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Generic name: belimumab [ be-LIM-ue-mab ]
Brand names: Benlysta, Benlysta Autoinjector
Dosage forms: intravenous powder for injection (120 mg; 400 mg), subcutaneous solution (200 mg/mL)
Drug class: Selective immunosuppressants

Medically reviewed by on Apr 5, 2023. Written by Cerner Multum.

What is belimumab?

Belimumab is used together with other medicines to treat active systemic lupus erythematosus (SLE) in adults and children at least 5 years old.

Beliumumab is also used to treat kidney problems (active lupus nephritis) in adults with SLE who are using other lupus medication.

Belimumab is not for use in people who have active SLE that affects the central nervous system (brain, nerves, and spinal cord).

Belimumab may also be used for other purposes not listed in this medication guide.

Belimumab side effects

Get emergency medical help if you have signs of an allergic reaction: hives, itching; feeling anxious or light-headed; difficult breathing; swelling of your face, lips, tongue, or throat.

Some people have had serious or fatal allergic reactions to belimumab within hours or days after an injection. Tell your doctor right away if you have symptoms such as muscle pain, headache, tiredness, slow heartbeats, rash, itching, swelling in your face or throat, anxiety, nausea, trouble breathing, and feeling dizzy or light-headed.

You may get infections more easily, even serious or fatal infections. Stop using belimumab and call your doctor right away if you have signs of infection such as:

  • fever, chills;

  • skin sores, warmth, or redness;

  • cough with mucus, chest pain, shortness of breath;

  • pain or burning when you urinate;

  • urinating more than usual; or

  • bloody diarrhea.

Belimumab may cause a serious brain infection that can lead to disability or death. Call your doctor right away if you have problems with speech, thought, vision, or muscle movement. These symptoms may start gradually and get worse quickly.

Also call your doctor at once if you have new or worsening depression, anxiety, mood or behavior changes, trouble sleeping, risk-taking behavior, or thoughts about hurting yourself or others.

Common side effects of belimumab may include:

  • nausea, diarrhea;

  • fever, sore throat, runny or stuffy nose, cough, chest tightness;

  • pain, itching, redness, or swelling where an injection was given under the skin;

  • pain in your arms or legs;

  • headache, depressed mood; or

  • sleep problems (insomnia).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Some people have had serious or fatal allergic reactions to this medicine within hours or days after an injection. Tell your doctor right away if you have symptoms such as headache, anxiety, rash, itching, swelling in your face or throat, nausea, trouble breathing, and feeling dizzy or light-headed.

Belimumab affects your immune system. You may get infections more easily, even serious or fatal infections. Call your doctor if you have a fever, chills, cough with mucus, skin sores, warmth or redness under your skin, increased urination, or burning when you urinate.

Report any new or worsening mental health symptoms to your doctor, such as: depression, mood or behavior changes, trouble sleeping, or thoughts about hurting yourself or others.

Before taking this medicine

You should not use belimumab if you are allergic to it.

Tell your doctor if you have ever had:

  • an active or chronic infection;

  • depression or mental illness;

  • suicidal thoughts or actions;

  • cancer;

  • a drug allergy;

  • if you recently received a vaccine; or

  • if you are using cyclophosphamide, biologic medicines, or other monoclonal antibody medicines.

Belimumab may increase your risk of certain cancers by changing the way your immune system works. Ask your doctor about your individual risk.

Some people have thoughts about suicide while using belimumab. Your doctor will need to check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Belimumab may affect the immune system of your baby if you use belimumab while you are pregnant. Use effective birth control to prevent pregnancy while you are using belimumab and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Belimumab may affect your baby's immune system, but having SLE during pregnancy may cause complications such as worsened lupus, eclampsia (dangerously high blood pressure), premature birth, miscarriage, or growth problems in the unborn baby. SLE in the mother may also cause lupus or heart problems to develop in the newborn. The benefit of treating SLE may outweigh any risks to the baby.

If you are pregnant, your name may be listed on a pregnancy registry to track the effects of belimumab on the baby. Make sure any doctor caring for your newborn baby knows if you used belimumab while you were pregnant.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.

How is belimumab given?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Belimumab is given as an infusion into a vein, usually every 2 to 4 weeks. A healthcare provider will give you this injection. The medicine must be given slowly, and the infusion can take about 1 hour to complete.

In adults, belimumab may also be injected under the skin, usually once weekly on the same day each week. A healthcare provider may teach you how to properly use the medication by yourself. Do not inject this medicine into skin that is bruised, tender, red, or hard.

If you give injections at home, read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Prepare an injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

You may be given other medications to help prevent serious side effects or an allergic reaction. Keep using these medicines for as long as your doctor has prescribed.

Store the prefilled syringe or injection pen in its original packaging in the refrigerator. Do not freeze or expose to light or high heat. Do not shake the medicine.

Take the syringe or injection pen out of the refrigerator and let it reach room temperature for 30 minutes before injecting your dose. Do not use if the medicine has been left at room temperature longer than 12 hours. Do not put it back into the refrigerator. Call your pharmacist for new medicine.

Each prefilled syringe or injection pen is for one use only. Throw it away after one use, even if there is still medicine left inside.

Throw away used needles, syringes, or injection pens in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

What happens if I miss a dose?

Use the medicine as soon as you remember. You can either restart a weekly schedule based on the new injection day, or you can go back to your regular injection schedule. Do not use 2 injections on the same day.

Call your doctor for instructions if you miss an appointment for an intravenous infusion of belimumab.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using belimumab?

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Do not receive a "live" vaccine while using belimumab. The vaccine may not work as well and may not fully protect you from disease. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

What other drugs will affect belimumab?

Other drugs may affect belimumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Popular FAQ

Although hair loss is not listed as a side effect in the product information for Benlysta, at least 3 people have reported hair loss as a side effect since the drug has been approved. The type of hair loss reported in these 3 people taking Benlysta was alopecia areata, symptoms include patchy hair loss on the scalp or other areas of the body, which is an autoimmune condition (like lupus). All 3 cases resolved but 2 out of 3 people stopped taking Benlysta.

Although weight gain is not listed as a side effect of Benlysta in the product information, a phase IV clinical study that analyzed side effect information from 14,100 people who had taken Benlysta reported weight gain as a side effect for 2.87% of them (404 people).

Weight gain is more likely in females aged 50 to 59 years who have been taking Benlysta for 1 - 6 months.

Weight gain can also be a side effect of other conditions, such as depression, and if you experience changes in your weight, you should talk with your doctor

Benylsta does stop inflammation by reducing the activity of certain white blood cells called autoreactive B-cells that produce antibodies that attack healthy cells. This reduces the inflammation that causes the symptoms of lupus.

Benlysta works by attaching to a specific protein, called B-lymphocyte stimulator (BLyS), preventing it from binding to its receptors on B cells. BLyS is important for the growth and development of B cells, and B cells have a crucial role in the development of lupus. Certain B cells, called autoreactive B-cells, stay in the body for longer than they should, producing autoantibodies that target important cellular components, such as DNA, causing disease flares. By binding to BLyS, Benlysta prevents the survival of B-cells and their differentiation into immunoglobulin-producing plasma cells.

Benlysta is a biologic therapy, not a steroid. It may be called a B-cell depleting therapy or a selective immunosuppressant.

Yes, Benlysta does help with fatigue although it may take 4 to 8 months before symptoms of fatigue resolve or reduce.

Benlysta injections given at home are injected subcutaneously (this means just under the skin) and there are 2 main areas where Benlysta can be injected:

  • The stomach area (your belly) except for a 2-inch circle around your navel (belly button)
  • The top and outer part of your thighs, but not your inner thighs or anywhere close to your knee.

The easiest way to inject Benlysta under the skin is to pinch up a fold of skin using your thumb and forefinger on your stomach or thigh or use your knee to create a pinched up area if you are injecting into your upper, outer arm (or have somebody else administer the injection for you).

To keep your skin from thickening or getting lumpy, try not to inject in the same spot. Instead, rotate injection places. If you need to give yourself 2 Benlysta injections, leave at least 2 inches between each injection.

Injections of Benlysta are usually less painful if you allow the autoinjector or prefilled syringe to warm up to room temperature for a couple of hours before using. Some people report injecting Benlysta into the stomach to be less painful than into the thighs, and that the prefilled syringe is less painful than the autoinjector because you can inject the prefilled syringe more slowly.

Benlysta and Saphnelo are both targeted treatments, but they target different parts of the immune system that are particularly overactive in lupus. Benlysta targets and blocks the activity of a type of white blood cell called a B cell, which produces antibodies that attack tissue, causing symptoms of SLE. It is classified as a B-lymphocyte stimulator (BLyS)-specific inhibitor. Saphnelo targets the type I interferon receptor and inhibits the activity of type 1 interferons. Activation of the interferon system is a common underlying characteristic of SLE that leads to the immune system being constantly “switched on”, contributing to SLE symptoms. Saphnelo is classified as a type 1 interferon receptor antagonist. Benlysta was first approved in 2011 and Saphnelo was approved in 2021. Continue reading

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.