What side effects can happen with a Stelara (ustekinumab) infusion?
Stelara (ustekinumab) side effects include both “infusion-related” reactions that can occur around the time it’s given and longer-lasting risks that can occur after treatment.
Infusion-related reactions are among the most commonly discussed immediate effects. These can include symptoms such as fever, flushing, itching, rash, chest tightness, dizziness, or shortness of breath. These reactions are more likely to show up during the infusion or shortly after.
Like other biologics that affect the immune system, Stelara can also cause other side effects over time, including infections (for example, upper respiratory infections), injection-site or skin reactions, fatigue, headache, and nausea. Because Stelara works by changing immune activity, infections are one of the key concerns clinicians monitor.
When should you call a doctor urgently after a Stelara infusion?
Seek urgent medical care if you get signs of a serious allergic reaction or severe infusion reaction, such as:
- Trouble breathing, wheezing, or throat tightness
- Swelling of the face, lips, tongue, or throat
- Severe dizziness or fainting
- Widespread hives or rapidly worsening rash
Also contact your clinician promptly if you develop symptoms that could indicate an infection, especially if they’re severe or worsening (for example, high fever, persistent cough, painful urination, or new/worsening skin redness with fever).
What symptoms are patients most likely to notice?
Patients commonly report general, non-emergency side effects such as:
- Feeling tired or weak
- Headache
- Nausea or stomach discomfort
- Mild skin reactions (itching, rash)
- Cold-like symptoms
Infusion-related symptoms are the ones that can feel more acute. These are typically monitored during administration so infusion centers can respond quickly if anything occurs.
How do infusion side effects differ from long-term Stelara risks?
Infusion side effects tend to happen during or soon after the infusion and often look like allergic or hypersensitivity-type symptoms (rash, flushing, chest tightness, shortness of breath, dizziness).
Long-term risks reflect Stelara’s immune effects. The main long-term category clinicians watch is infection risk. Patients are also monitored for other issues during follow-up visits, but infections and infusion reactions are the most commonly emphasized concerns.
What makes side effects more likely?
Risk can be higher if you:
- Have a history of allergic reactions to medications
- Have active or recurring infections
- Are taking other immune-modifying therapies at the same time
- Have significant underlying lung issues or a history of severe infusion reactions
Your prescriber may also adjust how the infusion is given based on prior reactions (for example, slowing the rate or using supportive medications if appropriate).
Are there ways to reduce infusion reactions?
Common approaches used in infusion settings include:
- Careful screening for current infections before dosing
- Monitoring during the infusion and shortly after
- Slowing or pausing the infusion if symptoms start
- Using supportive medications when clinically appropriate (your infusion team decides what fits your situation)
Never try to self-treat severe infusion symptoms (like breathing trouble) at home—get immediate help.
Who should not get Stelara or should get it only with extra caution?
Extra caution is usually needed if you have:
- Active infections
- A history of serious hypersensitivity to ustekinumab or similar biologics
- Certain chronic infections or risk factors for tuberculosis or other infections (your clinician typically screens before starting)
Your exact eligibility depends on your medical history and the condition Stelara is being used for.
What should you tell the infusion team before your dose?
Bring up any:
- Recent infections or fevers
- Previous infusion reactions
- New symptoms in the days leading up to the appointment
- Other medicines you’re taking (especially other immune therapies)
If you had a reaction before, can you still receive Stelara?
Sometimes yes, but it depends on the severity and type of reaction. Mild reactions may allow future dosing with monitoring and possible adjustments. Severe allergic reactions usually lead clinicians to stop Stelara and switch treatments.
If you tell me what symptoms you had (and how soon after the infusion they started), I can help you sort whether they sound like infusion-related effects versus infection or another side effect—and what questions to ask your care team.