Pyrimethamine

Pyrimethamine
Clinical data
Pronunciation/ˌpɪrɪˈmɛθəmɪn/
Trade namesDaraprim, others
AHFS/Drugs.comMonograph
MedlinePlusa601050
License data
Pregnancy
category
Routes of
administration		By mouth
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailabilitywell-absorbed
Protein binding87%
MetabolismLiver
Elimination half-life96 hours
ExcretionKidney
Identifiers
  • 5-(4-chlorophenyl)-6-ethyl- 2,4-pyrimidinediamine
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
PDB ligand
CompTox Dashboard (EPA)
ECHA InfoCard100.000.331 Edit this at Wikidata
Chemical and physical data
FormulaC12H13ClN4
Molar mass248.71 g·mol−1
3D model (JSmol)
Melting point233 to 234 °C (451 to 453 °F)
  • Clc2ccc(c1c(nc(nc1CC)N)N)cc2
  • InChI=1S/C12H13ClN4/c1-2-9-10(11(14)17-12(15)16-9)7-3-5-8(13)6-4-7/h3-6H,2H2,1H3,(H4,14,15,16,17) checkY
  • Key:WKSAUQYGYAYLPV-UHFFFAOYSA-N checkY
  (verify)

Pyrimethamine, sold under the brand name Daraprim among others, is a medication used with leucovorin (leucovorin is used to decrease side effects of pyrimethamine; it does not have intrinsic anti-parasitic activity) to treat the parasitic diseases toxoplasmosis and cystoisosporiasis.[3][4] It is also used with dapsone as a second-line option to prevent Pneumocystis jiroveci pneumonia in people with HIV/AIDS.[3] It was previously used for malaria but is no longer recommended due to resistance.[3] Pyrimethamine is taken by mouth.[3]

Common side effects include gastrointestinal upset, severe allergic reactions, and bone marrow suppression.[3] It should not be used by people with folate deficiency that has resulted in anemia.[3] There is concern that it may increase the risk of cancer.[3] While occasionally used in pregnancy it is unclear if pyrimethamine is safe for the baby.[1] Pyrimethamine is classified as a folic acid antagonist.[3] It works by inhibiting folic acid metabolism and therefore the making of DNA.[3]

Pyrimethamine was discovered in 1952 and came into medical use in 1953.[3][5] It is on the World Health Organization's List of Essential Medicines.[6] It was approved as a generic in the United States in February 2020.[7]

  1. ^ a b "Pyrimethamine (Daraprim) Use During Pregnancy". Drugs.com. 31 July 2019. Archived from the original on 3 December 2016. Retrieved 28 February 2020.
  2. ^ "Daraprim Tablets – Summary of Product Characteristics (SmPC)". (emc). 19 February 2020. Archived from the original on 29 February 2020. Retrieved 28 February 2020.
  3. ^ a b c d e f g h i j "Pyrimethamine". The American Society of Health-System Pharmacists. Archived from the original on 2 December 2016. Retrieved 2 December 2016.
  4. ^ Hamilton R (2015). Tarascon Pocket Pharmacopoeia 2015 Deluxe Lab-Coat Edition. Jones & Bartlett Learning. p. 54. ISBN 9781284057560.
  5. ^ Sylvie M, Pierre C, Jean M (2008). Biodiversity of Malaria in the world. John Libbey Eurotext. p. 6. ISBN 9782742009633. Archived from the original on 14 January 2023. Retrieved 10 September 2017.
  6. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  7. ^ Cite error: The named reference FDA PR 20200228 was invoked but never defined (see the help page).