What the FDA labels say about taking them together
Azathioprine and tofacitinib
Tofacitinib's FDA label of July 13, 2026 names azathioprine in its drug interactions section; the azathioprine label PlainMeds reads does not name tofacitinib. The tofacitinib label: “Clinically Significant Interactions Affecting XELJANZ/XELJANZ XR When Concomitantly Used with Other Drugs Strong CYP3A4 Inhibitors (e.g., ketoconazole) Clinical Impact Increased exposure to tofacitinib Intervention …”
Check it at the source: the azathioprine FDA label on DailyMed (effective November 8, 2025, Sebela Pharmaceuticals Inc.); the tofacitinib FDA label on DailyMed (effective July 13, 2026, U.S. Pharmaceuticals).
What does the azathioprine label say about tofacitinib?
Azathioprine's label (effective November 8, 2025) does not name tofacitinib 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 tofacitinib label say about azathioprine?
Tofacitinib label, drug interactions… Decreased exposure to tofacitinib and may result in loss of or reduced clinical response Intervention Concomitant use with XELJANZ/XELJANZ XR is not recommended [see Clinical Pharmacology, Figure 3 (12.3) ] Immunosuppressive Drugs (e.g., azathioprine, tacrolimus, cyclosporine) Clinical Impact Risk of added immunosuppression; concomitant use of XELJANZ/XELJANZ XR with biologic DMARDs or potent immunosuppressants has not been studied in patients with RA, PsA, AS, UC, or pcJIA. Intervention Concomitant use with XELJANZ/XELJANZ XR is not recommended [see Indications and Usage (1), Clinical Pharmacology, Figure 3 (12.3) ] See FPI for clinically significant drug interactions.
Source: FDA drug label (XELJANZ), NDA203214 (Pf Prism Cv), as published by U.S. Pharmaceuticals, effective July 13, 2026 (SPL set 68e3d6b2-7838-4d2d-a417-09d919b43e13), 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 | Tofacitinib | |
|---|---|---|
| Labeled for | Organ transplant rejection, Rheumatoid arthritis | Rheumatoid arthritis, Crohn's disease and ulcerative colitis |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.124 per tablet 50 mg tablet | $0.573 per tablet 5 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