Piracetam scientific update |
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Br J Pharmacol. 2004 Jun;142(3):594-608.
Naftalin RJ, Cunningham P, Afzal-Ahmed I.
Physiology Division, Centre for Vascular Biology and Medicine, Kings College London, Guys Campus, New Hunts House, London SE1 1UL.
Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport.
1 Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. 2 The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (P<0.01). Less potent nootropics, D-levetiracetam and D-pyroglutamate, have higher antagonist Ki's against pentobarbital inhibition of glucose transport than more potent L-stereoisomers (P<0.001). 3 Piracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. 4 There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. 5 Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis.
Int J Neuropsychopharmacol. 2004 Jul 1;:1-19.
Evans JG, Wilcock G, Birks J.
Cochrane Dementia and Cognitive Improvement Group, University of Oxford, UK.
Evidence-based pharmacotherapy of Alzheimers disease.
Dementia is an acquired global impairment of cognitive capacities. Approximately 5% of people aged over 65 yr are affected by dementia, and some 70% of cases are thought to be due primarily to Alzheimers disease. Descriptions of the clinical manifestations of Alzheimers disease have been increasingly refined in the last decade but there is no diagnostic test for what remains fundamentally a pathologically defined condition. At the present time interventions for Alzheimers disease are limited to those that modify the manifestations of the disease, and foremost amongst the candidates available are the cholinesterase inhibitors. The rationale for the use of cholinergic drugs for Alzheimers disease lies in enhancing the secretion of, or prolonging the half-life of, acetylcholine in the brain. Several potential compounds have been tested, but short half-lives and a high incidence of cholinergic and other adverse effects have eliminated most. Only three are widely licensed for use, donepezil, galantamine and rivastigmine. Their efficacy is relatively modest. These drugs have been tested in 32 randomized, placebo-controlled trials. The trials assess cognitive function primarily, and in addition they may assess global function, activities of daily living, quality of life and behavioural disturbance typically over 3 or 6 months. The performance of each drug is summarized in a Cochrane review, a systematic review carried out according to strict guidelines. There was a significant benefit in favour of treatment compared with placebo for cognition and activities of daily living, but withdrawals due to adverse events were significantly higher for treatment than placebo for all three drugs. There is little evidence from direct comparisons between the three drugs. There are several economic analyses of the cost-effectiveness of these drugs, but the findings cannot be considered robust owing to inadequate data. A range of other pharmacological treatments have been tested, including selegiline, piracetam, vitamin E, Ginkgo biloba, anti-inflammatory drugs and hormone replacement therapy, but, so far, Cochrane reviews have not established the efficacy of these interventions for Alzheimers disease. A Cochrane review of memantine shows benefits on cognitive and global function of the same order of magnitude as seen for the cholinesterase inhibitors. Memantine has been licensed in Europe for treatment of patients with moderately severe to severe Alzheimers disease.
Thromb Res. 1995 Jun 15;78(6):469-82.
Moriau M, Lavenne-Pardonge E, Crasborn L, von Frenckell R, Col-Debeys C.
Department of Internal Medicine, Haematology Division, Haemostasis and Thrombosis Unit, University of Louvain (UCL), St.-Luc University Clinics, Brussels, Belgium.
The treatment of severe or recurrent deep venous thrombosis. Beneficial effect of the co-administration of antiplatelet agents with or without rheological effects, and anticoagulants.
Deep venous thromboses can be divided into two groups according to their pathogenesis, anatomical features and differing responses to therapy. The first and most frequent consists of so-called simple venous thrombosis while the second group, which is less common, comprises severe or recurrent venous thrombosis characterised by a multifactorial pathogenesis, a mixed thrombus rich in platelets and by an incomplete response to both prophylactic and therapeutic treatment with anticoagulants (heparin or vitamin K antagonist). In a randomized, prospective blind study in patients with severe or recurrent venous thrombosis, which included 6 groups each of 100 patients, co-administration of anticoagulants with various types of antiplatelet agent, either with rheological effects (piracetam, buflomedil, pentoxifylline) or without them (dipyridamole), has shown a beneficial potentiating antithrombotic effect with those drugs possessing rheological effects and the absence of this effect with dipyridamole.
Epilepsy Behav. 2004 Dec;5(6):878-83.
Kelly K, Stephen LJ, Brodie MJ.
Epilepsy Unit, Division of Cardiovascular and Medical Sciences, Western Infirmary, Glasgow G11 6NT, Scotland, UK.
Levetiracetam for people with mental retardation and refractory epilepsy.
Levetiracetam (LEV) is a novel antiepileptic drug (AED) with efficacy against a wide range of seizures types. The aim of this observational study was to assess its effectiveness in patients with mental retardation and refractory epilepsy. Sixty-four patients were started on adjunctive LEV after a 3-month baseline. LEV was initially dosed at 250 mg daily and increased by 250 mg every 2 weeks thereafter according to clinical response. Caregivers rated the patient's sleep, appetite, alertness, and behavior as poor (1), reasonable (2), or good (3) at each clinic visit. Patients were reviewed until one of four endpoints was reached: seizure freedom for at least 6 months, > or = 50% reduction in seizure frequency (responder) over a 6-month period, <50% reduction in seizure frequency (marginal effect) over a 6-month period, or LEV withdrawal due to lack of efficacy, adverse effects, or both. Twenty-four (38%) patients became seizure-free, 10 of whom were controlled on LEV 250 mg twice daily. An additional 18 (28%) patients were classified as responders, and 8 (12%) reported only marginal benefit from adjunctive LEV. Fourteen (22%) patients discontinued LEV (6 worsening seizures, 1 lack of efficacy, 7 adverse effects). Caregivers rated combined sleep, appetite, alertness, and behavior scores as "improved" at the end of follow-up (P<0.001). LEV improved seizure control in the majority of patients with mental retardation and may also have enhanced their quality of life.
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Drug category:Nootropic and smart drugs
 Piracetam scientific update
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