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Belimumab Side Effects

Medically reviewed by Last updated on May 24, 2023.

Applies to belimumab: powder for solution, solution.

Serious side effects of Belimumab

Along with its needed effects, belimumab 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 immediately if any of the following side effects occur while taking belimumab:

More common

Less common

Other side effects of Belimumab

Some side effects of belimumab 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

Less common

For Healthcare Professionals

Applies to belimumab: intravenous powder for injection, subcutaneous solution.


The most common adverse events were nausea, diarrhea, pyrexia, nasopharyngitis, bronchitis, insomnia, pain in extremity, depression, migraine, pharyngitis, and injection-site reactions (subcutaneous administration).[Ref]


Common (1% to 10%): Skin reactions, rash, urticaria, acne

Uncommon (0.1% to 1%): Angioedema

Frequency not reported: Cellulitis


Very common (10% or more): Nausea (up to 15%), diarrhea (up to 12%)

Common (1% to 10%): Viral gastroenteritis, upper abdominal pain

Frequency not reported: Vomiting

Obese patients (body mass index [BMI] greater than 30 kg/m2) with SLE treated with this drug administered IV reported higher rates of nausea, vomiting, and diarrhea compared with normal-weight patients (BMI 18.5 to 30 kg/m2); none of these gastrointestinal events in obese patients were serious.


Very common (10% or more): Urinary tract infection (UTI; up to 19.2%)

Common (1% to 10%): Cystitis, bacterial UTI


Cases of myelosuppression (including febrile neutropenia, leukopenia, and pancytopenia) were observed in patients who received induction therapy with cyclophosphamide followed by maintenance therapy with azathioprine, or mycophenolate.

Common (1% to 10%): Leukopenia

Frequency not reported: Myelosuppression


Very common (10% or more): Hypersensitivity reactions (up to 13%)

Uncommon (0.1% to 1%): Anaphylactic reaction

Rare (0.01% to 0.1%): Delayed-type nonacute hypersensitivity reaction

Postmarketing reports: Fatal anaphylaxis

In clinical trials of this drug administered IV in patients with systemic lupus erythematosus (SLE), hypersensitivity reactions (occurring on the same day of infusion) and anaphylaxis were reported in 13% and 0.6% of patients receiving this drug, respectively. Manifestations included hypotension, angioedema, urticaria/other rash, pruritus, and dyspnea.

Delayed-type, nonacute hypersensitivity reactions included symptoms such as rash, nausea, fatigue, myalgia, headache, and facial edema.


Common (1% to 10%): Injection-site reactions (subcutaneous formulations only)

In clinical trials of this drug administered subcutaneously in patients with SLE, injection-site reactions were reported in 6.1% of patients receiving this drug (plus standard therapy). These injection site reactions (most commonly pain, erythema, hematoma, pruritus, and induration) were mild to moderate in severity and most (94%) did not require discontinuation of therapy.


Very common (10% or more): Arthralgia (up to 16.2%)

Common (1% to 10%): Pain in extremity, muscle spasms

Nervous system

Very common (10% or more): Headache (up to 21.1%)

Common (1% to 10%): Migraine


Uncommon (0.1% to 1%): Malignancies (including nonmelanoma skin cancers)


In clinical trials of this drug administered IV in patients with SLE, infusion-related events (occurring on the same day of infusion) were reported in 17% of patients receiving this drug. Serious infusion reactions (excluding hypersensitivity reactions) were reported in 0.5% of patients receiving this drug and included bradycardia, myalgia, headache, rash, urticaria, and hypotension. The most common infusion reactions were headache, nausea, and skin reactions.

Infusion- or injection-related systemic reactions included a group of terms and manifested as a range of symptoms (including bradycardia, myalgia, headache, rash, urticaria, pyrexia, hypotension, hypertension, dizziness, and arthralgia); due to overlap in signs/symptoms, it was not possible to distinguish between hypersensitivity reactions and infusion- or injection-related systemic reactions in all cases.

Very common (10% or more): Infections (up to 82%), infusion-related events (up to 17%), serious infections (up to 14%), bacterial infections (e.g., bronchitis, UTI)

Common (1% to 10%): Pyrexia, fatigue, infusion-/injection-related systemic reactions, postinjection systemic reactions, herpes zoster, death

Uncommon (0.1% to 1%): Fatal infections, all-cause mortality, serious infusion reactions, serious opportunistic infections


Very common (10% or more): Psychiatric events (up to 16%)

Common (1% to 10%): Insomnia, depression, depression-related events, anxiety, suicidal ideation/behavior, serious psychiatric events

Uncommon (0.1% to 1%): Serious depression, serious suicidal ideation/behavior/self-injury without suicidal intent, suicidal ideation, suicidal behavior, suicide


Very common (10% or more): Upper respiratory tract infection (up to 17.5%), cough (up to 12.5%)

Common (1% to 10%): Nasopharyngitis, bronchitis, pharyngitis, sinusitis, influenza, viral upper respiratory tract infection

Frequency not reported: Pneumonia

Frequently asked questions


1. Product Information. Benlysta (belimumab). GlaxoSmithKline. 2023;SUPPL-79.

2. Product Information. Benlysta (belimumab). GlaxoSmithKline Australia Pty Ltd. 2023;16.0.

3. Product Information. Benlysta (belimumab). GlaxoSmithKline UK Ltd. 2023.

Further information

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.