Leflunomide

Leflunomide
Clinical data
Trade names	Arava, Lefumide, Arabloc, others
AHFS/Drugs.com	Monograph
MedlinePlus	a600032
License data	EU EMA: by INN; US DailyMed: Leflunomide;
Pregnancy; category	AU: X (High risk);
Routes of; administration	By mouth
ATC code	L04AK01 (WHO) ;
Legal status
Legal status	AU: S4 (Prescription only); BR: Class C1 (Other controlled substances); CA: ℞-only; UK: POM (Prescription only); US: ℞-only; EU: Rx-only;
Pharmacokinetic data
Bioavailability	80%
Protein binding	>99%
Metabolism	GI mucosa and liver
Metabolites	Teriflunomide
Elimination half-life	14–18 days
Excretion	Faeces (48%), urine (43%)
Identifiers
	IUPAC name 5-methyl-N-[4-(trifluoromethyl) phenyl]-isoxazole-4-carboxamide;
CAS Number	75706-12-6 ;
PubChem CID	3899;
IUPHAR/BPS	6825;
DrugBank	DB01097 ;
ChemSpider	3762 ;
UNII	G162GK9U4W;
KEGG	D00749 ;
ChEBI	CHEBI:6402 ;
ChEMBL	ChEMBL960 ;
CompTox Dashboard (EPA)	DTXSID9023201 ;
ECHA InfoCard	100.123.883
Chemical and physical data
Formula	C12H9F3N2O2
Molar mass	270.211 g·mol−1
3D model (JSmol)	Interactive image;
	SMILES O=C(Nc1ccc(cc1)C(F)(F)F)c2c(onc2)C;
	InChI InChI=1S/C12H9F3N2O2/c1-7-10(6-16-19-7)11(18)17-9-4-2-8(3-5-9)12(13,14)15/h2-6H,1H3,(H,17,18) ; Key:VHOGYURTWQBHIL-UHFFFAOYSA-N ;
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Leflunomide, sold under the brand name Arava among others, is an immunosuppressive disease-modifying antirheumatic drug (DMARD), used in active moderate-to-severe rheumatoid arthritis and psoriatic arthritis. It is a pyrimidine synthesis inhibitor that works by inhibiting dihydroorotate dehydrogenase.