The most common side effects of abatacept are headache, dizziness, cough, and upset stomach. People may also get more infections such as colds or bronchitis.

Studies looked at people with RA taking abatacept. They compared them to similar people with RA taking a placebo. A placebo (sugar pill) does not contain any medicine. Studies use it to figure out what symptoms are actually due to medicine versus those that would occur normally. This table shows the most common side effects of abatacept found in these studies.

Abatacept Side Effects - PFT

Let’s Do the Math

Dizziness occurs in both RA study groups. Dizziness occurred in:

  • 9 out of 100 people taking abatacept
  • 7 out of 100 people taking a placebo

    So, 9 – 7 = 2 people.
    Dizziness may be due to abatacept in 2 out of 100 people.

Other Side Effects

Less than 5 out of 100 get herpes simplex or pneumonia. Less than 1 person has other reactions to the IV, like itching or a rash, but these reactions are usually not serious.

Between 5 and 13 people out of 100 get infections like an upper respiratory infection (URI), sinus infection, urinary tract infection, influenza, and bronchitis. These infections also happen to people who are not taking abatacept, but not quite as often. People with chronic obstructive pulmonary disease (COPD) and people who have had a serious infection in the past may need to be more careful when taking abatacept. Some but not all studies suggest their risk of serious infections is higher.

The Bottom Line

All medicines can cause side effects. All people react differently to medicines. As studies show, not everyone gets side effects from abatacept. Luckily, the most common side effects tend to be minor. Still, always talk to your doctor if you have concerns or experience side effects.

Side effects may be few, but tell your doctor if they happen to you!