How Long Does Ativan (Lorazepam) Stay In Your System?

Ativan, the brand name for lorazepam, is a benzodiazepine (benzo) commonly used to treat anxiety disorders. As a Schedule IV controlled substance in the United States, Ativan has the potential for abuse and dependence.
If you take Ativan you may be concerned with how long it stays in your system. Depending on several factors, lorazepam and its metabolite can stay in your system for at least 4 days. However, certain drug tests can detect trace amounts of the drug even longer.
How Ativan Works
As a benzodiazepine, Ativan enhances the neurotransmitter gamma-aminobutyric acid (GABA) in the central nervous system (CNS). Increasing the effects of GABA results in sedation, relaxation, and euphoria.
Along with sedation, side effects may include:
- drowsiness
- weakness
- dizziness
- unsteadiness
You may experience more intense side effects or a life-threatening overdose if you combine lorazepam with other CNS depressants. These drugs include alcohol, opioids, and hypnotic sleep-aids.
Effects Of Ativan
You should start to feel the effects of lorazepam within the first hour of taking it. It will reach peak plasma concentration levels in your system after about two hours. You will feel the most intense effects within these first two hours.
Half-Life Of Ativan
Elimination half-life refers to the amount of time it takes the amount of a drug in your system to reduce by 50 percent in your body. Most drugs need about five half-lives before they are eliminated from your body.
The half-life of lorazepam is about 12 hours and it should take about 2.5 days to be eliminated.
Your liver will break down lorazepam into a metabolite called lorazepam glucuronide. This metabolite has a half-life of 18 hours. After about 4 days lorazepam and its metabolites are eliminated from your system.
Drug Testing For Ativan
There are several drug tests that can detect lorazepam and its metabolites several days after your last dose. These are average time-frames because various factors can affect how long Ativan stays in your system.
Factors that affect detection times:
- dose
- frequency of use
- metabolism
- taking other medications
- health (especially of the liver)
Urine Tests
Urine testing is the most common and cost-effective drug test for benzodiazepines. Lorazepam can show up on a drug test two hours after ingestion and remain detectable for up to 6 days.
Blood Tests
Blood tests have a much shorter window of detection than urine screens. Lorazepam can be detected in blood six hours after your last dose and up to three days later.
Saliva Tests
Saliva has the shortest window of detection. It can detect lorazepam as soon as 15 minutes after ingestion and up to 8 hours later.
Hair Tests
Hair follicle tests are expensive but reliable for detecting most drugs for up to three months after last use. However, lorazepam is only reliable for about one month past last ingestion.
False Positive Drug Screens
According to the Food and Drug Administration (FDA), SSRIs (selective serotonin reuptake inhibitors), like Sertraline or Zoloft, may result in a false positive. Let your healthcare professional know of all prescription medications you are on while taking Ativan.
Ativan Addiction Treatment
Even if you take Ativan as prescribed, you may become addicted if you abuse it or take it for a long period of time.
Lorazepam withdrawal can become life-threatening and detox can provide you with supportive medical staff. Detoxes may use medications to ease severe withdrawal symptoms and help you safely taper from your medication.
Addiction is best treated with long-term aftercare programs, such as outpatient programs or inpatient rehab. These facilities can provide you with behavioral therapy that can address triggers and negative behavior patterns.
If you think you or a loved one may be addicted, please contact an Ark Behavioral Specialist for treatment options.
Written by Ark Behavioral Health Editorial Team
©2025 Ark National Holdings, LLC. | All Rights Reserved.
This page does not provide medical advice.
DailyMed - Ativan (Lorazepam) Tablets
Food and Drug Administration (FDA) - Drugs of Abuse Home Use Test
National Institute of Health - Windows of Detection of Lorazepam In Urine, Oral Fluid and Hair, With A Special Focus On Drug-Facilitated Crimes
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