Can an acth (cosyntropin) test make me sick?

Unlikely : It's a hormone produced by the body and the action is short lived. It's unlikely to make you feel sick. Some patients actually feel much better during the test as the body starts responding by increasing cortisol production.

Not usually: Cosyntropin breaks down very quickly after it is given, so any symptoms are usually very short-lived (3-5 minutes). These symptoms may include flushing, feeling hot, lightheadedness, nausea, funny taste in the mouth, and feeling like you have to urinate. These symptoms can be alarming because they occur suddenly, but do go away quickly. Fortunately, most people have no symptoms at all.