Like all medicines, this medicine can cause side effects, although not everybody gets them. The side effects caused by omalizumab are usually mild to moderate but can occasionally be serious.
Common side effects:
Reactions at the injection site including pain, swelling, itching and redness
Pain in the upper part of the tummy
Uncommon side effects
Feeling dizzy, sleepy or tired
Tingling or numbness of the hands or feet
Fainting, low blood pressure while sitting or standing (postural hypotension), flushing
Sore throat, coughing, acute breathing problems
Feeling sick (nausea), diarrhoea, indigestion
Itching, hives, rash, increased sensitivity of the skin to sun
Serious, but rare side effects:
Sudden severe allergic reactions: if you notice any serious sudden signs of allergy or combination of signs such as rash, itching or hives on the skin, swelling of the face, lips, tongue, larynx (voice box), windpipe or other parts of the body, fast heartbeat, dizziness and lightheadedness, shortness of breath, wheezing or trouble breathing, or any other new symptoms, tell your doctor or nurse immediately.
Development of one or more of the following symptoms: swelling, pain or rash around blood or lymph vessels, high level of a specific type of white blood cells (marked eosinophilia), worsening problems with breathing, nasal congestion, heart problems, pain, numbness, tingling in the arms and legs (signs of “Churg-Strauss syndrome or hypereosinophilic syndrome”).
Low blood platelet count with symptoms such as bleeding or bruising more easily than normal.
Development of any of the following symptoms, especially if in combination: joint pain with or without swelling or stiffness, rash, fever, swollen lymph nodes, muscle pain (signs of serum sickness).
If you or your child experience any of these, tell your doctor or nurse straight away.
Talk to your doctor before you or your child is given Omalizumab: