ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.
Overview
It blocks IgE, the antibody behind allergic reactions.
What it's used for
- Allergic asthma
- Chronic hives
- Nasal polyps
- Food allergy (reducing reactions)
How to take it
- Given every 2 to 4 weeks, at first in a clinic.
- Keep carrying epinephrine if you have food allergies.
Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.
Side effects
Common side effects
- Injection site reactions
- Headache
- Joint pain
Call 911Trouble breathing, throat swelling, or fainting after a dose (can happen hours later)
Warnings
- Boxed warning: anaphylaxis.
Other medicines, foods, and alcohol
- Few interactions.
Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.
Pregnancy and breastfeeding
Talk with your provider.
Missed doses, overdose, and storage
If you miss a dose
Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.
If someone takes too much
Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.
Storing it
Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.
Conditions it's used for
Sources
- DailyMed: FDA drug label for Omalizumab (U.S. National Library of Medicine)
- MedlinePlus: Drugs, herbs, and supplements
- FDA: Drugs@FDA
Last updated 2026-11-13.