Pronunciation: seh-LARS-dee
Generic name: ustekinumab-aekn
Dosage form: subcutaneous injection single-dose prefilled syringe (45 mg/0.5 mL or 90 mg/mL), injection for intravenous infusion (130 mg/26 mL)
Drug class: Interleukin inhibitors

Medically reviewed by Carmen Pope, BPharm. Last updated on May 13, 2025.

What is Selarsdi?

Selarsdi is used to treat adults and children aged 6 years and older with moderate to severe plaque psoriasis who are candidates for phototherapy or systemic therapy, or who have active psoriatic arthritis. Selarsdi is also approved for moderately to severely active Crohn's disease or ulcerative colitis in adults. It is an interchangeable biosimilar to Stelara.

Selarsdi (ustekinumab-aekn) binds specifically to a protein subunit called p40 used by interleukin-12 (IL-12) and -23 (IL-23) cytokines. Interleukins are made by various cells, such as lymphocytes, monocytes, and macrophages, and are involved in inflammatory and immune responses, including inflammation associated with autoimmune conditions. By blocking the activity of IL-12 and IL-23, Selarsdi reduces inflammation, pain, swelling, and skin symptoms.

Selarsdi is given as an injection under the skin (subcutaneously). Selarsdi is also available as a vial for intravenous infusion that may be used as the initial dose for Crohn's disease and ulcerative colitis.

Selarsdi was FDA-approved on April 16, 2024. Selarsdi is available and interchangeable in all presentations matching the reference product, including the treatment of adults and pediatric psoriatic arthritis and plaque psoriasis, as well as Crohn’s disease and ulcerative colitis.

• There are no clinically meaningful differences between Selarsdi and Stelara regarding safety, tolerability, and immunogenicity. 

What is Selarsdi used for?

Selarsdi is FDA-approved to treat:

• Plaque psoriasis (moderate to severe) in patients 6 years and older who are candidates for phototherapy or systemic therapy.
• Psoriatic arthritis (active) in patients 6 years and older
• Crohn's disease (moderate to severe) in adults
• Ulcerative colitis (moderate to severe) in adults.

Side effects

The most common side effects of Selarsdi are:

• nasal congestion
• a sore throat
• runny nose
• headaches
• tiredness
• upper respiratory infections, such as a cold or the flu.

Serious side effects and warnings

Get emergency medical help if you have signs of an allergic reaction to Selarsdi, such as hives, chest pain, difficulty breathing, feeling light-headed, or swelling of your face, lips, tongue, or throat.

Selarsdi can cause the following serious side effects:

• Infections. Selarsdi can lower the ability of your immune system to fight infections, increase your risk of severe infections, and worsen existing infections, such as tuberculosis (TB). Serious infections, some resulting in hospitalization, have occurred. Before starting Selarsdi, your doctor will check for TB, and you may need treatment for TB if you are at risk. You should not start taking Selarsdi if you have an infection unless your doctor says it is okay. Symptoms of an infection include:
  • fever, sweat, or chills
  • warm, red, or painful skin or sores on your body
  • muscle aches
  • diarrhea or stomach pain
  • cough
  • burning when you urinate or urinate more often
  • shortness of breath than normal
  • blood in phlegm
  • feel very tired
  • weight loss.

People who have a genetic problem where their body does not make any IL-12 or IL-23 are at a higher risk for certain serious infections when they take Selarsdi.

• Increased cancer risk. Selarsdi decreases the activity of your immune system, and there may be an increase in your risk for certain types of cancers. Tell your doctor if you have ever had any type of cancer. Some people who are receiving this medicine and have risk factors for skin cancer have developed certain types of skin cancers. During your treatment with this medicine, tell your doctor if you have:
  • a mole that has changed in size or color
  • painful skin sores
  • swelling, pain, warmth, or redness anywhere on your body;
  • stomach pain that is sudden and severe or comes on slowly, changes in bowel habits (diarrhea or constipation)
  • new or worsening cough, sudden chest pain, feeling short of breath
  • pain or burning when you urinate or
  • severe headache, confusion, change in mental status, vision problems, and/or seizures (convulsions).
• Posterior Reversible Encephalopathy Syndrome (PRES). A rare but serious condition affecting the brain. Tell your doctor right away if you have a headache, confusion, vision problems, or a seizure.

Avoid live vaccines while you are being treated with Selarsdi. It may also be risky for your household contacts to receive live vaccines because of the potential risk of virus shedding and transmission to you. Before starting treatment, you should receive all your age-appropriate immunizations as recommended by the current immunization guidelines. You should not use this medicine if you have received a BCG (Bacillus Calmette and Guérin) vaccine within 1 year before, during, or 1 year following treatment. Non-live vaccinations received during Selarsdi treatment may not elicit an immune response sufficient to prevent disease.

Some people have developed lung inflammation and serious pneumonia during treatment with ustekinumab products, such as Selarsdi. Tell your healthcare provider immediately if you become short of breath or develop a cough that doesn’t go away, particularly following the first few doses.

These are not all of the possible side effects of Selarsdi. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects to Teva Pharmaceuticals at 1-888-483-8279.

Related/similar drugs

Before taking this medicine

Do not take Selarsdi if you are allergic to ustekinumab, Selarsdi, Stelara, Wezlana, Imuldosa, Otulfi, Pyzchiva, Yesintek, or any of the inactive ingredients in the Selarsdi injection.

Before you receive Selarsdi, tell your doctor about all of your medical conditions, including if you:

• have recently received or are scheduled to receive an immunization (vaccine), including receiving a BCG (Bacillus Calmette and Guérin) vaccine within the past 12 months
• have an infection, have symptoms of an infection, or have any open cuts
• get a lot of infections or have infections that keep coming back
• have TB, or have been in close contact with someone with TB.
• have any new or changing lesions within psoriasis areas or on normal skin
• are receiving or have received allergy shots, especially for serious allergic reactions
• receive or have received phototherapy for your psoriasis
• have skin cancer
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

It is not known if Selarsdi can harm your unborn baby. You and your doctor should decide if you will receive Selarsdi. If you are pregnant, your name may be listed on a pregnancy registry to track the effects of ustekinumab on the baby.

If you did receive Selarsdi while you were pregnant, it may affect what vaccinations can be given to your baby.

Breastfeeding

Selarsdi can pass into breast milk. It may not be safe to breastfeed while using this medicine. Talk to your doctor about the best way to feed your baby if you receive this medicine.

How should I use Selarsdi?

Before you start treatment with this medicine, your doctor may perform tests to make sure you do not have tuberculosis or other infections. Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed. 

Selarsdi is given by a healthcare provider as an intravenous infusion or an injection under the skin (subcutaneous injection). People can be taught how to self-administer the subcutaneous injection.

• Adults with Crohn’s disease and ulcerative colitis will receive the first dose of Selarsdi through a vein in the arm (intravenous infusion) in a healthcare facility by a healthcare provider. It takes at least 1 hour to receive the full dose of medicine. You will then receive Selarsdi as an injection under the skin (subcutaneous injection) 8 weeks after the first dose, as described below.

If your doctor decides that you or a caregiver may give your injections at home, you should receive training on the right way to inject the Selarsdi prefilled syringe.

• The Selarsdi prefilled syringe may be given under the skin of your buttocks, upper legs (thighs), or stomach area (abdomen). A caregiver can give it to you in your upper arms.
• Do not give an injection in an area of the skin that is tender, bruised, red, or hard.
• Use a different injection site each time you use Selarsdi.
• Read the Selarsdi Medication Guide for detailed instructions about how to prepare and inject a dose of Selarsdi and properly throw away (dispose of) used needles and prefilled syringes. The needle and prefilled syringe must never be re-used because of the risk of infection. Throw away any unused portion of Selarsdi.

In children 6 years and older, it is recommended that this medicine be administered by a healthcare provider.

Selarsdi dosage

Selarsdi is given as a subcutaneous (SC) injection for psoriasis and psoriatic arthritis in adults and children.

Selarsdi dosage for psoriasis or psoriatic arthritis

The dosage of Selarsdi is based on body weight. Your doctor will determine the right dose for you.

Adult (less than or equal to 100 kg): Selarsdi 45 mg SC initially and 4 weeks later, followed by 45 mg administered SC every 12 weeks.

Adult (more than 100 kg): Selarsdi 90 mg SC initially and 4 weeks later, followed by 90 mg administered SC every 12 weeks.

Child (aged 6 to 17 years):

• Children 60 kg to 100 kg: Selarsdi 45 mg SC initially and 4 weeks later, then every 12 weeks.
• Children over 100 kg: Selarsdi 90 mg SC initially and 4 weeks later, then every 12 weeks.

Selarsdi dosage for Crohn's disease and ulcerative colitis

The dosage of Selarsdi is based on body weight. Your doctor will determine the right dose for you.

• Initial dose for adults (up to 55 kg): 260 mg (2 vials) by intravenous infusion
• Initial dose for adults (greater than 55 kg to 85 kg): 390 mg (3 vials) by intravenous infusion
• Initial dose for adults (greater than 85 kg): 520 mg (4 vials) by intravenous infusion
• Maintenance dose for adults (all weights): 90 mg SC given 8 weeks after the initial intravenous dose, then every 8 weeks thereafter.

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose.

What happens if I overdose?

If you inject more Selarsdi than prescribed, call your doctor right away seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Selarsdi?

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Do not receive a "live" vaccine while using this medicine, and avoid coming into contact with anyone who has recently received a live vaccine. There is a chance that the virus could be passed on to you. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

• The BCG vaccine should not be given for at least 1 year after you receive your last dose of Selarsdi.
• Non-live vaccines (including flu shots) may not work as well during your treatment, and may not fully protect you from disease. Make sure you are current on all vaccines before you begin treatment with this medicine.

What other drugs will affect Selarsdi?

Other drugs may interact with Selarsdi, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

It is important to tell your doctor if you are taking any of the following:

• anticoagulants (blood thinners) such as warfarin (Coumadin, Jantoven)
• medications that suppress the immune system such as azathioprine (Azasan, Imuran), cyclosporine (Gengraf, Neoral, Sandimmune), methotrexate (Otrexup, Rasuvo, Trexall, Xatmep), sirolimus (Rapamune), and tacrolimus (Astagraf, Envarsus, Prograf)
• oral steroids such as dexamethasone (Hemady), methylprednisolone (Medrol), and prednisone (Rayos)
• other medications that are metabolized by CYP450 enzymes, particularly those that have a narrow therapeutic index (such as warfarin and cyclosporin).

Ustekinumab products, including Selarsdi, have not been studied in patients who have undergone allergy immunotherapy. It may decrease the protective effect of allergen immunotherapy (decrease tolerance) which may increase the risk of an allergic reaction to a dose of allergen immunotherapy. Caution is advised especially in those who have received allergen immunotherapy, particularly for anaphylaxis.

Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Not all possible interactions are listed here.

Storage

Store Selarsdi prefilled syringes in a refrigerator between 36°F to 46°F (2°C to 8°C). Store it in the original carton to protect it from light until time to use it. Do not freeze and do not shake.

If needed, individual prefilled syringes may also be stored at room temperature up to 30°C (86°F) for a maximum single period of up to 30 days in the original carton to protect from light.

Record the date when the syringe is first removed from the refrigerator on the carton in the space provided. Once a syringe has been stored at room temperature, it should not be returned to the refrigerator. Discard if not used within 30 days.

Do not use after the expiry date. Keep out of the reach of children.

Selarsdi ingredients

Active ingredient: ustekinumab-aekn

Inactive ingredients (single-dose prefilled syringe for SC use): histidine, L-histidine monohydrochloride monohydrate, polysorbate 80, sucrose, and water for injection.

Inactive ingredients (single-dose vial for intravenous infusion): edetate disodium, histidine, L-histidine monohydrochloride monohydrate, methionine, polysorbate 80, sucrose, and water for injection.

Selarsdi is available as a 45 mg/0.5 mL single-dose prefilled syringe and a 90 mg/mL single-dose prefilled syringe.

Selarsdi is also available as a 130 mg/26 mL (5 mg/mL) solution in a single-dose vial for intravenous infusion.

Who makes Selarsdi?

Alvotech and Teva Pharmaceutical Industries make Selarsdi.

Selarsdi Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for Selarsdi.

Stelara interchangeable products

Interchangeable biosimilar products can be dispensed by a pharmacist without the intervention of the prescriber of the reference product.

Pharmacy laws for biosimilar prescribing may vary by state.

Stelara biosimilar products

Biosimilar products can only be dispensed in place of the reference product if the healthcare provider specifically prescribes the biosimilar product by name.

Pharmacy laws for biosimilar prescribing may vary by state

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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