What are the side effects of abatacept?

The most common side effects of abatacept are:
  • headache,
  • upper respiratory tract infections and
  • nausea.
Because abatacept depresses the immune system it reduces the body's ability to fight infection. Therefore, existing infections may worsen or new ones may develop. Other important side effects include infusion-related reactions such as:
  • dizziness,
  • headache,
  • hypotension,
  • hypertension,
  • nausea,
  • wheezing,
  • rash, and
  • shortness of breath.
The most serious side effects are infections and cancer.

Source: http://www.medicinenet.com