Folic acid (folate) and Sulfamethoxazole and trimethoprim interaction
Folic acid (folate) and Sulfamethoxazole and trimethoprim: the Sulfamethoxazole and trimethoprim prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Sulfamethoxazole and trimethoprim (SULFATRIM) label · effective 2026-01-05
CONTRAINDICATIONS Sulfamethoxazole and trimethoprim is contraindicated in patients with a known hypersensitivity to trimethoprim or sulfonamides, in patients with a history of drug-induced immune thrombocytopenia with use of trimethoprim and/or sulfonamides, and in patients with documented megaloblastic anemia due to folate deficiency.
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