Pyrimethamine 25mg tablets
Requires a prescription from a doctor or prescriber
One of the folic acid antagonists that is used as an antimalarial or with a sulfonamide to treat toxoplasmosis.
Official documents, adverse reaction reporting, and safety monitoring
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Official medicine documents
Safety monitoring data
Yellow Card reports
The MHRA Yellow Card scheme collects reports of suspected side effects from healthcare professionals and patients. View the Drug Analysis Profile (iDAP) for real-world adverse reaction data.
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Suspected adverse reactions reported for Pyrimethamine
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Submit a Yellow Card report to the MHRA
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.
EudraVigilance
The European Medicines Agency (EMA) collects suspected adverse reaction reports from across the EU/EEA through the EudraVigilance system. Search for safety data on this medicine.
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Suspected adverse reactions reported for Pyrimethamine
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EudraVigilance data is published by the European Medicines Agency (EMA). A suspected adverse reaction is not necessarily caused by the medicine.
1 branded products available
MHRA licensed products
View all licensed products for Pyrimethamine on the MHRA register
Daraprim 25mg tablets
This is the NHS Drug Tariff indicative price used for reimbursement purposes. It may not reflect the price paid by patients or pharmacies.
View full Drug TariffSource: NHS Drug Tariff via NHSBSA. Derived from dm+d VMPP (Virtual Medicinal Product Pack) pricing data. Contains public sector information licensed under the Open Government Licence v3.0.
WHO defined daily dose (DDD)
75 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
Check stock at pharmacies and supply information
Pharmacy stock checkers
Search for this medicine at major UK pharmacy chains. These links open the retailer's own website — results depend on their current online catalogue.
Supply & safety information
Official UK regulator monitoring and safety alerts
Pharmacy links redirect to the retailer's own search and do not represent real-time stock levels. Shortage and safety information sourced from MHRA drug safety updates (gov.uk, Crown Copyright under OGL v3.0).
Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
Browse tools
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: 11 · Randomised trials: 28 · 1988–2026
Showing the 50 most relevant studies, sorted by most relevant.
Ruben R. Ben-Harari, Elizabeth Goodwin, Júlio Casoy
Drugs in R&D, 2017
- Infectious Encephalitis
- Pyrimethamine
- Toxoplasmosis, Congenital
Anna Maria van Eijk, David A. Larsen, Kassoum Kayentao, et al.
The Lancet Infectious Diseases, 2019
- Drug Resistance
- Africa
- Antimalarials
Caroline Shulman, Caroline Shulman, E. Dorman, et al.
Lancet, 1999
- Anemia
- Antimalarials
- Bedding and Linens
T. Mutabingwa, D. Anthony, A. Heller, et al.
Lancet, 2005
- Artesunate
- Artemether
- Lumefantrine
Badara Cissé, Cheikh Sokhna, Denis Boulanger, et al.
The Lancet, 2006
- Artesunate
- Antimalarials
- Bedding and Linens
Lotje H. Bosch-Driessen, Frank D. Verbraak, Maria S.A. Suttorp-Schulten, et al.
American Journal of Ophthalmology, 2002
- Anti-Bacterial Agents
- Antiprotozoal Agents
- Drug Evaluation
Meghna Desai, Julie Gutman, Anne L’lanziva, et al.
The Lancet, 2015
- Antimalarials
- Drug Combinations
- Kenya
Masoud Soheilian, Mohammad-Mehdi Sadoughi, Mehdi Ghajarnia, et al.
Ophthalmology, 2005
- Antibodies, Protozoan
- Antiprotozoal Agents
- Chorioretinitis
Lorenz von Seidlein, Paul Milligan, Margaret Pinder, et al.
The Lancet, 2000
- Artesunate
- Antimalarials
- Drug Combinations
Masoud Soheilian, Alireza Ramezani, A Azimzadeh, et al.
Ophthalmology, 2010
- Antibodies, Protozoan
- Antiprotozoal Agents
- Clindamycin
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
96 hours
Mechanism
Pyrimethamine inhibits the dihydrofolate reductase of plasmodia and thereby bloc…
Food interactions
2 warnings
Human targets
3 targets
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
2 to 6 hours
Half-life
96 hours
Protein binding
87%
Metabolism
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
Known interactions with other medications. Always consult a healthcare professional.
Showing 50 of 225 interactions
How the body processes this drug — absorption, distribution, metabolism, and elimination
Proteins and enzymes this drug interacts with in the body
Binds its own mRNA and that of DHFR2
PMID:11707436 PMID:8123671 PMID:8672428 PMID:9694901
The isozyme B does not hydrolyze each of these substrates, however hydrolyzes efficiently neutral oligosaccharide .
PMID:11707436
Only the isozyme A is responsible for the degradation of GM2 gangliosides in the presence of GM2A .
PMID:8123671 PMID:8672428 PMID:9694901
During fertilization is responsible, at least in part, for the zona block to polyspermy. Present in the cortical granules of non-activated oocytes, is exocytosed during the cortical reaction in response to oocyte activation and inactivates the sperm galactosyltransferase-binding site, accounting for the block in sperm binding to the zona pellucida (By similarity)
PMID:19074442 PMID:23851396 PMID:23934049 PMID:2527252 PMID:8033114 PMID:8567728
Has high affinity for folate and folic acid analogs at neutral pH .
PMID:23851396 PMID:23934049 PMID:2527252 PMID:8033114 PMID:8567728
Exposure to slightly acidic pH after receptor endocytosis triggers a conformation change that strongly reduces its affinity for folates and mediates their release .
PMID:8567728
Required for normal embryonic development and normal cell proliferation (By similarity)
Enzymes involved in drug metabolism — important for understanding drug interactions
Proteins that transport this drug across cell membranes
PMID:16330770 PMID:17509534
Plays a physiological role in the excretion of cationic compounds including endogenous metabolites, drugs, toxins through the kidney and liver, into urine and bile respectively .
PMID:16330770 PMID:17495125 PMID:17509534 PMID:17582384 PMID:18305230 PMID:19158817 PMID:21128598 PMID:24961373
Mediates the efflux of endogenous compounds such as creatinine, vitamin B1/thiamine, agmatine and estrone-3-sulfate .
PMID:16330770 PMID:17495125 PMID:17509534 PMID:17582384 PMID:18305230 PMID:19158817 PMID:21128598 PMID:24961373
May also contribute to regulate the transport of cationic compounds in testis across the blood-testis-barrier (Probable)
Plays a physiological role in the excretion of drugs, toxins and endogenous metabolites through the kidney
ATC P01BF09
ATC P01BD01
ATC P01BD51
ATC P01BF04
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)
Pyrimethamine
Additional database identifiers
Drugs Product Database (DPD)
5918
ChemSpider
4819
BindingDB
18512
PDB
CP6
ZINC
ZINC000000057464
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2861
GenAtlas
DHFR
GeneCards
DHFR
GenBank Gene Database
J00140
GenBank Protein Database
182724
Guide to Pharmacology
2603
UniProt Accession
DYR_HUMAN
GenBank Gene Database
M22159
GenBank Protein Database
160260
UniProt Accession
DRTS_PLAFK
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4879
GenAtlas
HEXB
GeneCards
HEXB
GenBank Gene Database
M13519
GenBank Protein Database
179462
UniProt Accession
HEXB_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:3791
GenAtlas
FOLR1
GeneCards
FOLR1
GenBank Gene Database
M28099
Guide to Pharmacology
3212
UniProt Accession
FOLR1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:2622
GenAtlas
CYP2C8
GeneCards
CYP2C8
GenBank Gene Database
M17397
Guide to Pharmacology
1325
UniProt Accession
CP2C8_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:25588
GeneCards
SLC47A1
GenBank Gene Database
AK001709
GenBank Protein Database
7023138
Guide to Pharmacology
1216
UniProt Accession
S47A1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:26439
GeneCards
SLC47A2
Guide to Pharmacology
1217
UniProt Accession
S47A2_HUMAN
DrugBank citations
If you use DrugBank data in your research, please cite the following publications:
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Structured knowledge from the free knowledge base
ATC classifications (Wikidata)
Linked open data from Wikidata (Q421072), 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.