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Showing drug card for Phenobarbital (DB01174)

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Version 2.5
Creation Date 2005-06-13 13:24:05
Update Date 2009-02-19 16:04:52
Primary Accession Number DB01174
Secondary Accession Number
  • APRD00184
Name Phenobarbital
Drug Type
  • Approved
  • Small Molecule
Description A barbituric acid derivative that acts as a nonselective central nervous system depressant. It promotes binding to inhibitory gamma-aminobutyric acid subtype receptors, and modulates chloride currents through receptor channels. It also inhibits glutamate induced depolarizations. [PubChem]
Synonyms
  1. Fenobarbital
  2. Phenobarbitol
  3. Phenobarbituric Acid
  4. Phenylethylbarbiturate
  5. Phenylethylbarbituric Acid
  6. Phenylethylmalonylurea
Brand Names
  1. Adonal
  2. Aephenal
  3. Agrypnal
  4. Amylofene
  5. Aphenylbarbit
  6. Aphenyletten
  7. Barbenyl
  8. Barbinal
  9. Barbiphen
  10. Barbiphenyl
  11. Barbipil
  12. Barbita
  13. Barbivis
  14. Barbonal
  15. Barbophen
  16. Bardorm
  17. Bartol
  18. Bialminal
  19. Blu-Phen
  20. Cabronal
  21. Calmetten
  22. Calminal
  23. Cardenal
  24. Chinoin
  25. Codibarbita
  26. Coronaletta
  27. Cratecil
  28. Damoral
  29. Dezibarbitur
  30. Dormina
  31. Dormiral
  32. Dormital
  33. Doscalun
  34. Duneryl
  35. Ensobarb
  36. Ensodorm
  37. Epanal
  38. Epidorm
  39. Epilol
  40. Episedal
  41. Epsylone
  42. Eskabarb
  43. Etilfen
  44. Euneryl
  45. Fenbital
  46. Fenemal
  47. Fenosed
  48. Fenylettae
  49. Gardenal
  50. Gardepanyl
  51. Glysoletten
  52. Haplopan
  53. Haplos
  54. Helional
  55. Hennoletten
  56. Henotal
  57. Hypnaletten
  58. Hypnette
  59. Hypno-Tablinetten
  60. Hypnogen
  61. Hypnolone
  62. Hypnoltol
  63. Hysteps
  64. Lefebar
  65. Leonal
  66. Lephebar
  67. Lepinal
  68. Lepinaletten
  69. Linasen
  70. Liquital
  71. Lixophen
  72. Lubergal
  73. Lubrokal
  74. Lumen
  75. Lumesettes
  76. Lumesyn
  77. Luminal
  78. Lumofridetten
  79. Luphenil
  80. Luramin
  81. Molinal
  82. Neurobarb
  83. Nirvonal
  84. Noptil
  85. Nova-Pheno
  86. Nunol
  87. Parkotal
  88. Pharmetten
  89. Phen-Bar
  90. Phenaemal
  91. Phenemal
  92. Phenemalum
  93. Phenobal
  94. Phenobarbyl
  95. Phenoluric
  96. Phenolurio
  97. Phenomet
  98. Phenonyl
  99. Phenoturic
  100. Phenyletten
  101. Phenyral
  102. Phob
  103. Polcominal
  104. Promptonal
  105. Seda-Tablinen
  106. Sedabar
  107. Sedicat
  108. Sedizorin
  109. Sedlyn
  110. Sedofen
  111. Sedonal
  112. Sedonettes
  113. Sevenal
  114. Sinoratox
  115. Solfoton
  116. Solfoton Talpheno
  117. Solu-Barb
  118. Sombutol
  119. Somnolens
  120. Somnoletten
  121. Somnosan
  122. Somonal
  123. Spasepilin
  124. Starifen
  125. Starilettae
  126. Stental
  127. Stental Extentabs
  128. Talpheno
  129. Teolaxin
  130. Teoloxin
  131. Thenobarbital
  132. Theoloxin
  133. Triabarb
  134. Tridezibarbitur
  135. Triphenatol
  136. Versomnal
  137. Zadoletten
  138. Zadonal
Brand Mixtures Not Available
Chemical IUPAC Name 5-ethyl-5-phenyl-1,3-diazinane-2,4,6-trione
Chemical Formula C12H12N2O3
Chemical Structure Structure
CAS Registry Number 50-06-6
InChI Identifier InChI=1/C12H12N2O3/c1-2-12(8-6-4-3-5-7-8)9(15)13-11(17)14-10(12)16/h3-7H,2H2,1H3,(H2,13,14,15,16,17)/f/h13-14H
InChI Key DDBREPKUVSBGFI-KGCNKATMCV
KEGG Drug D00506 Link Image
KEGG Compound C07434 Link Image
PubChem Compound 4763 Link Image
PubChem Substance 7847572 Link Image
ChEBI ID 8069 Link Image
PharmGKB ID PA450911 Link Image
HET ID Not Available
GenBank ID Not Available
Drug ID Number [DIN] 00178799 Link Image
RxList Link http://www.rxlist.com/cgi/generic/phenbarb.htm Link Image
PDRhealth Link http://www.pdrhealth.com/drug_info/rxdrugprofiles/drugs/phe1334.shtml Link Image
Wikipedia Link http://en.wikipedia.org/wiki/Phenobarbital Link Image
FDA Label Not Available
Material Safety Data Sheet (MSDS)
Synthesis Reference Hoerlein, U.S. Pat. 1,025,872 (1912)
Average Molecular Weight 232.2353
Monoisotopic Molecular Weight 232.0848
State Solid
Melting Point 174 oC
Experimental Water Solubility 1.11 mg/mL at 25 oC [YALKOWSKY,SH & DANNENFELSER,RM (1992)] Source: PhysProp
Predicted Water Solubility 2.76e-01 mg/mL Calculated using ALOGPS
Experimental LogP/Hydrophobicity 1.47 [HANSCH,C ET AL. (1995)] Source: PhysProp
Predicted LogP 1.40 Calculated using ALOGPS
Experimental LogS Not Available
Predicted LogS -2.93 Calculated using ALOGPS
Experimental Caco2 Permeability Not Available
pKa/Isoelectric Point 7.3
Mass Spectrum Not Available
MOL File Show Link Image | Download Link Image
SDF File Show Link Image | Download Link Image
PDB File Show Link Image | Download Link Image
2D Structure
3D Structure
Experimental PDB ID Not Available
Isomeric SMILES CCC1(C(=O)NC(=O)NC1=O)C1=CC=CC=C1
Canonical SMILES CCC1(C(=O)NC(=O)NC1=O)C1=CC=CC=C1
Drug Category
  • Anticonvulsants
  • Excitatory Amino Acid Antagonists
  • GABA Modulators
  • Hypnotics and Sedatives
ATC Codes
AHFS Codes
  • 28:24.04
Indication For the treatment of all types of seizures except absence seizures.
Pharmacology Phenobarbital, the longest-acting barbiturate, is used for its anticonvulsant and sedative-hypnotic properties in the management of all seizure disorders except absence (petit mal).
Mechanism of Action Phenobarbital acts on GABAA receptors, increasing synaptic inhibition. This has the effect of elevating seizure threshold and reducing the spread of seizure activity from a seizure focus. Phenobarbital may also inhibit calcium channels, resulting in a decrease in excitatory transmitter release. The sedative-hypnotic effects of phenobarbital are likely the result of its effect on the polysynaptic midbrain reticular formation, which controls CNS arousal.
Absorption Absorbed in varying degrees following oral, rectal or parenteral administration. The salts are more rapidly absorbed than are the acids. The rate of absorption is increased if the sodium salt is ingested as a dilute solution or taken on an empty stomach.
Toxicity CNS and respiratory depression which may progress to Cheyne-Stokes respiration, areflexia, constriction of the pupils to a slight degree (though in severe poisoning they may wshow paralytic dilation), oliguria, tachycardia, hypotension, lowered body temperature, and coma. Typical shock syndrome (apnea, circulatory collapse, respiratory arrest, and death) may occur.
Protein Binding 20 to 45%
Biotransformation Hepatic (mostly via CYP2C19).
Half Life 53 to 118 hours (mean 79 hours)
Dosage Forms
Form Route
Elixir Oral
Solution Intramuscular
Tablet Oral
Patient Information Show Link Image
Contraindications Show Link Image
Interactions Show Link Image
Drug Interactions
Drug Interaction
Acenocoumarol The barbiturate decreases the anticoagulant effect
Aminophylline The barbiturate decreases the effect of theophylline
Anisindione The barbiturate decreases the anticoagulant effect
Betamethasone The barbiturate decreases the effect of the corticosteroid
Chlorotrianisene The enzyme inducer decreases the effect of hormones
Clomifene The enzyme inducer decreases the effect of hormones
Conjugated Estrogens The enzyme inducer decreases the effect of hormones
Cortisone acetate The barbiturate decreases the effect of the corticosteroid
Cyclosporine The barbiturate decreases the effect of cyclosporine
Dasatinib Decreased levels/efficacy of ddasatinib
Delavirdine The anticonvulsant decreases the effect of delavirdine
Dexamethasone The barbiturate decreases the effect of the corticosteroid
Dicumarol The barbiturate decreases the anticoagulant effect
Diethylstilbestrol The enzyme inducer decreases the effect of hormones
Disopyramide Phenobarbital decreases levels of disopyramide
Divalproex sodium Valproic acid increases the effect of barbiturate
Doxycycline The anticonvulsant decreases the effect of doxycycline
Dyphylline The barbiturate decreases the effect of theophylline
Estradiol The enzyme inducer decreases the effect of hormones
Estriol The enzyme inducer decreases the effect of hormones
Estrone The enzyme inducer decreases the effect of hormones
Estropipate The enzyme inducer decreases the effect of hormones
Ethinyl Estradiol This product may cause a slight decrease of contraceptive effect
Felbamate Felbamate increases the effect and toxicity of phenobarbital/primidone
Felodipine The barbiturate decreases the effect of felodipine
Fludrocortisone The barbiturate decreases the effect of the corticosteroid
Folic Acid Folic acid decreases the effect of anticonvulsant
Gefitinib This CYP3A4 inducer may reduce gefitinib plasma concentrations and pharmacological effects
Griseofulvin The barbiturate decreases the effect of griseofulvin
Hydrocortisone The barbiturate decreases the effect of the corticosteroid
Imatinib Phenobarbital decreases levels of imatinib
Itraconazole The barbiturate decreases the effect of itraconazole
Levonorgestrel Phenobarbital decreases the effect of levonorgestrel
Medroxyprogesterone The enzyme inducer decreases the effect of hormones
Megestrol The enzyme inducer decreases the effect of hormones
Mestranol This product may cause a slight decrease of contraceptive effect
Methadone The barbiturate decreases the effect of methadone
Methoxyflurane The barbiturate increases the renal toxicity of methoxyflurane
Methylprednisolone The barbiturate decreases the effect of the corticosteroid
Metoprolol The barbiturate decreases the effect of the metabolized beta-blocker
Metronidazole The barbiturate decreases the effect of metronidazole
Nifedipine The barbiturate decreases the effect of the calcium channel blocker
Norethindrone This product may cause a slight decrease of contraceptive effect
Oxtriphylline The barbiturate decreases the effect of theophylline
Paramethasone The barbiturate decreases the effect of the corticosteroid
Prednisolone The barbiturate decreases the effect of the corticosteroid
Prednisone The barbiturate decreases the effect of the corticosteroid
Propranolol The barbiturate decreases the effect of the metabolized beta-blocker
Quinestrol The enzyme inducer decreases the effect of hormones
Quinidine The anticonvulsant decreases the effect of quinidine
Sunitinib Possible decrease in sunitinib levels
Theophylline The barbiturate decreases the effect of theophylline
Triamcinolone The barbiturate decreases the effect of the corticosteroid
Verapamil The barbiturate decreases the effect of the calcium channel blocker
Voriconazole The barbiturate decreases the effect of voriconazole
Warfarin The barbiturate decreases the anticoagulant effect
Food Interactions
  • Avoid alcohol.
  • Avoid excessive quantities of coffee or tea (Caffeine).
  • Increase dietary intake of magnesium, folate, vitamin B6, B12, and/or consider taking a multivitamin.
  • Take on an empty stomach for quicker absorption
Pathways Not Available
General References
  1. Taylor S, Tudur Smith C, Williamson PR, Marson AG: Phenobarbitone versus phenytoin monotherapy for partial onset seizures and generalized onset tonic-clonic seizures. Cochrane Database Syst Rev. 2001;(4):CD002217. [PubMed Link Image]
  2. Tudur Smith C, Marson AG, Williamson PR: Carbamazepine versus phenobarbitone monotherapy for epilepsy. Cochrane Database Syst Rev. 2003;(1):CD001904. [PubMed Link Image]
  3. Kwan P, Brodie MJ: Phenobarbital for the treatment of epilepsy in the 21st century: a critical review. Epilepsia. 2004 Sep;45(9):1141-9. [PubMed Link Image]
  4. Booth D, Evans DJ: Anticonvulsants for neonates with seizures. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD004218. [PubMed Link Image]
  5. Kalviainen R, Eriksson K, Parviainen I: Refractory generalised convulsive status epilepticus : a guide to treatment. CNS Drugs. 2005;19(9):759-68. [PubMed Link Image]
  6. Wikipedia Link Image
  7. RxList Link Image
  8. PDRhealth Link Image
Organisms Affected
  • Humans and other mammals
Phase 1 Metabolizing Enzymes
  1. Cytochrome P450 2C19 (CYP2C19)
Targets
  1. Gamma-aminobutyric-acid receptor subunit alpha-1
Phase 1 Metabolizing Enzyme 1 [top]
Enzyme 1 Name Cytochrome P450 2C19 (CYP2C19)
Enzyme 1 Gene Name CYP2C19
Enzyme 1 SwissProt ID P33261 Link Image
Enzyme 1 SNPs SNPJam Report Link Image
Enzyme 1 Protein Sequence >sp|P33261|CP2CJ_HUMAN Cytochrome P450 2C19 (EC 1.14.13.80) 
MDPFVVLVLCLSCLLLLSIWRQSSGRGKLPPGPTPLPVIGNILQIDIKDVSKSLTNLSKI
YGPVFTLYFGLERMVVLHGYEVVKEALIDLGEEFSGRGHFPLAERANRGFGIVFSNGKRW
KEIRRFSLMTLRNFGMGKRSIEDRVQEEARCLVEELRKTKASPCDPTFILGCAPCNVICS
IIFQKRFDYKDQQFLNLMEKLNENIRIVSTPWIQICNNFPTIIDYFPGTHNKLLKNLAFM
ESDILEKVKEHQESMDINNPRDFIDCFLIKMEKEKQNQQSEFTIENLVITAADLLGAGTE
TTSTTLRYALLLLLKHPEVTAKVQEEIERVVGRNRSPCMQDRGHMPYTDAVVHEVQRYID
LIPTSLPHAVTCDVKFRNYLIPKGTTILTSLTSVLHDNKEFPNPEMFDPRHFLDEGGNFK
KSNYFMPFSAGKRICVGEGLARMELFLFLTFILQNFNLKSLIDPKDLDTTPVVNGFASVP
PFYQLCFIPV
Drug Target 1 [top]
Target 1 ID 872
Target 1 Name Gamma-aminobutyric-acid receptor subunit alpha-1
Target 1 Synonyms
  1. Gamma-aminobutyric-acid receptor subunit alpha-1 precursor
Target 1 Gene Name GABRA1
Target 1 Protein Sequence >Gamma-aminobutyric-acid receptor subunit alpha-1 precursor 
MRKSPGLSDCLWAWILLLSTLTGRSYGQPSLQDELKDNTTVFTRILDRLLDGYDNRLRPG
LGERVTEVKTDIFVTSFGPVSDHDMEYTIDVFFRQSWKDERLKFKGPMTVLRLNNLMASK
IWTPDTFFHNGKKSVAHNMTMPNKLLRITEDGTLLYTMRLTVRAECPMHLEDFPMDAHAC
PLKFGSYAYTRAEVVYEWTREPARSVVVAEDGSRLNQYDLLGQTVDSGIVQSSTGEYVVM
TTHFHLKRKIGYFVIQTYLPCIMTVILSQVSFWLNRESVPARTVFGVTTVLTMTTLSISA
RNSLPKVAYATAMDWFIAVCYAFVFSALIEFATVNYFTKRGYAWDGKSVVPEKPKKVKDP
LIKKNNTYAPTATSYTPNLARGDPGLATIAKSATIEPKEVKPETKPPEPKKTFNSVSKID
RLSRIAFPLLFGIFNLVYWATYLNREPQLKAPTPHQ
Target 1 Number of Residues 463
Target 1 Molecular Weight 51802
Target 1 Theoretical pI 9.61
Target 1 GO Classification
Function
neurotransmitter receptor activity
transporter activity
ion transporter activity
ion channel activity
ligand-gated ion channel activity
extracellular ligand-gated ion channel activity
signal transducer activity
receptor activity
transmembrane receptor activity
GABA receptor activity
GABA-A receptor activity
Process
cellular process
cell communication
signal transduction
cell surface receptor linked signal transduction
G-protein coupled receptor protein signaling pathway
gamma-aminobutyric acid signaling pathway
anion transport
inorganic anion transport
chloride transport
physiological process
cellular physiological process
transport
ion transport
Component
postsynaptic membrane
cell
membrane
intrinsic to membrane
integral to membrane
Target 1 General Function Involved in GABA-A receptor activity
Target 1 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
Target 1 Pathways Not Available
Target 1 Reactions Not Available
Target 1 Pfam Domain Function
Target 1 Signals
  • 1-27
Target 1 Transmembrane Regions
  • 252-273
  • 279-300
  • 313-334
  • 422-443
Target 1 Essentiality Non-Essential
Target 1 GenBank ID Protein 31631 Link Image
Target 1 UniProtKB/Swiss-Prot ID P14867 Link Image
Target 1 UniProtKB/Swiss-Prot Entry Name GBRA1_HUMAN Link Image
Target 1 PDB ID Not Available
Target 1 Cellular Location
  • Membrane
  • multi-pass membrane protein
Target 1 Gene Sequence >1371 bp 
ATGAGGAAAAGTCCAGGTCTGTCTGACTGTCTTTGGGCCTGGATCCTCCTTCTGAGCACA
CTGACTGGAAGAAGCTATGGACAGCCGTCATTACAAGATGAACTTAAAGACAATACCACT
GTCTTCACCAGGATTTTGGACAGACTCCTAGATGGTTATGACAATCGCCTGAGACCAGGA
TTGGGAGAGCGTGTAACCGAAGTGAAGACTGATATCTTCGTCACCAGTTTCGGACCCGTT
TCAGACCATGATATGGAATATACAATAGATGTATTTTTCCGTCAAAGCTGGAAGGATGAA
AGGTTAAAATTTAAAGGACCTATGACAGTCCTCCGGTTAAATAACCTAATGGCAAGTAAA
ATCTGGACTCCGGACACATTTTTCCACAATGGAAAGAAGTCAGTGGCCCACAACATGACC
ATGCCCAACAAACTCCTGCGGATCACAGAGGATGGCACCTTGCTGTACACCATGAGGCTG
ACAGTGAGAGCTGAATGTCCGATGCATTTGGAGGACTTCCCTATGGATGCCCATGCTTGC
CCACTAAAATTTGGAAGTTATGCTTATACAAGAGCAGAAGTTGTTTATGAATGGACCAGA
GAGCCAGCACGCTCAGTGGTTGTAGCAGAAGATGGATCACGTCTAAACCAGTATGACCTT
CTTGGACAAACAGTAGACTCTGGAATTGTCCAGTCAAGTACAGGAGAATATGTTGTTATG
ACCACTCATTTCCACTTGAAGAGAAAGATTGGCTACTTTGTTATTCAAACATACCTGCCA
TGCATAATGACAGTGATTCTCTCACAAGTCTCCTTCTGGCTCAACAGAGAGTCTGTACCA
GCAAGAACTGTCTTTGGAGTAACAACTGTGCTCACCATGACAACATTGAGCATCAGTGCC
AGAAACTCCCTCCCTAAGGTGGCTTATGCAACAGCTATGGATTGGTTTATTGCCGTGTGC
TATGCCTTTGTGTTCTCAGCTCTGATTGAGTTTGCCACAGTAAACTATTTCACTAAGAGA
GGTTATGCATGGGATGGCAAAAGTGTGGTTCCAGAAAAGCCAAAGAAAGTAAAGGATCCT
CTTATTAAGAAAAACAACACTTACGCTCCAACAGCAACCAGCTACACCCCTAATTTGGCC
AGGGGCGACCCGGGCTTAGCCACCATTGCTAAAAGTGCAACCATAGAACCTAAAGAGGTC
AAGCCCGAAACAAAACCACCAGAACCCAAGAAAACCTTTAACAGTGTCAGCAAAATTGAC
CGACTGTCAAGAATAGCCTTCCCGCTGCTATTTGGAATCTTTAACTTAGTCTACTGGGCT
ACGTATTTAAACAGAGAGCCTCAGCTAAAAGCCCCCACACCACATCAATAG
Target 1 GenBank Gene ID
Target 1 GeneCard ID GABRA1 Link Image
Target 1 GenAtlas ID GABRA1 Link Image
Target 1 HGNC ID HGNC:4075 Link Image
Target 1 Chromosome Location 5
Target 1 Locus 5q34-q35
Target 1 SNPs SNPJam Report Link Image
Target 1 General References
  1. Cossette P, Liu L, Brisebois K, Dong H, Lortie A, Vanasse M, Saint-Hilaire JM, Carmant L, Verner A, Lu WY, Wang YT, Rouleau GA: Mutation of GABRA1 in an autosomal dominant form of juvenile myoclonic epilepsy. Nat Genet. 2002 Jun;31(2):184-9. Epub 2002 May 6. [PubMed Link Image]
  2. Schofield PR, Pritchett DB, Sontheimer H, Kettenmann H, Seeburg PH: Sequence and expression of human GABAA receptor alpha 1 and beta 1 subunits. FEBS Lett. 1989 Feb 27;244(2):361-4. [PubMed Link Image]
  3. Garrett KM, Duman RS, Saito N, Blume AJ, Vitek MP, Tallman JF: Isolation of a cDNA clone for the alpha subunit of the human GABA-A receptor. Biochem Biophys Res Commun. 1988 Oct 31;156(2):1039-45. [PubMed Link Image]
Target 1 Drug References
  1. 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 Link Image]
  2. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. [PubMed Link Image]

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