Vandetanib is a prescription medication used to treat medullary thyroid cancer that cannot be treated by surgery or that has spread to other parts of the body. Vandetanib belongs to a group of drugs called kinase inhibitors which work by blocking the action of a protein that signals cancer cells to multiply.

This medication comes in tablet form and is usually taken once daily, with or without food.

Common side effects of vandetanib include diarrhea, nausea, rash, and acne.