How lone does 4Mg of diazepam taken one time stay in system?

Diazepam has a half-life that can range from about 20 to 50 hours, depending on individual factors like metabolism, age, and overall health. After a single dose of 4 mg, it may take several days for the drug to be eliminated from the system. Generally, diazepam and its metabolites can be detectable in urine for up to a week or longer after use. However, the effects of the medication will typically wear off much sooner, usually within a few hours.