Acetaminophen and codeine and Diflunisal interaction
Acetaminophen and codeine and Diflunisal: the Diflunisal prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Diflunisal label · effective 2026-08-04
Acetaminophen In normal volunteers, concomitant administration of diflunisal and acetaminophen resulted in an approximate 50% increase in plasma levels of acetaminophen.
Since acetaminophen in high doses has been associated with hepatotoxicity, concomitant administration of diflunisal tablets and acetaminophen should be used cautiously, with careful monitoring of patients.
Concomitant administration of diflunisal and acetaminophen in dogs, but not in rats, at approximately 2 times the recommended maximum human therapeutic dose of each (40 to 52 mg/kg/day of diflunisal/acetaminophen), resulted in greater gastrointestinal toxicity than when either drug was administered alone.
Acetaminophen had no effect on plasma levels of diflunisal.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.