The types of adverse events associated with pyrimethamine-based treatment of toxoplasmosis differed across the three clinical manifestations of the disease: ocular toxoplasmosis, toxoplasmic encephalitis, and congenital toxoplasmosis.

The differences in adverse event profiles among the three manifestations and between studies within each manifestation are likely due to differences in patient populations, dosing regimens, study protocols, and pharmacokinetics of pyrimethamine.

Hematologic adverse events were observed across all manifestations, highlighting the importance of monitoring blood in patients receiving pyrimethamine plus other drugs to treat toxoplasmosis.