Could someone please tell me how long it will take before Dasatinib is out your system after stop using this medication? My mom is seriously ill from this medication and it does not stop. ## Hello, Christina! How is your mom doing? This is a medication that is used to treat cancer and they are well known to cause a lot of side effects, you aren't going to find one that doesn't. What symptoms is she experiencing? The U.S. FDA lists the typical ones for this medication as possibly including nausea, dizziness, headache, weight loss, and high blood pressure.