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Racetams are a class of nootropic drugs that share a pyrrolidone nucleus.

Contents

Mechanism

There is no generally accepted mechanism for racetams. They generally show no affinity for the most important receptors, although modulation of most important central neurotransmitters, including acetylcholine and glutamate have been reported. Although aniracetam and nebracetam show affinity for muscarinic receptors, only nefiracetam shows it at the nanomolar range. Modulation of protein synthesis and protein Kinase C could be a mechanism. Modification of membrane-located mechanisms of central signal transduction is another hypothesis.[1]

Racetams are understood to work by activating glutamate receptors that are colocalized with cholinergic receptors, thus increasing the firing of the latter. The racetams consequently increase memory capacity by nearly the same method as the acetylcholinesterase inhibitors.

Examples

  • Piracetam - Water-soluble racetam; The first of the racetams to be discovered (in the mid-1960s)
  • Oxiracetam - Water-soluble racetam (2 to 4 times more potent than Piracetam)
  • Aniracetam - Fat-soluble racetam (4 to 8 times more potent than Piracetam)
  • Pramiracetam - Fat-soluble racetam (8 to 30 times more potent than Piracetam)
  • Phenylpiracetam (Carphedon) - Fat-soluble racetam
  • Etiracetam
  • Levetiracetam - anticonvulsant medication used to treat epilepsy. It is the S- enantiomer of etiracetam.
  • Nefiracetam - an antidepressant (M1 acetylcholine receptor agonist)
  • Nicoracetam - racetam structure bonded to niacin.
  • Rolziracetam
  • Nebracetam
  • Fasoracetam
  • Imuracetam
  • Coluracetam - may have potential use in prevention and treatment of ischemic retinopathy and retinal and optic nerve injury
  • Dimiracetam - currently being studied in the treatment of neuropathic pain.
  • Brivaracetam - anticonvulsant properties
  • Seletracetam - anticonvulsant, not expected to be nootropic
  • Rolipram - anti-inflammatory, antipsychotic and antidepressant drug that improves long term memory, increases wakefulness and neuroprotection (in rats).

Side effects of Levetiracetam

A 2005 review of the benefits and risks of levetiracetam found that the effects reported which differed from placebo group included somnolence, asthenia, dizziness, and infection. Irritability, agitation, anger and aggressive behavior have also been reported and appear to be more common among learning disabled. Slightly lower white and red blood cell counts have been observed. The author concluded that levetiracetam exhibits a favorable safety profile. Interactions with other drugs have been reported and it is metabolized independently of the cytochrome P450 enzyme system.[2]

Levitiracetam inhibits communication between the two halves of the brain, thus being efficacious in epilepsy. Levetiracetam is unique in this respect. Most racetams promote communication between hemispheres. [3] [4]

References

  1. ^ Gualtieri F, Manetti D, Romanelli MN, Ghelardini C (2002). "Design and study of piracetam-like nootropics, controversial members of the problematic class of cognition-enhancing drugs". Curr. Pharm. Des. 8 (2): 125–38. doi:10.2174/1381612023396582. PMID 11812254.  
  2. ^ Abou-Khalil B (2005). "Benefit-risk assessment of levetiracetam in the treatment of partial seizures". Drug Saf 28 (10): 871–90. PMID 16180937.  
  3. ^ Buresová O, Bures J. (1976). "Piracetam-induced facilitation of interhemispheric transfer of visual information in rats.". Psychopharmacologia. 46 (1): 93-102. PMID 1257371. http://www.ncbi.nlm.nih.gov/pubmed/1257371.  
  4. ^ Vernon MW, Sorkin EM. (January 1991). "Piracetam. An overview of its pharmacological properties and a review of its therapeutic use in senile cognitive disorders.". Drugs Aging. 1 (1): 17-35. PMID 1794001. http://www.ncbi.nlm.nih.gov/pubmed/1794001.  







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