Ativan Half-Life, Peak Concentration & Duration

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How long does Ativan last for?

Ativan typically lasts from 6-8 hours and is out of the system after 72 hours. The drug’s effect will first be felt within 2 hours after administration, and the drug’s half-life is between 12 and 18 hours. When taken orally, the drug is absorbed through the gastrointestinal tract.

Ativan Half-Life

Ativan (Lorazepam) is a drug that’s used to treat generalized anxiety, insomnia, nausea, and seizures. It’s also used in hospitals to sedate aggressive patients. Ativan is an active benzodiazepine and some people abuse the drug due to its recreational effects.

Recreational use equals abuse and is illegal. Note that Ativan is habit-forming and even administered as prescribed, the drug can induce tolerance and lead to dependency.

Ativan has an intermediate half-life. Users and medical data prove that its half-life is longer than Xanax but shorter than Valium. The average half-life of Ativan is around 12 hours, but some studies suggest that it could be up 18 hours.

Note that the primary metabolite of Lorazepam, Lorazepam Glucuronide, has a longer half-life: up to 18 hours.

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Ativan Peak Concentration

The peak concentration of the drug occurs up to 2 hours after intake. Although it doesn’t take too long to kick in, people who take Ativan to treat anxiety and seizures may not notice improvement for a few weeks. Ativan is absorbed directly by the gastrointestinal tract when the drug is taken orally. The drug can be administered intravenously as well.

Ativan Duration

Users can feel the initial kick of the drug up to 2 hours after administration, as stated above. The effects Ativan has typically will last from 6-8 hours. When the drug is prescribed by a health professional, multiple doses every day are recommended.

Note that when Ativan is taken intravenously, the drug has a longer duration.

Although there’s minimal risk of excessive accumulation in the system, Ativan shouldn’t be taken over extended periods because it can be habit-forming and can have various life-threatening withdrawal symptoms.

How Long Does Ativan Stay In The System?

Research shows that usually, Ativan is out of the system after 72 hours. Those figures also rely on Ativan’s half-life. Some studies suggest that if the average half-life of the drug is 12 hours, then it will take up to 3 days for someone to get clean. However, some tests show that the half-life of Ativan is around 15.7 hours, meaning it would take 3.59 days for the body to rid itself of the drug.

Various factors influence how long Ativan can stay in the body:

  • Individual factors (age, weight, height, genetics, general health)
  • Dosage (note that the body metabolizes higher doses at a slower pace)
  • Frequency and history of abuse
  • Other drugs (data shows that alcohol, for example, reduces the clearance by 18%)

Depending on different factors, Ativan can still be detected in the body for up to 6 weeks after cessation.

Before one starts taking Ativan, it is important to learn more about its side effects and abuse potential. Never stop the drug abruptly because it can lead to fatal withdrawal symptoms. Always consult a doctor for the right dosage, a course of administration and available treatment options.

View Sources
  1. Greenblatt D. J. Clinical pharmacokinetics of oxazepam and lorazepam. Clinical Pharmacokinetics. 1981; 6(2):89-105.
  2. The U.S. Department of Health & Human Services. Lorazepam – Medical Countermeasures Database. 2019.
  3. The U.S. Food and Drug Administration. Ativan® CIV (lorazepam) Tablets Rx only. 2007.


Leave a comment

  • Sol
    I’ve heard that irritability can set in as the Ativan wears off that is significant. I’ve also heard Ativan use correlates to having automobile accidents more frequently due to Ativan’s blocking normal (healthy) inhibitions. Is any of this true?