Skip to Content

Siltuximab Side Effects

For the Consumer

Applies to siltuximab: intravenous powder for solution

As well as its needed effects, siltuximab may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking siltuximab, check with your doctor or nurse immediately:

More common:
  • Abdominal or stomach pain
  • black, tarry stools
  • bleeding gums
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bloody urine
  • blurred vision
  • body aches or pain
  • chills
  • confusion
  • cough
  • decreased frequency or amount of urine
  • difficulty with breathing
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • ear congestion
  • fever
  • full or bloated feeling
  • headache
  • increased thirst
  • loss of appetite
  • loss of voice
  • lower back or side pain
  • nasal congestion
  • nausea
  • pinpoint red spots on the skin
  • pressure in the stomach
  • rapid weight gain
  • runny nose
  • sneezing
  • sore throat
  • sweating
  • swelling of the abdominal or stomach area
  • tingling of the hands or feet
  • troubled breathing
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • unusual weight gain or loss
  • vomiting
Less common:
  • Back pain
  • chest pain or discomfort
  • dizziness
  • dry mouth
  • fainting
  • fast, irregular, pounding, or racing heartbeat or pulse
  • feeling of warmth
  • flushing or redness of the skin
  • lightheadedness
  • rapid breathing
  • redness of the face, neck, arms, and occasionally, upper chest
  • sunken eyes
  • unusually warm skin
  • wrinkled skin
  • Difficulty with swallowing
  • hives, itching, or skin rash
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • tightness in the chest

Minor Side Effects

Some siltuximab side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common:
  • Difficulty having a bowel movement (stool)
  • difficulty with moving
  • joint pain, stiffness, or swelling
  • muscle pain or stiffness
  • rash with flat lesions or small raised lesions on the skin
Less common:
  • Darkening of the skin
  • decreased appetite
  • dry skin
  • skin rash, encrusted, scaly, and oozing

For Healthcare Professionals

Applies to siltuximab: intravenous powder for injection


The most common adverse reactions were pruritus, increased weight, rash, hyperuricemia, and upper respiratory tract infection.[Ref]


Very common (10% or more): Upper respiratory tract infection (up to 63%)
Common (1% to 10%): Lower respiratory tract infection, oropharyngeal pain[Ref]


Very common (10% or more): Rash (28%), pruritus (28%)
Common (1% to 10%): Skin hyperpigmentation, eczema, psoriasis, dry skin[Ref]


Very common (10% or more): Diarrhea (up to 32%), abdominal pain/abdominal distention (12%)
Common (1% to 10%): Constipation
Frequency not reported: Gastrointestinal perforation[Ref]


Very common (10% or more): Weight increased (19%), hyperuricemia (11%)
Common (1% to 10%): Hypertriglyceridemia, hypercholesterolemia, decreased appetite, dehydration[Ref]


Very common (10% or more): Edema (26%)
Common (1% to 10%): Hypotension[Ref]


Uncommon (0.1% to 1%): Anaphylactic reaction[Ref]


Very common (10% or more): Fatigue (21%)
Common (1% to 10%): Infusion related reaction[Ref]

Infusion related reactions included back pain, chest pain/discomfort, nausea and vomiting, flushing, erythema, and palpitations.[Ref]


Very common (10% or more): Pain in extremities (21%), arthralgia (21%)[Ref]


Common (1% to 10%): Renal impairment[Ref]


Common (1% to 10%): Thrombocytopenia[Ref]

Nervous system

Common (1% to 10%): Headache[Ref]


Uncommon (0.1% to 1%): Positive test for anti-siltuximab antibodies[Ref]


1. "Product Information. Sylvant (siltuximab)." Janssen Biotech, Inc., Horsham, PA, PA.

It is possible that some side effects of siltuximab may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.