Abatacept Injection: What It Treats, Dosing, Side Effects
Last updated September 6, 2026.
**Abatacept is a prescription biologic drug, given by injection under the skin or by infusion into a vein, that belongs to a class called selective T-cell costimulation modulators.** It is a fusion protein that binds to signaling molecules on antigen-presenting cells, which blocks one of the two signals T cells need to switch on. With fewer activated T cells, the joint inflammation that drives swelling, pain, and cartilage damage settles down over weeks to months. The most important safety point is infection risk: you need a tuberculosis test before your first dose, and you should not take abatacept together with a TNF blocker such as etanercept or adalimumab, because the combination raises the chance of serious infection without adding benefit.
What does it treat?
Abatacept is approved for moderately to severely active rheumatoid arthritis in adults, where the pattern is symmetric swelling and morning stiffness lasting more than an hour in the small joints of the hands, wrists, and feet. It is also approved for active psoriatic arthritis in adults, and for moderately to severely active polyarticular juvenile idiopathic arthritis in children age 2 and older. A separate approved use is prevention of acute graft versus host disease, given with a calcineurin inhibitor and methotrexate, in adults and children age 2 and older receiving a stem cell transplant from an unrelated donor. In rheumatoid arthritis it is often used along with methotrexate, though it can be used on its own; it is not combined with other biologic DMARDs or with JAK inhibitors such as tofacitinib. Abatacept is sold as Orencia and Orencia ClickJect, and there is no combination pill or fixed-dose combination product.
How do you take it?
Abatacept comes as a 125 mg single-dose prefilled syringe and autoinjector for subcutaneous injection, and as a vial of powder for intravenous infusion given by a nurse. For adult rheumatoid arthritis or psoriatic arthritis, the usual subcutaneous dose is 125 mg once weekly, with or without a single weight-based IV loading infusion first. The intravenous regimen for adults is weight-based: 500 mg for under 60 kg, 750 mg for 60 to 100 kg, and 1000 mg for over 100 kg, given at week 0, week 2, week 4, and every 4 weeks after that, so 1000 mg per infusion is the ceiling for adults. For polyarticular juvenile idiopathic arthritis, weekly subcutaneous dosing is 50 mg for 10 to under 25 kg, 87.5 mg for 25 to under 50 kg, and 125 mg for 50 kg and above. Food and drink do not affect it. Store syringes in the refrigerator at 36 to 46 degrees F, let one sit at room temperature about 30 minutes before injecting, do not shake it, and rotate sites on the thigh or abdomen at least one inch from the last spot. If you miss a weekly dose, inject it as soon as you remember and then go back to your regular weekly day; if it is nearly time for the next dose, skip the missed one and do not double up. Hold your dose and call your clinician if you develop a fever, a cough that will not clear, burning with urination, or any infection that needs antibiotics.
Side effects to know
- Common: The most common effects are headache, upper respiratory infections such as colds and sinus infections, sore throat, nausea, and mild redness or itching where you inject.
- Serious: Stop injecting and get medical help for signs of serious infection such as fever with chills, a productive cough, night sweats, unexplained weight loss, a warm spreading skin sore, or burning with urination, since abatacept can allow tuberculosis, hepatitis B, or fungal infections to reactivate. Get emergency care for an allergic reaction with hives, swelling of the lips, tongue, or throat, wheezing, or lightheadedness, and call your clinician promptly if you have COPD and your breathing, cough, or sputum gets worse.
Who should not take it?
Do not start abatacept if you have an active serious infection, and do not use it with TNF blockers such as etanercept, adalimumab, or infliximab, with other biologic DMARDs such as tocilizumab or rituximab, or with JAK inhibitors such as tofacitinib or upadacitinib. Everyone needs screening for latent tuberculosis before the first dose, and treatment for latent TB has to be started first if the test is positive. Tell your clinician if you have ever had hepatitis B or C, recurrent infections, diabetes, or COPD, and if you live somewhere fungal infections such as histoplasmosis or coccidioidomycosis are common. Live vaccines, including the nasal spray flu vaccine, MMR, and the live shingles vaccine, should not be given while you are on abatacept or for 3 months after your last dose; inactivated vaccines such as the flu shot and Shingrix are fine but may work less well. Blood glucose meters that use glucose dehydrogenase pyrroloquinoline quinone strips can read falsely high on infusion days because of maltose in the IV formulation, so use a different meter type if you have diabetes. In pregnancy, there are no adequate human data, abatacept crosses the placenta in the third trimester and may affect the infant immune response and vaccine timing, so the decision is made case by case and a pregnancy exposure registry is available. There are no data on abatacept in human milk, so discuss breastfeeding with your clinician. Abatacept itself has no alcohol interaction, but if you also take methotrexate, keep alcohol low or skip it because of liver strain.
When is it an emergency?
Call 911 if you have trouble breathing, throat or tongue swelling, widespread hives with dizziness, chest pain, or you collapse, since these can mean anaphylaxis or a severe infusion reaction. Go to an emergency department the same day for a fever above 100.4 F with shaking chills, confusion, a fast heart rate with low blood pressure, a rapidly spreading red painful patch of skin, or coughing up blood, because sepsis and reactivated tuberculosis are the drug-specific red flags. If someone injects too much abatacept or a child gets hold of a syringe, call Poison Control at 1-800-222-1222 for guidance; doses far above the usual amount have been given in studies without a specific toxic pattern, but you still want a clinician tracking for infection signs afterward.
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Common questions
What is the maximum dose of abatacept I can take?
For adults with rheumatoid arthritis or psoriatic arthritis, the subcutaneous dose is 125 mg once weekly, and there is no benefit to injecting more often. If you get the intravenous form, the ceiling is 1000 mg per infusion, which applies to adults over 100 kg, and infusions are spaced every 4 weeks after the first month. Children on the weekly injection are dosed by weight, from 50 mg up to 125 mg. Taking extra doses raises infection risk without improving joint control, so stick to the schedule your clinician set.
Can I drink alcohol while taking abatacept?
Abatacept itself does not interact with alcohol, and moderate drinking does not change how the injection works. The real issue is what else you take with it. Most people on abatacept for rheumatoid arthritis also take methotrexate, which is hard on the liver, and combining it with regular drinking raises the chance of liver injury. If you are on methotrexate, keep alcohol to a minimum or skip it, and get the liver blood tests your clinician orders.
Is abatacept safe during pregnancy or breastfeeding?
There are no adequate studies in pregnant people, so abatacept is not automatically continued or stopped. It is an antibody-based protein that crosses the placenta in the second and third trimesters, which can affect a newborn immune system, so babies exposed late in pregnancy may need their live vaccines delayed. Tell your obstetrician and rheumatologist if you are pregnant or planning to be, and ask about enrolling in the pregnancy exposure registry. There is no information on abatacept in human milk or on the nursing infant, so the decision to breastfeed is made together with your clinician based on how much you need the drug.
Do I need to take abatacept with food?
No. Abatacept is an injection under the skin or an infusion into a vein, so it never passes through your stomach and food has no effect on it. You can inject before or after a meal, at any time of day. What matters more is consistency: pick one day each week and keep it. Let the prefilled syringe sit out of the refrigerator for about 30 minutes first, because a cold injection stings more.
What are the signs I took too much or that something is wrong?
Abatacept overdose does not cause a classic poisoning picture, and doses well above the usual amount have been given in studies without a specific toxic pattern. The bigger concern after an extra dose is infection, so watch for fever, chills, night sweats, a cough that will not clear, or burning with urination over the following weeks. Call Poison Control at 1-800-222-1222 for advice after any accidental extra dose or a child getting hold of a syringe. Call 911 for throat swelling, wheezing, hives with dizziness, or collapse, which point to an allergic reaction rather than overdose.
What medicines and vaccines interact with abatacept?
Do not combine abatacept with TNF blockers such as etanercept, adalimumab, certolizumab, golimumab, or infliximab, because the combination raised serious infection rates without better results. The same caution applies to other biologics such as tocilizumab, rituximab, and anakinra, and to JAK inhibitors such as tofacitinib and upadacitinib. Live vaccines including MMR, the nasal spray flu vaccine, and the live shingles vaccine should be avoided while on abatacept and for 3 months after the last dose, so plan them before you start. Inactivated vaccines such as the flu shot, Shingrix, and pneumococcal vaccine are safe, though your response may be weaker. If you use a blood glucose meter, note that maltose in the intravenous formulation can make certain test strips read falsely high on infusion day.