What the FDA labels say about taking them together
Allopurinol and bendamustine
Allopurinol's FDA label of May 21, 2026 names bendamustine in its drug interactions section, and bendamustine's label names allopurinol too. The bendamustine label: “However, there may be an increased risk of severe skin toxicity when bendamustine hydrochloride and allopurinol are administered concomitantly.”
Check it at the source: the allopurinol FDA label on DailyMed (effective May 21, 2026, Rising Pharma Holdings, Inc.); the bendamustine FDA label on DailyMed (effective May 11, 2026, Meitheal Pharmaceuticals Inc.).
What does the allopurinol label say about bendamustine?
Allopurinol label, drug interactionsDRUG INTERACTIONS The following drugs may increase the risk of serious skin reactions: bendamustine, thiazide diuretics, ampicillin and amoxicillin.
Allopurinol label, warnings and precautionsConcomitant 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) ].
Aloprim label (Mylan Institutional LLC, February 18, 2022), drug interactionsKnown 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.
Source: FDA drug label (Aloprim, NDA020298), Mylan Institutional LLC, effective February 18, 2022 (SPL set 10cc918f-aa44-415b-932d-2404695ac449), via openFDA
Source: FDA drug label (Allopurinol), Rising Pharma Holdings, Inc., effective May 21, 2026 (SPL set 30ad5ba2-1cef-4933-b104-0597f6a2aaa2), via openFDA; the full label on DailyMed
What does the bendamustine label say about allopurinol?
Bendamustine label, warnings and precautionsHowever, there may be an increased risk of severe skin toxicity when bendamustine hydrochloride and allopurinol are administered concomitantly [see Warnings and Precautions ( 5.6 )].
Source: FDA drug label (Bendamustine), Meitheal Pharmaceuticals Inc., effective May 11, 2026 (SPL set 40f6f58d-d9ac-4f65-9fc7-16984bf1f180), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Allopurinol | Bendamustine | |
|---|---|---|
| Labeled for | Gout | Leukemia, lymphoma and myeloma |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0315 per tablet 100 mg tablet | n/a |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once