Benlysta (belimumab) Side Effects, Warnings, and Drug Interactions

Benlysta (belimumab) is a monoclonal antibody that reduces the activity of immune cells called B-cells in patients with systemic lupus erythematosus (SLE). SLE is an inflammatory autoimmune disease, which means that the body's immune system attacks its own tissues and causes inflammation.

Parts of the body affected by SLE include:

• the heart,
• skin,
• joints,
• kidneys,
• lungs, and
• brain. 

Common side effects of Benlysta include:

• nausea,
• diarrhea,
• vomiting,
• stomach pain,
• fever,
• stuffy or runny nose,
• cough (bronchitis),
• insomnia,
• leg or arm pain,
• migraine,
• sore throat, and
• allergic or infusion-related reactions (such as itching; swelling of the face, lips, tongue, mouth, or throat, difficulty breathing, low blood pressure, dizziness, fainting, rash, redness, and swelling of the skin).

Serious side effects of Benlysta include:

• infections,
• heart problems,
• depression, and
• increased risk of certain cancers.

Drug interactions of Benlysta have not been studied. Since Benlysta reduces the activity of the immune system it may interfere with the response to immunizations. Live vaccines should not be administered concurrently with Benlysta or at least 30 days before administration of Benlysta. 

Benlysta has not been adequately studied in pregnant women. Benlysta can cross the placenta. 

It is unknown Benlysta is excreted in human breast milk. Since antibodies are usually excreted in breast milk, mothers should consider not breastfeeding or discontinuing Benlysta if they want to breastfeed.

Common side effects of Benlysta include:

• nausea,
• diarrhea,
• vomiting,
• stomach pain,
• fever,
• stuffy or runny nose,
• cough (bronchitis),
• insomnia,
• leg or arm pain,
• migraine,
• sore throat, and
• allergic or infusion-related reactions such as:
  • itching;
  • swelling of the face, lips, tongue, mouth, or throat;
  • difficulty breathing;
  • low blood pressure;
  • dizziness;
  • fainting; rash;
  • redness; and
  • swelling of the skin.

Serious side effects of Benlysta include:

• infections,
• heart problems,
• depression, and
• increased risk of certain cancers.

The most common adverse reactions of belimumab are:

• nausea,
• diarrhea,
• vomiting,
• stomach pain,
• fever,
• stuffy or runny nose,
• cough (bronchitis),
• insomnia,
• leg or arm pain,
• migraine, and sore throat.

Other important side effects of belimumab include:

• allergic or infusion-related reactions such as itching;
• swelling of the face, lips, tongue, mouth, or throat; 
• difficulty breathing;
• low blood pressure;
• dizziness;
• fainting;
• rash;
• redness; or
• swelling of the skin.

Infections, heart problems, depression, and suicide have also occurred in patients taking belimumab. Like other drugs that reduce the activity of the immune system, belimumab may increase the risk of certain cancers.

Belimumab has not been adequately studied in pregnant women. Belimumab can cross the placenta. A pregnancy registry has been established for monitoring the safety of belimumab in pregnant women. The number for the registry is 1-877-681-6296.

It is not known whether belimumab is excreted in human breast milk. Since antibodies are usually excreted in breast milk, mothers should consider not breastfeeding or discontinuing belimumab if they want to breastfeed.

Drug interactions have not been studied. Since belimumab reduces the activity of the immune system it may interfere with the response to immunizations. Live vaccines should not be administered concurrently with belimumab or at least 30 days before administration of belimumab.