The most commonly reported side effects of pyrimethamine include off label use, nausea, and vomiting, based on 1,554 FDA adverse event reports from 2004 to 2025. 4.3% of reports found the drug to be ineffective.
Percentages show how often each reaction appears relative to total reports for pyrimethamine.
These are voluntary reports and do not establish that pyrimethamine caused these reactions.
Report severity
Seriousness is determined by the reporter, not by OpenClaim.
Other drugs that appear in adverse event reports alongside pyrimethamine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.
Also suspected
Taken alongside
Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.
41.2% of pyrimethamine adverse event reports involve female patients and 52.4% involve male patients. The largest age group is adult at 76%. These figures reflect who reports side effects, not underlying risk.
Sex
Age group
Conditions and purposes for which patients were taking pyrimethamine when the adverse event was reported.
Showing 15 of 110 indications
Pyrimethamine is sold under the brand name Fansidar.
An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.
Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.