Pyrimethamine
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From MedlinePlus, U.S. National Library of Medicine
Dihydrofolate Reductase Inhibitor Antimalarial
Dosing in kidney impairment
This label has no separate kidney-impairment dosing section. Check warnings and clinical pharmacology in the full label.
Drug interactions
Check pyrimethamine against a medication listLabel text (2 paragraphs)
Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. If signs of folate deficiency develop, pyrimethamine should be discontinued. Folinic acid (leucovorin) should be administered until normal hematopoiesis is restored (see WARNINGS ).
Mild hepatotoxicity has been reported in some patients when lorazepam and pyrimethamine were administered concomitantly.
Contraindications
Use of DARAPRIM is contraindicated in patients with known hypersensitivity to pyrimethamine or to any component of the formulation. Use of the drug is also contraindicated in patients with documented megaloblastic anemia due to folate deficiency.
Safety data
Reported adverse events (FAERS)
Liver injury (LiverTox)
LiverTox has no chapter for pyrimethamine. Check the label's hepatic warnings.
Pregnancy and lactation
Pregnancy
Pregnancy: Teratogenic Effects: Pregnancy Category C. Pyrimethamine has been shown to be teratogenic in rats when given in oral doses 2.5 times the human dose for treatment of toxoplasmosis. At these doses in rats, there was a significant increase in abnormalities such as cleft palate, brachygnathia, oligodactyly, and microphthalmia. Pyrimethamine has also been shown to produce terata such as meningocele in hamsters and cleft palate in miniature pigs when given in oral doses 5 times the human dose for the treatment of toxoplasmosis. There are no adequate and well-controlled studies in pregnant women.
DARAPRIM should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Concurrent administration of folinic acid is strongly recommended when used during pregnancy.
Lactation
Nursing Mothers: Pyrimethamine is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from pyrimethamine and from concurrent use of a sulfonamide with DARAPRIM for treatment of some patients with toxoplasmosis, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother (see WARNINGS and PRECAUTIONS: Pregnancy ).
Breastfeeding (LactMed)
No adverse reactions in breastfed infants have been reported during maternal pyrimethamine use. It is acceptable to use in nursing mothers. In HIV-infected women, elevated viral HIV loads in milk were decreased after treatment with chloroquine to a greater extent than other women who were treated with the combination of sulfadoxine and pyrimethamine. It has been suggested that maternal pyrimethamine clearance might be increased during lactation, but data are insufficient to make a definitive conclusion.
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
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