Side effects

The side effects of targeted therapy are different and usually less toxic than those of the more standard chemotherapy.

They still occur because, although targeted therapies are aimed at molecules more common in tumor cells, they usually also exist in healthy cells.

The side effects in targeted therapy are more frequent when there is more than one target, but especially when its action is to be felt throughout the body (e.g., treatments that inhibit the formation of blood vessels).

Reactions include skin changes, high blood pressure, possible bleedings, blood clots, or delayed healing (these last ones from drugs that block blood vessel formation). 

Less common side effects include fever, feeling weak or cold, nausea, vomiting, cough, diarrhea, and headaches.