About a week
half life is about one day, meaning the amount of drug in your systems drops by 1/2 each day.
So there is 50% left after day 1, 25% after day 2, 12.5% after day 3, etc. So after about a week the drug is generally out of your system. Discontinuation symptoms, like feeling "brain zaps", can last 1 - 2 weeks after stopping the medication.