Pyrimethamine, sold under the brand name Daraprim among others, is a medication used with leucovorin to treat the parasite diseases toxoplasmosis and cystoisosporiasis. It is also used with dapsone as a second-line option to prevent Pneumocystis jiroveci pneumonia in people with HIV/AIDS. It was previously used for malaria but is no longer recommended due to resistance.
Pyrimethamine is typically given with a sulfonamide and folinic acid.
It is used for the treatment of toxoplasmosis, actinomycosis, and isosporiasis, and for the treatment and prevention of Pneumocystis jirovecii pneumonia.