How Long Do Benzodiazepines Stay in Your System?
Benzodiazepines or “benzos” are a class of prescription medications used to treat anxiety and seizure disorders. Examples of common oral benzodiazepines (and their brand names) include:
- Alprazolam (Xanax)
- Chlordiazepoxide (Librium)
- Diazepam (Valium)
- Lorazepam (Ativan)
- Temazepam (Restoril)
Each benzodiazepine stays in the body for different amounts of time, depending on the drug. For example, some benzodiazepines are more soluble in fat tissue and accumulate, causing them to stay in the body longer. Others cannot be broken down and must be excreted by the kidneys instead of the liver.
All benzodiazepines are Schedule IV substances according to the Drug Enforcement Agency (DEA). Schedule IV substances have recognized medical usage but the potential for abuse and addiction.
Duration of Effects of Benzodiazepines
Duration of action is how long a drug works to treat the condition it was prescribed for. Each benzodiazepine has a different length of effect based on its pharmacological properties.
Some of the most common benzodiazepines and the duration of their effects include:
- Alprazolam: 2–4 hours
- Diazepam: 6–8 hours
- Chlordiazepoxide (Librium): 6–8 hours
- Lorazepam: 4–6 hours
- Temazepam: 4–6 hours
A drug’s half-life is how long it takes for the body to remove half of the drug. Drugs are completely removed from the body in about five half-lives.
Examples of benzodiazepine half-lives are:
- Alprazolam: 11 hours
- Diazepam: 60–72 hours
- Chlordiazepoxide (Librium): 24–36 hours
- Lorazepam: 12 hours
- Temazepam: 4–18 hours
Benzodiazepines Drug Test Detection Time
How long benzos can be detected on a drug screening depends on the method of testing. The most common type of drug test is a urine drug screen because it is not invasive or expensive. Blood tests are much less common because the detection window is smaller, and blood draws are invasive.
Urine Detection Time
Benzodiazepines can be detected in urine for up to 30 days.
Blood Detection Time
Benzodiazepines may be detectable in the blood for 1–15 days, depending on the benzodiazepine.
Saliva Detection Time
Benzodiazepines may be detectable in saliva for up to 50 hours after ingestion.
Hair Detection Time
Hair testing is unique because it measures the last 90 days of drug use. Since hair grows at a fixed rate of about 0.5 cm per month, hair drug tests look back three months by taking 1.5 cm of hair. Hair tests have the longest detection window but can be expensive, so they aren’t used very often.
Factors that Affect How Long Benzos Stay in Your System
Individual characteristics play a large role in the metabolism of benzodiazepine drugs, such as:
- Age: Older adults have a shift from muscle (lean) tissue to more fat (lipophilic) tissue. For this reason, benzos can accumulate and stay in the body for longer.
- Weight & Body Fat: Many benzodiazepines are lipophilic, meaning they dissolve and stay in fat tissue. Because of this property, people at higher body fat percentages may accumulate benzodiazepines for longer than people with more lean muscle.
- Type of Benzo Taken: This has the biggest impact on detection time. In general, the benzodiazepines that are detectable for the longest amount of time are clonazepam (Klonopin), diazepam (Valium) and flurazepam (Dalmane).
- Liver and Kidney Function: Most benzos are broken down by the liver, so someone with impaired liver function will store the drug in their body for longer. Some may also be excreted by the kidneys, which means that impaired kidney function can also affect storage time.
- Frequency of Use: More frequent benzo use lengthens detection time.
False Positives for Benzodiazepines
Drugs that are known to cause false-positive for benzos include:
A positive result will be confirmed with liquid- or gas chromatography/mass spectrometry (LC-MS or GC-MS). These types of tests are very sensitive and specific and measure the individual “fingerprint” of a drug.
How Are Benzodiazepines Metabolized in the Body?
Benzodiazepine metabolism varies depending on each drug. For information about a specific drug, people should speak with their doctor or pharmacist.
Benzodiazepines stay in the blood for a long time, and the only guaranteed way to pass a drug test to not use benzos. If you or someone you know is struggling to stop using benzodiazepines, call The Recovery Village Ridgefield. Our team of addiction professionals can answer your questions and guide you down the right treatment pathway.
Cone, Edward. “Interpretation of Oral Fluid Tests for Drugs of Abuse.” 2007. Accessed Aug 5, 2019.
DailyMed. “Alprazolam Package Insert.” 2017. Accessed Aug 5, 2019.
DailyMed. “Chlordiazepoxide Package Insert.” 2019,. Accessed Aug 5, 2019.
DailyMed. “Diazepam Package Insert.” 2011. Accessed Aug 5, 2019.
DailyMed. “Lorazepam Package Insert.” 2018. Accessed Aug 5, 2019.
DailyMed. “Temazepam Package Insert.” 2019. Accessed Aug 5, 2019.
DEA Office of Diversion Control. “Benzodiazepines.” 2013. Accessed Aug 5, 2019.
Moeller, Karen E., et al. “Urine Drug Screening: Practical Guide for Clinicians.” 2008. Accessed Aug 5, 2019.