I could not find anywhere a half life indication for it. However, if you have not been on it
long, there should be no
withdrawal effects. It is like adderall ( a stimulant) and should be out of your system fairly quickly. Of course, it does depend if you took the extended release version or not. Essentially, if you look at the label, the time it gives between doses plus half again should be a pretty good indicator that most of it is out of your system.