Hi- The safest way is to talk with a physician. Barbiturate withdrawal is serious and dangerous; it needs to be done correctly. The secret is to taper a little and slowly but you need a doctor to put that in place. It's dangerous to stop cold turkey!
Good luck and stay in touch!
Have you tried before, and if so, what stopped you? Withdrawal, or just not ready? Has tolerance increased? What were you taking 3 months ago? Not being nosy, but have a little experience here, and the more I know, the better I may be able to help.