How Long Does Diazepam Stay in Your System?

Know How Long Diazepam Has Effects and Can Be Detected in Drug Tests

Diazepam is a prescription sedative that you may know by its brand names of Valium, Diastat, Dizac, and Valrelease. It may be prescribed for treating anxiety, muscle spasms, seizures, or to control agitation during alcohol withdrawal. Knowing how it affects your system and for how long can help you understand why you should only take it as directed and avoid interactions with alcohol and other drugs.

Diazepam may also test positive on a urine drug screen and blood drug screen for up to 10 days, but much longer for high-level use. This is important to know if you are going to have a screen for employment or other purposes. If you have a prescription for diazepam, report this when you are tested so it is accounted for during the test. It may also be detected via a saliva test that may be used for impaired driving.

How Long Does Diazepam Affect Your System?

Diazepam is a long-acting benzodiazepine. It is active in your system longer than some other sedatives of this type. How fast it takes effect depends on how it is taken. If taken orally with food, it takes about 45 minutes to take effect but will take effect in 15 minutes if you take it on an empty stomach. It reaches peak effects in 1.5 to 2.5 hours and the effects last for 4-6 hours after a therapeutic dose. It is slowly metabolized and has a half-life of up to 48 hours.

The absorption and effects of diazepam are influenced by food and also by many other medications and substances such as antacids, alcohol, and even smoking. These can either reduce the effects of the medication or enhance them. Discuss all of the medications you take with your doctor so you will get the correct dosage and instructions to prevent side effects and possibly dangerous drug interactions.

Prevent Severe Diazepam Side-Effects

Serious side-effects of diazepam can be avoided by knowing how long in remains in the system so that the dosage is not repeated too quickly. Do not drink alcohol or use street drugs while taking diazepam or you can risk life-threatening side effects. If you experience any of the following symptoms, call your healthcare provider immediately:

How Long Is Diazepam Detected in Drug Screening Tests?

Diazepam can be detected for a shorter time with some tests but can be "visible" for up to three months in other tests. How often you take Valium and the strength of the dosage can also play a role in how long in remains in the system.

The timetable for detecting diazepam in the system is also dependent upon each individual's metabolism, body mass, age, hydration level, physical activity, health conditions and other factors, making it almost impossible to determine an exact time diazepam will show up on a drug test.

The detection window in a urine drug screen is generally up to 10 days, but depending on individual variation, the amount of the drug, and other factors it might be detected for up to 6 weeks with high-level use.

It is detectable in blood tests for 6-48 hours and in saliva for 1-10 days. Diazepam, like like many other drugs, can be detected with a hair follicle drug test for up to 90 days.

If you have been prescribed diazepam, do not discontinue using it without consulting with your doctor.


Approximate Detection Times. Drugs of Abuse: Mayo Medical Laboratories.

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Diazepam. MedlinePlus NIH.

Drugs of Abuse Testing. American Association for Clinical Chemistry Lab Tests Online. Updated May 19, 2016.

Toxicology Screen: MedlinePlus Medical Encyclopedia. NIH MedlinepPus. Updated 1/26/2015.

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