Key takeaways

  • Benlysta (belimumab) is a prescription medication that treats lupus nephritis and systemic lupus erythematosus by weakening the immune system, which can increase infection risk.
  • Common side effects include diarrhea, fever, infections like bronchitis or urinary tract infections, and injection site reactions. Most are mild and manageable with medical guidance.
  • Serious side effects requiring immediate medical attention include new or worsening depression, severe allergic or infusion reactions, serious infections, and certain cancers. Your doctor will monitor you closely and may pause your treatment if these occur.

Benlysta (belimumab) is a prescription drug used in adults and certain children to treat lupus nephritis and systemic lupus erythematosus.

Most side effects of Benlysta are temporary and manageable. Do not stop treatment without consulting with your doctor, but do notify them if symptoms persist or become bothersome.

The following mild side effects were commonly reported in Benlysta’s clinical trials:

For more information about some of these side effects, see the “Side effects explained” section.

Experiencing side effects? After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking this drug and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

While rare, the following conditions require immediate medical attention. If you experience life threatening symptoms, call 911 or your local emergency services number.

Contact your doctor immediately if you have any of the side effects listed here. Your doctor may pause or permanently stop your Benlysta treatment.

For more information about some of these side effects, see the “Side effects explained” section.

Note: Benlysta may cause side effects other than the ones listed in this article. For more information, talk with your doctor or see the drug’s prescribing information.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Suicide and Crisis Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

While long-term side effects such as cancer or mood changes were rare in Benlysta studies, they can persist after treatment ends. Your risk may be higher if you have a history of these conditions.

Discuss your medical history and current medications with your doctor. They will monitor you closely and may have you stop Benlysta treatment if serious side effects occur.

No, hair loss wasn’t a side effect reported in Benlysta studies. But hair loss is a possible symptom of lupus, which Benlysta is used to treat.

If you have concerns about hair loss during treatment with Benlysta, talk with your doctor.

No, Benlysta shouldn’t cause weight gain. This wasn’t a side effect reported in the drug’s studies. But other medications you may be taking to manage your condition, such as corticosteroids, can cause weight gain. And weight changes could be the result of other side effects of Benlysta, such as depression.

If you’re concerned about weight gain with Benlysta, talk with your doctor. They can help determine the cause.

Learn more about a few of the side effects Benlysta may cause.

Depression

Benlysta may cause depression in some people. This was a common side effect reported in studies of the drug.

Symptoms of depression may include:

Depression may also be a side effect of other medications you’re taking.

What might help

Tell your doctor about any history of depression or mood disorders before starting Benlysta. Report any mood or behavior changes immediately during or after treatment, as your doctor may need to switch your medication or provide additional care.

Diarrhea

Some people experience diarrhea when using Benlysta. This was a common side effect in studies of the drug. Most cases of diarrhea are mild. But tell your doctor if you have severe diarrhea, as this can lead to dehydration.

Dehydration can cause dizziness, extreme thirst, and reduced urination.

What might help

For mild cases of diarrhea, your doctor may suggest:

  • drinking plenty of fluids to avoid dehydration
  • eating a bland diet, such as the BRAT diet (bananas, rice, applesauce, toast)
  • taking an over-the-counter antidiarrheal medication such as loperamide (Imodium)

Call your doctor if you experience severe or ongoing diarrhea.

Serious infection

Benlysta weakens your immune system which can increase your risk of developing an infection. Although it’s rare, this includes serious infections such as pneumonia, serious urinary tract infection (UTI), bronchitis, or cellulitis.

Symptoms of infection may include:

In some cases, other medications you take for lupus could also increase your risk of infection. These include methotrexate and corticosteroids such as prednisone.

What might help

You should not start Benlysta treatment if you have an infection. Your doctor will screen for and treat any existing infection before you start this medication. During your Benlysta treatment, report any symptoms of infection immediately. Your doctor may have you pause Benlysta treatment until they’ve determined it’s safe to resume.

Benlysta may not be right for you if you have certain medical conditions or other factors affecting your health.

Talk with your doctor about your health history before starting this medication and tell them if any of the following apply to you:

Vaccines

You should not receive any live vaccines during Benlysta treatment or in the 30 days before starting treatment. These include vaccines for:

Live vaccines contain a small amount of the virus they’re meant to protect against. Benlysta weakens your immune system, so receiving a live vaccine could increase your risk of illness from the vaccine.

Benlysta may also make non-live vaccines less effective. Examples of these vaccines include those for:

In some cases, your doctor may suggest getting certain vaccines before you begin treatment with Benlysta.

Alcohol and Benlysta

There’s no known interaction between Benlysta and alcohol. But both substances can cause nausea, so combining them may raise your risk of nausea. And alcohol may interact with other drugs you may be taking for your condition.

If you drink alcohol, talk with your doctor about how much (if any) may be safe to consume with your treatment plan.

Pregnancy and Benlysta

It’s not known whether Benlysta treatment is safe during pregnancy.

Benlysta weakens the immune system which could affect a fetus or newborn if you use Benlysta while pregnant. But it’s important to note that untreated systemic lupus erythematosus (one of the conditions Benlysta treats) can also increase pregnancy risks, such as pregnancy loss or premature birth.

If you’re pregnant or planning a pregnancy, talk with your doctor before starting Benlysta treatment. They can help determine whether this drug is right for you.

If you use Benlysta during pregnancy, consider joining the Benlysta MotherToBaby pregnancy registry. This registry gathers information about the drug’s effects when used during pregnancy.

If you can become pregnant, your doctor will likely tell you to avoid pregnancy during Benlysta treatment. They’ll recommend using effective birth control during your treatment and for at least 4 months after your last Benlysta dose.

Breastfeeding and Benlysta

It’s not known whether Benlysta is safe to use while breastfeeding. If you’re breastfeeding or planning to do so, talk with your doctor before starting this medication.

Disclaimer: While Healthline strives for factual, comprehensive, and current information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.