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Identification
NameMetharbital
Accession NumberDB00463  (APRD00757)
TypeSmall Molecule
GroupsWithdrawn
DescriptionMetharbital was patented in 1905 by Emil Fischer working for Merck. It was marketed as Gemonil by Abbott Laboratories. It is a barbiturate anticonvulsant, used in the treatment of epilepsy. It has similar properties to phenobarbital [Wikipedia].
Structure
Thumb
Synonyms
Metarbital
Metharbital
Metharbitalum
External Identifiers Not Available
Approved Prescription ProductsNot Available
Approved Generic Prescription ProductsNot Available
Approved Over the Counter ProductsNot Available
Unapproved/Other Products Not Available
International Brands
NameCompany
GemonilAbbott Laboratories
Brand mixturesNot Available
SaltsNot Available
Categories
UNII02OS7K758T
CAS number50-11-3
WeightAverage: 198.2191
Monoisotopic: 198.100442324
Chemical FormulaC9H14N2O3
InChI KeyInChIKey=FWJKNZONDWOGMI-UHFFFAOYSA-N
InChI
InChI=1S/C9H14N2O3/c1-4-9(5-2)6(12)10-8(14)11(3)7(9)13/h4-5H2,1-3H3,(H,10,12,14)
IUPAC Name
5,5-diethyl-1-methyl-1,3-diazinane-2,4,6-trione
SMILES
CCC1(CC)C(=O)NC(=O)N(C)C1=O
Taxonomy
DescriptionThis compound belongs to the class of organic compounds known as barbituric acid derivatives. These are compounds containing a perhydropyrimidine ring substituted at C-2, -4 and -6 by oxo groups.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassDiazines
Sub ClassPyrimidines and pyrimidine derivatives
Direct ParentBarbituric acid derivatives
Alternative Parents
Substituents
  • Barbiturate
  • Ureide
  • 1,3-diazinane
  • Urea
  • Tertiary amine
  • Carboxamide group
  • Azacycle
  • Carboxylic acid derivative
  • Hydrocarbon derivative
  • Organooxygen compound
  • Organonitrogen compound
  • Carbonyl group
  • Amine
  • Aliphatic heteromonocyclic compound
Molecular FrameworkAliphatic heteromonocyclic compounds
External DescriptorsNot Available
Pharmacology
IndicationMetharbital is used for the treatment of epilepsy.
PharmacodynamicsMetharbital, a barbiturate, is used for the treatment of short term insomnia. It belongs to a group of medicines called central nervous system (CNS) depressants that induce drowsiness and relieve tension or nervousness. Little analgesia is conferred by barbiturates; their use in the presence of pain may result in excitation.
Mechanism of actionMetharbital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. All of these effects are associated with marked decreases in GABA-sensitive neuronal calcium conductance (gCa). The net result of barbiturate action is acute potentiation of inhibitory GABAergic tone. Barbiturates also act through potent (if less well characterized) and direct inhibition of excitatory AMPA-type glutamate receptors, resulting in a profound suppression of glutamatergic neurotransmission.
Related Articles
AbsorptionNot Available
Volume of distributionNot Available
Protein bindingNot Available
MetabolismNot Available
Route of eliminationNot Available
Half lifeNot Available
ClearanceNot Available
ToxicitySigns of overdose include confusion (severe), decrease in or loss of reflexes, drowsiness (severe), fever, irritability (continuing), low body temperature, poor judgment, shortness of breath or slow or troubled breathing, slow heartbeat, slurred speech, staggering, trouble in sleeping, unusual movements of the eyes, weakness (severe).
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
ADMET
Predicted ADMET features
PropertyValueProbability
Human Intestinal Absorption+0.9716
Blood Brain Barrier+0.9862
Caco-2 permeable+0.5234
P-glycoprotein substrateNon-substrate0.6518
P-glycoprotein inhibitor INon-inhibitor0.6178
P-glycoprotein inhibitor IINon-inhibitor0.95
Renal organic cation transporterNon-inhibitor0.92
CYP450 2C9 substrateNon-substrate0.8243
CYP450 2D6 substrateNon-substrate0.9033
CYP450 3A4 substrateNon-substrate0.6773
CYP450 1A2 substrateNon-inhibitor0.8845
CYP450 2C9 inhibitorNon-inhibitor0.8616
CYP450 2D6 inhibitorNon-inhibitor0.9379
CYP450 2C19 inhibitorNon-inhibitor0.8585
CYP450 3A4 inhibitorNon-inhibitor0.9702
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.9834
Ames testNon AMES toxic0.8918
CarcinogenicityNon-carcinogens0.8406
BiodegradationNot ready biodegradable0.8078
Rat acute toxicity2.8286 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.9806
hERG inhibition (predictor II)Non-inhibitor0.9557
ADMET data is predicted using admetSAR, a free tool for evaluating chemical ADMET properties. (23092397 )
Pharmacoeconomics
Manufacturers
  • Abbott laboratories pharmaceutical products div
PackagersNot Available
Dosage formsNot Available
PricesNot Available
PatentsNot Available
Properties
StateSolid
Experimental Properties
PropertyValueSource
melting point150.5 °CPhysProp
water solubility1980 mg/L (at 25 °C)YALKOWSKY,SH & DANNENFELSER,RM (1992)
logP1.15HANSCH,C ET AL. (1995)
logS-2.23ADME Research, USCD
pKa8.01 (at 25 °C)HANSCH,C & LEO,AJ (1985)
Predicted Properties
PropertyValueSource
Water Solubility19.5 mg/mLALOGPS
logP1.18ALOGPS
logP0.94ChemAxon
logS-1ALOGPS
pKa (Strongest Acidic)8.75ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count3ChemAxon
Hydrogen Donor Count1ChemAxon
Polar Surface Area66.48 Å2ChemAxon
Rotatable Bond Count2ChemAxon
Refractivity49.15 m3·mol-1ChemAxon
Polarizability19.6 Å3ChemAxon
Number of Rings1ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Mass Spec (NIST)Download (9.12 KB)
Spectra
Spectrum TypeDescriptionSplash Key
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, PositiveNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, NegativeNot Available
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, NegativeNot Available
MSMass Spectrum (Electron Ionization)splash10-0ab9-5900000000-a7d47fbe125ceae08efbView in MoNA
References
Synthesis ReferenceNot Available
General ReferencesNot Available
External Links
ATC CodesN03AA30
AHFS CodesNot Available
PDB EntriesNot Available
FDA labelNot Available
MSDSNot Available
Interactions
Drug Interactions
Drug
MefloquineThe therapeutic efficacy of Metharbital can be decreased when used in combination with Mefloquine.
MianserinThe therapeutic efficacy of Metharbital can be decreased when used in combination with Mianserin.
OrlistatThe serum concentration of Metharbital can be decreased when it is combined with Orlistat.
Food InteractionsNot Available

Targets

Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
Component of the heteropentameric receptor for GABA, the major inhibitory neurotransmitter in the vertebrate brain. Functions also as histamine receptor and mediates cellular responses to histamine. Functions as receptor for diazepines and various anesthetics, such as pentobarbital; these are bound at a separate allosteric effector binding site. Functions as ligand-gated chloride channel (By si...
Gene Name:
GABRA1
Uniprot ID:
P14867
Molecular Weight:
51801.395 Da
References
  1. Whiting PJ: The GABAA receptor gene family: new opportunities for drug development. Curr Opin Drug Discov Devel. 2003 Sep;6(5):648-57. [PubMed:14579514 ]
  2. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
  3. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  4. Krasowski MD, Harrison NL: General anaesthetic actions on ligand-gated ion channels. Cell Mol Life Sci. 1999 Aug 15;55(10):1278-303. [PubMed:10487207 ]
  5. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352 ]
  6. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. [PubMed:17139284 ]
  7. Imming P, Sinning C, Meyer A: Drugs, their targets and the nature and number of drug targets. Nat Rev Drug Discov. 2006 Oct;5(10):821-34. [PubMed:17016423 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.
Gene Name:
GABRA2
Uniprot ID:
P47869
Molecular Weight:
51325.85 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.
Gene Name:
GABRA3
Uniprot ID:
P34903
Molecular Weight:
55164.055 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.
Gene Name:
GABRA4
Uniprot ID:
P48169
Molecular Weight:
61622.645 Da
References
  1. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Transporter activity
Specific Function:
GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.
Gene Name:
GABRA5
Uniprot ID:
P31644
Molecular Weight:
52145.645 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
Kind
Protein
Organism
Human
Pharmacological action
yes
Actions
potentiator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
GABA, the major inhibitory neurotransmitter in the vertebrate brain, mediates neuronal inhibition by binding to the GABA/benzodiazepine receptor and opening an integral chloride channel.
Gene Name:
GABRA6
Uniprot ID:
Q16445
Molecular Weight:
51023.69 Da
References
  1. Mehta AK, Ticku MK: An update on GABAA receptors. Brain Res Brain Res Rev. 1999 Apr;29(2-3):196-217. [PubMed:10209232 ]
  2. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
antagonist
General Function:
Ligand-gated ion channel activity
Specific Function:
After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane permeable to sodium ions.
Gene Name:
CHRNA4
Uniprot ID:
P43681
Molecular Weight:
69956.47 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Arias HR, Bhumireddy P: Anesthetics as chemical tools to study the structure and function of nicotinic acetylcholine receptors. Curr Protein Pept Sci. 2005 Oct;6(5):451-72. [PubMed:16248797 ]
  3. Krasowski MD, Harrison NL: General anaesthetic actions on ligand-gated ion channels. Cell Mol Life Sci. 1999 Aug 15;55(10):1278-303. [PubMed:10487207 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
antagonist
General Function:
Toxic substance binding
Specific Function:
After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. The channel is blocked by alpha-bungarotoxin.
Gene Name:
CHRNA7
Uniprot ID:
P36544
Molecular Weight:
56448.925 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Arias HR, Bhumireddy P: Anesthetics as chemical tools to study the structure and function of nicotinic acetylcholine receptors. Curr Protein Pept Sci. 2005 Oct;6(5):451-72. [PubMed:16248797 ]
  3. Krasowski MD, Harrison NL: General anaesthetic actions on ligand-gated ion channels. Cell Mol Life Sci. 1999 Aug 15;55(10):1278-303. [PubMed:10487207 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
antagonist
General Function:
Ionotropic glutamate receptor activity
Specific Function:
Receptor for glutamate that functions as ligand-gated ion channel in the central nervous system and plays an important role in excitatory synaptic transmission. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and t...
Gene Name:
GRIA2
Uniprot ID:
P42262
Molecular Weight:
98820.32 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Krasowski MD, Harrison NL: General anaesthetic actions on ligand-gated ion channels. Cell Mol Life Sci. 1999 Aug 15;55(10):1278-303. [PubMed:10487207 ]
Kind
Protein
Organism
Human
Pharmacological action
unknown
Actions
antagonist
General Function:
Kainate selective glutamate receptor activity
Specific Function:
Ionotropic glutamate receptor. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inacti...
Gene Name:
GRIK2
Uniprot ID:
Q13002
Molecular Weight:
102582.475 Da
References
  1. Yamakura T, Bertaccini E, Trudell JR, Harris RA: Anesthetics and ion channels: molecular models and sites of action. Annu Rev Pharmacol Toxicol. 2001;41:23-51. [PubMed:11264449 ]
  2. Krasowski MD, Harrison NL: General anaesthetic actions on ligand-gated ion channels. Cell Mol Life Sci. 1999 Aug 15;55(10):1278-303. [PubMed:10487207 ]
Kind
Protein group
Organism
Human
Pharmacological action
yes
Actions
positive allosteric modulator
General Function:
Inhibitory extracellular ligand-gated ion channel activity
Specific Function:
Component of the heteropentameric receptor for GABA, the major inhibitory neurotransmitter in the vertebrate brain. Functions also as histamine receptor and mediates cellular responses to histamine. Functions as receptor for diazepines and various anesthetics, such as pentobarbital; these are bound at a separate allosteric effector binding site. Functions as ligand-gated chloride channel (By similarity).
Components:
NameUniProt IDDetails
Gamma-aminobutyric acid receptor subunit alpha-1P14867 Details
Gamma-aminobutyric acid receptor subunit alpha-2P47869 Details
Gamma-aminobutyric acid receptor subunit alpha-3P34903 Details
Gamma-aminobutyric acid receptor subunit alpha-4P48169 Details
Gamma-aminobutyric acid receptor subunit alpha-5P31644 Details
Gamma-aminobutyric acid receptor subunit alpha-6Q16445 Details
Gamma-aminobutyric acid receptor subunit beta-1P18505 Details
Gamma-aminobutyric acid receptor subunit beta-2P47870 Details
Gamma-aminobutyric acid receptor subunit beta-3P28472 Details
Gamma-aminobutyric acid receptor subunit deltaO14764 Details
Gamma-aminobutyric acid receptor subunit epsilonP78334 Details
Gamma-aminobutyric acid receptor subunit gamma-1Q8N1C3 Details
Gamma-aminobutyric acid receptor subunit gamma-2P18507 Details
Gamma-aminobutyric acid receptor subunit gamma-3Q99928 Details
Gamma-aminobutyric acid receptor subunit piO00591 Details
Gamma-aminobutyric acid receptor subunit thetaQ9UN88 Details
References
  1. ChEMBL Compound Report Card [Link]
Comments
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Drug created on June 13, 2005 07:24 / Updated on August 17, 2016 12:23