Penicillins/Food Interaction Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug, changing your diet or commencing any course of treatment.

Medical warning:

Very important. A change in your diet, medicine, or dosage may be necessary. Promptly consult your doctor or pharmacist.

How the interaction occurs:

When food is taken with this medicine, it increases the amount of time that this medicine is exposed to stomach acid. Stomach acid inactivates certain penicillins.

What might happen:

Food may cause a decrease in the level of this medicine in your blood. This may decrease the effectiveness of this medicine.

What you should do about this interaction:

This medicine should be taken on an empty stomach (one hour before or two hours after food). Contact your healthcare professional (e.g., doctor or pharmacist) for more information regarding your particular penicillin-type antibiotic.Your healthcare professionals may be aware of this interaction and may be monitoring you for it. Do not start, stop, or change your medicine or diet before checking with them first.

  • 1.Finkel Y, Bolme P, Eriksson M. The effect of food on the oral absorption of penicillin V preparations in children. Acta Pharmacol Toxicol (Copenh) 1981 Oct;49(4):301-4.
  • 2.Eshelman FN, Spyker DA. Pharmacokinetics of amoxicillin and ampicillin: crossover study of the effect of food. Antimicrob Agents Chemother 1978 Oct;14(4):539-43.
  • 3.Neu HC. Antimicrobial activity and human pharmacology of amoxicillin. J Infect Dis 1974 Jun;129(0):suppl:S123-31.
  • 4.Welling PG, Huang H, Koch PA, Craig WA, Madsen PO. Bioavailability of ampicillin and amoxicillin in fasted and nonfasted subjects. J Pharm Sci 1977 Apr;66(4):549-52.
  • 5.KLEIN JO, SABATH LD, FINLAND M. Laboratory studies on oxacillin. I. In vitro activity against staphylococci and some other bacterial pathogens. II. Absorption and urinary excretion in normal young men. Am J Med Sci 1963 Apr;245:399-412.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.