Does Allopurinol Interact With Amoxicillin?
7 DRUG INTERACTIONS The following drugs may increase the risk of serious skin reactions: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
Severity: Moderate
Severity basis: drug interactions section (keywords: may increase). Combining Allopurinol (Xanthine oxidase inhibitor) and Amoxicillin (Penicillin antibiotic) is classified as a moderate interaction.
What to Do
Use this combination with caution. Your prescriber may monitor you more closely or adjust doses.
How This Interaction Works
Interactions like this one can happen when two medicines have overlapping effects, or when one changes how the other is absorbed, broken down, or cleared from the body. Allopurinol is a xanthine oxidase inhibitor and Amoxicillin is a penicillin antibiotic; together they are documented as a moderate interaction. How much this matters depends on your dose, your other medications, and your overall health.
If You Take Both Medications
If you have been prescribed both Allopurinol and Amoxicillin, do not start, stop, or change either medication on your own — some medicines are unsafe to stop suddenly. Tell your prescriber and pharmacist that you take both so they can decide whether the combination is right for you, adjust the dose, monitor you more closely, or suggest an alternative.
From the FDA Label
7 DRUG INTERACTIONS The following drugs may increase the risk of serious skin reactions: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
Source: FDA structured product labeling (set_id 005048dd-844f-468c-bf56-1a09727e3477).
Check these against your full medication list in our free Interaction Checker
Frequently Asked Questions
Can you take Allopurinol and Amoxicillin together?
Allopurinol and Amoxicillin have a documented moderate interaction. Use this combination with caution. Your prescriber may monitor you more closely or adjust doses.
How serious is the Allopurinol and Amoxicillin interaction?
It is classified as a moderate interaction, based on the FDA label's drug interactions section (keywords: may increase). A moderate interaction can be clinically meaningful and usually calls for monitoring or a dose adjustment.
What should I do if I'm taking both Allopurinol and Amoxicillin?
If you have been prescribed both Allopurinol and Amoxicillin, do not start, stop, or change either medication on your own — some medicines are unsafe to stop suddenly. Tell your prescriber and pharmacist that you take both so they can decide whether the combination is right for you, adjust the dose, monitor you more closely, or suggest an alternative.
This information is educational — not medical advice.
This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.