Identification

Name
Metharbital
Accession Number
DB00463  (APRD00757)
Type
Small Molecule
Groups
Withdrawn
Description

Metharbital 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
International/Other Brands
Gemonil (Abbott Laboratories)
Categories
UNII
02OS7K758T
CAS number
50-11-3
Weight
Average: 198.2191
Monoisotopic: 198.100442324
Chemical Formula
C9H14N2O3
InChI Key
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

Pharmacology

Indication

Metharbital is used for the treatment of epilepsy.

Pharmacodynamics

Metharbital, 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 action

Metharbital 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.

TargetActionsOrganism
AGamma-aminobutyric acid receptor subunit alpha-1
potentiator
Human
AGamma-aminobutyric acid receptor subunit alpha-2
potentiator
Human
AGamma-aminobutyric acid receptor subunit alpha-3
potentiator
Human
AGamma-aminobutyric acid receptor subunit alpha-4
potentiator
Human
AGamma-aminobutyric acid receptor subunit alpha-5
potentiator
Human
AGamma-aminobutyric acid receptor subunit alpha-6
potentiator
Human
UNeuronal acetylcholine receptor subunit alpha-4
antagonist
Human
UNeuronal acetylcholine receptor subunit alpha-7
antagonist
Human
UGlutamate receptor 2
antagonist
Human
UGlutamate receptor ionotropic, kainate 2
antagonist
Human
AGABA-A receptor (anion channel)
positive allosteric modulator
Human
Absorption
Not Available
Volume of distribution
Not Available
Protein binding
Not Available
Metabolism
Not Available
Route of elimination
Not Available
Half life
Not Available
Clearance
Not Available
Toxicity

Signs 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
Pathways
Not Available
Pharmacogenomic Effects/ADRs
Not Available

Interactions

Drug Interactions
DrugInteraction
1,10-PhenanthrolineThe therapeutic efficacy of Metharbital can be decreased when used in combination with 1,10-Phenanthroline.
2,5-Dimethoxy-4-ethylthioamphetamineThe risk or severity of adverse effects can be increased when Metharbital is combined with 2,5-Dimethoxy-4-ethylthioamphetamine.
3-isobutyl-1-methyl-7H-xanthineMetharbital may increase the excretion rate of 3-isobutyl-1-methyl-7H-xanthine which could result in a lower serum level and potentially a reduction in efficacy.
3,4-MethylenedioxyamphetamineThe risk or severity of adverse effects can be increased when Metharbital is combined with 3,4-Methylenedioxyamphetamine.
4-Bromo-2,5-dimethoxyamphetamineThe risk or severity of adverse effects can be increased when Metharbital is combined with 4-Bromo-2,5-dimethoxyamphetamine.
4-MethoxyamphetamineThe risk or severity of adverse effects can be increased when Metharbital is combined with 4-Methoxyamphetamine.
5-methoxy-N,N-dimethyltryptamineThe risk or severity of adverse effects can be increased when Metharbital is combined with 5-methoxy-N,N-dimethyltryptamine.
6-O-benzylguanineMetharbital may increase the excretion rate of 6-O-benzylguanine which could result in a lower serum level and potentially a reduction in efficacy.
7-DeazaguanineMetharbital may increase the excretion rate of 7-Deazaguanine which could result in a lower serum level and potentially a reduction in efficacy.
7-NitroindazoleThe risk or severity of adverse effects can be increased when Metharbital is combined with 7-Nitroindazole.
Food Interactions
Not Available

References

General References
Not Available
External Links
Human Metabolome Database
HMDB0014606
KEGG Drug
D01382
PubChem Compound
4099
PubChem Substance
46508167
ChemSpider
3957
ChEBI
31827
ChEMBL
CHEMBL450
Therapeutic Targets Database
DAP000675
PharmGKB
PA164746525
Wikipedia
Metharbital
ATC Codes
N03AA30 — Metharbital

Clinical Trials

Clinical Trials
Not Available

Pharmacoeconomics

Manufacturers
  • Abbott laboratories pharmaceutical products div
Packagers
Not Available
Dosage forms
Not Available
Prices
Not Available
Patents
Not Available

Properties

State
Solid
Experimental Properties
PropertyValueSource
melting point (°C)150.5 °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 RuleNoChemAxon
MDDR-like RuleNoChemAxon
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)

Spectra

Mass Spec (NIST)
Download (9.12 KB)
Spectra
SpectrumSpectrum TypeSplash Key
Predicted GC-MS Spectrum - GC-MSPredicted GC-MSNot Available
GC-MS Spectrum - EI-BGC-MSsplash10-00di-8900000000-5c20588bb225d0b4ed7c
Mass Spectrum (Electron Ionization)MSsplash10-0ab9-5900000000-a7d47fbe125ceae08efb
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

Taxonomy

Description
This 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.
Kingdom
Organic compounds
Super Class
Organoheterocyclic compounds
Class
Diazines
Sub Class
Pyrimidines and pyrimidine derivatives
Direct Parent
Barbituric acid derivatives
Alternative Parents
N-acyl ureas / Diazinanes / Dicarboximides / Azacyclic compounds / Organopnictogen compounds / Organonitrogen compounds / Organic oxides / Hydrocarbon derivatives / Carbonyl compounds
Substituents
Barbiturate / N-acyl urea / Ureide / 1,3-diazinane / Dicarboximide / Urea / Carbonic acid derivative / Carboxylic acid derivative / Azacycle / Organic nitrogen compound
Molecular Framework
Aliphatic heteromonocyclic compounds
External Descriptors
Not 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...
Gene Name
GABRA1
Uniprot ID
P14867
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-1
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
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-2
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
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-3
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
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-4
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
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-5
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
Uniprot Name
Gamma-aminobutyric acid receptor subunit alpha-6
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 permeabl...
Gene Name
CHRNA4
Uniprot ID
P43681
Uniprot Name
Neuronal acetylcholine receptor subunit alpha-4
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 cha...
Gene Name
CHRNA7
Uniprot ID
P36544
Uniprot Name
Neuronal acetylcholine receptor subunit alpha-7
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 ne...
Gene Name
GRIA2
Uniprot ID
P42262
Uniprot Name
Glutamate receptor 2
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 co...
Gene Name
GRIK2
Uniprot ID
Q13002
Uniprot Name
Glutamate receptor ionotropic, kainate 2
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]

Drug created on June 13, 2005 07:24 / Updated on November 02, 2018 04:44