I've always been able to count on regular release Ambien to put me to sleep within twenty minutes and to keep me asleep all night. One caution, though: At least in my experience, Ambien with an antipsychotic will knock you out cold. I was taking Ambien before Seroquel was added. Seroquel, in addition to being an antipsychotic, is a pretty good sleep aid as well. The combination had me sleepwalking and sleepeating. I wouldn't have heard a fire alarm go off. I only take Ambien now when Seroquel doesn't let me drift off to sleep.