Amoxicillin and Ceftriaxone interaction
Amoxicillin and Ceftriaxone: 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 Amoxicillin label · effective 2026-07-07
AMOXIL is contraindicated in patients who have experienced a serious hypersensitivity reaction (e.g., anaphylaxis or Stevens-Johnson syndrome) to AMOXIL or to other β-lactam antibacterial drugs (e.g., penicillins and cephalosporins).
History of a serious hypersensitivity reaction (e.g., anaphylaxis or Stevens-Johnson syndrome) to Amoxicillin or to other beta-lactams (e.g., penicillins or cephalosporins).
There have been reports of individuals with a history of penicillin hypersensitivity who have experienced severe reactions when treated with cephalosporins.
Before initiating therapy with amoxicillin, careful inquiry should be made regarding previous hypersensitivity reactions to penicillins, cephalosporins, or other allergens.
From the Ceftriaxone (CEFTRIAXONE AND DEXTROSE) label · effective 2022-01-13
Anaphylaxis to ceftriaxone or other cephalosporin class antibacterials, penicillins, or other beta-lactam antibacterials ( 4.1 )
Anaphylaxis to Ceftriaxone or the Cephalosporin Class of Antibacterials, Penicillins, or Other Beta-lactam Antibacterials Ceftriaxone for Injection and Dextrose Injection is contraindicated in patients who have a history of anaphylaxis to ceftriaxone or the cephalosporin class of antibacterials, penicillins, or other beta-lactam antibacterials [see Warnings and…
Hypersensitivity Reactions to Ceftriaxone, Cephalosporins, Penicillins, or Other Drugs Serious, occasionally fatal, hypersensitivity (anaphylactic) reactions have been reported with ceftriaxone.
Exercise caution if this product is to be given to penicillin-sensitive patients because cross-hypersensitivity among beta-lactam antibacterials has been clearly documented and may occur in up to 10% of patients with a history of penicillin allergy.
Cross-hypersensitivity may occur in up to 10% of patients with a history of penicillin allergy.
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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.