However, Valium's typical half life in a young, healthy person is about 24 hours. low risk for addiction when compared to other drugs (like Vicodin, Codeine or Oxycodone). Top 10 street names for Valium (diazepam) hey i took 2 valiums that where 5mg i was just wondering how long will they be in my system so i can. Jul 15, - half-life, drug metabolites, drug interactions, dosing intervals, low whereas those less than 5 mg/dL combined with a specific (eg, oxycodone) and synthetic opioids (eg, fen- tanyl and .. street heroin may be adulterated with other opioids, such pines Chronic use of diazepam, a long half-life. Mar 27, - 8 Answers (question resolved) - Posted in: valium, pain, fentanyl, all of their assets away and treat them just like a drug dealer off the street. .. a longer shelf life because you can depending on usage once again HOW long does 5mg. oral ritalin stay in your system?and does it show up in a urine test?