Our library of drug research abstracts drawn from the medical literature is updated on a regular schedule, and you can be assured that new fluoxetine research articles will be listed here shortly after becoming available to us.
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Medical research on fluoxetine
Environ Pollut. 2008 Nov 18;
Gust M, Buronfosse T, Giamberini L, Ramil M, Mons R, Garric J
Fluoxetine is a widely used antidepressant, frequently found in aquatic ecosystems. We investigated its effects on two freshwater prosobranch gastropods: Valvata piscinalis (European valve snail) and Potamopyrgus antipodarum (New Zealand mudsnail), which have different reproductive modes. The fecundity of V. piscinalis (cumulate number of eggs at day 42) was not affected with an NOEC of 100mug/L nominal concentration (69mug/L measured concentration). The mudsnail P. antipodarum responded in a biphasic dose-effect curve at low concentrations. The cumulate number of neonates at day 42 had an LOEC of 100mug/L (69mug/L) and an NOEC of 33.3mug/L (13mug/L), whereas the embryos in the brood pouch at day 42 only showed an LOEC of 3.7mug/L (1mug/L). We also observed histological effects in P. antipodarum (gonadal thickness). Among the sexual steroids we measured only testosterone which varied, independent of reproduction. Moreover the use of two closely related species highlights the interspecific variability.
Pharmacol Biochem Behav. 2008 Oct 29;
Mutlu O, Ulak G, Laugeray A, Belzung C
Nitric oxide is an intracellular messenger which is involved in several functions and pathologies such as depression, anxiety, learning and memory. In many studies nitric oxide synthase inhibitors (NOSI) were shown to possess antidepressant-like effects in animal models of depression. The aim of this study is to investigate the effects of a selective neuronal and inducible nitric oxide synthase inhibitor TRIM (30 mg/kg/day, 35 days) in mice subjected to unpredictable chronic mild stress and then compare it's effect with a conventional selective serotonin reuptake inhibitor fluoxetine (15 mg/kg/day, 35 days). Stressed vehicle animals showed a significant disturbed coat state when compared with nonstressed animals and this effect was reversed by TRIM or fluoxetine. Both TRIM and fluoxetine prevented the stress-induced deficit in the grooming behaviour in the splash test. TRIM and fluoxetine also significantly decreased the attack frequency when compared to the stressed control group in the resident-intruder test. These results support the assumption that NOS inhibitors can be a new class of antidepressant drugs possibly acting on neuronal NOS.
Therapeutic Strategies in Congenital Myasthenic Syndromes.
Neurotherapeutics. 2008 Oct; 5(4): 542-547
Schara U, Lochmüller H
Congenital myasthenic syndromes (CMS) are classified in terms of the located defect: presynaptic, postsynaptic, and synaptic. They are inherited disorders caused by various genetic defects, all but the slow-channel CMS by recessive inheritance. To date, 10 different CMS are known and further CMS subtypes and their genetic cause may be disclosed by future investigations. Prognosis in CMS is variable and largely depends on the pathophysiological and genetic defect. Subtypes showing progression and life-threatening crises with apneas are generally less favorable than others. Therapeutic agents used in CMS depend on the underlying defect and include acetylcholinesterase inhibitor, 3,4-diaminopyridine, quinidine sulfate, fluoxetine, acetazolamide, and ephedrine. Although there are no double-blind, placebo-controlled clinical trials for CMS, several drugs have shown convincingly positive clinical effects. It is therefore necessary to start a rational therapy regime as early as possible. In most CMS, however, mild and severe clinical courses are reported, which makes assessment on an individual basis necessary. This review emphasizes therapeutic strategies in CMS.
Clin Exp Pharmacol Physiol. 2008 Oct 31;
Mackay GM, Forrest CM, Christofides J, Bridel MA, Mitchell S, Cowlard R, Stone TW, Darlington LG
1. Depression could result from changes in tryptophan availability caused by activation of the kynurenine pathway as a result of inflammation. In the present study, we examined patients newly diagnosed with depression to determine whether kynurenines and related factors change in parallel with improvements in mood. 2. Concentrations of 5-hydroxytryptamine (5-HT; serotonin), 5-hydroxyindoleacetic acid (5-HIAA), oxidized tryptophan metabolites, brain-derived neurotrophic factor (BDNF) and inflammatory mediators (interleukin (IL)-2, C-reactive protein (CRP), neopterin) were measured in peripheral blood during an 18 week period of treatment with fluoxetine, fluoxetine plus tri-iodothyronine (T(3)) or psychiatric counselling. 3. The results showed significant improvements in mood, with reduced 5-HT concentrations in patients given fluoxetine and a rise in plasma tryptophan in patients given counselling or fluoxetine and T(3). The addition of T(3) to the fluoxetine regimen appeared to slow recovery from depression, although the use of T(3) was associated with a fall in thyroxine concentrations. Changes in 5-HT concentrations did not correlate with psychiatric scores and were seen only in drug-treated groups, not those given counselling. There were no associated changes in absolute concentrations of kynurenines, BDNF, CRP, neopterin or IL-2. With fluoxetine treatment, there were correlations between the concentrations of kynurenine metabolites and the psychiatric rating scores, whereas no correlations were found with BDNF or inflammatory markers. 4. It is concluded that depression scores are largely independent of inflammatory status, but kynurenine metabolism may be related to the degree of depression after fluoxetine treatment.
Ann Intern Med. 2008 Nov 18; 149(10): 734-750
Gartlehner G, Gaynes BN, Hansen RA, Thieda P, Deveaugh-Geiss A, Krebs EE, Moore CG, Morgan L, Lohr KN
BACKGROUND: Second-generation antidepressants dominate the management of major depressive disorder, dysthymia, and subsyndromal depression. Evidence on the comparative benefits and harms is still accruing. PURPOSE: To compare the benefits and harms of second-generation antidepressants (bupropion, citalopram, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine) for the treatment of depressive disorders in adults. DATA SOURCES: MEDLINE, EMBASE, PsychLit, Cochrane Central Register of Controlled Trials, and International Pharmaceutical Abstracts from 1980 to April 2007, limited to English-language articles. Reference lists of pertinent review articles were manually searched and the Center for Drug Evaluation and Research database was explored to identify unpublished research. STUDY SELECTION: Abstracts and full-text articles were independently reviewed by 2 persons. Six previous good- or fair-quality systematic reviews or meta-analyses were included, as were 155 good- or fair-quality double-blind, placebo-controlled, or head-to-head randomized, controlled trials of at least 6 weeks' duration. For harms, 35 observational studies with at least 100 participants and follow-up of at least 12 weeks were also included. DATA EXTRACTION: Using a standard protocol, investigators abstracted data on study design and quality-related details, funding, settings, patients, and outcomes. DATA SYNTHESIS: If data were sufficient, meta-analyses of head-to-head trials were conducted to determine the relative benefit of response to treatment and the weighted mean differences on specific depression rating scales. If sufficient evidence was not available, adjusted indirect comparisons were conducted by using meta-regressions and network meta-analyses. Second-generation antidepressants did not substantially differ in efficacy or effectiveness for the treatment of major depressive disorder on the basis of 203 studies; however, the incidence of specific adverse events and the onset of action differed. The evidence is insufficient to draw conclusions about the comparative efficacy, effectiveness, or harms of these agents for the treatment of dysthymia and subsyndromal depression. Limitation: Adjusted indirect comparisons have methodological limitations and cannot conclusively rule out differences in efficacy. CONCLUSION: Current evidence does not warrant the choice of one second-generation antidepressant over another on the basis of differences in efficacy and effectiveness. Other differences with respect to onset of action and adverse events may be relevant for the choice of a medication.
Ann Intern Med. 2008 Nov 18; 149(10): 725-733
Qaseem A, Snow V, Denberg TD, Forciea MA, Owens DK,
Description: The American College of Physicians developed this guideline to present the available evidence on the pharmacologic management of the acute, continuation, and maintenance phases of major depressive disorder; dysthymia; subsyndromal depression; and accompanying symptoms, such as anxiety, insomnia, or neurovegetative symptoms, by using second-generation antidepressants. Methods: Published literature on this topic was identified by using MEDLINE, EMBASE, PsychLit, the Cochrane Central Register of Controlled Trials, and International Pharmaceutical Abstracts from 1980 to April 2007. Searches were limited to English-language studies in adults older than 19 years of age. Keywords for search included terms for depressive disorders and 12 specific second-generation antidepressants-bupropion, citalopram, duloxetine, escitalopram, fluoxetine, fluvoxamine, mirtazapine, nefazodone, paroxetine, sertraline, trazodone, and venlafaxine-and their specific trade names. This guideline grades the evidence and recommendations by using the American College of Physicians clinical practice guidelines grading system. Recommendation 1: The American College of Physicians recommends that when clinicians choose pharmacologic therapy to treat patients with acute major depression, they select second-generation antidepressants on the basis of adverse effect profiles, cost, and patient preferences (Grade: strong recommendation; moderate-quality evidence). Recommendation 2: The American College of Physicians recommends that clinicians assess patient status, therapeutic response, and adverse effects of antidepressant therapy on a regular basis beginning within 1 to 2 weeks of initiation of therapy (Grade: strong recommendation; moderate-quality evidence). Recommendation 3: The American College of Physicians recommends that clinicians modify treatment if the patient does not have an adequate response to pharmacotherapy within 6 to 8 weeks of the initiation of therapy for major depressive disorder (Grade: strong recommendation; moderate-quality evidence). Recommendation 4: The American College of Physicians recommends that clinicians continue treatment for 4 to 9 months after a satisfactory response in patients with a first episode of major depressive disorder. For patients who have had 2 or more episodes of depression, an even longer duration of therapy may be beneficial (Grade: strong recommendation; moderate-quality evidence).
Psychiatry Res. 2008 Nov 17;
Sijens PE, Mostert JP, Irwan R, Potze JH, Oudkerk M, De Keyser J
The antidepressant fluoxetine stimulates astrocytic glycogenolysis, which serves as an energy source for axons. In multiple sclerosis patients fluoxetine administration may improve energy supply in neuron cells and thus inhibit axonal degeneration. In a preliminary pilot study, 15 patients with multiple sclerosis (MS) were examined by diffusion tensor imaging (DTI) and (1)H magnetic resonance spectroscopy (MRS) in order to quantify the brain tissue diffusion properties (fractional anisotropy, apparent diffusion coefficient) and metabolite levels (choline, creatine and N-acetylaspartate) in cortical gray matter brain tissue, in normal appearing white matter and in white matter lesions. After oral administration of fluoxetine (20 mg/day) for 1 week, the DTI and MRS measurements were repeated and after treatment with a higher dose (40 mg/day) during the next week, a third series of DTI/MRS examinations was performed in order to assess any changes in diffusion properties and metabolism. One trend was observed in gray matter tissue, a decrease of choline measured at weeks 1 and 2 (significant in a subgroup of 11 relapsing remitting/secondary progressive MS patients). In white matter lesions, the apparent diffusion coefficient was increased at week 1 and N-acetylaspartate was increased at week 2 (both significant). These preliminary results provide evidence of a neuroprotective effect of fluoxetine in MS by the observed partial normalization of the structure-related MRS parameter N-acetylaspartate in white matter lesions.
Can fluoxetine alone cause serotonin syndrome in adolescents?
Psychopharmacol Bull. 2008; 41(4): 76-9
Ghanizadeh A, Ghanizadeh M, Seifoori M
Objective: Serotonin syndrome is usually reported by the use of a combination of drugs. This is a possible case of serotonin syndrome after using Fluoxetine. Method: This is a case report of serotonin syndrome in an adolescent patient during treatment of depression with the medications. Subsequently, he developed headache, hyperhydrosis (diaphoresis), flushing, shaking, nausea, and vomiting, slurred speech (scanning speech), anxiety, restlessness, agitation, confusion, hallucination, and insomnia. Serotonin syndrome is suggested as one of the most probable diagnosis. Conclusion: Clinicians treating adolescents should be aware of the potential for serotonin syndrome.
Imaging the Neural Circuitry and Chemical Control of Aggressive Motivation.
BMC Neurosci. 2008 Nov 13; 9(1): 111
Ferris CF, Stolberg T, Kulkarni P, Murugavel M, Blanchard R, Blanchard DC, Febo M, Brevard M, Simon NG
ABSTRACT: BACKGROUND: With the advent of functional magnetic resonance imaging (fMRI) in awake animals it is possible to resolve patterns of neuronal activity across the entire brain with high spatial and temporal resolution. Synchronized changes in neuronal activity across multiple brain areas can be viewed as functional neuroanatomical circuits coordinating the thoughts, memories and emotions for particular behaviors. To this end, fMRI in conscious rats combined with 3D computational analysis was used to identifying the putative distributed neural circuit involved in aggressive motivation and how this circuit is affected by drugs that block aggressive behavior. RESULTS: To trigger aggressive motivation, male rats were presented with their female cage mate plus a novel male intruder in the bore of the magnet during image acquisition. As expected, brain areas previously identified as critical in the organization and expression of aggressive behavior were activated, e.g., lateral hypothalamus, medial basal amygdala. Unexpected was the intense activation of the forebrain cortex and anterior thalamic nuclei. Oral administration of a selective vasopressin V1a receptor antagonist SRX251 or the selective serotonin reuptake inhibitor fluoxetine, drugs that block aggressive behavior, both caused a general suppression of the distributed neural circuit involved in aggressive motivation. However, the effect of SRX251, but not fluoxetine, was specific to aggression as brain activation in response to a novel sexually receptive female was unaffected. CONCLUSIONS: The putative neural circuit of aggressive motivation identified with fMRI includes neural substrates contributing to emotional expression (i.e. cortical and medial amygdala, BNST, lateral hypothalamus), emotional experience (i.e. hippocampus, forebrain cortex, anterior cingulate, retrosplenial cortex) and the anterior thalamic nuclei that bridge the motor and cognitive components of aggressive responding. Drugs that block vasopressin neurotransmission or enhance serotonin activity suppress activity in this putative neural circuit of aggressive motivation, particularly the anterior thalamic nuclei.
Sumatriptan inhibits synaptic transmission in the rat midbrain periaqueductal grey.
Mol Pain. 2008 Nov 11; 4(1): 54
Jeong HJ, Chenu D, Johnson EE, Connor M, Vaughan CW
ABSTRACT: BACKGROUND: There is evidence to suggest that the midbrain periaqueductal grey (PAG) has a role in migraine and the actions of the anti-migraine drug sumatriptan. In the present study we examined the serotonergic modulation of GABAergic and glutamatergic synaptic transmission in rat midbrain PAG slices in vitro. RESULTS: Serotonin (5-hydroxytriptamine, 5-HT, IC50 = 142 nM) and the selective serotonin reuptake inhibitor fluoxetine (30 micoM) produced a reduction in the amplitude of GABA-A mediated evoked inhibitory postsynaptic currents (IPSCs) in all PAG neurons which was associated with an increase in the paired-pulse ratio of evoked IPSCs. Real time PCR revealed that 5-HT1A, 5-HT1B, 5-HT1D and 5-HT1F receptor mRNA was present in the PAG. The 5-HT1A, 5-HT1B and 5-HT1D receptor agonists 8-OH-DPAT (3 micoM), CP93129 (3 micoM) and L694247 (3 micoM), but not the 5-HT1F receptor agonist LY344864 (1 - 3 micoM) inhibited evoked IPSCs. The 5-HT (1 micoM) induced inhibition of evoked IPSCs was abolished by the 5-HT1B antagonist NAS181 (10 micoM), but not by the 5-HT1A and 5-HT1D antagonists WAY100135 (3 micoM) and BRL15572 (10 micoM). Sumatriptan also inhibited evoked IPSCs with an IC50 of 261 nM, and reduced the rate, but not the amplitude of spontaneous miniature IPSCs. The sumatriptan (1 micoM) induced inhibition of evoked IPSCs was abolished by NAS181 (10 micoM) and BRL15572 (10 micoM), together, but not separately. 5-HT (10 micoM) and sumatriptan (3 micoM) also reduced the amplitude of non-NMDA mediated evoked excitatory postsynaptic currents (EPSCs) in all PAG neurons tested. CONCLUSIONS: These results indicate that sumatriptan inhibits GABAergic and glutamatergic synaptic transmission within the PAG via a 5-HT1B/D receptor mediated reduction in the probability of neurotransmitter release from nerve terminals. These actions overlap those of other analgesics, such as opioids, and provide a mechanism by which centrally acting 5-HT1B and 5-HT1D ligands might lead to novel anti-migraine pharmacotherapies.