Ambien sedative effects last for about 8 hours after you take the medication. But the half life of Ambien is only 1.5 hours. More on the duration of action and Ambien uses and side effects here. Plus, a section for your questions about Ambien at the end.mbien time in the body. After more than a day or two, it’s unlikely that Ambien will still be present in the blood. Ambien will show up on urine screens for 1-2 days, but can stay present in hair samples for 90 days or even longer.