Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Xolair (Omalizumab).

Acute asthma attacks: Xolair (Omalizumab) will not help to stop an asthma attack and should not be used to treat an acute asthma attack. If you start developing an asthma attack, be sure to use your "reliever" medication for rapid relief of your asthma symptoms. Contact your doctor immediately if you find you are using your "reliever" medications (e.g., salbutamol, terbutaline, formoterol) more often or if they are not working as well as they used to.

Cancer: Although early studies comparing those taking Xolair (Omalizumab) and those not taking Xolair (Omalizumab) showed a small difference in the percentage of people developing cancer, additional observation and studies have shown that this is not the case.

Corticosteroid withdrawal: Oral or inhaled corticosteroids for asthma should not be stopped suddenly when treatment with Xolair (Omalizumab) is started. Decreases in corticosteroid doses should be closely supervised by your doctor. Check with your doctor before stopping or decreasing the dose of any of your asthma medications.

Heart problems: Xolair (Omalizumab) has been linked to heart problems, although the exact frequency with which this happens is not clear. If you have any heart problems, such as abnormal heart rhythms, heart failure, or a history of Heart Attack, discuss with your doctor how Xolair (Omalizumab) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xolair (Omalizumab), and whether any special monitoring is needed.

Kidney function: Xolair (Omalizumab) has not been studied for use by people with kidney problems. If you have reduced kidney function or Kidney Disease, discuss with your doctor how Xolair (Omalizumab) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xolair (Omalizumab), and whether any special monitoring is needed.

Liver function: Xolair (Omalizumab) has not been studied for use by people with liver problems. If you have reduced liver function or liver disease, discuss with your doctor how Xolair (Omalizumab) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xolair (Omalizumab), and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Xolair (Omalizumab).

Parasite infections: Xolair (Omalizumab) may weaken your resistance to parasite infections. If you are living in or travelling to a region where parasite infections are frequent, discuss with your doctor any special precautions that may be needed.

Serum sickness: In rare cases, serum sickness can occur with the use of Xolair (Omalizumab). This is a delayed allergic reaction that can happen at any time during treatment with Xolair (Omalizumab) and occurs between 1 and 5 days after an injection. If you experience painful joints or muscles, swollen lymph nodes with a rash and fever, contact your doctor immediately.

Severe allergic reactions: Although rare, severe allergic reactions to Xolair (Omalizumab) may occur. After your injection, the doctor may ask you to remain at the office or clinic for a short period of time. This way, if you do have an allergic reaction, medical attention will be nearby.

If you experience sudden difficulty breathing, fainting, swelling of the throat or tongue, or severe dizziness (especially when rising from a sitting or lying position), get medical attention immediately.

Stroke: Although rare, there is the possibility of experiencing a stroke when using Xolair (Omalizumab). If you have a history of stroke or are at risk of stroke, discuss with your doctor how Xolair (Omalizumab) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Xolair (Omalizumab), and whether any special monitoring is needed.

If you experience weakness or inability to move arms, legs, or face; numbness on one side of the body; difficulty speaking or understanding; loss of vision; or sudden headache, get medical attention immediately.

Pregnancy: Xolair (Omalizumab) has not been studied for use by pregnant women. Xolair (Omalizumab) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Xolair (Omalizumab), contact your doctor immediately.

Breast-feeding: It is not known whether Xolair (Omalizumab) passes into breast milk. If you are a breast-feeding mother and are taking Xolair (Omalizumab), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of Xolair (Omalizumab) for the treatment of allergic asthma have not been established for use by children under the age of 6 years of age. The safety and effectiveness of Xolair (Omalizumab) for the treatment of chronic idiopathic urticaria have not been established for use by children under the age of 12 years of age.