MEPHOBARBITAL

US Previously Marketed

First marketed in 1921

Details

Stereochemistry	RACEMIC
Molecular Formula	C13H14N2O3
Molecular Weight	246.2619
Optical Activity	( + / - )
Defined Stereocenters	0 / 1
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

CCC1(C(=O)NC(=O)N(C)C1=O)C2=CC=CC=C2

InChI

InChIKey=ALARQZQTBTVLJV-UHFFFAOYSA-N

InChI=1S/C13H14N2O3/c1-3-13(9-7-5-4-6-8-9)10(16)14-12(18)15(2)11(13)17/h4-8H,3H2,1-2H3,(H,14,16,18)

HIDE SMILES / InChI

Molecular Formula	C13H14N2O3
Molecular Weight	246.2619
Charge	0
Count

Stereochemistry	RACEMIC
Additional Stereochemistry	No
Defined Stereocenters	0 / 1
E/Z Centers	0
Optical Activity	( + / - )

Description
Sources: https://www.drugs.com/pro/mephobarbital.html

Mephobarbital us a barbiturate derivative used primary as an anticonvulsant, but also as a sedative and anxiolytic. Marketing of mephobarbital was discontinued in 2012.

CNS Activity

Originator

Approval Year

Targets

Primary Target	Pharmacology	Condition	Potency
GABA-A receptor; anion channel 203 Target ID: CHEMBL2093872 Sources: https://www.ncbi.nlm.nih.gov/pubmed/2427687	Activator 1447		19.0 µM [EC50]

Conditions

Condition	Modality	Targets	Highest Phase	Product
Anxiety 275 Sources: https://www.drugs.com/pro/mephobarbital.html	Primary		Approved 8583	MEBARAL Approved Use Mephobarbital tablets are indicated for use as a sedative for the relief of anxiety, tension, and apprehension, and as an anticonvulsant for the treatment of grand mal and petit mal epilepsy.
Epilepsy 121 Sources: https://www.drugs.com/pro/mephobarbital.html	Primary		Approved 8583	MEBARAL Approved Use Mephobarbital tablets are indicated for use as a sedative for the relief of anxiety, tension, and apprehension, and as an anticonvulsant for the treatment of grand mal and petit mal epilepsy.

C_max

Value	Dose	Co-administered	Analyte	Population
0.73 μg/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE food status: FASTED
0.24 μg/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: MALE food status: FASTED

AUC

Value	Dose	Co-administered	Analyte	Population
7.95 μg × h/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE food status: FASTED
1.29 μg × h/mL EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: MALE food status: FASTED

T_1/2

Value	Dose	Co-administered	Analyte	Population
6.94 h EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE food status: FASTED
3.05 h EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2249375	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: MALE food status: FASTED

F_unbound

Value	Dose	Co-administered	Analyte	Population
32.6% EXPERIMENT https://pubmed.ncbi.nlm.nih.gov/2083148	400 mg single, oral dose: 400 mg route of administration: Oral experiment type: SINGLE co-administered:		MEPHOBARBITAL plasma	Homo sapiens population: HEALTHY age: ADULT sex: FEMALE / MALE food status: UNKNOWN

Overview

CYP3A4	CYP2C9	CYP2D6	hERG
substrate 1946	substrate 1193	substrate 1388

OverviewOther

Other Inhibitor	Other Substrate	Other Inducer
	P-gp 2052 MRP1 113 CYP2C19 1119 CYP2B6 776 CYP1A1 389 CYP1A2 1197 CYP2A6 626 CYP2C8 810 CYP2E1 729

Drug as victim

Target	Modality	Activity
CYP1A1 389	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP1A2 1197	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP2A6 626	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP2C8 810	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP2C9 1193	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP2D6 1388	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP2E1 729	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
CYP3A4 1946	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/10570024/	no
MRP1 113	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/22342565/	no
P-gp 2052	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/22342565/	no
CYP2B6 776	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/11124227/ \| https://pubmed.ncbi.nlm.nih.gov/15284537/	yes
CYP2C19 1119	substrate 4014 Sources: https://pubmed.ncbi.nlm.nih.gov/11124227/ \| https://pubmed.ncbi.nlm.nih.gov/15284537/ \| https://pubmed.ncbi.nlm.nih.gov/15499191/	yes

Sourcing

Vendor/Aggregator	ID	URL
ChEBI	CHEBI:6758	https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:6758
eMolecules	2729386	https://www.emolecules.com/cgi-bin/more?vid=2729386

PubMed

Title	Date	PubMed
A high-throughput multivariate optimization for the simultaneous enantioseparation and detection of barbiturates in micellar electrokinetic chromatography-mass spectrometry.	2010-08	20819283
Monitoring antiepileptic drugs: a level-headed approach.	2009-06	19949569
The influence of sulfur substituents on the molecular geometry and packing of thio derivatives of N-methylphenobarbital.	2009-02	19190392
A categorical structure-activity relationship analysis of the developmental toxicity of antithyroid drugs.	2009	20111734
Fetal malformations associated with the use of methylphenobarbital and carbamazepine during pregnancy. Two case reports and review of the literature.	2009	19218807
Phenotype-genotype analysis of CYP2C19 in Colombian mestizo individuals.	2007-07-11	17623107
[Intoxication due to replacement of the precursor methylphenobarbital by phenobarbital].	2006-04-29	17225740
The history of barbiturates a century after their clinical introduction.	2005-12	18568113
Pharmacogenetic roles of CYP2C19 and CYP2B6 in the metabolism of R- and S-mephobarbital in humans.	2004-08	15284537
A novel single nucleotide polymorphism (SNP) of the CYP2C19 gene in a Japanese subject with lowered capacity of mephobarbital 4'-hydroxylation.	2004-06	15499191
Key structural features of ligands for activation of human pregnane X receptor.	2004-04	15039302
Monolithic silica columns with chemically bonded beta-cyclodextrin as a stationary phase for enantiomer separations of chiral pharmaceuticals.	2003-11	13680065
Determination of two ternary mixtures containing phenobarbitone by second derivative of the ratio spectrum-zero-crossing and HPLC methods.	2003-05	12729832
Withdrawal of methylphenobarbitone.	2003-01-06	12492392
Essential requirements for substrate binding affinity and selectivity toward human CYP2 family enzymes.	2003-01-01	12464242
Prediction of adsorption from multicomponent solutions by activated carbon using single-solute parameters. Part II--Proposed equation.	2002	12916938
Role of CYP2C19 in stereoselective hydroxylation of mephobarbital by human liver microsomes.	2001-01	11124227
Ependymoblastoma associated with prenatal exposure to diphenylhydantoin and methylphenobarbitone.	1985-05-01	3978571
Myasthenia gravis syndrome associated with trimethadione.	1970-06-29	4987393

Patents

Sample Use Guides

In Vivo Use Guide

Mephobarbital shoudl be administered orally. For treatment of epilepsy the average dose for adults and children 12 years of age and older: 400 mg to 600 mg daily.

Route of Administration: Oral

In Vitro Use Guide

Uptake of [36]Cl- ions by membranes from mouse brain was measured using liquid scintillation spectrometry. Mephobarbital simulated GABA-dependent Cl- uptake with EC50 of 19 uM.

Substance Class	Chemical Created by `admin` on `Mon Mar 31 18:56:09 GMT 2025` Edited by `admin` on `Mon Mar 31 18:56:09 GMT 2025`
Record UNII	5NC67NU76B
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

METHYLPHENOBARBITAL

Preferred Name

English

MEPHOBARBITAL

Common Name

English

MEPHOBARBITAL [USP MONOGRAPH]

Common Name

English

ISONAL

Common Name

English

MEPHOBARBITAL CIV [USP-RS]

Common Name

English

ENPHENEMAL

Common Name

English

METHYLPHENOBARBITAL [EP MONOGRAPH]

Common Name

English

METHYLPHENOBARBITONE

Common Name

English

MEPHOBARBITAL [MI]

Common Name

English

BARBITURIC ACID, 5-ETHYL-1-METHYL-5-PHENYL-

Systematic Name

English

methylphenobarbital [INN]

Common Name

English

MENTA-BAL

Brand Name

English

MEPHOBARBITAL [JAN]

Common Name

English

MEPHOBARBITAL CIV

Common Name

English

5-Ethyl-1-methyl-5-phenylbarbituric acid

Systematic Name

English

PHEMETONE

Common Name

English

MEBARAL

Brand Name

English

2,4,6(1H,3H,5H)-PYRIMIDINETRIONE, 5-ETHYL-1-METHYL-5-PHENYL-

Systematic Name

English

MEPHOBARBITAL [VANDF]

Common Name

English

METYLFENEMAL

Common Name

English

MEPHOBARBITAL [HSDB]

Common Name

English

Methylphenobarbital [WHO-DD]

Common Name

English

METHYLPHENOBARBITAL [MART.]

Common Name

English

Classification Tree Code System Code

DEA NO.

2250