• Neuroscience & Pharmacology Discussion Welcome Guest
    Posting Rules Bluelight Rules
    Recent Journal Articles Chemistry Mega-Thread
    FREE Chemistry Databases! Self-Education Guide

  • N&PD Moderators: Skorpio

half-life and detection in urine

B

bantaren

Bluelighter
Joined
Aug 30, 2007
Messages
35
I signed up to participate in a clinical study for a new drug. However I'm currently on escitalopram 10 mg/day. It has a half life of 30 h and the main metabolites even longer. How many days before the start of the study will I have to stop the escitalopram if I don't want it to be detected in my urine? In other words, what is the correlation between the half life and later detection in a urine sample?
 
Drug testing questions aren't allowed.

However, there is software available (usually as an applet) that allows you to calculate material left after radioactive decay. This isn't radioactive decay, but the math is the same. You enter half life and start volume and time passed, and it will output how much will be left.

This is fairly complicated though, because you'll have to determine what percentage of the starting material is converted to the various metabolites in order to determine starting quantities for these drugs.
 
Escitalopram isn't really a drug of abuse, or even intoxicating, hence employers and legal authorities won't test for it. Since this is the case, half-life is what the question's really about. Its lexapro, right? I was on it for quite a while myself, the half life is roughly 27-32hrs, possibly somewhat longer if it has been taken at intervals shorter than 27hrs (once a day) for more than a week. Half life will also be increased by decreased liver function, as its metabolized mostly in the liver. Lexapro is metabolized into S-demethylcitalopram (S-DCT) and S-didemethylcitalopram (S-DDCT). The latter of which isn't really even detectable. The former, S-DCT is, but plasma levels only reach 1/3 of peak levels of escitalopram, and hence wouldn't be there for more than a couple or three days at the longest, in my opinion.

EDIT: I read up on all this to mitigate the dulling effect SSRI's had on my psychedelic experiences during the few years I was on various SSRI's. ha
 
Last edited:
Did you tell the clinical trial people you're taking it? Because there could be some reaction with the SSRI that's very bad for you, or very bad for them (deaths don't exactly get drugs approved). If so, then they should have given you clear instructions for when to stop taking it, if you can still take it, etc.

If you haven't told them....you really shouldn't be in their clinical trial.
 
Four half-lives is generally considered to be the point at which the drug can no longer easily be detected in blood, urine etc. Fat-soluble drugs can be sequestered into fatty tissue for longer periods, but this shouldn't be an issue with citalopram.
 
Right. What is the study for though? SSRIs are relatively benign, but combining them with other things that raise serotonin levels is a bad idea.
 
I would also like to know what drug is being tested. Always on the look out for nearby open clinical trials for interesting drugs. Is it Rolipram? Or an SNDRI?
 
Thank you for your great answers!

The drug being tested is to be used to against a disease that ranked sixth as the cause of death in 1990, worldwide.
 
bantaren said:
...How many days before the start of the study will I have to stop the escitalopram if I don't want it to be detected in my urine?...
Click to expand...

Zero days! Simply snort a healthy amount of coke a few hours before the study: they won't even bother to look for the ssri.

What makes you think they'll test you for an ssri?
 
You must log in or register to reply here.
Top