Sulfadoxine (also spelled sulphadoxine) is an ultra-long-lasting sulfonamide used in combination with pyrimethamine to treat malaria.

[1] It is also used to prevent malaria[2] but due to high levels of sulphadoxine-pyrimethamine resistance, this use has become less common.

[3] It is also used, usually in combination with other drugs, to treat or prevent various infections in livestock.

[citation needed] Sulfadoxine competitively inhibits dihydropteroate synthase, interfering with folate synthesis.

This systemic antibiotic-related article is a stub.