Jae asked
How’s long is Valium detectable in the system?
Answer
Valium (diazepam) is a benzodiazepine medication that is noted for its long half-life when compared to other medications in the class. Due to the long half-life of the drug, data indicates that Valium is detectable in your system (i.e. on a drug test) for up to 30 days.
Valium Half-Life
Half-life refers to the time it takes for 50% of a drug to be metabolized and eliminated from the body. Therefore, drugs with a long half-life tend to be detectable on standard urine drug tests for a longer period of time than drugs with a short half-life.
The active ingredient in Valium, diazepam, has a half-life of around 48 hours while one of its metabolites (i.e. metabolism by-product), N-desmethyldiazepam, has a half life of nearly 100 hours. In addition, diazepam can accumulate in the body after prolonged and consistent dosing, which may prolong the half-life even further.
Diazepam, and its metabolites are excreted mainly in the urine, making standard urine drug tests a popular option for testing.
Most employers and medical offices use a simple, urine based immunoassay tests known as an EIA (Enzyme Linked Immunoassay) test. Immunoassay tests work by utilizing antibodies to react to specific drug compounds. A positive result will occur, when a specified drug is present in a test urine sample and an antibody binds to it. This produces a reaction which is recorded as a positive result.
How Long Is Valium Detectable?
Most immunoassay urine tests designed to detect N-desmethyldiazepam (also known as nordiazepam), not the parent compound (diazepam) according to studies. Therefore, to determine how long diazepam is detectable in your system (i.e. a drug test), you need to considered N-desmethyldiazepam, which has an extremely long half life.
Most sources state that N-desmethyldiazepam, the metabolite being tested for, will be detectable in your system on urine tests for up to 30 days. When we consider the 100 hour half life, this makes sense.
A general rule of thumb is that it takes around 5 half-lives for a drug to no longer be detectable in your system, which translates to 500 hours, or around 21 days for the diazepam metabolite N-desmethyldiazepam. Considering that diazepam can accumulate in the system, prolonging the half life, up to 30 days is a good estimate for how long it lasts in your system.
