Venlafaxine: A 2003 update

Effect of venlafaxine on anhedonia and amotivation in patients with major depressive disorder

OBJECTIVE

Serotonin norepinephrine reuptake inhibitors (SNRIs) have been postulated to afford benefits in alleviating anhedonia and amotivation. This post hoc pooled analysis evaluated the effect of venlafaxine XR, an SNRI, on these symptoms in patients with major depressive disorder (MDD).

METHODS

Data was pooled from five short-term randomized, placebo-controlled studies of venlafaxine XR for the treatment of MDD, comprising 1087 (venlafaxine XR, n = 585; placebo, n = 502) adult subjects. The change from baseline score in the MADRS anhedonia factor (based on items 1 [apparent sadness], 2 [reported sadness], 6 [concentration difficulties], 7 [lassitude], and 8 [inability to feel]) for anhedonia, and in motivational deficits (based on 3 items of HAM-D17: involvement in work and activities, psychomotor retardation, and energy level [ie, general somatic symptoms]) for amotivation, were measured through 8 weeks. Mixed model repeated measures (MMRMs) were used to analyze changes over time and ANCOVA to analyze the change from baseline at week 8 with LOCF employed to handle missing data.

RESULTS

At the end of 8 weeks, the change from baseline was significantly greater in patients on venlafaxine XR in both anhedonia (mean, 95% CI: -2.73 [-3.63, -1.82], p < 0.0001) and amotivation scores (mean, 95% CI: -0.78 [-1.04, -0.52], p < 0.0001) than those on placebo. For both measures, the between-group separation from baseline was statistically significant starting from week 2 onwards, and it increased over time.

CONCLUSION

This analysis demonstrates that venlafaxine XR is effective in improving symptoms of anhedonia and motivational deficits in patients with MDD.

Optimization of Nasal Liposome Formulation of Venlafaxine Hydrochloride using a Box-Behnken Experimental Design

Background

Intranasal administration is among the most effective alternatives to deliver drugs directly to the brain and prevent first-pass metabolism. Venlafaxine-loaded liposomes are biocompatible carriers that enhance transport qualities over the nasal mucosa.

Objective

This research aimed to develop, formulate, characterize, and observe the prepared formulation.

Methods

The formulation was developed using the thin-film hydration technique. The response surface plot interrelationship between three independent variables are lipid, cholesterol and polymer and four dependent variables such as particle size, percentage entrapment efficiency, and percentage drug release were ascertained using the Box-Behnken design.

Results

The drug-release chitosan-coated liposomes were reported to have a particle size distribution, entanglement efficiency, and 84%, respectively, of 191 ± 34.71 nm, 94 ± 2.71% and 94 ± 2.71%. According to in vitro investigations, liposomes as a delivery system for the nasal route provided a more sustained drug release than the oral dosing form.

Conclusions

The intranasal administration of venlafaxine liposomal vesicles effectively enhanced the absolute bioavailability, retention time, and brain delivery of venlafaxine.

Venlafaxine increases aromatization, reduces apical V-ATPase in clear cells and induces increased number of mast cells and smooth muscle cells death in rat cauda epididymis

Depressive disorders (DD) have affected millions of people worldwide. Venlafaxine, antidepressant of the class of serotonin and norepinephrine reuptake inhibitors, has been prescribed for the treatment of DD. In rat testes, venlafaxine induces testosterone (T) aromatization and increases estrogen levels. Aromatase is a key enzyme for the formation of estrogen in the epididymis, an essential organ for male fertility. We investigated the impact of serotonergic/noradrenergic venlafaxine effect on the epididymal cauda region, focusing on aromatase, V-ATPase and EGF epithelial immunoexpression, smooth muscle (SM) integrity and mast cells number (MCN). Male rats were distributed into control (CG; n = 10) and venlafaxine (VFG, n = 10) groups. VFG received 30 mg/kg b.w. of venlafaxine for 35 days. The epididymal cauda was processed for light and transmission electron microscopy (TEM). The expression of connexin 43 (Cx43) and estrogen alpha (Esr1), adrenergic (Adra1a) and serotonergic (Htr1b) receptors were analyzed. Clear cells (CCs) area, SM thickness, viable spermatozoa (VS) and MCN were evaluated. Apoptosis was confirmed by TUNEL and TEM. The following immunoreactions were performed: T, aromatase, T/aromatase co-localization, V-ATPase, EGF, Cx43 and PCNA. The increased Adra1a and reduced Htr1b expressions confirmed the noradrenergic and serotonergic venlafaxine effects, respectively, corroborating the increased MCN, apoptosis and atrophy of SM. In VFG, the epithelial EGF increased, explaining Cx43 overexpression and basal cells mitotic activity. T aromatization and Esr1 downregulation indicate high estrogen levels, explaining CCs hypertrophy and changes in the V-ATPase localization, corroborating VS reduction. Thus, in addition to serotonergic/noradrenergic effects, T/estrogen imbalance, induced by venlafaxine, impairs epididymal structure and function.

Venlafaxine-induced adrenergic signaling stimulates Leydig cells steroidogenesis via Nur77 overexpression: a possible role of EGF

Venlafaxine, a norepinephrine and serotonin reuptake inhibitor, impairs rat sperm parameters, spermatogenesis and causes high intratesticular estrogen and testosterone levels, indicating that Leydig cells (LCs) may be a venlafaxine target. We evaluated the effect of venlafaxine treatment on LCs in vivo, focusing on adrenergic signaling, EGF immunoexpression and steroidogenesis. Germ cells mitotic/meiotic activity and UCHL1 levels were also evaluated in the seminiferous epithelium. Adult male rats received venlafaxine (30 mg/kg) or distilled water. In testicular sections, the seminiferous tubules, epithelium and the LCs nuclear areas were measured, and the immunoexpression of Ki-67, UCHL1, StAR, EGF, c-Kit and 17β-HSD was evaluated. UCHL1, StAR and EGF protein levels and Adra1a, Nur77 and Ndrg2 expression were analyzed. MDA and nitrite testicular levels, and serum estrogen and testosterone levels were measured. Venlafaxine induced LCs hypertrophy and Ndrg2 upregulation, in parallel to increased number of Ki-67, c-Kit- and 17β-HSD-positive interstitial cells, indicating that this antidepressant stimulates LCs lineage proliferation and differentiation. Upregulation of Adra1a and Nur77 could explain the high levels of StAR and testosterone levels, as well as aromatization. Enhanced EGF immunoexpresion in LCs suggests that this growth fact is involved in adrenergically-induced steroidogenesis, likely via upregulation of Nur77. Slight tubular atrophy and weak Ki-67 immunoexpression in germ cells, in association with high UCHL1 levels, indicate that spermatogenesis is likely impaired by this enzyme under supraphysiological estrogen levels. These data corroborate the unchanged MDA and nitrite levels. Therefore, venlafaxine stimulates LCs steroidogenesis via adrenergic signaling, and EGF may be involved in this process.

Venlafaxine Caffeic Acid Salt: Synthesis, Structural Characterization, and Hypoglycemic Effect Analysis

Depression is a recurrent and chronic mental disorder requiring long-term treatment. Major depressive disorder is present in 15-20% of patients with type 1 or type 2 diabetes. Large-scale evidence revealed that depression and depressive symptoms are independent risk factors for the development of type 2 diabetes, and they may contribute to hyperglycemia and even accelerate the premature onset of diabetes complications. Venlafaxine is a clinical first-line antidepressant used for more than 30 years. Recently, clinical reports showed that venlafaxine overdose might cause hypoglycemia. Venlafaxine is insoluble and salt formation technology is the most appropriate method to improve the physicochemical properties and the pharmacokinetic profile of the drug. In the present work, the use of the solvent evaporation method, slurry, and the liquid-assisted grinding method resulted in the crystalline salt venlafaxine-caffeic acid (1:1). The compounds were characterized using a series of solid-state techniques, viz., powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and solid-state nuclear magnetic resonance, and the crystal structure was determined by single-crystal X-ray diffraction. Besides, a comparative study of solubility, dissolution, and hypoglycemic activity of the parent drug and the new salt has been carried out. The tested venlafaxine-caffeic acid salt showed about 16-fold higher solubility than the pure drug. Moreover, the glucose consumption assay results showed that the novel salt possesses potent hypoglycemic activity in vitro, suggesting that it is a promising candidate effective for major depressive disorder patients with type 2 diabetes.

Venlafaxine-induced damage to seminiferous epithelium, spermiation, and sperm parameters in rats: A correlation with high estrogen levels

BACKGROUND

Venlafaxine (selective serotonin and norepinephrine reuptake inhibitor) use has increased worldwide. However, the impact of venlafaxine on testes and sperm parameters has not been investigated.

OBJECTIVES

We evaluated venlafaxine impact on testicular and sperm parameters and verified whether the changes are reversible.

METHODS

Animals from venlafaxine-35 days and venlafaxine-65 days groups received 30 mg/kg of venlafaxine for 35 days. Control-35 days and control-65 days received distilled water. In control-65 days and venlafaxine-65 days, the treatment was interrupted for 30 days. Sperm concentration, morphology, motility, and mitochondrial activity were analyzed. Number of step 19 spermatids (NLS), frequency of tubules with spermiation failure, Sertoli cells number, and TUNEL-positive germ cells were quantified. Testicular aromatase, connexin 43 (Cx43) immunoexpression, Cx43 protein levels, and Cx43 expression were evaluated. Either intratesticular testosterone or estrogen levels were measured.

RESULTS

Venlafaxine impaired sperm morphology, reduced sperm concentration, mitochondrial activity, and sperm motility. The frequency of tubules with spermiation failure and NLS increased in parallel to increased Cx43 immunoexpression; mRNA and protein levels; and aromatase, testosterone, and estrogen levels. An increase in germ cell death and decreased Sertoli cells number were observed. In venlafaxine-65 days, except for sperm motility, mitochondrial activity, Sertoli cells number, and germ cell death, all other parameters were partially or totally recovered.

CONCLUSION

Venlafaxine increases testosterone aromatization and Cx43. This drug, via high estrogen levels, disturbs Sertoli cells, induces germ cell death, and impairs spermiation and sperm parameters. The restoration of spermiation associated with the decreased Cx43 and hormonal levels in venlafaxine-65 days reinforces that high estrogen levels are related to venlafaxine-induced changes. The presence of damaged Sertoli cells, germ cell death, and low sperm motility in venlafaxine-65 days indicates that interruption of treatment for 30 days was insufficient for testicular recovery and points to a long-term estrogen impact on the seminiferous epithelium.

Norfluoxetine and venlafaxine in zebrafish larvae: Single and combined toxicity of two pharmaceutical products relevant for risk assessment

Antidepressant metabolites are found in natural and waste waters. However, investigation of their toxic effects on aquatic animals, single or in mixture with other occurring psychoactive drugs, has been neglected. Here, effects of 80hpf exposure to norfluoxetine (0.64-400 ng/L), venlafaxine (16-10000 ng/L) or their combination (3.2 ng/L +2000 ng/L, respectively) were investigated in embryos and zebrafish larvae. Mortality, embryonic malformations, sensorymotor reflexes and the expression of 34 genes involved in the toxicants mode-of-action (MoA) and metabolism were evaluated (i.e. monoamine receptors and transporters, nuclear receptors, and detoxification transporters and enzymes). Compared to controls, norfluoxetine treatments only caused depigmentation of embryos and larvae. Venlafaxine-exposed larvae exhibited depigmentation and spinal deformities, impaired sensorymotor reflexes, alterations in the expression of genes belonging to the serotonergic, noradrenergic and dopaminergic pathways, as well as nuclear receptors related to lipid and drug metabolism. The mixture elicited distinct interaction effects, depending on the level of biological organisation analysed and the neurotransmitter pathways affected; synergism (lethality), no interaction (sensorymotor reflexes), antagonism and inverse agonism (gene expression). The results call for investigation of the toxicity of pharmaceutical metabolites single and in mixture, as well as their risk assessment in approaches accounting for possible interactions with other endocrine-disrupting compounds.

Clustering patients by depression symptoms to predict venlafaxine ER antidepressant efficacy: Individual patient data analysis

OBJECTIVE

To identify clusters of patients with major depressive disorder (MDD) based on the baseline 17-item Hamilton Rating Scale for Depression (HAM-D₁₇) items and to evaluate the efficacy of venlafaxine extended release (VEN) vs placebo, and the potential effect of dose on efficacy, in each cluster.

METHODS

Cluster analysis was performed to identify clusters based on standardized HAM-D₁₇ item scores of individual patient data at baseline from 9 double-blind, placebo-controlled studies of VEN for MDD. Change from baseline in HAM-D₁₇ total score was analyzed using a mixed-effects model for repeated measures for each cluster; response and remission rates at week 8 were analyzed using logistic regression. Discontinuation rates were also evaluated in each cluster.

RESULTS

In 2599 patients, 3 patient clusters were identified, characterized as High modified Core (mCore) Symptoms/High Anxiety (cluster 1), High mCore Symptoms/Medium Anxiety (cluster 2), and Medium mCore Symptoms/Medium Anxiety (cluster 3). Significant effects of VEN vs placebo were observed on change from baseline in HAM-D₁₇ total score at week 8 for both clusters 1 and 2 (both P < 0.001), but not for cluster 3. In cluster 3, a significant treatment effect of VEN was observed at week 8 in the lower-dose subgroup but not in the higher-dose subgroup. All-cause discontinuation rates were significantly higher in placebo than VEN in each cluster.

CONCLUSIONS

Three unique clusters of patients were identified differing in baseline mCore symptoms and anxiety. Cluster membership may predict efficacy outcomes and contribute to dose effects in patients treated with VEN.

CLINICAL TRIALS REGISTRATION

NCT01441440; other studies included in this analysis were conducted before the requirement to register clinical studies took effect.

Stimuli-responsive In situ gelling system for nose-to-brain drug delivery

The diagnosis and treatment of neurological ailments always remain an utmost challenge for research fraternity due to the presence of BBB. The intranasal route appeared as an attractive and alternative route for brain targeting of therapeutics without the intrusion of BBB and GI exposure. This route directly and effectively delivers the therapeutics to different regions of the brain via olfactory and trigeminal nerve pathways. However, shorter drug retention time and mucociliary clearance curtail the efficiency of the intranasal route. The in situ mucoadhesive gel overthrow the limitations of direct nose-to-brain delivery by not only enhancing nasal residence time but also minimizing the mucociliary clearance and enzymatic degradation. This delivery system further improves the nasal absorption as well as bioavailability of drugs in the brain. The in situ mucoadhesive gel is a controlled and sustained release system that facilitates the absorption of various proteins, peptides and other larger lipophilic and hydrophilic moieties. Owing to multiple benefits, in situ gelling system has been widely explored to target the brain via nasal route. However, very few review works are reported which explains the application of in situ nasal gel for brain delivery of CNS acting moieties. Hence, in this piece of work, we have initially discussed the global statistics of neurological disorders reported by WHO and other reputed organizations, nasal anatomy, mechanism and challenges of nose-to-brain drug delivery. The work mainly focused on the use of different stimuli-responsive polymers, specifically thermoresponsive, pH-responsive, and ion triggered systems for the development of an effective and controlled dosage form, i.e., in situ nasal gel for brain targeting of bioactives. We have also highlighted the origin, structure, nature and phase transition behavior of the smart polymers found suitable for nasal administration, including poloxamer, chitosan, EHEC, xyloglucan, Carbopol, gellan gum and DGG along with their application in the treatment of neurological disorders. The article is aimed to gather all the information of the past 10 years related to the development and application of stimuli-responsive in situ nasal gel for brain drug delivery.

Pre-pubertal, low-intensity exercise does not require concomitant venlafaxine to induce robust, late-life antidepressant effects in Flinders sensitive line rats

A significant number of adolescents are considered insufficiently active. This is of concern considering the negative association between physical activity and major depressive disorder (MDD). There is a lack of approved pharmacological treatment options in this population partly due to limited information on the risks associated with lasting effects during early life. Therefore, interest in non-pharmacological strategies is gaining popularity with low- to moderate-intensity exercise being especially attractive for its antidepressant-like effects and augmentation properties in combination with antidepressants. Early-life development might present a unique "window of opportunity" to induce long-term beneficial effects in individuals treated with central acting drugs, such as antidepressants. Therefore, we investigated the bio-behavioural effects of pre-pubertal, low-intensity exercise (EXE) and/or venlafaxine (VEN) on depressive-like behaviour in juvenile (postnatal day 35 (PND35)) and young adult (PND60) stress-sensitive Flinders sensitive line (FSL) rats. Interventions were introduced during pre-pubertal development, that is PND21-34, followed by a 26-day washout/sedentary period, when bio-behavioural analyses were performed in the early adulthood group. VEN, alone or in combination with EXE, proved ineffective in inducing any bio-behavioural changes in either age group. EXE did not induce early-life antidepressant-like effects, despite increasing frontal serotonin (5-HT) and noradrenaline (NA) levels. Later in life (PND60), pre-pubertal exercise reduced immobility and increased coping behaviours, together with increased cortical 5-HT levels, despite a significant reduction in locomotor activity. These findings emphasize a strong serotonergic basis to the observed delayed antidepressant effects of EXE later in life.

Diagnosis and Management of Functional Chest Pain in the Rome IV Era

Functional chest pain accounts for about a third of the patients with noncardiac chest pain. It is a very common functional esophageal disorder that remains even today a management challenge to the practicing physician. Based on the definition offered by the Rome IV criteria, diagnosis of functional chest pain requires a negative workup of noncardiac chest pain patients that includes, proton pump inhibitor test or empirical proton pump inhibitor trial, endoscopy with esophageal mucosal biopsies, reflux testing, and esophageal manometry. The mainstay of treatment are neuromodulators that are primarily composed of anti-depressants. Alternative medicine and psychological interventions may be provided alone or in combination with other therapeutic modalities.

Determination of Venlafaxine in Bulk and Pharmaceutical Formulations Using Stability Indicating RP-HPLC Method with UV Detector

Background:

A robust and validated analytical method is a key component at various stages of pharmaceutical product development to ensure identity, purity and quality of drugs and formulations.

Objective:

The aim of proposed work was to develop and validate a simple, sensitive and stability indicating high performance liquid chromatographic method for the estimation of venlafaxine hydrochloride in bulk and formulations for routine analysis as well as for preformulation studies.

Methods:

Efficient chromatographic separation has been performed on a HpyercloneTM 5µm BDS C18 column using a mobile phase consisting of a mixture of phosphate buffer (25 mM, pH 3.0) and acetonitrile (70:30 v/v) at a flow rate of 1 ml min-1. Venlafaxine hydrochloride was analyzed using UV detector at 225nm. Developed method was validated as per ICH guidelines.

Results:

The method has demonstrated linearity over the range of 100 to 2000 ng ml-1 with regression equation, mean peak area (y) = 93.32 x concentration - 322.00 (R2 = 1). The method has demonstrated good and consistent recovery (99.34 to 101.16%). Precision of the method reflected by the relative standard deviation values at intra-day and inter-day levels was less than 1.79%. The detection and quantitation limits were 6.55 ng ml-1 and 19.84 ng ml-1 respectively indicating sensitivity of the method. The method was successfully applied for the estimation of venlafaxine hydrochloride in marketed and inhouse formulations. Also, developed method was successfully used in drug-excipients compatibility studies for VEN.

Conclusion:

The method was found to be accurate, precise, sensitive and selective for the determination venlafaxine hydrochloride in bulk and pharmaceutical formulations.

A meta-analysis of the efficacy of venlafaxine extended release 75-225 mg/day for the treatment of major depressive disorder

OBJECTIVE

To evaluate the short-term efficacy of venlafaxine extended release (ER) 75-225 mg/day compared with placebo for treating major depressive disorder (MDD) and to examine associations between baseline characteristics and efficacy outcomes in MDD patients treated with venlafaxine ER 75-225 mg/day.

RESEARCH DESIGN AND METHODS

This meta-analysis included published and unpublished short-term, double-blind, placebo-controlled, Wyeth/Pfizer sponsored studies of venlafaxine ER at doses up to 225 mg/day in adults with MDD.

CLINICAL TRIAL REGISTRATION

All trials were conducted before trial registration became mandatory.

MAIN OUTCOME MEASURES

Change from baseline in the 17-item Hamilton Rating Scale for Depression (HAM-D₁₇) total score was analyzed over time using a mixed-effects model for repeated measures with terms for study, treatment group, visit, interaction between treatment group and visit, and baseline score as a covariate. Associations between baseline demographic and clinical characteristics and the probability of HAM-D₁₇ response and remission at week 8 were evaluated using logistic regression models, with terms for study, treatment group, and baseline characteristics in the models. Safety and tolerability was assessed based on adverse events (AEs) and discontinuations due to AEs.

RESULTS

The full analysis set included 1087 patients from five studies that fulfilled selection criteria. Statistically significant separation between venlafaxine ER and placebo groups for HAM-D₁₇ total score was seen at week 2 and all subsequent assessments (p-values <.0001). There was no significant interaction between treatment and baseline HAM-D₁₇ total score. Probability of HAM-D₁₇ remission at week 8 decreased with increasing baseline HAM-D₁₇ total score (p = .0012; OR: 0.94); however, baseline HAM-D₁₇ total score did not predict response. Discontinuations due to AEs were reported for 9.4% of venlafaxine-ER-treated patients compared with 3.6% of placebo-treated patients. Key limitations: Five studies met the criteria for inclusion. Several differences in design between included studies limited the analysis: one study did not include a week 3 assessment (the week 3 time point was therefore dropped from the analysis), one study had two venlafaxine ER dose arms, which were combined into one group for the meta-analysis, and mixed- and flexible-dose studies were pooled.

CONCLUSIONS

Venlafaxine ER 75-225 mg/day effectively reduced symptoms of depression in patients with MDD overall and in patients with either lower (≤23) or higher (>23) HAM-D₁₇ total score at baseline.

Duloxetine in treating generalized anxiety disorder in adults: A meta-analysis of published randomized, double-blind, placebo-controlled trials

INTRODUCTION

We carried out a meta-analysis of published randomized, double-blind, placebo-controlled trails to assess the efficacy and tolerability of duloxetine in treating generalized anxiety disorder (GAD).

METHODS

A literature search was conducted using PubMed, ISI Web of Science, Medline, Cochrane Central Register of Controlled Trials databases until October 2014. The search terms used were "anxiety or anxious or generalized anxiety disorder" and "duloxetine or Cymbalta." Meta-analysis was conducted using Revman 5.1. A fixed-effects model was carried out on the response rates, remission rates, and symptom improvement. Risk ratio (RR) and mean difference (MD) were calculated. The overall effect size was calculated with 95% confidence intervals (CIs).

RESULTS

Seven studies (n = 2,674) were found eligible for inclusion in analysis. Six studies provided data on response, which showed a significant difference between duloxetine and placebo (n = 1,975, RR = 1.48, 95% CI, 1.34-1.63). Remission rates revealed significant superiority of duloxetine (n = 2,399, RR = 1.60, 95% CI, 1.43-1.80). Change from baseline scores on Hamilton Rating Scale for Anxiety showed a reduction in anxiety symptoms to be significantly efficient for duloxetine (n = 1,135, MD = 3.34, 95% CI, 2.37-4.32). Duloxetine increased statistically Sheehan Disability Scale total score (n = 1,652, MD = 2.84, 95% CI, 2.08-3.60). The discontinuation of the duloxetine was not significantly different from that of the placebo.

CONCLUSION

Duloxetine is moderately effective in treating GAD with improvement in overall function and well tolerability.

The nosologic relationship between generalized anxiety disorder and major depression

Generalized anxiety disorder (GAD) has undergone a series of revisions in its diagnostic criteria that has moved it, nosologically, away from its original affiliation with panic disorder (PD) and closer to major depressive disorder (MDD). This, together with its high comorbidity and putative shared genetic risk with MDD, has brought into question its place in future psychiatric nosology, prompting the planners of Diagnostic and Statistical Manual-V (DSM-V) and International Classification of Diseases-11 (ICD-11) to set up a workgroup tasked to better understand the relationship between GAD and MDD. This review attempts to summarize the extant data to compare GAD and MDD on a series of research validators to explore this relationship. Although insufficient data currently exist for GAD in several key validator classes, tentative conclusions can be drawn on the diagnostic status of GAD in relation to MDD. Although GAD possesses substantial overlap with MDD in the areas of genetics, childhood environment, demographics, and personality traits, this tends to hold true for other anxiety disorders (ADs) as well, with the strongest evidence for PD. Data from life events, personality disorders, biology, comorbidity, and pharmacology are mixed, showing some areas of similarity between GAD and MDD but some clear differences, again with a moderate degree of nonspecificity. Thus, although the bulk of evidence supports a close underlying relationship between them, the relatively nonspecific nature of these findings provides little more reason to question the nosologic validity of GAD in relation to MDD than that of some other anxiety disorders.

Pre-hatching fluoxetine-induced neurochemical, neurodevelopmental, and immunological changes in newly hatched cuttlefish

Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 μg L(-1)) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at hatching. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 μg L(-1)) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.

Invariom based electron density studies on the C/Si analogues haloperidol/sila-haloperidol and venlafaxine/sila-venlafaxine

Hirshfeld surfaces of haloperidol hydropicrate (left) and sila-haloperidol hydrochloride (right) show comparable sites of ED concentrations due to comparable intermolecular environments.

New therapies for non-cardiac chest pain

After excluding a cardiac cause, potent anti-reflux therapy should be administered to patients with non-cardiac chest pain since gastroesophageal reflux disease (GERD) is the most common underlying mechanism of this disorder. If GERD is an unlikely cause of patient's symptoms, an esophageal motor disorder should be excluded. Spastic motility disorders can be treated with a smooth muscle relaxant (such as calcium channel blocker, nitrate, or phosphodiesterase 5 inhibitors). Alternatively, spastic motility disorders may respond to anti-spasmodics, pain modulators, botulinum toxin injection into the distal esophagus, and/or surgery. Patients with functional chest pain have recently seen an expanded treatment armamentarium including medications such as trazadone, tricyclic anti-depressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, pregabalin, and/or ramelteon.

Accelerated hypertension after venlafaxine usage

Venlafaxine is the first antidepressant that acts via inhibiting serotonin and noradrenaline reuptake. Hypertension is observed in doses exceeding 300 mg/day and is the most feared complication. We report a patient with accelerated hypertension after venlafaxine use observed at a dose of 150 mg/day. A 23-year-old patient with symptoms of insomnia, depression, anhedonia, fatigue admitted our clinic. Venlafaxine at a dose of 75 mg/day was initiated after he was diagnosed with major depressive disorder. After 5 months, venlafaxine dose was uptitrated to 150 mg/day due to inadequate response to drug. After using venlafaxine for ten months at the dose of 150 mg/day, he admitted our clinic with headache and epistaxis. He was hospitalized after his blood pressure was measured as 210/170 mmHg. No secondary causes for hypertension were found, and venlafaxine treatment was considered possible etiologic factor. After stopping venlafaxine treatment, his blood pressure was reverted back to normal limits. While mild elevation of blood pressure could be observed after venlafaxine treatment, this case shows that accelerated hypertension with a diastolic blood pressure rise above 120 mmHg could be observed at relatively low doses of venlafaxine. Close monitoring of blood pressure is necessary after initiation of treatment, as accelerated hypertension could cause endorgan damage with potentially catastrophic results.

Analgesic effects of antidepressants alone and after their local co-administration with morphine in a rat model of neuropathic pain

BACKGROUND

The therapy of neuropathic pain may include the use of co-analgesics, such as antidepressants, however, their desired analgesic effect is associated with significant side effects. An alternative approach to this is their local administration which has been proposed, but there is little data regarding their local co-administration with morphine and the nature of the interaction between morphine and either doxepin or venlafaxine, two antidepressant drugs that have been recently used in neuropathic pain therapies.

METHODS

This study was performed on rats after chronic constriction injury (CCI) to the sciatic nerve. The von Frey and Hargreaves' tests were used to assess mechanical allodynia and thermal hyperalgesia, respectively, after intraplantar (ipl) or subcutaneous (sc) administration of amitriptyline, doxepin, or venlafaxine, or their ipl co-administration with morphine on day 12-16 after injury.

RESULTS

The ipl administration of amitriptyline (3, 15 mg), doxepin (1, 5, 10, 15 mg), or venlafaxine (2, 7 mg) was effective in antagonizing CCI-induced allodynia. Their sc injection at a site distal to the injured side, did not induce alterations in pain thresholds, which supports the local mode of action. Of the three antidepressants used in this study, only ipl co-administration of amitriptyline with morphine significantly enhanced its effect in contrast to doxepin and venlafaxine, both of which weakened the analgesic effect of morphine.

CONCLUSIONS

In summary, the results suggest that when amitriptyline (but not doxepin or venlafaxine) is locally co-administered with morphine the effectiveness under neuropathic pain is enhanced, although additional studies are necessary to explain differential mechanisms of interaction of antidepressant drugs with morphine after local administration.

Phenolic esters of O-desmethylvenlafaxine with improved oral bioavailability and brain uptake

O-Desmethylvenlafaxine (desvenlafaxine, ODV) is a recently approved antidepressant which in some clinical studies failed to meet a satisfactory end-point. The aim of this study was to prepare a series of phenolic esters of ODV and evaluate their potential as ODV prodrugs with improved brain uptake. Fifteen phenolic esters (compounds 1a-o) were synthesized and their pharmacokinetic profiles evaluated in rat. The four compounds producing the highest relative bioavailability of ODV in rat (compounds 1c, 1e, 1n, 1o) were then studied to evaluate their brain uptake. Of these four compounds, compound 1n (the piperonylic acid ester of ODV) demonstrated the highest C(max) of ODV both in the rat hypothalamus and total brain. Finally the pharmacokinetics of 1n were evaluated in beagle dog where the increase in relative bioavailability of ODV was found to be as great as in rat. This high relative bioavailability of ODV coupled with its good brain penetration make 1n the most promising candidate for development as an ODV prodrug.

The effect of venlafaxine on ongoing and experimentally induced pain in neuropathic pain patients: a double blind, placebo controlled study

BACKGROUND AND AIM

The aim of this randomized double blind placebo controlled study was to investigate the effectiveness and the safety of venlafaxine XR 75 and 150 mg on ongoing pain and on quantitative sensory tests in 60 patients with neuropathic pain for 8 weeks.

METHODS

Evaluation parameters consisted of ongoing pain intensity (VAS), patient satisfaction, side effects, global efficacy and tolerance. Quantitative sensory measurements taken from the affected area before and after the drug treatment included pin-prick hyperalgesia, allodynia, detection and pain thresholds to electrical and heat stimuli, temporal summation of repetitive electrical and heat stimuli.

RESULTS

A total of 55 patients completed the study. VAS scores decreased significantly compared to the baseline measurements in all groups. There was no significant difference between the groups regarding pain intensity and escape medication. The areas of allodynia and pin-prick hyperalgesia decreased significantly in venlafaxine groups compared to the placebo. There was no significant difference between the groups regarding the detection thresholds (electrical and heat). The pain threshold and the summation threshold to electrical stimuli and the summation threshold to heat stimuli increased significantly following treatment in both venlafaxine groups. In addition, the degree of the temporal summation to electrical and heat stimuli decreased significantly following treatment in both venlafaxine groups compared to the placebo.

CONCLUSION

The study showed significant effect of venlafaxine in the manifestations of hyperalgesia and temporal summation, but not on the ongoing pain intensity. Furthermore, the quantitative sensory tests provided complementing information to the clinical measures.

Time to discontinuation among the three second-generation antidepressants in a naturalistic outpatient setting of depression

AIM

This study compared the discontinuation time among the three second-generation antidepressants (paroxetine, venlafaxine, and mirtazapine) in a naturalistic setting for outpatient treatment of depression.

METHODS

This study used data from retrospectively reviewed medical records of patients admitted to an outpatient psychiatric clinic between January 2003 and December 2005. Patient groups (paroxetine-, venlafaxine-, and mirtazapine-treated) were compared with each other with regard to their discontinuation times for a 6-month period after treatment initiation. The data were analyzed, using a Kaplan-Meier survival analysis, and a Cox proportional hazards regression model.

RESULTS

There were no significant differences in discontinuation times among the three second-generation antidepressants during the 6-month period after initiation of drug therapy.

CONCLUSIONS

In a naturalistic setting for the care of depression, it seems that there are no differences in discontinuation times among these three second-generation antidepressants.

Antidepressant prescribing patterns in Korea: results from the clinical research center for depression study

OBJECTIVE

This study aimed to investigate antidepressant prescribing patterns, including initial choice, switching and combining, and concomitant use of non-antidepressant agents, for depressive disorders in naturalistic clinical care settings in Korea.

METHODS

Patients with depressive disorder were recruited from both outpatient and inpatient settings in 18 hospitals from all over Korea. Treatment was performed in naturalistic patterns based on each clinician's decision. Data were collected on the prescription of antidepressants and concomitant agents from baseline to 12-week follow-up.

RESULTS

Selective serotonin reuptake inhibitors (SSRIs) were the most commonly prescribed initial antidepressant (48.9%), followed by newer dual-action antidepressants (45.8%). When an SSRI was the initial antidepressant, 46.2% of patients whose medication was changed were moved to newer dual-action antidepressants, and 67.4% of combination cases were combined with newer dual-action ones. When a newer dual-action antidepressant was the initial antidepressant, 70.6% of patients whose medication was changed were moved to SSRIs, and other antidepressants including tricyclic antidepressants were most commonly added for combination treatment (50% of combination cases). During the treatment period, 20.6% of antidepressants prescribed were augmented by non-antidepressant agents, and 75.1% were used concomitantly with anxiolytics or hypnotics. The most commonly used concomitant non-antidepressant agent was quetiapine.

CONCLUSION

The selection of antidepressants and the concomitant use of non-antidepressant agents are becoming increasingly diversified, and the results of this study reflect changes in the prescribing pattern in actual Korean practices.

Review: Pharmacogenetic aspects of the effect of cytochrome P450 polymorphisms on serotonergic drug metabolism, response, interactions, and adverse effects

The field of pharmacogenetics contains a wealth of potential for the enhancement of clinical practice by providing a more effective match between patient and drug, consequently reducing the probability of an adverse drug reaction. Although a relatively novel concept in the forensic context, pharmacogenetics has the capability to assist in the interpretation of drug related deaths, particularly in unintentional drug poisonings where the cause of death remains unclear. However, the complex pharmacology of the drugs when subjected to genetic variations in metabolism makes interpretation of the expected response and adverse events difficult. Many possess multiple metabolic pathways, narrow therapeutic indices and active metabolites or enantiomers which may be eliminated via different pathways to the parent drug. A number of these drugs, which are metabolised primarily by the CYP450 system, are also associated with serotonin syndrome, or serotonin toxicity, especially when used concomitantly with other serotonin active drugs which rely on the same metabolic pathways for drug elimination. A comprehensive understanding of polymorphic drug metabolism and its expected outcomes is therefore essential when interpreting the involvement of drugs in adverse reactions. This review examines the genetically variable CYP450-mediated metabolism of a number of serotonin-active drugs that are often implicated in cases of serotonin toxicity, to assess the impact of pharmacogenetics on drug metabolism, response, interactions and adverse effects.

Venlafaxine versus methylphenidate in pediatric outpatients with attention deficit hyperactivity disorder: a randomized, double-blind comparison trial

OBJECTIVE

The present report aimed to investigate the efficacy and tolerability of venlafaxine compared to methylphenidate in children and adolescents with Attention Deficit/Hyperactivity Disorder (ADHD).

METHODS

This was a 6-week, parallel group, randomized clinical trial. Thirty-eight patients (27 boys and 11 girls) with a DSM-IV-TR diagnosis of ADHD were the study population of this trial. All study subjects were randomly assigned to receive treatment using capsules of venlafaxine at doses of 50-75 mg/day depending on weight (50 mg/day for <30 kg and 75 mg/day for >30 kg (group 1) or methylphenidate at a dose of 20-30 mg/day depending on weight (group 2) for a 6-week double blind, randomized clinical trial. The principal measure of outcome was the Teacher and Parent Attention Deficit/Hyperactivity Disorder Rating Scale-IV.

RESULTS

No significant differences were observed between the two groups on the Parent and Teacher Rating Scale scores (df = 1; F = 1.77; p = 0.19 and df = 1; F = 1.64; p = 0.20, respectively). Side effects of headaches and insomnia were observed more frequently in the methylphenidate group.

CONCLUSIONS

The results suggest that venlafaxine may be useful for the treatment of ADHD. In addition, a tolerable side-effect profile is one of the advantages of venlafaxine in the treatment of ADHD.

Efficacy of venlafaxine for symptomatic relief in young adult patients with functional chest pain: a randomized, double-blind, placebo-controlled, crossover trial

OBJECTIVES

Esophageal hypersensitivity is currently believed to have a crucial role in the pathogenesis of functional chest pain (FCP). The aim of this study was to evaluate the clinical efficacy of venlafaxine, a serotonin-norepinephrine reuptake inhibitor (SNRI), for FCP in young adult patients.

METHODS

Patients diagnosed with FCP were randomized to either an extended-release formulation of venlafaxine (75 mg hora somni) or a placebo for 4 weeks. After a washout period of 2 weeks, patients crossed over to the other arm of the study. The primary efficacy variable was the number of patients with >50% improvement in symptom scores. The secondary efficacy variables were (i) the symptom intensity score during each week, (ii) quality of life (QOL), (iii) the Beck Depression Inventory (BDI) score, and (iv) side effects.

RESULTS

A total of 43 patients (37 men, mean age 23.5 + or - 1.9 years) completed the study. A positive response was observed in 52.0% of patients during venlafaxine treatment; 4.0% had a positive response with placebo treatment as assessed by the intention-to-treat analysis (venlafaxine vs. placebo: odds ratio 26.0; 95% confidence interval 5.7-118.8; P<0.001). Results of Short-Form 36 (SF-36) indicated that patients who received venlafaxine treatment had a significantly greater improvement in body pain and emotional role compared with those who received placebo treatment (P=0.002 and P=0.002, respectively). No significant change was noted in the depression score after venalafaxine or placebo treatment. One patient withdrew from the study because of sleep disturbance and loss of appetite while receiving venlafaxine.

CONCLUSIONS

Venlafaxine, an SNRI antidepressant, significantly improved symptoms in young adult patients with FCP.

Association between generalized anxiety levels and pain in a community sample: evidence for diagnostic specificity

BACKGROUND

It is unclear whether generalized anxiety disorder (GAD) has a specific relationship to pain syndromes, going beyond the established association of pain with anxiety syndromes in general.

METHODS

Mental disorders were assessed in a community sample (N=4181; 18-65 years) using the DSM-IV/M-CIDI. Several threshold definitions were used to define GAD and medically unexplained pain.

RESULTS

The association between pain and GAD (odds ratio, OR=5.8 pain symptoms; OR=16.0 pain disorder) is stronger than the association between pain and other anxiety disorders (OR=2.4 pain symptoms; OR=4.0 pain disorder). This association extends to subthreshold level definitions of GAD with some indication for a non-linear dose-response relationship. The GAD-pain link cannot sufficiently be explained by demographic factors, comorbid mental or physical disorders.

CONCLUSIONS

The association of pain and generalized anxiety is not artifactual. Compared to other anxiety syndromes, it appears to be stronger and more specific suggesting the need to explore clinical and public health implications.

A double-blind, randomly assigned, placebo-controlled study of desvenlafaxine efficacy and safety for the treatment of vasomotor symptoms associated with menopause

OBJECTIVE

The objective of the study was to assess the efficacy and safety of desvenlafaxine (administered as desvenlafaxine succinate) for menopausal vasomotor symptoms.

STUDY DESIGN

Postmenopausal women (n = 458) experiencing 50 or more moderate to severe hot flushes per week received desvenlafaxine 100 or 150 mg/d, with titration at therapy initiation, or placebo. Hot flush number and severity were assessed at weeks 4 and 12. Safety data were collected throughout the trial.

RESULTS

Desvenlafaxine 100 and 150 mg/d significantly reduced the number of hot flushes compared with placebo at weeks 4 and 12 (all P < or = .012), achieving 65.4% and 66.6% reductions from baseline at week 12, respectively (placebo, 50.8%). Hot flush severity and number of nighttime awakenings were significantly reduced at both time points (all P < or = .048). Desvenlafaxine groups reported significantly more adverse events compared with placebo during week 1 only. No difference in discontinuations because of adverse events was observed.

CONCLUSION

Desvenlafaxine is an effective nonhormonal treatment for menopausal hot flushes. Dose titration improves initial tolerability.

Screening of venlafaxine hydrochloride for transdermal delivery: passive diffusion and iontophoresis

The objective of the study was to investigate in vitro transdermal delivery of venlafaxine hydrochloride across the pigskin by passive diffusion and iontophoresis. For passive diffusion, experiments were carried out in Franz diffusion cell whereas for iontophoretic permeation, the diffusion cell was modified to contain both the donor and return electrode on the same side of skin. Anodal iontophoresis was carried out using a current density of 0.5 mA/cm(2). Donor concentrations used were 585.5 mg/ml (saturated solution) and 100 mg/ml. Experiments initially performed to determine the transport efficiency of venlafaxine ions showed promising results. Iontophoresis increased the permeation rate at both concentration levels over their passive counterparts (P < 0.01), but surprisingly higher steady-state flux was obtained from lower donor drug load (P < 0.01). The favorable pH of the unsaturated solutions is suggested to be the cause for this effect. Mild synergistic effect was observed when iontophoresis was carried out incorporating peppermint oil in the donor but the same was not found in passive diffusion. Highest steady-state flux obtained in the experiment was 3.279 mumol/cm(2)/h when peppermint oil (0.1%) was included in the donor. As the maintenance requirement of venlafaxine hydrochloride is approximately 9.956 mumol/h, the results suggested that the drug is a promising candidate for iontophoretic delivery.

Adequacy of venlafaxine dose prescribing in major depression and hospital resources implications

Venlafaxine, a dual serotonin and noradrenaline re-uptake inhibitor, has been found to be effective at doses below 375 mg daily, but for patients with major depression higher doses can be required. In this retrospective naturalistic study, we investigated the effectiveness and resource implications of prescribing higher than standard doses of venlafaxine (tablet preparation). Ninety-six outpatients fulfilling DSM-IV criteria for major depressive disorder were assigned to two demographically matched cohorts: cohort A, receiving high doses (n = 38; doses > or =375 mg/day) and cohort B, receiving standard doses (n = 58; doses <375 mg/day). Data on hospital resources, drugs and medical profiles were extracted from patients' records. Information on cohort A was also obtained before their high-dose regime, while taking standard doses. A within-group analysis of cohort A showed that patients spent fewer days in hospital (P = 0.03) and had fewer outpatients visits (P < 0.01) when on high doses than when on standard doses. A between-group analysis found that cohort A, while on higher doses, had fewer outpatient visits compared with cohort B (P < 0.01). Patients in both groups had satisfactory drug tolerability and efficacy profiles. There were no differences between cohorts with regard to baseline characteristics, a part from the more intensive use of additional medications made by cohort A. Our preliminary investigation suggests that higher doses of venlafaxine may be cost-saving in relation to selected hospital resources. However, one cannot firmly conclude that the change in service use is due to the higher-dose regime, and we recommend further research to ascertain the cost-effectiveness of adequate dose prescribing in patients with poor symptom resolution at lower doses of venlafaxine.

Serotonin syndrome: a complex but easily avoidable condition

Serotonin syndrome is a potentially life-threatening adverse drug reaction caused by excessive serotonergic agonism in central and peripheral nervous system serotonergic receptors (Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005;352:1112-1120). Symptoms are characterized by a triad of neuron-excitatory features, which include (a) neuromuscular hyperactivity -- tremor, clonus, myoclonus, hyperreflexia and, in advanced stages, pyramidal rigidity; (b) autonomic hyperactivity -- diaphoresis, fever, tachycardia and tachypnea; (c) altered mental status -- agitation, excitement and, in advanced stages, confusion (Gillman PK. Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity. Br J Anaesth 2005;95:434-441). It arises when pharmacological agents increase serotonin neurotransmission at postsynaptic 5-hydroxytryptamine 1A and 5-hydroxytryptamine 2A receptors through increased serotonin synthesis, decreased serotonin metabolism, increased serotonin release, inhibition of serotonin reuptake or direct agonism of the serotonin receptors (Houlihan D. Serotonin syndrome resulting from coadministration of tramodol, venlafaxine, and mirtazapine. Ann Pharmacother 2004;38:411-413). The etiology is often the result of therapeutic drug use, intentional overdosing of serotonergic agents or complex interactions between drugs that directly or indirectly modulate the serotonin system (Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005;352:1112-1120). Due to the increasing availability of agents with serotonergic activity, physicians need to more aware of serotonin syndrome. The following case highlights the complex nature in which serotonin syndrome can arise, as well as the proper recognition and treatment of a potentially life-threatening yet easily avoidable condition.

Change in Pain Severity With Open Label Venlafaxine Use in Patients With a Depressive Symptomatology: An Observational Study in Primary Care

Purpose.

Venlafaxine has shown benefit in the treatment of depression and pain. Worldwide data are extensively lacking investigating the outcome of chronic pain patients with depressive symptoms treated by venlafaxine in the primary care setting. This observational study aimed to elucidate the efficacy of venlafaxine and its prescription by Swiss primary care physicians and psychiatrists in patients with chronic pain and depressive symptomatology.

Subjects and methods.

We studied 505 patients with depressive symptoms suffering from chronic pain in a prospective naturalistic Swiss community based observational trial with venlafaxine in primary care. These patients have been treated with venlafaxine by 122 physicians, namely psychiatrists, general practitioners, and internists.

Results.

On average, patients were treated with 143 ± 75 mg (0–450 mg) venlafaxine daily for a follow-up of three months. Venlafaxine proved to be beneficial in the treatment of both depressive symptoms and chronic pain.

Discussion.

Although side effects were absent in most patients, physicians might have frequently omitted satisfactory response rate of depression by underdosing venlafaxine. Our results reflect the complexity in the treatment of chronic pain in patients with depressive symptoms in primary care.

Conclusion.

Further randomized dose-finding studies are needed to learn more about the appropriate dosage in treating depression and comorbid pain with venlafaxine.

Venlafaxine–Propafenone Interaction Resulting in Hallucinations and Psychomotor Agitation

Objective:

To report a case of visual hallucinations and psychomotor agitation probably induced by an interaction between venlafaxine and propafenone.

Case Summary:

An 85-year-old woman was admitted for evaluation of a mood disorder on March 20, 2006. Her general practitioner had prescribed sertraline for treatment, which had started about 6 months earlier. The patient's medical history included hypertension, supraventricular tachycardia, chronic bronchitis, and arthritis, for which she received ramipril, ticlopidine, torsemide, theophylline, acetaminophen, and triazolam. The patient had also received propafenone 150 mg every 12 hours for 3 years. Results of biochemical tests were normal; however, a computed tomography (CT) scan of the brain showed signs of cortical atrophy. Sertraline was discontinued after a few days because of its reduced effectiveness and was replaced with extended-re lease venlafaxine 75 mg/day. No other changes to the patient's drug therapy were made. Four weeks later, because of the persistence of psychiatric disturbance, the venlafaxine dosage was increased to 150 mg/day. Ten days later the patient returned to our observation due to the onset of visual hallucinations lasting about 2 hours, especially at night, and psychomotor agitation. Venlafaxine was discontinued, with a complete remission of hallucinations and psychomotor agitation in about 4 days. The Naranjo probability scale indicated a probable relationship between venlafaxine and the patient's symptoms. Citalopram was started one month later for the persistence of mood disorders, with no adverse effects.

Discussion:

A CT scan documented signs of cortical atrophy in our patient's brain but excluded vascular brain injury, while clinical evaluation and anamnesis excluded a relationship between hallucinations and cortical atrophy. Genetic and pharmacologic factors may be involved in venlafaxine-induced adverse effects. Venlafaxine is metabolized primarily by CYP2D6 and is a substrate of P-glycoprotein. Propafenone, a known substrate and inhibitor of both CYP2D6 and P-glycoprotein, could therefore be involved in venlafaxine-induced hallucinations through the increase of venlafaxine plasma concentrations.

Conclusions:

To prevent the onset of clinical disturbances during venlafaxine treatment, we suggest careful evaluation of concomitant treatment with CYP2D6 or P-glycoprotein inhibitors (eg, propafenone) and, when possible, venlafaxine serum concentration monitoring.

Venlafaxine reverses chronic fatigue-induced behavioral, biochemical and neurochemical alterations in mice

A state of chronic fatigue was produced in mice by subjecting them to forced swim inside a rectangular jar of specific dimensions everyday for a 6 min session for 15 days. Immobility period was recorded on alternate days. The effect of venlafaxine, a dual reuptake inhibitor of serotonin and norepinephrine was evaluated in this murine model of chronic fatigue. Venlafaxine was administered daily and on the days of testing, it was injected 30 min before forced swim session. On the 16th day i.e. 24 h after the last dose of venlafaxine, various behavioral, biochemical and neurotransmitter estimations in the brain were carried out. There was a significant increase in immobility period in vehicle treated mice on successive days, the maximum immobility score reaching on the 7th day and sustained till 15th day. Behavioral parameters revealed hyperlocomotion, anxiety response, muscle incoordination, hyperalgesia and memory deficit. Biochemical analysis showed a significant increase in lipid peroxidation, nitrite and myeloperoxidase levels and a decrease in the reduced glutathione (GSH) levels in brain homogenates. Further, there was a decrease in adrenal ascorbic acid following chronic forced swim. The neurotransmitter estimations in the brain samples revealed a decrease in norepinephrine, serotonin and dopamine levels on chronic exposure to forced swim for 15 days. Daily treatment with venlafaxine (8 and 16 mg/kg, i.p.) for 15 days produced a significant reduction in immobility period and reversed various behavioral, biochemical and neurotransmitter alterations induced by chronic fatigue. Venlafaxine could be of therapeutic potential in the treatment of chronic fatigue.

Venlafaxine in the treatment of children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

The objectives of this pilot study were to explore the changes in symptom severity, tolerability, and the pharmacodynamics of venlafaxine treatment in youths with attention-deficit/hyperactivity disorder (ADHD).

METHODS

This was a 2-week, open-label, outpatient trial of venlafaxine in children and adolescents, ages 5-17 years, with ADHD. Three dosing strata, 0.5, 1.0, and 2.0 mg/kg per day, were examined. ADHD symptom severity and improvement assessments included the ADHD Rating Scale (ARS-IV) and the Clinical Global Impressions Scale (CGI). During this study, venlafaxine, O-desmethylvenlafaxine (ODV), norepinephrine, and serotonin concentrations were obtained.

RESULTS

Thirty-eight participants (33 males) were treated in this trial. Overall, parent-completed and teacher-completed ARS-IV total scores showed a statistically significant positive change at the end of the study when compared to baseline (p < 0.05). Significant increases in plasma venlafaxine concentrations were observed at day 15 when compared to day 8 (p = 0.04). In addition, plasma norepinephrine and serotonin concentrations were found to be significantly decreased from baseline at end of study (p < 0.05). Four patients ended participation in the study prematurely: lost to follow up (n = 2), withdrawal of consent (n = 1), and worsening of ADHD symptoms after 8 days of treatment (n = 1). There were no discontinuations due to other adverse events.

CONCLUSIONS

Venlafaxine appeared to offer some benefit and appears to be relatively safe for the short-term treatment of ADHD in this open-label trial. The pharmacodynamics of venlafaxine in youths are consistent with serotonergic and neuradrenergic modulation.

Extended-release formulation of venlafaxine in the treatment of post-traumatic stress disorder

There is abundant evidence for abnormalities of both norepinephrine and serotonin neurotransmitter systems in post-traumatic stress disorder (PTSD). Venlafaxine extended-release formulation (venlafaxine XR) is a serotonin and norepinephrine re-uptake inhibitor with antidepressant and anxiolytic properties relevant to the pathophysiology of PTSD. Venlafaxine XR is currently approved for the treatment of panic disorder, generalized anxiety disorder and social anxiety disorder, as well as major depression in adults, based on a number of randomized, double blind, placebo-controlled clinical trials. Limited data also demonstrate that venlafaxine XR maintains a therapeutic response for more than 6 months in these anxiety disorders. Venlafaxine XR has demonstrated short- and long-term efficacy for the treatment of PTSD in two recent randomized, double-blind, placebo-controlled clinical trials, although it has not been extensively studied for PTSD, compared with other anxiety disorders. This review focuses on the potential role of venlafaxine XR in the treatment of PTSD, based on currently available evidence.