Abatacept and Ustekinumab: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 16, 2026 · Source data updated Jul 16, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Abatacept
Ustekinumab
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Both of these medicines calm down your immune system. Abatacept (Orencia) and ustekinumab are both biologic drugs used for conditions like arthritis or psoriasis. Each one lowers a different part of your body's defense against germs.
When you take two of these together, your immune system can be turned down too much. That can make it easier to catch infections, and some of those infections can be serious. Studies of abatacept with similar biologic drugs also showed the combo didn't work any better than one drug alone. Because of this, using them together usually isn't recommended. Please don't stop or change anything on your own, but do talk with your doctor or pharmacist so they can pick the safest plan for you.
Effect: Additive immunosuppression increasing risk of serious infection, with no added therapeutic benefit.
- Mechanism: Unknown/additive; both are biologic immunomodulators (abatacept is a T-cell costimulation modulator, ustekinumab an IL-12/23 inhibitor). Neither is a prodrug; this is a pharmacodynamic, not PK, interaction.
- Direction/magnitude: Increased infection risk; magnitude undefined. Extrapolated from abatacept plus TNF antagonist trial data.
- Evidence: Theoretical for this specific pair; safety/efficacy of abatacept with RA/PsA biologics not established.
- Management: Concurrent use not recommended. If transitioning from one biologic to abatacept, monitor for signs of infection.
What happens
An increased risk of infection
Interaction Deep Dive
In controlled clinical trials, combining abatacept with tumor necrosis factor (TNF) antagonists was shown to raise the likelihood of serious infection while offering no incremental benefit. Data are inadequate to assess how safe and effective abatacept is when given together with anakinra or with biologic agents used for rheumatoid arthritis or psoriatic arthritis. For this reason, using these drugs at the same time is not advised. Patients being switched from TNF antagonist therapy over to abatacept should be watched for indications of infection1.
Why it happens (mechanism)
Unknown
How to manage this interaction
The main point: combining these two biologics is generally not recommended. Your care team may choose to use one biologic rather than both at the same time.
- Keep taking your medicines as prescribed, and do not stop or start anything on your own.
- Ask your prescriber whether you should be on both drugs together or switch to a single agent.
- If you are switching from one biologic to abatacept, your team will likely watch you closely for signs of infection.
- Report fever, chills, cough, sore throat, or any new signs of infection to your doctor promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Taking abatacept together with etanercept produced no added benefit but raised the likelihood of serious infection relative to etanercept used by itself. In a 1-year randomized trial (N=121) followed by an open-label long-term extension (LTE; n=80), rheumatoid arthritis patients who were already receiving etanercept 25 mg twice/week continued that etanercept and were randomized to either abatacept 2 mg/kg IV on days 1, 15, and 30, and then every 4 weeks (n=85) or placebo (n=36). After finishing the double-blind portion, patients could enter the LTE phase, at which point the abatacept dose was raised to roughly 10 mg/kg. At 6 months, the 2 mg/kg abatacept group demonstrated no meaningful improvement versus placebo in modified American College of Rheumatology 20% (ACR20; 48.2% vs 30.6%) or ACR50 (25.9% vs 19.4%) response rates, although a significant difference was seen in modified ACR70 rates (10.6% vs 0%). At 1 year, no significant differences in ACR20, 50, or 70 response rates existed between the two groups. Serious adverse events occurred more often in the 2 mg/kg abatacept group (16.5%) at one year and in the 10 mg/kg abatacept group after 2 years of LTE (32.5%) than in the placebo group (2.8%). Serious infections at 1 year were noted in 3.5% of the 2 mg/kg abatacept group and 0% of the placebo group 2.
b) In controlled clinical trials involving adults with active rheumatoid arthritis who received abatacept together with a tumor necrosis factor (TNF) antagonist (n=204) versus TNF antagonist therapy alone (n=134), the rate of infection (63% vs 43%, respectively) and of serious infection (4.4% vs 0.8%, respectively) was higher with the combined regimen; furthermore, the combined regimen offered no additional benefit 1.
Common questions
Can I take Abatacept and Ustekinumab together?
Using abatacept and ustekinumab together can raise your risk of serious infection without added benefit, so this combination is generally not recommended. Talk with your doctor or pharmacist about the safest single-drug plan. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abatacept and Ustekinumab interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abatacept and Ustekinumab interaction managed?
The main point: combining these two biologics is generally not recommended. Your care team may choose to use one biologic rather than both at the same time. Keep taking your medicines as prescribed, and do not stop or start anything on your own. Ask your prescriber whether you should be on both drugs together or switch to a single agent. If you are switching from one biologic to abatacept, your te… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Abatacept or Ustekinumab need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: ORENCIA(R) intravenous, subcutaneous injection, abatacept intravenous, subcutaneous injection. Bristol-Myers Squibb Company (per FDA), Princeton, NJ, 2020. DailyMed
- Weinblatt M, Schiff M, Goldman A, et al: Selective costimulation modulation using abatacept in patients with active rheumatoid arthritis while receiving etanercept: a randomised clinical trial. Ann Rheum Dis 2007; 66(2):228-234. PubMed
Keep reading about Abatacept
Keep reading about Ustekinumab
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