Primidone

Summary

Primidone (CHEMBL856) is an approved small-molecule anticonvulsant (ATC N03AA03) targeting TRPM3; indicated across 2 conditions including epilepsy and stroke disorder.

At a glance

• Status: Approved (max clinical phase 4)
• Modality: Small molecule
• ATC class: N03AA03
• Targets: 1 (TRPM3)
• Indications: 2 conditions
• Clinical trials: 4
• Chemistry: 218.25 Da · C12H14N2O2

Identifiers

Drug identity and classification

Field	Value
ChEMBL ID	CHEMBL856
Name	Primidone
Type	Small molecule
Max phase	4
FDA approved	yes
PubChem CID	4909
ChEBI	CHEBI:8412
ATC	N03AA03
Molecular formula	C12H14N2O2
Molecular weight	218.25
InChIKey	DQMZLTXERSFNPB-UHFFFAOYSA-N

SMILES: CCC1(C(=O)NCNC1=O)C2=CC=CC=C2

IUPAC name: 5-ethyl-5-phenyl-1,3-diazinane-4,6-dione

ChEBI definition: A pyrimidone that is dihydropyrimidine-4,6(1H,5H)-dione substituted by an ethyl and a phenyl group at position 5. It is used as an anticonvulsant for treatment of various types of seizures.

Pharmacological roles (ChEBI): anticonvulsant.

Other ChEBI roles (chemical / environmental): environmental contaminant, xenobiotic.

Also known as: Lepimidin, Liskantin, Lepsiral, Mysoline, NSC-41701, Primaclone, Primidona, Primidone, Resimatil, SID11111659, SID11113350, SID17389534

Patent coverage: 4,544 distinct patent families (16,088 SureChEMBL compound mentions), from 1 matched compound structure(s). Mentions count patents naming the compound (not distinct inventions), so promiscuous / reference molecules inflate the mention figure — families are the dedup metric.

Targets

Targets

Primary targets (GtoPdb curated mechanism): the Cancer dependency column is the DepMap CRISPR fitness signal (% of screened cell lines dependent on the target).

Gene	Target	Action	pAffinity	Cancer dependency	UniProt
TRPM3	TRPM3		6.2	0.1%	Q9HCF6

Broader ChEMBL bioactivity targets: 6 (assay-derived). Sample: Tyrosyl-DNA phosphodiesterase 1, Thyrotropin receptor, Menin/Histone-lysine N-methyltransferase MLL, DNA polymerase beta, Cytochrome P450 1A2, DNA repair nuclease/redox regulator APEX1.

Bioactivity

ChEMBL activities: 3 potent at pChembl ≥ 5 of 7 total. Top 30 by potency (10 = 0.1 nM, 6 = 1 µM):

Target	pChembl	Type	Value	Unit	Activity ID
TDP1	5.3	Potency	5012	nM	CHEMBL_ACT_3929806
TSHR	5.2	Potency	6310	nM	CHEMBL_ACT_3920903
TSHR	5.2	Potency	6310	nM	CHEMBL_ACT_4618140

Target pathways

Aggregated over 1 target gene(s): TRPM3.

Top Reactome pathways

1 total, by targets touching each:

Pathway	Targets	Genes
TRP channels	1	TRPM3

Dominant GO biological processes

GO term	Targets
monoatomic cation transport	1
calcium ion transport	1
protein homotetramerization	1
calcium ion transmembrane transport	1
zinc ion transmembrane transport	1
monoatomic cation transmembrane transport	1
monoatomic ion transport	1
monoatomic ion transmembrane transport	1
protein tetramerization	1
transmembrane transport	1

Indications & clinical

Indications

2 indications (1 at ChEMBL trial phase 4). Phase below is the highest clinical-trial phase recorded for this drug against each disease — not the molecule’s overall approval status (that is in the Summary).

Indication	Trial phase	MONDO	EFO
epilepsy	4	MONDO:0005027	EFO:0000474
stroke disorder	2	MONDO:0005098	EFO:0000712

Clinical trials

Total trials: 4.

Phase distribution

Phase	Trials
Not specified	2
PHASE2	1
PHASE1	1

Top trials by phase / activity

NCT	Phase	Status	Title
NCT02008123	PHASE2	WITHDRAWN	Effect of Primidone on Platelet Responsiveness in Patients Determined to be Clopidogrel Resistant
NCT01132040	PHASE1	COMPLETED	Bioequivalence Study of Primidone Tablets 50 mg of Dr. Reddy’s Under Fasting Conditions
NCT03196466	Not specified	COMPLETED	Population Pharmacokinetics of Antiepileptic in Pediatrics
NCT04692844	Not specified	COMPLETED	Pathophysiology of Tremor-modulating Mechanisms of Propranolol and Primidone in Essential Tremor

Clinical evidence (CIViC)

No CIViC predictive evidence (expected for non-precision-medicine drugs).

Pharmacology

Pharmacogenomics

No CPIC/DPWG dosing guideline, but PharmGKB curates 0 clinical and 5 variant annotation(s) for this drug (gene-keyed; see PharmGKB).

Related molecules

Related molecules

Molecules sharing ≥1 of this drug’s curated primary targets, merged from two biobtree sources and ranked by shared-target count, then clinical phase: ChEMBL clinical-stage candidates (development phase ≥2) and PubChem drug-class bioactivity (approved / known drugs acting on the target). Deduplicated by drug name; the drug’s own salt forms are excluded. Note: for a drug with few primary targets a shared-target match can reflect off-target / promiscuous binding rather than the same therapeutic mechanism — the phase ordering surfaces bona-fide therapeutics first.

3 molecules share ≥1 primary target. Top 3 by shared-target count:

Molecule	Source	Status	Shared targets
Mefenamic Acid	PubChem	Approved	TRPM3
Pioglitazone	PubChem	Approved	TRPM3
Rosiglitazone	PubChem	Approved	TRPM3