Belimumab belongs to the class of medications called immunosuppressants. Specifically, it is a monoclonal antibody. It is used in addition to standard treatments to reduce the symptoms of systemic lupus erythematosus (SLE). It is also used to treat adults with active lupus nephritis in.

SLE is a disease where the body's natural defenses (immune system) attack the tissues and organs of the body. In lupus nephritis, autoantibodies in the immune system attack the kidneys, causing kidney inflammation. Belimumab works to reduce the activity of the body's immune system and control the symptoms caused by the damage to skin, joints, and organs.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Belimumab can be given as an intravenous (into a vein) infusion or a subcutaneous (under the skin) injection.

When belimumab is given as an intravenous (into a vein) infusion, the recommended adult dose for SLE or lupus nephritis is calculated as 10 mg per kilogram of body weight. It is given over 1 hour every 2 weeks for the first 3 doses. After the first 3 doses, it is given once every 4 weeks. Careful handling of this medication is required. It is always given under the supervision of a doctor in a hospital or similar setting with access to sterile equipment for preparation.

When belimumab is given as a subcutaneous (under the skin) injection, the recommended adult dose for the treatment of SLE is 200 mg injected, once a week, on the same day each week. When treating lupus nephritis, the dose is 400 mg subcutaneously (2 x 200 mg injections) once weekly for 4 doses, then 200 mg once weekly thereafter.

Subcutaneous belimumab is used with the guidance and supervision of a doctor. Your doctor or nurse will assist you in the preparation and injection of your first dose (or first few doses). Do not attempt to inject this medication on your own until you completely understand how to inject a dose. Rotate the injection sites (stomach, upper thighs) to minimize injection site skin irritation.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important this medication be given exactly as recommended by your doctor. If you miss an appointment to receive belimumab, contact your doctor as soon as possible to reschedule your appointment. If you are injecting the medication yourself and you miss a dose, take it as soon as possible. After that you can go back to having your injection on the usual day or you can start a new weekly schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Refrigerate this medication between 2°C and 8°C, protect it from direct sunlight, and keep it out of the reach of children. Do not allow the medication to freeze. Store this medication in its original box until ready for use. If you are using the subcutaneous injection, remove it from the refrigerator 30 minutes prior to injection. Do not use if it is left out at room temperature for more than 12 hours.

120 mg/5 mL vial
After reconstitution with sterile water for injection, each vial containing a sterile white-to-off-white, preservative-free, lyophilized powder contains 120 mg of belimumab in a concentration of 80 mg/mL. Nonmedicinal ingredients: citric acid, polysorbate 80, sodium citrate, and sucrose.

400 mg/20 mL vial
After reconstitution with sterile water for injection, each vial containing a sterile white-to-off-white, preservative-free, lyophilized powder contains 400 mg of belimumab in a concentration of 80 mg/mL. Nonmedicinal ingredients: citric acid, polysorbate 80, sodium citrate, and sucrose.

200 mg/mL Subcutaneous Injection
Each mL of clear to opalescent, colourless-to-pale-yellow solution contains 200 mg of belimumab. Nonmedicinal ingredients: L-arginine hydrochloride, L-histidine, L-histidine monohydrochloride, polysorbate 80, sodium chloride, and water for injections.

Do not take this medication if you are allergic to belimumab or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea
• dizziness
• dry eyes
• fever
• headache
• heartburn
• joint pain
• nausea
• pain in legs or arms
• redness, pain, swelling, itching, warmth, and bruising at the injection site
• sore throat
• stuffy or runny nose
• symptoms of vaginal yeast infection (women; e.g., vaginal odour, curd-like discharge, itching)
• toothache
• trouble sleeping
• vomiting
• weight gain

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• fast heartbeat
• persistent cough
• signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of low potassium levels in the blood (e.g., weakness, fatigue, muscle cramps, irregular heartbeat)
• speech difficulty
• stomach pain
• sudden high blood pressure
• symptoms of a urinary tract infection (e.g., pain when urinating, urinating more often than usual, low back or flank pain)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
• symptoms of an infusion reaction (e.g., low blood pressure, dizziness, slow heartbeat, shortness of breath)
• symptoms of progressive multifocal leukoencephalopathy (e.g., memory loss, trouble thinking, confusion, vision loss)
• thoughts of suicide or self-harm

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: In rare cases, some people may develop a serious allergic reaction to this medication. Signs of an allergic reaction include a severe rash, hives, swollen face or throat, or difficulty breathing. If these occur, get immediate medical attention.

Cancer: As with other medications that reduce the effectiveness of the immune system, belimumab may increase the risk of developing cancer. Discuss any concerns you may have with your doctor. Report any unusual infections, swelling or persistent pain, or unintentional weight loss to your doctor as soon as possible.

Depression: This medication may cause or worsen symptoms of depression. If you have depression or a history of depression, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking this medication, contact your doctor as soon as possible.

Infection: This medication can reduce the number of cells that fight infection in the body (white blood cells), increasing the risk of developing an infection or reactivating an inactive infection (e.g., herpes, shingles). Avoid contact with people with contagious infections when possible.

If you notice signs of an infection such as fever, chills, pain, redness and swelling, pus, cough, or difficult or painful urination, contact your doctor as soon as possible.

This medication should also not be started while you have an active infection or a weakened immune system. While you are taking belimumab, your doctor will monitor you for signs of infection.

Infusion-related reactions: As with other biologic therapies, belimumab can cause severe infusion-related reactions, sometimes resulting in death. Your health care provider will closely monitor you during and after the infusion. These reactions usually occur within 30 minutes to 2 hours of starting the infusion.

If you experience symptoms of an infusion reaction, such as fever, chills, difficulty breathing, tightness of chest or throat, stomach upset, and rash, tell your health care provider immediately.

It is important to take the medication(s) recommended by your doctor before your infusion of belimumab. If you experience a severe infusion reaction, your doctor will give you additional medications to treat the reaction. Ask your doctor for more information.

Progressive multifocal leukoencephalopathy (PML): There have been reports of PML after using belimumab. PML is a rare disorder that causes nerve damage in the brain. If you experience memory loss, vision loss, trouble thinking, or difficulty walking, contact your doctor immediately.

Suicide or self-harm: People using this medication sometimes have thoughts of suicide or self-harm. If you have depression when you start to use belimumab, you may be at an increased risk of feeling agitated (restless, anxious, aggressive, emotional, and feeling not like yourself), or wanting to hurt yourself or others. If you experience these side effects or notice them in a family member who is taking this medication, contact your doctor immediately.

Vaccines: Belimumab may reduce the effectiveness of these vaccines. Live vaccines should not be given within 30 days of receiving belimumab, or while using belimumab. Talk to your doctor if you need any vaccinations while taking this medication.

Pregnancy: This medication is not recommended for use during pregnancy. If you may become pregnant, use an effective method of birth control while you are using this medication, and for at least 4 months after the last treatment. Tell your doctor immediately if you become pregnant.

Breast-feeding: It is not known if belimumab passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

There may be an interaction between belimumab and any of the following:

• abatacept
• anakinra
• baricitinib
• BCG
• certolizumab pegol
• cladribine
• cyclophosphamide
• denosumab
• echinacea
• etanercept
• fingolimod
• leflunomide
• other monoclonal antibodies (e.g., adalimumab, golimumab, infliximab, ixekizumab, ocrelizumab, rituximab, sarilumab, secukinumab, tocilizumab)
• natalizumab
• ozanimod
• pimecrolimus
• roflumilast
• siponimod
• tofacitinib
• upadacitinib
• vaccines

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.