What are the side effects of Agalsidase beta Injection?
Last updated September 7, 2026.
**The most common side effects of agalsidase beta injection are infusion-associated reactions such as chills, fever, feeling hot or cold, headache, nausea, and flushing, which usually start during the infusion or within a few hours after it.** Agalsidase beta is an enzyme replacement therapy for Fabry disease, given by vein about every two weeks, and reactions are most likely in the first several months of treatment. Serious allergic reactions, including anaphylaxis, have happened, so infusions are given in a setting with trained staff and emergency medicines on hand. Many people are premedicated with an antihistamine, acetaminophen, or a corticosteroid, and slowing the infusion rate often reduces symptoms. Some people develop antibodies to the drug, which can make infusion reactions more likely, so your team may check antibody levels. Keep a simple log of what you feel at each infusion and at what point in the drip it started, since that helps your team adjust the rate or the premedication.
What to do
- Time your symptoms: Note when a reaction starts relative to the infusion, since that guides rate changes and premedication.
- Ask about premedication: An antihistamine, acetaminophen, or a corticosteroid before the infusion often prevents chills and fever.
- Treat breathing symptoms as urgent: Trouble breathing, throat or face swelling, hives, or feeling faint needs immediate medical care.
- Do not skip doses on your own: Call your specialist before stopping, because Fabry symptoms can return when treatment is interrupted.
- Bring your full medicine list: Share every prescription, supplement, and pregnancy or breastfeeding plan with the team managing your infusions.
- Report new reactions: You and your clinician can send serious side effects to the FDA MedWatch program.