Overview
Xolair is approved by the U.S. Food and Drug Administration (FDA) for the treatment of chronic spontaneous urticaria (CSU) in adults and adolescents aged 12 years and older who continue to have hives despite taking H1 antihistamines. It is not approved for other forms of urticaria. Xolair is also known by its drug name, omalizumab.

Xolair is an anti-IgE (immunoglobulin E) monoclonal antibody, a type of biologic. Scientists believe it works by blocking IgE, a protein that triggers allergic reactions. By reducing the effects of IgE, Xolair may help control immune responses that lead to hives.

How do I take it?
Prescribing information states that Xolair is given as a subcutaneous (under the skin) injection once every four weeks. Xolair should be administered exactly as prescribed by a healthcare provider.

Side effects
Common side effects of Xolair include nausea, nasopharyngitis (common cold), sinusitis (sinus infection), upper respiratory tract infection, viral upper respiratory tract infection, arthralgia (joint pain), headache, and cough.

Rare but serious side effects may include anaphylaxis (a severe allergic reaction), which can occur after the first dose or even after more than a year of treatment. Signs of anaphylaxis include wheezing, low blood pressure, fainting, hives, and swelling of the throat or tongue. Other serious reactions may include malignancies (cancers), fever, rash, or joint pain suggestive of serum sickness (a delayed immune reaction), and eosinophilic conditions (disorders involving a type of white blood cell).

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Xolair (Omalizumab) Injection, for Subcutaneous Use — Genentech