SIDE EFFECTS: Bruising, itching, pain, redness, swelling, or hardening of the skin at the injection site may occur. Injection site reactions usually go away after 1 or 2 days. Headache, back pain, or sinus/throat pain may also occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication can affect your immune system. It can lower your body's ability to fight an infection. You may be more likely to get serious infections, such as pneumonia, bone/joint infections, skin infections, or sinusitis. It may also be harder to fight an infection you already have. Tell your doctor promptly if you develop any signs of an infection, such as worsening redness/swelling/tenderness at the injection site after 2 days, fever/chills, or cold/flu symptoms. (See also Precautions section.)

Ustekinumab may cause a rare (sometimes fatal) condition called RPLS (reversible posterior leukoencephalopathy syndrome). Get medical help right away if you develop persistent headache, seizures, sudden vision changes, mental/mood changes (such as confusion).

There is a rare risk of developing cancer due to this medication. Discuss the risks and benefits of treatment with your doctor. Tell your doctor immediately if you develop symptoms such as unusual lumps/growths, swollen glands, unexplained weight loss.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the Stelara Injection (ustekinumab) Side Effects Center for a complete guide to possible side effects »

PRECAUTIONS: Before using ustekinumab, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as natural rubber/latex found in the needle cover on the prefilled syringe), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: current/recent/returning infection (including hepatitis and tuberculosis), cancer.

Ustekinumab can make you more likely to get infections or may worsen any current infections. Therefore, do not have immunizations/vaccinations without the consent of your doctor, and avoid contact with people who have recently received oral polio vaccine or flu vaccine inhaled through the nose. Avoid receiving BCG vaccines for one year after completing treatment with ustekinumab. Also avoid contact with people who have infections that may spread to others (such as chickenpox, flu). Wash your hands well to prevent the spread of infections.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug may pass into breast milk. Consult your doctor before breast-feeding.