Omalizumab Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Feb 20, 2024.

Applies to omalizumab: subcutaneous powder for solution, subcutaneous solution.

Important warnings This medicine can cause some serious health issues

Subcutaneous route (powder for solution; solution)

Anaphylaxis. Anaphylaxis presenting as bronchospasm, hypotension, syncope, urticaria, and/or angioedema of the throat or tongue, has been reported to occur after administration of omalizumab. Anaphylaxis has occurred as early as after the first dose of omalizumab, but also has occurred beyond 1 year after beginning regularly administered treatment.

Because of the risk of anaphylaxis, initiate omalizumab therapy in a healthcare setting and closely observe patients for an appropriate period of time after omalizumab administration.

Health care providers administering omalizumab should be prepared to manage anaphylaxis which can be life-threatening.

Inform patients of the signs and symptoms of anaphylaxis and instruct them to seek immediate medical care should symptoms occur.

Selection of patients for self-administration of omalizumab should be based on criteria to mitigate risk from anaphylaxis.

Common side effects of omalizumab

Some side effects of omalizumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• bleeding, blistering, burning, coldness, discoloration of skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
• body aches or pain
• cold or flu-like symptoms
• congestion
• dryness or soreness of the throat
• headache
• hoarseness
• leg pain
• lumps
• pain or tenderness around the eyes and cheekbones
• stuffy or runny nose
• voice changes

Less common

• arm pain
• cracked, dry, or scaly skin
• earache

Incidence not known

• hair loss

Serious side effects of omalizumab

Along with its needed effects, omalizumab may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking omalizumab:

Less common

• blistering, crusting, irritation, itching, or reddening of the skin
• body produces substance that can bind to drug making it less effective or cause side effects
• difficulty in moving
• muscle pain or stiffness
• pain in the joints
• stomach pain

Rare

• chest tightness
• cough
• difficulty with swallowing
• dizziness
• fast heartbeat
• hives, itching, or skin rash
• malignant tumor
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• unusual tiredness or weakness

Incidence not known

• black, tarry stools
• bleeding gums
• blood in the urine or stools
• chest pain
• chills
• fever
• painful or difficult urination
• pinpoint red spots on the skin
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swollen glands
• unusual bleeding or bruising

For healthcare professionals

Applies to omalizumab: subcutaneous powder for injection, subcutaneous solution.

General

The more commonly reported side effects included injection site reactions, headache, and nasopharyngitis.^[Ref]

Local

• Very common (10% or more): Any injection site reaction, including pain, swelling, itching, redness, bruising, bleeding, induration, or mass (up to 45%), severe injection site reaction (up to 12%)
• Uncommon (0.1% to 1%): Arm swelling^[Ref]

In clinical trials, any injection site reaction occurred in 45% and 43% of patients given this drug and placebo, respectively; severe reactions occurred in 12% and 9%, respectively.^[Ref]

Immunologic

• Very common (10% or more): Viral infection (up to 37%)
• Uncommon (0.1% to 1%): Moniliasis, parasitic infection
• Rare (0.01% to 0.1%): Anti-omalizumab antibody development
• Postmarketing reports: Serum sickness, allergic granulomatous angiitis (Churg-Strauss syndrome), lymphadenopathy^[Ref]

In clinical studies, viral infection occurred in 37% and 39% or patients given this drug or placebo, respectively. Increased parasitic infections, compared to placebo, were not statistically significant.^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 27%)
• Common (1% to 10%): Dizziness
• Uncommon (0.1% to 1%): Syncope, vasovagal syncope, somnolence, paresthesia
• Frequency not reported: Migraine, sinus headache^[Ref]

In clinical trials, headache occurred in 37% of patients given either this drug (n=716) or placebo (n=694); headache occurred very commonly in patients 6 to 12 years old.^[Ref]

Musculoskeletal

• Very common (10% or more): Back pain (up to 13%)
• Common (1% to 10%): Arthralgia, myalgia, sprains, strains, extremity pain, fracture
• Postmarketing reports: Joint swelling^[Ref]

Respiratory

• Common (1% to 10%): Nasopharyngitis, sinusitis, viral upper respiratory infection (URI), URI
• Uncommon (0.1% to 1%): Pharyngitis, cough, allergic bronchospasm
• Rare (0.01% to 0.1%): Laryngoedema
• Frequency not reported: Asthma, oropharyngeal pain^[Ref]

In clinical trials with chronic idiopathic urticarial, patients reported nasopharyngitis 9.1%, 6.6%, and 7% in 150 mg, 300 mg, and placebo, respectively; sinusitis (1.1%, 4.9%, 2.1%), cough (1.1%, 2.2%,1.2%), and upper respiratory infection (11.1%, 3.4%, 2.1%) were also reported by patients, respectively.^[Ref]

Dermatologic

• Common (1% to 10%): Dermatitis, pruritus
• Uncommon (0.1% to 1%): Skin rashes, flushing, photosensitivity
• Postmarketing reports: Alopecia, hair loss^[Ref]

Other

• Common (1% to 10%): Fever, earache
• Uncommon (0.1% to 1%): Fatigue, post-injection phenomena^[Ref]

In clinical trials, fever occurred very commonly in patients 6 to 12 years old.^[Ref]

Gastrointestinal

• Common (1% to 10%): Upper abdominal pain, nausea
• Uncommon (0.1% to 1%): Diarrhea, dyspepsia, gastroenteritis
• Frequency not reported: Toothache^[Ref]

In clinical trials, upper abdominal pain was very common in patients 6 to 12 years old. In clinical trials with chronic idiopathic urticarial, patients reported nausea 1.1%, 2.7%, and 2.5% of the time with 150 mg, 300 mg, and placebo, respectively.^[Ref]

Genitourinary

• Common (1% to 10%): Urinary tract infection^[Ref]

Hypersensitivity

• Uncommon (0.1% to 1%): Urticaria
• Rare (0.01% to 0.1%): Anaphylactic reactions, angioedema
• Postmarketing reports: Anaphylactoid reactions^[Ref]

Cardiovascular

• Uncommon (0.1% to 1%): Postural hypotension
• Frequency not reported: Peripheral edema, arterial thrombotic events (including transient ischemic attack, myocardial infarction, unstable angina, and cardiovascular death)
• Postmarketing reports: Hypotension, chest tightness^[Ref]

Hematologic

• Uncommon (0.1% to 1%): Asymptomatic platelet decreases
• Postmarketing reports: Idiopathic severe thrombocytopenia, eosinophilic conditions^[Ref]

In clinical trials, 0.6% of patients developed decreased platelet counts below the normal laboratory range; these patients did not have associated bleeding episodes or decreased hemoglobin.^[Ref]

Metabolic

• Uncommon (0.1% to 1%): Weight increases^[Ref]

Psychiatric

• Frequency not reported: Anxiety^[Ref]

Frequently asked questions

• What are the most common skin conditions? (with photos)
• Is Xolair an immunosuppressant?
• How long before Xolair starts working?
• How does Xolair work?
• Does Xolair cause weight gain?
• What is omalizumab's mechanism of action?
• Can Xolair be self-administered at home?
• Omalizumab and Covid-19 vaccine, what should I know?
• What is Xolair approved for?

Further information

Omalizumab side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer