Native American History. Native American cultures in the United States include a wide array of socially and geographically diverse groups, whose nomadic ancestors are believed to have traveled via a long-gone land bridge across the Bering Strait at least 13,000 years ago.
182. Valium can stay in your system and be detected in urine for up to 5-7 days after therapeutic use. Chronic use (over one year) of Valium, however, can be detected much longer. The detection window for Valium in urine screens is up to 4-6 weeks. More here on the detection window and drug testing for Valium.
Valium duration of action. The half-life of Valium is 20 hours, sometimes longer. It reaches peak levels in the blood just 1-1.5 hours after being taken. Despite taking several days to leave the body, the effects wear off within 4-6 hours, so it does need to be taken throughout the day.