venlafaxine (Effexor)
Simple and an efficient method for the synthesis of 1-[2-dimethylamino-1-(4-methoxy-phenyl)-ethyl]-cyclohexanol hydrochloride: (+/-) venlafaxine racemic mixtures.

Basappa, Kavitha CV, Rangappa KS.

Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570006, India.

A novel synthetic method was developed for the synthesis of venlafaxine using inexpensive reagents. An improvement in the method, in the yield was achieved for the conversion of the venlafaxine. This is an improved version, simple and efficient method for the large-scale synthesis of venlafaxine.

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Effexor, Effexor XR

venlafaxine (Effexor)
Efficacy of duloxetine, a potent and balanced serotonin-norepinephrine reuptake inhibitor in persistent pain models in rats.

Iyengar S, Webster AA, Hemrick-Luecke SK, Xu JY, Simmons RM.

Eli Lilly & Co., Lilly Corporate Center, Indianapolis, IN 46285, USA. iyengar lilly.com

5-Hydroxytryptamine (serotonin) (5-HT) and norepinephrine (NE) are implicated in modulating descending inhibitory pain pathways in the central nervous system. Duloxetine is a selective and potent dual 5-HT and NE reuptake inhibitor (SNRI). The ability of duloxetine to antagonize 5-HT depletion in para-chloramphetamine-treated rats was comparable with that of paroxetine, a selective serotonin reuptake inhibitor (SSRI), whereas its ability to antagonize NE depletion in alpha-methyl-m-tyrosine-treated rats was similar to norepinephrine reuptake inhibitors (NRIs), thionisoxetine or desipramine. In this paradigm, duloxetine was also more potent than other SNRIs, including venlafaxine or milnacipran and amitriptyline. Low doses of the SSRI paroxetine or the NRI thionisoxetine alone did not have an effect on late phase paw-licking pain behavior in the formalin model of persistent pain; however, when combined, significantly attenuated this pain behavior. Duloxetine (3-15 mg/kg intraperitoneal) significantly attenuated late phase paw-licking behavior in a dose-dependent manner in the formalin model and was more potent than venlafaxine, milnacipran, and amitriptyline. These effects of duloxetine were evident at doses that did not cause neurologic deficits in the rotorod test. Duloxetine (5-30 mg/kg oral) was also more potent and efficacious than venlafaxine and milnacipran in reversing mechanical allodynia behavior in the L5/L6 spinal nerve ligation model of neuropathic pain. Duloxetine (3-30 mg/kg oral) was minimally efficacious in the tail-flick model of acute nociceptive pain. These data suggest that inhibition of both 5-HT and NE uptake may account for attenuation of persistent pain mechanisms. Thus, duloxetine may have utility in treatment of human persistent and neuropathic pain states.

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venlafaxine (Effexor)
Efficacy of low and higher dose extended-release venlafaxine in generalized social anxiety disorder: a 6-month randomized controlled trial.

Stein MB, Pollack MH, Bystritsky A, Kelsey JE, Mangano RM.

Department of Psychiatry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0985, USA. mstein ucsd.edu

RATIONALE: There is a need for new pharmacological treatments for generalized social anxiety disorder (GSAD), which is a common, often disabling condition. OBJECTIVE: To compare the efficacy and safety over 6 months duration of two dose ranges of venlafaxine extended-release (ER) with placebo in patients with GSAD. METHOD: Twenty-eight-week, double-blind, multi-center study in 386 adult outpatients with DSM-IV GSAD. Patients were randomized to placebo, venlafaxine ER fixed low dose (75 mg/day), or venlafaxine ER flexible higher dose (150-225 mg/day). Primary efficacy variable was change on the Liebowitz Social Anxiety Scale (LSAS). Secondary efficacy variables included, among others, the proportion of responders on the CGI Global Improvement Item (score 1 or 2), and the proportion of remitters (defined as an LSAS score of <or=30). RESULTS: Improvement on the LSAS was greater with venlafaxine ER (at 75 mg/day or 150-225 mg/day) than placebo, and was sustained throughout the 6-month trial. Of patients receiving venlafaxine ER (at any dose), 58% responded to treatment compared to 33% of those receiving placebo (P<0.001); corresponding remission rates were 31% and 16% (P<0.01). There were no differences in outcome according to venlafaxine ER dosage. CONCLUSIONS: Venlafaxine ER was effective in the treatment of GSAD. The comparable efficacy at low and higher doses may indicate that norepinephrine reuptake blockade does not contribute to therapeutic effect in GSAD. This hypothesis should be tested using agents with specific actions on norepinephrine reuptake blockade.

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venlafaxine (Effexor)
Tolerability of high-dose venlafaxine in depressed patients.

Harrison CL, Ferrier N, Young AH.

School of Neurology, Neurobiology and Psychiatry, Psychiatry, Royal Victoria Infirmary, Newcastle upon Tyne, UK.

High doses of antidepressants are often used for treatment-resistant depression. Venlafaxine, a dual serotonin and noradrenaline reuptake inhibitor, has been shown to have a tolerable side-effect profile in previous studies using doses of up to 375 mg/day. We investigated the tolerability of higher than currently recommended doses of venlafaxine using the UKU side-effect rating scale. Seventy outpatients fulfilling DSM-IV criteria for major depressive disorder were recruited into two demographically matched groups according to their daily dosage of venlafaxine: high dose n = 35 (> or = 375 mg/day, range 375-600 mg, average 437 mg/day) or standard dose n = 35 (< 375 mg/day, range 75-300 mg, average 195 mg/day. Clinical characteristics were noted and the UKU side-effect rating scale was administered to a subsample of patients. The most frequently reported complaints in both groups were increased fatigue (48%), concentration difficulties (48%), sleepiness/sedation (37%), failing memory (44.4%) and weight gain (29.6%). Apart from weight gain, the complaints were found to be experienced significantly more severely by the high-dose group. Six patients discontinued venlafaxine due to intolerable side-effects but only two of these patients were on a high dose. There was a tendency for mildly raised blood pressure in 10% of patients on an average dose of 342 mg/day. However, no difference between the two groups was found. This preliminary open study demonstrates that venlafaxine is tolerated at higher than British National Formulary recommended doses (i.e. up to 600 mg daily). However, increased frequency and severity of reported side-effects in the high-dose group are not associated with increased rates of discontinuation.

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venlafaxine (Effexor)
Recovery of hippocampal cell proliferation and BDNF levels, both of which are reduced by repeated restraint stress, is accelerated by chronic venlafaxine.

Xu H, Luo C, Richardson JS, Li XM.

Neuropsychiatry Research Unit, Department of Psychiatry, University of Saskatchewan, Saskatoon, Canada SK S7N 5E4.

The present study investigated the poststress (PS) cellular and molecular changes in the hippocampus of rats subjected to repeated restraint stress (RS) and the effects of chronic administration of an antidepressant drug, venlafaxine, on these changes. It was found that RS suppressed hippocampal cell proliferation, decreased brain-derived neurotrophic factor (BDNF) levels, and increased both the levels of copper/zinc superoxide dismutase (Cu/Zn-SOD) and the number of Cu/Zn-SOD immunostained hippocampal interneurons. In venlafaxine-treated rats, the changes in cell proliferation, BDNF levels, and the number of Cu/Zn-SOD interneurons returned to control levels on PS Days 21, 14, 7, respectively. In vehicle-injected rats, BDNF and the number of Cu/Zn-SOD interneurons returned to control levels on PS Days 21 and 14, respectively, but cell proliferation was still suppressed on PS Day 21. The stress-induced elevation of Cu/Zn-SOD protein remained during the 3-week PS period, and it was further increased by about 20% after 3 weeks of venlafaxine administration.

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Effexor, Effexor XR