Selarsdi (ustekinumab or ustekinumab-aekn) is a biologic medication that's a biosimilar to Stelara (ustekinumab). It's used to treat autoimmune conditions like plaque psoriasis, psoriatic arthritis, Crohn's disease, and ulcerative colitis. The medication works by blocking certain proteins called interleukins that cause inflammation in your body. It’s most often given as an injection under the skin. Common side effects include common cold symptoms, headache, and feeling tired.
Selarsdi (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 Selarsdi (ustekinumab) from a prefilled syringe:
Selarsdi (ustekinumab) became available in the United States starting February 2025, after it was approved by the FDA in April 2024.
Not exactly, but they are very similar. Selarsdi (ustekinumab) is a biosimilar to Stelara (ustekinumab), which means it’s made to work the same way, with no meaningful differences in safety, strength, or how well it works. Both medications contain the active ingredient ustekinumab and treat the same conditions. But biosimilars like Selarsdi (ustekinumab) are made by different manufacturers and might have small differences in packaging or inactive ingredients. If you have questions comparing the two, talk to your prescriber.
Yes, Selarsdi (ustekinumab) is interchangeable with Stelara (ustekinumab). This means the FDA allows pharmacies to switch from Stelara (ustekinumab) to Selarsdi (ustekinumab) without needing a new prescription, making it easier if you and your prescriber decide to switch medications.
Yes. Selarsdi (ustekinumab) is a biologic medication. Biologic medications are made from living sources, like cells or proteins.
Selarsdi (ustekinumab) prefilled syringes can be stored out of the refrigerator for up to 30 days, as long as the temperature stays below 30°C (86°F). Once the syringe has been at room temperature, don't put it back in the refrigerator. Don’t use the medication if it has been left out for too long, exposed to heat or sunlight, or if you see any changes in color or particles. Be sure to follow the storage instructions on the product label or from your pharmacist.
Selarsdi (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.
Selarsdi (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 Selarsdi (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.
Selarsdi (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 Selarsdi (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 Selarsdi (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 Selarsdi (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 Selarsdi (ustekinumab). Check with your care team before getting any vaccines during treatment.
Different types of pneumonia have been reported in people taking Selarsdi (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: