCLUSIONS

Agomelatine appears to be safe and efficacious in treating depressive symptoms in patients with schizophrenia. The risk of pharmacokinetic interactions with antipsychotic agents warrants the need of therapeutic drug monitoring, and regular recording of vital signs seems necessary. Further randomized trials will have to confirm these findings.

Clinically relevant interactions between newer antidepressants and second-generation antipsychotics

INTRODUCTION

Combinations of newer antidepressants and second-generation antipsychotics (SGAs) are frequently used by clinicians. Pharmacokinetic drug interaction (PK DI) and poorly understood pharmacodynamic (PD) drug interaction (PD DI) can occur between them.

AREAS COVERED

This paper comprehensively reviews PD DI and PK DI studies.

EXPERT OPINION

More PK DI studies are needed to better establish dose correction factors after adding fluoxetine and paroxetine to aripiprazole, iloperidone and risperidone. Further PK DI studies and case reports are also needed to better establish the need for dose correction factors after adding i) fluoxetine to clozapine, lurasidone, quetiapine and olanzapine; ii) paroxetine to olanzapine; iii) fluvoxamine to asenapine, aripiprazole, iloperidone, lurasidone, olanzapine, quetiapine and risperidone; iv) high sertraline doses to aripiprazole, clozapine, iloperidone and risperidone: v) bupropion and duloxetine to aripiprazole, clozapine, iloperidone and risperidone; and vi) asenapine to paroxetine and venlafaxine. Possible beneficial PD DI effects occur after adding SGAs to newer antidepressants for treatment-resistant major depressive and obsessive-compulsive disorders. The lack of studies combining newer antidepressants and SGAs in psychotic depression is worrisome. PD DIs between newer antidepressants and SGAs may be more likely for mirtazapine and bupropion. Adding selective serotonin reuptake inhibitors and SGAs may increase QTc interval and may very rarely contribute to torsades de pointes.

Drug-drug conditioning between citalopram and haloperidol or olanzapine in a conditioned avoidance response model: implications for polypharmacy in schizophrenia

Patients with schizophrenia often have anxiety and depression, and thus are treated with multiple psychotherapeutic medications. This practice of polypharmacy increases the possibility for drug-drug interactions. However, the pharmacological and behavioral mechanisms underlying drug-drug interactions in schizophrenia remain poorly understood. In the present study, we adopted a preclinical approach and examined a less known behavioral mechanism, drug-drug conditioning (DDC) between haloperidol (a typical antipsychotic) or olanzapine (atypical antipsychotic) and citalopram (a selective serotonin reuptake inhibitor). A rat two-way conditioned avoidance response paradigm was used to measure antipsychotic activity and determine how DDC may alter the antipsychotic efficacy in this model. Following acquisition of the avoidance response, rats were then randomly assigned to receive vehicle, citalopram (10.0 mg/kg, intraperitoneally), haloperidol (0.05 mg/kg, subcutaneously), olanzapine (1.0 mg/kg, subcutaneously), combined haloperidol with citalopram, or combined olanzapine with citalopram treatment for seven avoidance test sessions. In comparison with antipsychotic treatment alone, combined treatment with citalopram potentiated the antiavoidance effect of olanzapine or haloperidol (to a lesser extent) during the seven drug-test sessions. In addition, repeated pairing of citalopram with haloperidol or olanzapine caused citalopram to show a newly acquired avoidance-disruptive effect. This effect was context specific because citalopram paired with haloperidol or olanzapine outside the avoidance testing context (i.e. home cages) did not show such an effect. These findings indicate that concurrent antidepressant and antipsychotic treatments may engender a DDC process that follows the general Pavlovian associative conditioning principles. They also indicate that adjunctive citalopram treatment may enhance the antipsychotic efficacy of haloperidol and olanzapine in the treatment of schizophrenia.

Treatment-resistant Schizophrenia: Evidence-based Strategies

Treatment-resistant symptoms complicate the clinical course of schizophrenia, and a large proportion of patients do not reach functional recovery. In consequence, polypharmacy is frequently used in treatment-refractory cases, addressing psychotic positive, negative and cognitive symptoms, treatment-emergent side effects caused by antipsychotics and comorbid depressive or obsessive-compulsive symptoms. To a large extent, such strategies are not covered by pharmacological guidelines which strongly suggest antipsychotic monotherapy. Add-on strategies comprise combinations of several antipsychotic agents and augmentations with mood stabilizers; moreover, antidepressants and experimental substances are applied. Based on the accumulated evidence of clinical trials and meta-analyses, combinations of clozapine with certain second-generation antipsychotic agents and the augmentation of antipsychotics with antidepressants seem recommendable, while the augmentation with mood stabilizers cannot be considered superior to placebo. Forthcoming investigations will have to focus on innovative pharmacological agents, the clinical spectrum of cognitive deficits and the implementation of cognitive behavioral therapy.

Duloxetine: clinical pharmacokinetics and drug interactions

Duloxetine, a potent reuptake inhibitor of serotonin (5-HT) and norepinephrine, is effective for the treatment of major depressive disorder, diabetic neuropathic pain, stress urinary incontinence, generalized anxiety disorder and fibromyalgia. Duloxetine achieves a maximum plasma concentration (C(max)) of approximately 47 ng/mL (40 mg twice-daily dosing) to 110 ng/mL (80 mg twice-daily dosing) approximately 6 hours after dosing. The elimination half-life of duloxetine is approximately 10-12 hours and the volume of distribution is approximately 1640 L. The goal of this paper is to provide a review of the literature on intrinsic and extrinsic factors that may impact the pharmacokinetics of duloxetine with a focus on concomitant medications and their clinical implications. Patient demographic characteristics found to influence the pharmacokinetics of duloxetine include sex, smoking status, age, ethnicity, cytochrome P450 (CYP) 2D6 genotype, hepatic function and renal function. Of these, only impaired hepatic function or severely impaired renal function warrant specific warnings or dose recommendations. Pharmacokinetic results from drug interaction studies show that activated charcoal decreases duloxetine exposure, and that CYP1A2 inhibition increases duloxetine exposure to a clinically significant degree. Specifically, following oral administration in the presence of fluvoxamine, the area under the plasma concentration-time curve and C(max) of duloxetine significantly increased by 460% (90% CI 359, 584) and 141% (90% CI 93, 200), respectively. In addition, smoking is associated with a 30% decrease in duloxetine concentration. The exposure of duloxetine with CYP2D6 inhibitors or in CYP2D6 poor metabolizers is increased to a lesser extent than that observed with CYP1A2 inhibition and does not require a dose adjustment. In addition, duloxetine increases the exposure of drugs that are metabolized by CYP2D6, but not CYP1A2. Pharmacodynamic study results indicate that duloxetine may enhance the effects of benzodiazepines, but not alcohol or warfarin. An increase in gastric pH produced by histamine H(2)-receptor antagonists or antacids did not impact the absorption of duloxetine. While duloxetine is generally well tolerated, it is important to be knowledgeable about the potential for pharmacokinetic interactions between duloxetine and drugs that inhibit CYP1A2 or drugs that are metabolized by CYP2D6 enzymes.

Adverse reactions to duloxetine in depression

INTRODUCTION

Untreated or inadequately treated depression is the largest risk factor for suicide. However, treatment with different antidepressants can have considerable adverse effects, including the increase of the frequency of suicidal thoughts and behavior. This review summarizes the frequency and severity of adverse events observed during the treatment of depression with duloxetine and considers their relevance to clinical practice.

AREAS COVERED

A comprehensive review of the literature was conducted using PubMed and Medline databases listing data published until December 2010. Articles describing safety and tolerability of duloxetine were selected and reference lists of these articles were scrutinized for further relevant papers. In addition, US and EU Summaries of Product Characteristics were studied.

EXPERT OPINION

Treatment with duloxetine was associated with mild to moderate adverse events; sexual dysfunction, nausea, headache, dry mouth, somnolence and dizziness being the most frequent among them. No increase in death from suicide and suicidal thoughts and behavior were detected as compared to placebo. So as to avoid discontinuation syndrome as a consequence of abrupt withdrawal of duloxetine, 2 weeks tapering has been recommended before discontinuation. Overall, duloxetine was found to be well tolerated and can be safely administered even in older patients and in those with concomitant illnesses.

[Polypharmacy in schizophrenia]

BACKGROUND

While most guidelines recommend monotherapy with second-generation antipsychotics (SGA) in schizophrenia, the combined application of multiple psychotropic agents is very common, especially in treatment-refractory cases.

METHODS

This review summarizes the evidence of combined antipsychotic treatment strategies and the augmentation of antipsychotics with mood stabilizers, antidepressants and experimental substances, based on publications accessible in public databases (Medline/Ovid, Google, http://www.clinicaltrials.gov) up to October 2009.

RESULTS

Polypharmacy aims to address several aspects of treatment resistance and side effects of antipsychotics. Some evidence supports the augmentation of antipsychotics with antidepressants for negative symptoms and comorbid major depressive episodes. The add-on of lithium and mood stabilizers lacks compelling evidence but might be beneficial for specific subgroups. For treatment-resistant cognitive symptoms, cognitive re-mediation seems most promising as no pharmacological add-on strategy has gained convincing evidence so far. Acute dystonic movements should be treated with anticholinergic agents while agitation and anxiety might respond to short-term application of benzodiazepines. Treatment-resistant positive and/or negative symptoms should primarily lead to clozapine monotherapy; the add-on of a second SGA may be considered in single cases.

CONCLUSIONS

In general, rigorous data on combination therapy in schizophrenia are rare, and further randomized controlled trials (RCT), naturalistic and head-to-head-studies are necessary.

Polypharmacy in schizophrenia

PURPOSE OF REVIEW

Although most guidelines recommend monotherapy in schizophrenia, the combined application of multiple psychotropic agents is very common, especially in treatment-refractory cases. We review the empirical basis supporting these attempts and their relevance for clinical practice.

RECENT FINDINGS

Polypharmacy intends to address different aspects of treatment resistance, most importantly insufficient response of psychotic positive and negative symptoms, but also cognitive disturbances, affective comorbidity, obsessive-compulsive syndromes and side-effects of antipsychotic drugs. This review summarizes the current state of evidence of combined antipsychotic treatment strategies and the augmentation of antipsychotics with mood stabilizers, antidepressants and experimental substances.

SUMMARY

In general, rigorous data on combination therapy in schizophrenia are rare and further randomized controlled trials, naturalistic trials and head-to-head-trials are necessary. Some evidence supports a combination of antipsychotics and antidepressants for negative symptoms and comorbid major depressive episodes. The add-on of lithium and mood stabilizers lacks compelling evidence, but might be beneficial for specific subgroups. For treatment-resistant cognitive symptoms, antipsychotic medication should be combined with cognitive remediation, as no pharmacological add-on strategy has gained convincing evidence so far. Treatment-emergent positive and/or negative symptoms under clozapine monotherapy might benefit from adding a second atypical substance.