What the FDA labels say about taking them together
Azathioprine and febuxostat
Azathioprine's FDA label of November 8, 2025 names febuxostat in its drug interactions section, and febuxostat's label names azathioprine too. The febuxostat label: “CONTRAINDICATIONS ULORIC is contraindicated in patients being treated with azathioprine or mercaptopurine.”
Check it at the source: the azathioprine FDA label on DailyMed (effective November 8, 2025, Sebela Pharmaceuticals Inc.); the febuxostat FDA label on DailyMed (effective December 24, 2025, Takeda Pharmaceuticals America, Inc.).
What does the azathioprine label say about febuxostat?
Azathioprine label, drug interactionsDrug Interactions: Use with xanthine oxidase (XO) inhibitors: One of the pathways for inactivation of azathioprine is inhibited by XO inhibitors (allopurinol or febuxostat).
Source: FDA drug label (IMURAN), NDA016324 (Legacy), as published by Sebela Pharmaceuticals Inc., effective November 8, 2025 (SPL set 606101a0-6244-7eff-e053-2a91aa0acadd), via openFDA; the full label on DailyMed
What does the febuxostat label say about azathioprine?
Febuxostat label, contraindicationsCONTRAINDICATIONS ULORIC is contraindicated in patients being treated with azathioprine or mercaptopurine [see Drug Interactions (7) ].
Febuxostat label, drug interactionsDRUG INTERACTIONS Concomitant administration of ULORIC with XO substrate drugs, azathioprine or mercaptopurine could increase plasma concentrations of these drugs resulting in severe toxicity.
Source: FDA drug label (ULORIC), Takeda Pharmaceuticals America, Inc., effective December 24, 2025 (SPL set 54de10ef-fe5f-4930-b91d-6bbb04c664bd), 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
| Azathioprine | Febuxostat | |
|---|---|---|
| Labeled for | Organ transplant rejection, Rheumatoid arthritis | Gout |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.124 per tablet 50 mg tablet | $0.191 per tablet 40 mg tablet |
| Shortage now | No current entry | No current entry |
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