Xolair, a popular anti-asthma drug, was linked to life-threatening side effects in clinical trials. The U.S. Food and Drug Administration (FDA) has warned about blood vessel side effects in the heart and brain. Another concern the agency has is a possible risk of cancer.

Xolair is an injectable drug that is primarily used for the prevention of asthma attacks. It is also sometimes used for patients who suffer from chronic hives. It is prescribed for those whose asthma cannot be controlled by inhaled corticosteroids. Xolair is also prescribed for off-label treatment of allergic rhinitis. Xolair has shown to decrease the frequency of worsening asthmatic episodes.

Xolair Side Effects

Xolair can cause a serious allergic reaction called anaphylaxis. The following are the most common symptoms of anaphylaxis:

• Trouble breathing caused by a narrowing of the airways (bronchospasm)
• Chest tightness
• Itching
• Hives/Rash
• Swelling of the tongue or throat
• Dizziness
• Fainting
• A drop in blood pressure

The risk of anaphylaxis from Xolair has been known since before the FDA approved the drug. In pre-marketing clinical trials, Xolair was found to cause serious anaphylaxis in one out of every 1,000 patients. Despite this risk, Xolair was allowed on the market with some warnings.

Due to numerous post-marketing reports of Xolair side effect risks, the FDA has ordered that additional warnings be included, and that Genentech provide a Medication Guide to all patients, warning them of these risks.

The Xolair FDA Black Box Warning

In February 2007, the FDA ordered the addition of a Xolair black box warning on all product packaging for this asthma treatment. A black box warning is the most serious caution the FDA can order short of pulling a medication off the shelves.

The FDA decided to order this additional Xolair warning because of the nature of the anaphylaxis reports the agency had received since the drug was approved, including the risk of fatal Xolair reactions, the frequency of Xolair side effects, and the risk of a delayed onset of adverse reaction.

Between June 2003 and December 2005, the FDA received 48 reports of anaphylaxis caused by Xolair. Of these patients, at least seven required hospitalization because of the severity of their Xolair adverse reaction.

The FDA also reports that Xolair anaphylaxis can occur long after the medication is administered. For example, a person may suffer a serious reaction to Xolair two to 24 hours after receiving the injection.

Additionally, the FDA states that an adverse Xolair reaction can happen after the administration of any dose. Patients who have taken Xolair in the past with no adverse reactions are still at risk for suffering the side effect anaphylaxis.