Piracetam

Identification

Name
Piracetam
Accession Number
DB09210
Type
Small Molecule
Groups
Approved, Investigational
Description

Piracetam is a nootropic drug in the racetams group, with chemical name 2-oxo-1-pyrrolidine acetamide. It shares the same 2-oxo-pyrrolidone base structure with pyroglutamic acid and is a cyclic derivative of the neurotransmitter γ-aminobutyric acid (GABA). However its mechanism of action differ from that of endogenous GABA.Piracetam has neuroprotective and anticonvulsant properties and is reported to improve neural plasticity [1]. Its efficacy is documented in cognitive disorders and dementia, vertigo, cortical myoclonus, dyslexia, and sickle cell anemia although the clinical application in these conditions is not yet established. Piracetam has effects on the vascular system by reduce erythrocyte adhesion to vascular endothelium, hinder vasospasm and facilitate microcirculation [1].

Originally marketed by UCB Pharma in 1971, piracetam was the first nootropic drug to modulate cognitive function without causing sedation or stimulation [1]. In the United States, it is not approved by the US Food and Drug Administration for any medical use and it is not permitted to be sold as a dietary supplement. In the UK, piracetam is prescribed mainly for myoclonus, but is used off-label for other conditions such as learning difficulties in children, memory loss or other cognitive defects in the elderly, and sickle-cell vaso-occlusive crises [4]. Evidence to support its use for many conditions is unclear.

Structure
Thumb
Synonyms
Not Available
International/Other Brands
Myocalm (Taiho Pharmaceuticals)
Categories
UNII
ZH516LNZ10
CAS number
7491-74-9
Weight
Average: 142.1558
Monoisotopic: 142.074227574
Chemical Formula
C6H10N2O2
InChI Key
GMZVRMREEHBGGF-UHFFFAOYSA-N
InChI
InChI=1S/C6H10N2O2/c7-5(9)4-8-3-1-2-6(8)10/h1-4H2,(H2,7,9)
IUPAC Name
2-(2-oxopyrrolidin-1-yl)ethanimidic acid
SMILES
OC(=N)CN1CCCC1=O

Pharmacology

Indication

Indicated in adult patients suffering from myoclonus of cortical origin, irrespective of aetiology, and should be used in combination with other anti-myoclonic therapies [5].

Pharmacodynamics

Piracetam is known to mediate various pharmacodynamic actions:

Neuronal effects:

Piracetam modulates the cholinergic, serotonergic, noradrenergic, and glutamatergic neurotransmission although the drug does not display high affinity to any of the associated receptors (Ki >10μM). Instead, piracetam increases the density of postsynaptic receptors and/or restore the function of these receptors through stabilizing the membrane fluidity [1]. In the forebrain of aging mice, the density of NMDA receptors was increased by approximately 20% following 14 days of piracetam treatment. Based on the findings of various animal and human studies, the cognitive processses including learning, memory, attention and consciousness were enhanced from piracetam therapy without inducing sedation and psychostimulant effects [5]. Piracetam mediate neuroprotective effects against hypoxia-induced damage, intoxication, and electroconvulsive therapy [5].

In two studies involving alcohol-treated rats with evidences of withdrawal-related neuronal loss, piracetam was shown to reduce the extent of neuronal loss and increase the numbers of synapses in the hippocampus by up to 20% relative to alcohol-treated or alcohol-withdrawn rats [1]. This suggests that piracetam is capable in promoting neuroplasticity when recoverable neural circuits are present [1]. Although the mechanism of action is not fully understood, administration of piracetam prior to a convulsant stimulus reduces the seizure severity and enhances the anticonvulsant effectiveness of conventional antiepileptics such as carbamazepine and diazepam [3].

Vascular effects:

Piracetam is shown to increase the deformability of erythrocytes, reduce platelet aggregation in a dose-dependent manner, reduce the adhesion of erythrocytes to vascular endothelium and capillary vasospasm. In healthy volunteers, piracetam mediated a direct stimulant effect on prostacycline synthesis and reduced the plasma levels of fibrinogen and von Willebrand’s factors (VIII: C; VIII R: AG; VIII R: vW) by 30 to 40% [5]. Potentiated microcirculation is thought to arise from a combination of effects on erythrocytes, blood vessels and blood coagulation [1].

Mechanism of action

Piracetam interacts with the polar heads in the phospholipids membrane and the resulting mobile drug-lipid complexes are thought to reorganize the lipids and influence membrane function and fluidity [1]. Such interaction has been reported in a study that investigated the effects of neuronal outgrowth induced by beta amyloid peptides; while amyloid peptides cause lipid disorganization within the cell membranes leading to neuronal death, piracetam demonstrated to decrease the destabilizing effects of amyloid peptide [2]. The authors suggest that piracetam induces a positive curvature of the membrane by occupying the polar groups in the phospholipids to counteract the negative curvature induced by amyloid peptides , which in turn would decrease the likelihood of membrane fusion [1]. This mechanism of action is thought to improve membrane stability, allowing the membrane and transmembrane proteins to maintain and recover the three-dimensional structure or folding for normal function [4] such as membrane transport, chemical secretion, and receptor binding and stimulation [1].

Through restored membrane fluidity, piracetam promotes restored neurotransmission such as glutamatergic and cholinergic systems, enhances neuroplasticity and mediates neuroprotective and anticonvulsant effects at the neuronal level [1]. It is also demonstrated that piracetam also improves the fluidity of platelet membranes. At the vascular level, piracetam decreases adhesion of erythrocytes to cell wall and reduces vasospasm which in turn improves microcirculation including cerebral and renal blood flow [1].

Absorption

Piracetam displays a linear and time-dependent pharmacokinetic properties with low intersubject variability over a large range of doses. Piracetam is rapidly and extensively absorbed following oral administration with the peak plasma concentration is reached within 1 hour after dosing in fasted subjects. Following a single oral dose of 3.2 g piracetam, the peak plasma concentration (Cmax) was 84 µg/mL. Intake of food may decrease the Cmax by 17% and increase the time to reach Cmax (Tmax) from 1 to 1.5 hours. Tmax in the cerebrospinal fluid is achieved approximately 5 hours post-administration [4].

The absolute bioavailability of piracetam oral formulations is close to 100% and the steady state plasma concentrations are achieved within 3 days of dosing [4].

Volume of distribution

Vd is approximately 0.6L/kg. Piracetam may cross the blood-brain barrier as it was measured in the cerebrospinal fluid following intravenous administration [4]. Piracetam diffuses to all tissues except adipose tissues, crosses placental barrier and penetrates the membranes of isolated red blood cells [4].

Protein binding

Piracetam is not reported to be bound to plasma proteins [4].

Metabolism

As large proportion of total piracetam administered is excreted as unchanged drug, there is no known major metabolism of piracetam [4].

Route of elimination

Piracetam is predominantly excreted via renal elimination, where about 80-100% of the total dose is recovered in the urine. Approximately 90% of the dose of piracetam is excreted in the urine as unchanged drug [4].

Half life

The plasma half life of piracetam is approximately 5 hours following oral or intravenous administration. The half life in the cerebrospinal fluid was 8.5 hours [4].

Clearance

The apparent total body clearance is 80-90 mL/min [4].

Toxicity

The cases of overdose with piracetam is rare. The highest reported overdose with piracetam was oral intake of 75g which was associated with diarrhea and abdominal pain; the signs were most likely related to the extreme high dose of sorbitol contained in the used formulation. In cases of acute, significant overdosage, stomach emptying by gastric lavage or induced emesis is recommended as there are no known antidotes for piracetam [4]. Management for an overdose will most likely be symptomatic treatment and may include hemodialysis, where the extraction efficacy of the dialyser is 50 to 60% for the drug [4].

Oral LD50 in a mouse acute toxicity study was 2000 mg/kg [MSDS].

Affected organisms
Not Available
Pathways
Not Available
Pharmacogenomic Effects/ADRs
Not Available

Interactions

Drug Interactions
DrugInteraction
3,5-diiodothyropropionic acidThe risk or severity of confusion, irritability, and sleep disorders can be increased when 3,5-diiodothyropropionic acid is combined with Piracetam.
AbacavirAbacavir may decrease the excretion rate of Piracetam which could result in a higher serum level.
AbaloparatideThe risk or severity of confusion, irritability, and sleep disorders can be increased when Abaloparatide is combined with Piracetam.
AcarboseAcarbose may decrease the excretion rate of Piracetam which could result in a higher serum level.
AceclofenacAceclofenac may decrease the excretion rate of Piracetam which could result in a higher serum level.
AcemetacinAcemetacin may decrease the excretion rate of Piracetam which could result in a higher serum level.
AcetaminophenAcetaminophen may decrease the excretion rate of Piracetam which could result in a higher serum level.
AcetazolamideAcetazolamide may increase the excretion rate of Piracetam which could result in a lower serum level and potentially a reduction in efficacy.
Acetylsalicylic acidAcetylsalicylic acid may decrease the excretion rate of Piracetam which could result in a higher serum level.
AclidiniumAclidinium may decrease the excretion rate of Piracetam which could result in a higher serum level.
Food Interactions
Not Available

References

General References
  1. Winblad B: Piracetam: a review of pharmacological properties and clinical uses. CNS Drug Rev. 2005 Summer;11(2):169-82. [PubMed:16007238]
  2. Kurz C, Ungerer I, Lipka U, Kirr S, Schutt T, Eckert A, Leuner K, Muller WE: The metabolic enhancer piracetam ameliorates the impairment of mitochondrial function and neurite outgrowth induced by beta-amyloid peptide. Br J Pharmacol. 2010 May;160(2):246-57. doi: 10.1111/j.1476-5381.2010.00656.x. Epub 2010 Mar 9. [PubMed:20218980]
  3. Fischer W, Kittner H, Regenthal R, Russo E, De Sarro G: Effects of piracetam alone and in combination with antiepileptic drugs in rodent seizure models. J Neural Transm (Vienna). 2004 Sep;111(9):1121-39. doi: 10.1007/s00702-004-0155-6. Epub 2004 May 14. [PubMed:15338329]
  4. Nootropil tablets Drug Summary [Link]
  5. electronic Medicines Compendium (eMC): Nootripil Summary of Product Characteristics [Link]
External Links
ChemSpider
4677
BindingDB
62877
ChEBI
32010
ChEMBL
CHEMBL36715
HET
PZI
Wikipedia
Piracetam
ATC Codes
N06BX03 — Piracetam
PDB Entries
3lsf / 3lsl / 3lsx
MSDS
Download (47.2 KB)

Clinical Trials

Clinical Trials
PhaseStatusPurposeConditionsCount
1CompletedTreatmentCocaine-Related Disorders1
1WithdrawnTreatmentCocaine-Related Disorders1
3CompletedTreatmentTardive Dyskinesia1
3TerminatedTreatmentAnxiety Disorders / Dementias / Depression / Psychosomatic Disorders / Schizophrenic Disorders1
3WithdrawnTreatmentPostpoliomyelitis Syndrome1
4CompletedNot AvailableAlzheimer's Disease (AD) / Dementia, Vascular / Dementias1
4CompletedTreatmentVertigo, Peripheral1
4TerminatedTreatmentAcute Ischaemic Middle Cerebral Artery Stroke1
Not AvailableCompletedTreatmentMemory Disorders1

Pharmacoeconomics

Manufacturers
Not Available
Packagers
Not Available
Dosage forms
Not Available
Prices
Not Available
Patents
Not Available

Properties

State
Solid
Experimental Properties
PropertyValueSource
melting point (°C)152MSDS
boiling point (°C)DecomposesMSDS
Predicted Properties
PropertyValueSource
Water Solubility4.76 mg/mLALOGPS
logP-1.4ALOGPS
logP-3.5ChemAxon
logS-1.5ALOGPS
pKa (Strongest Acidic)-1.4ChemAxon
pKa (Strongest Basic)12.88ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count2ChemAxon
Polar Surface Area64.39 Å2ChemAxon
Rotatable Bond Count2ChemAxon
Refractivity46 m3·mol-1ChemAxon
Polarizability14.02 Å3ChemAxon
Number of Rings1ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleNoChemAxon
MDDR-like RuleNoChemAxon
Predicted ADMET features
Not Available

Spectra

Mass Spec (NIST)
Not Available
Spectra
SpectrumSpectrum TypeSplash Key
Predicted MS/MS Spectrum - 10V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 20V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 40V, Positive (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 10V, Negative (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 20V, Negative (Annotated)Predicted LC-MS/MSNot Available
Predicted MS/MS Spectrum - 40V, Negative (Annotated)Predicted LC-MS/MSNot Available
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-002b-9400000000-651dc28016b653b55d23
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-002b-9400000000-9c47f9c6616fbfad2c93
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-0002-9100000000-079c7eb43e2dcfe07d5f
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-0002-9000000000-94d697783ea2c537498f
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-0002-9000000000-5dd797bddeacd8764c16
LC-MS/MS Spectrum - LC-ESI-QFT , positiveLC-MS/MSsplash10-006t-9000000000-e270872ffd02b3d53ab2

Taxonomy

Description
This compound belongs to the class of organic compounds known as alpha amino acids and derivatives. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon), or a derivative thereof.
Kingdom
Organic compounds
Super Class
Organic acids and derivatives
Class
Carboxylic acids and derivatives
Sub Class
Amino acids, peptides, and analogues
Direct Parent
Alpha amino acids and derivatives
Alternative Parents
Pyrrolidine-2-ones / N-alkylpyrrolidines / Tertiary carboxylic acid amides / Primary carboxylic acid amides / Lactams / Azacyclic compounds / Organopnictogen compounds / Organonitrogen compounds / Organic oxides / Hydrocarbon derivatives
show 1 more
Substituents
Alpha-amino acid or derivatives / N-alkylpyrrolidine / 2-pyrrolidone / Pyrrolidone / Pyrrolidine / Tertiary carboxylic acid amide / Carboxamide group / Lactam / Primary carboxylic acid amide / Azacycle
show 10 more
Molecular Framework
Aliphatic heteromonocyclic compounds
External Descriptors
Not Available

Drug created on October 20, 2015 13:46 / Updated on November 02, 2018 07:00