Allopurinol and Bendamustine interaction
Allopurinol and Bendamustine: 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 Bendamustine (BENDAMUSTINE HYDROCHLORIDE) label · effective 2026-05-14
However, there may be an increased risk of severe skin toxicity when bendamustine hydrochloride and allopurinol are administered concomitantly. [see Warnings and Precautions (5.6) ] 5.6 Skin Reactions Fatal and serious skin reactions have been reported with bendamustine hydrochloride injection treatment in clinical trials and postmarketing safety reports, including…
Allopurinol has also been used during the beginning of bendamustine hydrochloride therapy.
Events occurred when bendamustine hydrochloride was given as a single agent and in combination with other anticancer agents or allopurinol.
From the Allopurinol label · effective 2026-05-21
Concomitant use of the following drugs may also increase the risk of skin rash, which may be severe: bendamustine, ampicillin and amoxicillin [ see Drug Interactions (7.1) ].
The following drugs may increase the risk of serious skin reactions: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
Drugs Known to Affect the Occurrence of Skin Rash and Hypersensitivity Concomitant use of the following drugs may increase the risk of skin rash, which may be severe: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
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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.