Cephalexin and Probenecid interaction
Cephalexin and Probenecid: both prescribing labels 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 Cephalexin label · effective 2026-03-25
Co-administration of probenecid with cephalexin for oral suspension is not recommended.
Co-administration of probenecid with cephalexin is not recommended.
• Probenecid-The renal excretion of cephalexin for oral suspension is inhibited by probenecid.
Probenecid The renal excretion of cephalexin is inhibited by probenecid.
From the Probenecid label · effective 2026-04-29
Drug Interactions When probenecid is used to elevate plasma concentrations of penicillin or other beta-lactams, or when such drugs are given to patients taking probenecid therapeutically, high plasma concentrations of the other drug may increase the incidence of adverse reactions associated with that drug.
In the case of penicillin or other beta-lactams, psychic disturbances have been reported.
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.