Yesintek (ustekinumab or ustekinumab-kfce) is a prescription injection and a biosimilar to Stelara (ustekinumab). It's used to treat long-term autoimmune conditions like plaque psoriasis, psoriatic arthritis, Crohn's disease, and ulcerative colitis. Like Stelara (ustekinumab), it lowers inflammation by blocking proteins in the body called interleukins. It’s usually given as a shot under the skin, with maintenance doses every 8 to 12 weeks. Common side effects include tiredness, headache, or getting cold-like symptoms.
Yesintek (ustekinumab) is an interleukin antagonist. It works by blocking two proteins in your immune system — interleukin-12 (IL-12) and interleukin-23 (IL-23) — that play a major role in inflammation. By targeting these proteins, the medication helps to lower inflammation and relieve symptoms from autoimmune conditions.
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Plaque psoriasis
Psoriatic arthritis
Crohn's disease
Ulcerative colitis:
Contact your healthcare provider immediately if you experience any of the following.
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
How to inject Yesintek (ustekinumab) from a prefilled syringe:
Yes. Yesintek (ustekinumab) is available in the United States as of February 2025. It was approved by the FDA in December 2024.
No. Yesintek (ustekinumab) and Stelara (ustekinumab) aren't exactly the same, but they're very similar. Yesintek (ustekinumab) is a biosimilar to Stelara (ustekinumab), which means it works the same way and treats the same conditions. Both have the same active ingredient and do the same job in your body. Even if they look a little different, they're both expected to be just as safe and work just as well. If you have questions comparing the two, talk to your prescriber.
Yes. Yesintek (ustekinumab) is interchangeable with Stelara (ustekinumab). That means that pharmacies can give you Yesintek (ustekinumab) instead of Stelara (ustekinumab) without a new prescription. This makes it more convenient for you if you decide to switch between the two.
You can keep taking Yesintek (ustekinumab) as long as it's working well for you and you're not having any serious problems. Your prescriber will regularly check in with you to make sure the medication is still helping and safe to continue.
Yes, you should keep Yesintek (ustekinumab) in the refrigerator in its original box to protect it from light. If you take a prefilled syringe out of the fridge, you can keep it at room temperature (up to 86°F or 30°C) for up to 30 days, but once it warms up, you can’t put it back in . Throw it away after 30 days at room temperature or if the syringe shows changes in color or particles.
Yesintek (ustekinumab) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Yesintek (ustekinumab) can raise your risk of infections, including serious ones that might need hospital care. These can be caused by bacteria, viruses, or fungi. Tell your prescriber about your medical history before starting Yesintek (ustekinumab), especially if you've ever had tuberculosis (TB). Let your care team know right away if you have signs of infection, such as fever, chills, cough, or tiredness — your treatment might need to be paused until you recover.
Yesintek (ustekinumab) weakens your immune system and can raise your risk of certain cancers. Some people developed skin cancer while taking this medication, especially those with a higher risk. Your care team will check your skin regularly during treatment, particularly if you have a history of cancer or other risk factors. Let your prescriber know if you’ve had cancer before or if you notice any new or changing spots on your skin.
Serious allergic reactions, including anaphylaxis and angioedema, have been reported with Yesintek (ustekinumab). If you have a severe reaction, your care team will stop the medication and treat you right away. Get medical help immediately if you have symptoms like trouble breathing, swelling of your face or throat, or a serious rash.
Rare cases of a brain condition called posterior reversible encephalopathy syndrome (PRES) have been reported in people taking Yesintek (ustekinumab). Symptoms can include headache, seizures, confusion, or vision changes. These symptoms can appear anywhere from a few days to months after starting the medication, sometimes even after a year or more. If you have PRES, your care team will stop the medication and provide treatment. Let your prescriber know right away if you notice any of these signs.
Before starting Yesintek (ustekinumab), you or your child should be up to date on all recommended vaccines. While you're being treated, avoid getting live vaccines. You should also avoid the BCG vaccine during treatment, as well as for one year before starting and one year after stopping the medication. Be careful if someone in your household gets a live vaccine since it can spread and pose a risk to you. Non-live vaccines are generally safe, but they might not work as well while you're taking Yesintek (ustekinumab). Check with your care team before getting any vaccines during treatment.
Different types of pneumonia have been reported in people taking Yesintek (ustekinumab), and in some cases, these conditions were serious. Symptoms can include cough and trouble breathing. Let your care team know right away if you have new or worsening breathing problems. You might have to stop taking the medication and receive the appropriate treatment.
Plaque psoriasis
Psoriatic arthritis
Crohn's disease and ulcerative colitis: