can someone explain to me how half lives work?

[warmduck]

lets say someone who has no tolerance to drugs takes 20mg of xanax

they will obviously be severely intoxicated within 30 minutes.

since the half life of xanax is 11 hours, does this mean that there will be 10mg of xanax left in their blood, a still very high dose?

and 22 hours later, there will be 5MG of xanax. a still very high dose.

so how long would they be intoxicated for total? like a whole 24 hours? It only takes about 2mg of xanax to make a noobie feel out of it.


im just trying to understand how the half lives of drugs work, i am not stupid enough to take this high of a dosage. :D

 

[BeachBum4u]

Basically, I think you've got it.

 

[crzydiamond]

You understand the concept of half lives. (The amount of time it takes 50% to leave the body)

What is confusing you is the time you feel the effects. That can be completely different from the half life. Just because a drug had a certain half life doesn't necessarily mean you feel the effects for the same time...

Google half lives and duration of action, that can explain it better than me probably.

 

[warmduck]

You understand the concept of half lives. (The amount of time it takes 50% to leave the body)

What is confusing you is the time you feel the effects. That can be completely different from the half life. Just because a drug had a certain half life doesn't necessarily mean you feel the effects for the same time...

Google half lives and duration of action, that can explain it better than me probably.

if a noobie took 20mg of xanax. it would take 33 hours in order for 3 mg of xanax to be in their blood

11 hours - 10 mg / 50%
22 hours - 5 mg / 25%
33 hours - 3 mg / 13%
44 hours - 1 mg / 6%
55 hours - 1 mg / 3%
66 hours - 0 mg / 1%
77 hours - 0 mg / 0%

Source: Drug Half Life Calculator - Drugsdb.com http://www.drugsdb.com/resources/drug-half-life-calculator/#ixzz3roeR1Gdd



Does this mean that for 33 hours, they would be very intoxicated on xanax?

 

[belligerent drunk]

Not necessarily. For one, tolerance develops. Secondly, "feeling" it is subjective, so after the a lot stronger effects become weaker, you may mistake it for "not feeling" it, even though there's still a considerable amount of the drug in you. I doubt you'd feel intoxicated for more than 24 hours off a single 20 mg. What would follow is what people call "afterglow", as in you're not really intoxicated, but still not really back to baseline - feeling nice.

 

[crzydiamond]

No. Not at all. The half life of Xanax is 11 hours. Half life has to do with how long it takes the drug to leave your body

What you want to know about is called "duration of action"--that's how long you actually feel effects

With Xanax, you hit peak effects around 2 hours, and after 4 hours its effects are almost gone from the body, which is why it is often prescribed to be taken multiple times per day