pyrimethamine
American Heritage Dictionary:
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py·ri·meth·a·mine
(pī'rə-mĕth'ə-mēn', -mĭn) 
n.
A drug, C12H13ClN4, used principally in the prophylactic treatment of malaria.
n.
A drug, C12H13ClN4, used principally in the prophylactic treatment of malaria.
[PYRIM(IDINE) + ETH(YL) + AMINE.]
Drug Info:
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Pyrimethamine
Brand names: Daraprim®
Chemical formula:
- Espa�ol:
- Pirimetamina, Tableta oral
Pyrimethamine Oral tablet
What is this medicine?
PYRIMETHAMINE (pahy ruh METH uh meen) is an anti-parasitic medicine. It is used to treat and to prevent malaria. This medicine is also used to treat an infection of toxoplasmosis.
This medicine may be used for other purposes; ask your health care provider or pharmacist if you have questions.
What should I tell my health care provider before I take this medicine?
They need to know if you have any of these conditions:
•anemia or other blood disorders
•folate deficiency
•history of an alcohol abuse problem
•kidney disease
•liver disease
•nutrition problems
•seizures
•an unusual or allergic reaction to pyrimethamine, other medicines, foods, dyes, or preservatives
•pregnant or trying to get pregnant
•breast-feeding
How should I use this medicine?
Take this medicine by mouth with a glass of water. Follow the directions on the prescription label. If this medicine upsets your stomach take it with food or milk. Take your medicine at regular intervals. Do not take your medicine more often than directed. Take all of your medicine as directed even if you think your are better. Do not skip doses or stop your medicine early.
Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.
Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once.
NOTE: This medicine is only for you. Do not share this medicine with others.
What may interact with this medicine?
•sulfonamide antibiotics
This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.
What should I watch for while using this medicine?
Visit your doctor or health care professional for regular check ups. Tell your doctor if your symptoms do not improve or if you get new symptoms. If you get a skin rash, stop taking your medicine and contact your doctor right away.
Do not get pregnant while taking this drug. Talk to your doctor about effective birth control methods.
You may need to take folinic acid while you are taking this medicine. Talk to your health care professional.
What side effects may I notice from receiving this medicine?
Side effects that you should report to your doctor or health care professional as soon as possible:
•allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue
•dark urine
•difficulty breathing
•feeling faint or lightheaded
•fever or chills, sore throat
•increased sensitivity to the sun or ultraviolet light
•irregular heartbeat
•seizures
•sore mouth
•redness, blistering, peeling, or loosening of skin, including skin inside the mouth
•unusual bleeding or bruising
•unusually weak or tired
Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):
•diarrhea
•loss of appetite
•nausea, vomiting
•stomach upset
This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Where should I keep my medicine?
Keep out of the reach of children. This medicine is very dangerous in overdose.
Store at room temperature between 15 and 25 degrees C (59 and 77 degrees F). Protect from light and moisture. Keep container tightly closed. Throw away any unused medicine after the expiration date.
Last updated: 7/1/2002
Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.
Oxford A-Z of Medicinal Drugs:
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pyrimethamine
A drug that prevents the replication of the parasite that causes malaria. It is used in combination with sulfadoxine (a sulphonamide) for the treatment of malaria. Pyrimethamine may also be used in the treatment of toxoplasmosis, but it does not have a licence for this. It is available as tablets on prescription only.
Side effects:
include rashes and insomnia; because pyrimethamine interferes with folic acid metabolism (the antifolate effect) there is a risk of anaemia or other blood disorders. See also co-trimoxazole.
Precautions:
pyrimethamine should be used with caution in people with liver or kidney disease and in women who are breastfeeding. Pregnant women should take folate supplements. See also co-trimoxazole.
Interactions with other drugs:
Antibiotics co-trimoxazole and trimethoprim enhance the antifolate effect of pyrimethamine.
Methotrexate enhances the antifolate effect of pyrimethamine.
Phenytoin enhances the antifolate effect of pyrimethamine and its anticonvulsant effect is antagonized by pyrimethamine.
See also co-trimoxazole.
Proprietary preparation:
Daraprim.
| pyridoxine, pyridostigmine, pyrazinamide | |
| quetiapine, quinagolide, quinapril |
Saunders Veterinary Dictionary:
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pyrimethamine
A folic acid antagonist used in combination with sulfonamides in the treatment of toxoplasmosis and avian coccidiosis.
Mosby's Dental Dictionary:
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pyrimethamine
(pir′meth′ə-mēn)
n
n
A folic acid inhibitor that acts against Toxoplasma gondii and Plasmodium spp., which cause toxoplasmosis and malaria.
Wikipedia on Answers.com:
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Pyrimethamine
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|---|---|
| Systematic (IUPAC) name | |
| 5-(4-chlorophenyl)-6-ethyl- 2,4-pyrimidinediamine | |
| Clinical data | |
| Trade names | Daraprim |
| AHFS/Drugs.com | monograph |
| MedlinePlus | a601050 |
| Pregnancy cat. | B3 (AU) C (US) |
| Legal status | ℞ Prescription only |
| Routes | Oral |
| Pharmacokinetic data | |
| Bioavailability | well-absorbed |
| Protein binding | 87% |
| Metabolism | Hepatic |
| Half-life | 96 hours |
| Excretion | Renal |
| Identifiers | |
| CAS number | 58-14-0  |
| ATC code | P01BD01 |
| PubChem | CID 4993 |
| DrugBank | DB00205 |
| ChemSpider | 4819 |
| UNII | Z3614QOX8W |
| KEGG | D00488 |
| ChEBI | CHEBI:8673 |
| ChEMBL | CHEMBL36 |
| Chemical data | |
| Formula | C12H13ClN4 |
| Mol. mass | 248.71 g/mol |
| SMILES | eMolecules & PubChem |
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 (what is this?) (verify) |
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Pyrimethamine (Daraprim) is a medication used for protozoal infections. It is commonly used as an antimalarial drug (for both treatment and prevention of malaria), and is also used (combined with sulfadiazine) in the treatment of Toxoplasma gondii infections in immunocompromised patients, such as HIV-positive individuals. It is also currently being evaluated[1] in clinical trials as a treatment for ALS.
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Contents
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Mechanism of action
Pyrimethamine interferes with tetrahydrofolic acid synthesis from folic acid by inhibiting the enzyme dihydrofolate reductase (DHFR). Tetrahydrofolic acid is needed for DNA and RNA synthesis in many species, including protozoa. Pyrimethamine has also found to inhibit SOD1, a key protein involved in ALS
Mechanism of resistance
Resistance to pyrimethamine is widespread. Mutations in the malarial gene for dihydrofolate reductase may reduce the effectiveness of pyrimethamine.[2] These mutations decrease the binding affinity between pyrimethamine and dihydrofolate reductase via loss of hydrogen bonds and steric interactions.[3]
Clinical use
Pyrimethamine is typically given with a sulfonamide and folinic acid:
- sulfonamides inhibit dihydropteroate synthetase, an enzyme that participates in folic acid synthesis from para-aminobenzoic acid. Hence, sulfonamides work synergistically[citation needed] with pyrimethamine by blocking a different enzyme needed for folic acid synthesis.
- folinic acid (leucovorin) is a folic acid derivative that is converted to tetrahydrofolate (the primary active form of folic acid) in vivo without relying on dihydrofolate reductase. By doing so, folinic acid reduces side effects related to folate deficiency.
Use in mass drug administrations
Pyrimethamine has been extensively used as monotherapy in mass drug administrations in Asia and South America which is likely to have contributed to the emergence and spread of pyrimethamine resistant Plasmodium falciparum strains.
Side effects
Pyrimethamine may deplete folic acid in humans, resulting in hematologic side effects associated with folate deficiency.
Side effects include:
- hypersensitivity reactions
- megaloblastic anemia
- leukopenia
- thrombocytopenia
- pancytopenia
- atrophic glossitis
- hematuria
- cardiac arrhythmias
- pulmonary eosinophilia (rare)
- hyperphenylalaninemia (particularly when used with a sulfonamide)
- Stevens–Johnson syndrome (particularly when used with a sulfonamide)
- toxic epidermal necrolysis (particularly when used with a sulfonamide)
Contraindications
Pyrimethamine is contraindicated in patients with:
- hypersensitivity to pyrimethamine
- megaloblastic anemia – depletion of folic acid may aggravate this condition
Notes
- ^ "Pyrimethamine ALS trial". http://clinicaltrials.gov/ct2/show/NCT01083667.
- ^ Gatton M.L. et al. (2004). "Evolution of resistance to sulfadoxine-pyrimethamine in Plasmodium falciparum". Antimicrob Agents Chemother 48 (6): 2116–23. doi:10.1128/AAC.48.6.2116-2123.2004. PMC 415611. PMID 15155209. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=415611.
- ^ Sirichaiwat C. et al. (2004). "Target guided synthesis of 5-benzyl-2,4-diamonopyrimidines: their antimalarial activities and binding affinities to wild type and mutant dihydrofolate reductases from Plasmodium falciparum". J Med Chem 47 (2): 345–54. doi:10.1021/jm0303352. PMID 14711307.
References
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Copyrights:
American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
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Oxford A-Z of Medicinal Drugs
Market University Press. © 2000, 2003, 2010 An A-Z of Medicinal Drugs. All rights reserved.
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Saunders Veterinary Dictionary
Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.
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Mosby's Dental Dictionary
Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.
Read more
