What the FDA labels say about taking them together
Azathioprine and mesalamine
Mesalamine's FDA label of August 27, 2026 names azathioprine in its drug interactions section; the azathioprine label PlainMeds reads does not name mesalamine. The mesalamine label: “Azathioprine or 6-Mercaptopurine: Increased risk of blood dyscrasias; monitor complete blood cell counts and platelet counts.”
Check it at the source: the azathioprine FDA label on DailyMed (effective November 8, 2025, Sebela Pharmaceuticals Inc.); the mesalamine FDA label on DailyMed (effective August 27, 2026, Salix Pharmaceuticals, Inc.).
What does the azathioprine label say about mesalamine?
Azathioprine's label (effective November 8, 2025) does not name mesalamine in these sections. A label lists what its studies and reports found; it is not a complete list.
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 mesalamine label say about azathioprine?
Mesalamine label, drug interactionsDRUG INTERACTIONS Nephrotoxic Agents including NSAIDs: Increased risk of nephrotoxicity; monitor for changes in renal function and mesalamine-related adverse reactions. ( 7.2 ) Azathioprine or 6-Mercaptopurine:
Rowasa label (Viatris Specialty LLC, August 3, 2026), drug interactionsAzathioprine or 6-Mercaptopurine: Increased risk of blood dyscrasias; monitor complete blood cell counts and platelet counts.
Source: FDA drug label (Lialda, NDA022000), Takeda Pharmaceuticals America, Inc., effective March 24, 2026 (SPL set 3098a080-be86-4265-9818-7fc4beab77b7), via openFDA
Source: FDA drug label (Pentasa, NDA020049), Takeda Pharmaceuticals America, Inc., effective January 15, 2025 (SPL set e39d9a3d-5d3a-4bb6-aab1-fdbb2a598606), via openFDA
Source: FDA drug label (Rowasa, NDA019618), Viatris Specialty LLC, effective August 3, 2026 (SPL set e505ab99-1943-4216-a178-4d5dbe64e3b2), via openFDA
Source: FDA drug label (APRISO), Salix Pharmaceuticals, Inc., effective August 27, 2026 (SPL set 7951139c-b271-45a4-b523-34b23800917b), 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 | Mesalamine | |
|---|---|---|
| Labeled for | Organ transplant rejection, Rheumatoid arthritis | Crohn's disease and ulcerative colitis |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.124 per tablet 50 mg tablet | $0.781 per tablet 1.2 g tablet |
| Shortage now | No current entry | 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