Severe. These medicines may interact and cause very harmful effects and are usually not taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Vaccines cause the body to produce antibodies to protect you against infections. Because efalizumab decreases your body's ability to fight infections, the vaccine may not work.
What might happen:
The vaccine may not work.
What you should do about this interaction:
Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking efalizumab before any vaccinations. The vaccination may need to be delayed until your immune system is working better or it may need to be repeated after you are done taking efalizumab.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Raptiva (efalizumab) US prescribing information. Genentech, Inc. March 13, 2009..