Leflunomide 100mg tablets
Leflunomide is a pyrimidine synthesis inhibitor belonging to the DMARD (disease-modifying antirheumatic drug) class of drugs, which are chemically and pharmacologically very heterogeneous.
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Yellow Card reports
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Suspected adverse reactions reported for Leflunomide
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Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
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Suspected adverse reactions reported for Leflunomide
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1 branded products available
WHO defined daily dose (DDD)
20 mg
Not a recommended dose. The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults. It is a statistical measure used for research and comparison purposes only.
Source: WHO Collaborating Centre for Drug Statistics Methodology, distributed via the NHS dm+d supplementary BNF/ATC mapping files (NHSBSA). Contains public sector information licensed under the Open Government Licence v3.0.
Therapeutically similar medicines
Similarity is based on WHO Anatomical Therapeutic Chemical (ATC) classification and on a factual NHS dm+d therapeutic-grouping code prefix. Source data: NHS dm+d via TRUD (OGL v3.0), WHO ATC/DDD Index.
NHS prescribing volume and spending trends
Guidelines from the National Institute for Health and Care Excellence
NICE clinical guidance(5)
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Source: National Institute for Health and Care Excellence (NICE). Contains public sector information licensed under the Open Government Licence v3.0.
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Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
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SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0. BNF code shown is the factual mapping value distributed by NHS Business Services Authority (NHSBSA) in the dm+d supplementary file under OGL v3.0; it is not affiliated with, nor licensed from, the publishers of the British National Formulary. ATC codes from the WHO Collaborating Centre for Drug Statistics Methodology (whocc.no).
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Academic studies and reviews for this medicine's active substance
Showing the 50 most relevant studies.
Reviews & meta-analyses: 26 · Randomised trials: 11 · 2001–2026
Showing the 50 most relevant studies, sorted by most relevant.
Reumatologia clinica, 2017
R. Conway, C. Low, R. Coughlan, et al.
The Journal of Rheumatology, 2016
Zhu LM, Mendel A, Ross C, et al.
2025
ObjectivesThe objective of this systematic review is to assess the effectiveness and safety of leflunomide in the treatment of new-onset refractory or relapsing giant cell arteritis (GCA) as a glucocorticoid (GC)-sparing agent.MethodsWe searched MEDLINE, Cochrane Library, Embase, clinical trial registries and other grey literature sources for randomized controlled trials, cohort studies, case-control studies and case series that reported on the use of leflunomide in GCA. The primary effectiveness outcome was the incidence (proportion) of patients who attained sustained GC-free remission at 6 to12 months, defined by the absence of signs or symptoms of GCA, and/or normalization of inflammatory markers, and/or radiologic response, plus complete discontinuation of GC. The secondary outcomes were remission on low-dose GC and adverse events. There was no available comparator. We performed a meta-analysis using a random effects model. Included studies were appraised for risk of bias.ResultsOf 366 screened studies, 11 observational studies were included in the analysis, pooling data from 358 patients. The pooled proportion of patients achieving sustained GC-free remission was 45% (95% CI 25-64, P I 2 test = 90.3% (Q = 70.65, P P P ConclusionLeflunomide's utility as a GC-sparing agent is promising but remains to be elucidated in future higher-quality studies. PROSPERO protocol registration CRD42023490373.
Abstract licence: CC BY
Dongxu Zhang, Bowen Xia, Xin Zhang, et al.
BMC Urology, 2024
Zhu LM, Mendel A, Ross C, et al.
2025
J. Yi, Zhihong He, Shizhang Xu, et al.
International Urology and Nephrology, 2019
L. Schneidewind, T. Neumann, Desirée L. Dräger, et al.
Transplantation reviews, 2020
Runyue Huang, Hu-dan Pan, Jia-qi Wu, et al.
Phytomedicine : international journal of phytotherapy and phytopharmacology, 2019
E. van der Heijden, S. Blokland, M. Hillen, et al.
The Lancet. Rheumatology, 2020
H. Cao, Yuefeng Rao, Lin Liu, et al.
PLoS ONE, 2015
Sources: aggregated from Europe PMC (EMBL-EBI), OpenAlex, Crossref, PubMed and other open scholarly databases. Retracted articles are excluded. Study information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
None known
Half-life
Not available
Mechanism
Leflunomide is a prodrug that is rapidly and almost completely metabolized follo…
Food interactions
1 warning
Human targets
3 targets
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
6-12 hours
Half-life
2 weeks
Protein binding
99.3%
Volume of distribution
0.13 L/kg
Metabolism
Elimination
28 day
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
Known interactions with other medications. Always consult a healthcare professional.
Showing 50 of 921 interactions
How the body processes this drug — absorption, distribution, metabolism, and elimination
Many drugs are excreted in human milk, and there is a potential for serious adverse reactions in nursing infants from leflunomide.
Proteins and enzymes this drug interacts with in the body
Regulates cytoskeleton rearrangement and cell spreading in T-cells, and contributes to the regulation of T-cell responses. Promotes osteoclastic bone resorption; this requires both PTK2B/PYK2 and SRC. May inhibit differentiation and activity of osteoprogenitor cells.
Functions in signaling downstream of integrin and collagen receptors, immune receptors, G-protein coupled receptors (GPCR), cytokine, chemokine and growth factor receptors, and mediates responses to cellular stress. Forms multisubunit signaling complexes with SRC and SRC family members upon activation; this leads to the phosphorylation of additional tyrosine residues, creating binding sites for scaffold proteins, effectors and substrates. Regulates numerous signaling pathways.
Promotes activation of phosphatidylinositol 3-kinase and of the AKT1 signaling cascade. Promotes activation of NOS3. Regulates production of the cellular messenger cGMP.
Promotes activation of the MAP kinase signaling cascade, including activation of MAPK1/ERK2, MAPK3/ERK1 and MAPK8/JNK1. Promotes activation of Rho family GTPases, such as RHOA and RAC1. Recruits the ubiquitin ligase MDM2 to P53/TP53 in the nucleus, and thereby regulates P53/TP53 activity, P53/TP53 ubiquitination and proteasomal degradation.
Acts as a scaffold, binding to both PDPK1 and SRC, thereby allowing SRC to phosphorylate PDPK1 at 'Tyr-9, 'Tyr-373', and 'Tyr-376'. Promotes phosphorylation of NMDA receptors by SRC family members, and thereby contributes to the regulation of NMDA receptor ion channel activity and intracellular Ca(2+) levels. May also regulate potassium ion transport by phosphorylation of potassium channel subunits.
Phosphorylates SRC; this increases SRC kinase activity. Phosphorylates ASAP1, NPHP1, KCNA2 and SHC1. Promotes phosphorylation of ASAP2, RHOU and PXN; this requires both SRC and PTK2/PYK2
PMID:23275542 PMID:30373764 PMID:32818467 PMID:7961644
Upon ligand binding, translocates into the nucleus, where it heterodimerizes with ARNT and induces transcription by binding to xenobiotic response elements (XRE) .
PMID:23275542 PMID:30373764 PMID:7961644
Regulates a variety of biological processes, including angiogenesis, hematopoiesis, drug and lipid metabolism, cell motility and immune modulation .
PMID:12213388
Xenobiotics can act as ligands: upon xenobiotic-binding, activates the expression of multiple phase I and II xenobiotic chemical metabolizing enzyme genes (such as the CYP1A1 gene) .
PMID:7961644 PMID:33193710
Mediates biochemical and toxic effects of halogenated aromatic hydrocarbons .
PMID:34521881 PMID:7961644
Next to xenobiotics, natural ligands derived from plants, microbiota, and endogenous metabolism are potent AHR agonists .
PMID:18076143
Tryptophan (Trp) derivatives constitute an important class of endogenous AHR ligands .
PMID:32818467 PMID:32866000
Acts as a negative regulator of anti-tumor immunity: indoles and kynurenic acid generated by Trp catabolism act as ligand and activate AHR, thereby promoting AHR-driven cancer cell motility and suppressing adaptive immunity .
PMID:32818467
Regulates the circadian clock by inhibiting the basal and circadian expression of the core circadian component PER1 .
PMID:28602820
Inhibits PER1 by repressing the CLOCK-BMAL1 heterodimer mediated transcriptional activation of PER1 .
PMID:28602820
The heterodimer ARNT:AHR binds to core DNA sequence 5'-TGCGTG-3' within the dioxin response element (DRE) of target gene promoters and activates their transcription PMID:28602820
Enzymes involved in drug metabolism — important for understanding drug interactions
Proteins that transport this drug across cell membranes
PMID:11306452 PMID:12958161 PMID:19506252 PMID:20705604 PMID:28554189 PMID:30405239 PMID:31003562
Involved in porphyrin homeostasis, mediating the export of protoporphyrin IX (PPIX) from both mitochondria to cytosol and cytosol to extracellular space, it also functions in the cellular export of heme .
PMID:20705604 PMID:23189181
Also mediates the efflux of sphingosine-1-P from cells .
PMID:20110355
Acts as a urate exporter functioning in both renal and extrarenal urate excretion .
PMID:19506252 PMID:20368174 PMID:22132962 PMID:31003562 PMID:36749388
In kidney, it also functions as a physiological exporter of the uremic toxin indoxyl sulfate (By similarity). Also involved in the excretion of steroids like estrone 3-sulfate/E1S, 3beta-sulfooxy-androst-5-en-17-one/DHEAS, and other sulfate conjugates .
PMID:12682043 PMID:28554189 PMID:30405239
Mediates the secretion of the riboflavin and biotin vitamins into milk (By similarity). Extrudes pheophorbide a, a phototoxic porphyrin catabolite of chlorophyll, reducing its bioavailability (By similarity).
Plays an important role in the exclusion of xenobiotics from the brain (Probable). It confers to cells a resistance to multiple drugs and other xenobiotics including mitoxantrone, pheophorbide, camptothecin, methotrexate, azidothymidine, and the anthracyclines daunorubicin and doxorubicin, through the control of their efflux .
PMID:11306452 PMID:12477054 PMID:15670731 PMID:18056989 PMID:31254042
In placenta, it limits the penetration of drugs from the maternal plasma into the fetus (By similarity). May play a role in early stem cell self-renewal by blocking differentiation (By similarity).
In inflammatory macrophages, exports itaconate from the cytosol to the extracellular compartment and limits the activation of TFEB-dependent lysosome biogenesis involved in antibacterial innate immune response
ATC L04AK01
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
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Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Leflunomide
Additional database identifiers
Drugs Product Database (DPD)
11980
ChemSpider
3762
BindingDB
50054601
ZINC
ZINC000000004840
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2867
GenAtlas
DHODH
GeneCards
DHODH
GenBank Gene Database
M94065
GenBank Protein Database
555594
Guide to Pharmacology
2604
UniProt Accession
PYRD_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:9612
GenAtlas
PTK2B
GeneCards
PTK2B
GenBank Gene Database
U33284
GenBank Protein Database
988305
Guide to Pharmacology
2181
UniProt Accession
FAK2_HUMAN
GenBank Gene Database
CR382398
GenBank Protein Database
46362265
UniProt Accession
PYRD_PLAF7
HUGO Gene Nomenclature Committee (HGNC)
HGNC:348
GeneCards
AHR
GenBank Gene Database
D16354
GenBank Protein Database
533324
Guide to Pharmacology
2951
UniProt Accession
AHR_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2623
GenAtlas
CYP2C9
GeneCards
CYP2C9
GenBank Gene Database
AY341248
Guide to Pharmacology
1326
UniProt Accession
CP2C9_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2596
GenAtlas
CYP1A2
GeneCards
CYP1A2
GenBank Gene Database
Z00036
Guide to Pharmacology
1319
UniProt Accession
CP1A2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:74
GenAtlas
ABCG2
GeneCards
ABCG2
GenBank Gene Database
AF103796
GenBank Protein Database
4185796
Guide to Pharmacology
792
UniProt Accession
ABCG2_HUMAN
DrugBank citations
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Structured knowledge from the free knowledge base
ATC classifications (Wikidata)
Linked open data from Wikidata (Q248550), a free and open knowledge base operated by the Wikimedia Foundation. Data is available under the Creative Commons CC0 1.0 Public Domain Dedication. WHO INN from the World Health Organization.