Belinda asked
How long does lorazepam stay in your urine?
At a glance
- Every person metabolizes lorazepam at a slightly different rate; however it has a half-life of 10-20 hours on average. Additionally, the primary metabolite has a half-life of about 18 hours.
- It depends on the test itself. If a test was specifically looking for lorazepam or its primary metabolite, it would be detectable for 9-10 days.
Answer
Hi Belinda and thank you for your question.
Every person metabolizes lorazepam at a slightly different rate due to things like genetics, age, kidney function, liver function, etc. For most adults, I’ve found that it has a half-life of 10-20 hours, or the time it takes your body to metabolize half of the dose.
For example, if you took a 1mg dose of lorazepam and you were a slow metabolizer (it has a half-life of about 20 hours), after 20 hours, 0.5mg would still be in your body. After another 20 hours, 0.25mg would be in your body. We usually consider a drug to be entirely metabolized after 5-6 half-lives. Now, lorazepam isn’t entirely eliminated during this timeframe. It’s metabolized into an inactive form called lorazepam-glucuronide which seems to have a half-life of about 18 hours.
All that being said, it depends on the sensitivity of the test itself which is going to be determined by the lab. If a test is looking specifically for lorazepam and lorazepam-glucuronide, it would be detectable for a while, especially if it’s a medication that’s taken routinely. I’ve found cases where it’s detectable for up to 9 days. If the lab is using a less specific and less sensitive test, you only take your lorazepam rarely and as needed; I imagine that a urine drug screen would show negative after just a few days.
References
- Lorazepam Monograph, PubChem
- Lorazepam-glucuronide Information, PubChem
- Metabolism of Lorazepam , British Journal of Anesthesia
- Goodman and Gilman’s The Pharmacological Basis of Therapeutics
