Harm Reduction All Drugs - Short Half-Life vs. Long Half-Life Drugs

[dalpat077]

I've noticed discrepancies both when is comes to understanding what the half-life of a drug actually means as well as incorrect half-lives of certain drugs being misquoted (particularly when it comes to "long acting" vs. "short acting" benzodiazapenes). For most of the old-timers and experienced here: this is probably old news and there's probably already a thread or two about this (although as I said: some of the inaccuracies and incorrect information I've seen on a few threads when it comes to withdrawal I found rather concerning). And for new members: this information may be worth something (most only read the first two or three pages of topics on a forum and give up or move on and/or refuse to use the search function).

AdCare: Drug & Alcohol Rehab in Rhode Island and Massachusetts

Drug & alcohol rehab centers in Rhode Island and Massachusetts, providing both inpatient and outpatient addiction treatment services.

sunrisehouse.com

By the way: there's also some pretty interesting and useful links that show up on the top right hand corner of each page.

For verification purposes here's a table from Prof. Ashton's Manual:

Table 1

 

[Jabberwocky]

Interesting. I had my understanding of Valium and Xanax completely backwards if this is correct.

 

[dalpat077]

There's a difference between "elimination half-life" and "plasma half-life".

 

[dalpat077]

Interesting. I had my understanding of Valium and Xanax completely backwards if this is correct.

I took a look at this again after your post. And maybe the exact reason for the confusion (both your's and mine) is indeed the difference between "elimination half-life" and "plasma half-life".

Take a look at Valium:

Valium (diazepam): Considered a short-acting benzodiazepine (benzo) sedative and hypnotic drug prescribed for the short-term relief of anxiety or panic disorders, Valium has a short elimination half-life of 2-4 hours but a much longer plasma half-life; therefore, it can remain detectable in urine for several days, per the S. Food and Drug Administration (FDA) prescribing information.

Take a look at Xanax:

Xanax (alprazolam): A longer-acting benzodiazepine, Xanax has a plasma-elimination half-life of around 11 hours. Librium (chlordiazepoxide) is an even longer-acting benzodiazepine drug.

Maybe that explains the confusion,

And of course I make the assumption that because the original article is published by "Sunrise House" it should in fact be correct information.

 

[Lorne???]

YES!

Valium (diazepam) is a short acting drug, not just because of it 's elimination, though also it's lipophillicity; highly lipophillic drugs can NEVER be long lasting because they hide in fatty tissue (preferring the heart and other organs)

Valium is also a fast acting drug, with a Tmax of less than 100 minutes - yet another reason it is not long acting

Xanax is also a rapid acting Benzodiazepine, however it last slightly longer than Valium, as does nordazepam (Tranxene)

Clonazepam is the granddaddy of Benzodiazepines; it is the longest lasting RX Benzodiazepine and most potent

Lorazepam (Ativan) is also long lasting, because of its poor lipophillicity, allowing it to hang around for several hours despite its apparent T1/2

Both it and Clonazepam have equal lipophillicity (well Clonazepams is just a tad lower) and so both are long lasting Benzodiazepines. Klonopin happens to have the longer elimination half life, so combined with its low lipo figure, it is the champ

I will try to give that a read later, though one thing is clear: Ashton did NOT understand how the elimination of Benzodiazepines and the disposition worked

Thanks

 

[Lorne???]

Wow

It actually says to replace Valium with Librium, Clonazepam, or even Xanax!

It also correctly states that Methadone and Buprenorphine are the best for detox or ORT, yet oddly, they did not seem to understand that heroin is an inactive (basically) prodrug for Morphine and, to a MUCH lesser extent, MAM

Anyway interesting read I may click on the Benzodiazepine section and find out if there is any more info about Klonopin; it's plasma half life is 7-14 hours, I think (at least that would match the duration of action )

Thank You again

 

[Las Veghost grower]

So there 2 half-life times, one for duration of action and one for time it’s in the bloodstream ?

 

[G_Chem]

Another thing that surprised me and that I didn't know:

There's a difference between "elimination half-life" and "plasma half-life".

I’ve always kinda “knew” this but first time I’ve ever had someone explain it to me...

I remember reading over plasma half lives of drugs and feeling like for some drugs they simply didn’t match the duration of said substance.

MDMA is one which doesn’t really match its half life completely in duration. Cocaine is one which does.

I think this might have something to do with receptor and/or enzyme saturation which I clearly don’t fully understand. Look at the “redosability” of MDMA vs Cocaine too and we see cocaine redoses a lot better.

-GC

 

[ageingpartyfiend]

Have always been confused why I always 'feel' xanax for much longer than valium - from all I've read I thought it was just a quirk of my metabolism - seems not

 

[Lorne???]

^ It is mostly because Valium is more lipophillic, so it is rapidly redistributed from Blood into tissues

Yes, there are two half lives: one is basically what matches the duration better, the amount of time you have full free fraction plasma concentrations, and the other is how long it takes for half of the drug to be completely eliminated from the body; Valium has a short redistribution phase, and then a much longer, more gradual elimination phase, so it is described as being biphasic

I try to explain this to people and, well some listen, others just refuse to acknowledge the obvious and the truth.

What will effect a drugs duration are many factors, among them, its redistribution "half- life " and another its solubility, which are directly correlated

Yes, cocaine has a duration that matches its T1/2, Valium and nordazepam/Tranxene do NOT

Really, this is a nice find

 

[dalpat077]

On the Klonopin issue:

"Some doctors in the US switch patients onto clonazepam (Klonopin, [Rivotril in Canada]), believing that it will be easier to withdraw from than say alprazolam (Xanax) or lorazepam (Ativan) because it is more slowly eliminated. However, Klonopin is far from ideal for this purpose. It is an extremely potent drug, is eliminated much faster than diazepam (See Table 1, Chapter I), and the smallest available tablet in the US is 0.5mg (equivalent to 10mg diazepam) and 0.25mg in Canada (equivalent to 5mg Valium). It is difficult with this drug to achieve a smooth, slow fall in blood concentration, and there is some evidence that withdrawal is particularly difficult from high potency benzodiazepines, including Klonopin. Some people, however, appear to have particular difficulty in switching from Klonopin to diazepam. In such cases it is possible to have special capsules made up containing small doses, e.g. an eighth or a sixteenth of a milligram or less, which can be used to make gradual dosage reductions straight from Klonopin. These capsules require a doctor's prescription and can be made up by hospital pharmacists and some chemists in the UK, and by compounding pharmacists in North America. A similar technique can be used for those on other benzodiazepines who find it hard to substitute diazepam. To locate a compounding pharmacist in the USA or Canada this web site may be useful: www.iacprx.org. Care must be taken to ensure that the compounding pharmacist can guarantee the same formula on each prescription renewal. It should be noted, however, that this approach to benzodiazepine withdrawal can be troublesome and is not recommended for general use."

Taken from this page: Chapter II

 

[Las Veghost grower]

So the fat solubility is why thc says around so long and say heroin dosent ? So even though the effects are long gone is is just being stored in fats n what not ?

 

[G_Chem]

So the fat solubility is why thc says around so long and say heroin dosent ? So even though the effects are long gone is is just being stored in fats n what not ?

Heroins an interesting one where the acetyl ester makes it more lipophilic but soon as it gets in there it metabolizes quickly to 6-MAM and morphine. So it doesn’t really stay as fat soluble as it does upon entry.

THC stays as is, keeping it around longer.

The benzoyl ester of morphine 6-monobenzoylmorphine doesn’t undergo hydrolysis as easy as it’s acetyl brother and because of that lasts much longer in the body overall than heroin.

-GC

 

[Lorne???]

Thanks for the incredible info. and responses.

I'm one ahead on you on the Klonopin issue though! Lol! I looked it up as a fellow forum member has been using the stuff for close on 20 years and now wants to stop so I did a bit of looking around to try give some insight. Here's a paragraph from the manual:

"Some doctors in the US switch patients onto clonazepam (Klonopin, [Rivotril in Canada]), believing that it will be easier to withdraw from than say alprazolam (Xanax) or lorazepam (Ativan) because it is more slowly eliminated. However, Klonopin is far from ideal for this purpose. It is an extremely potent drug, is eliminated much faster than diazepam (See Table 1, Chapter I), and the smallest available tablet in the US is 0.5mg (equivalent to 10mg diazepam) and 0.25mg in Canada (equivalent to 5mg Valium). It is difficult with this drug to achieve a smooth, slow fall in blood concentration, and there is some evidence that withdrawal is particularly difficult from high potency benzodiazepines, including Klonopin. Some people, however, appear to have particular difficulty in switching from Klonopin to diazepam. In such cases it is possible to have special capsules made up containing small doses, e.g. an eighth or a sixteenth of a milligram or less, which can be used to make gradual dosage reductions straight from Klonopin. These capsules require a doctor's prescription and can be made up by hospital pharmacists and some chemists in the UK, and by compounding pharmacists in North America. A similar technique can be used for those on other benzodiazepines who find it hard to substitute diazepam. To locate a compounding pharmacist in the USA or Canada this web site may be useful: www.iacprx.org. Care must be taken to ensure that the compounding pharmacist can guarantee the same formula on each prescription renewal. It should be noted, however, that this approach to benzodiazepine withdrawal can be troublesome and is not recommended for general use."

Taken from this page: Chapter II

See that page just contains misinformation; Klonopin wafers are available in 0.25mg and 0.125mg strengths, both ideal for tApering. And below 1/8th of a mg (or even half the wafer really, 1/16th mg) it would just be psychological and not physical

However Clonazepam is highly potent and that can be a problem

And you are absolutely right, none of these values are set in stone, they shall vary from person to person

Good info on the Morphine derivatives, I am not sure how long M6M last(apparently you do) however it is longer than H for sure!

^ 1/8th mg Klonopin wafer

 

[Deru]

I cannot answer the question as I'm unsure of the terminology being used. But I know we have experts looking at the thread so I'm sure they'll be able to clarify.

Elimination half-life is inter-connected with volume of distribution. The drug molecules distribute into the organs, tissues, lipids and/or fats depending upon the drug's volume of distribution, so a drug like fentanyl with an incredibly short plasma half-life has an insanely long elimination half-life difference, especially because volume of distribution actually increases with long-term use and it's highly lipid/fat soluble.

Another component is it's pH and solubility, as @Lorne??? mentioned above, and is an incredibly critical variable when it comes to a drug's ability to bind into the lipids and fats, specifically.

This contributes to drugs like marijuana and fentanyl being able to be detected in urine drug tests for weeks. More interesting, it contributes to the complex issue of transitioning from fentanyl to buprenorphine and precipitated withdrawals up to 36 to 48 hours after last use, considering it's a drug with a short half-life and you may be in severe withdrawals.

From what point is the half-life (either of them) measured?

It's measured from the start of maximum plasma concentration level.

 

[Drag2019]

This information needs to spread around the forums and other forums for heavens sakes. Unfortunately, the lowest Clonazepam dose is 0.5MG in my country.

 

[Shant]

Call this one of my more useful posts i.e. sort of like a harm reduction public service announcement type post (I'll be back on my favorite topic of Fentanyl soon enough)! Lol!

I was looking for something specific this morning and just happened to come across a fairly decent site where the half-life of certain drugs is described in layman's terms in great way. So I thought I'd post a link to it here (link) below.

My main reason for posting this, if the truth be told, is that I've done a lot of reading of these forums since starting to actively post and I've noticed discrepancies both when is comes to understanding what the half-life of a drug actually means as well as incorrect half-lives of certain drugs being misquoted (particularly when it comes to "long acting" vs. "short acting" benzodiazapenes). For most of the old-timers and experienced here: this is probably old news and there's probably already a thread or two about this (although as I said: some of the inaccuracies and incorrect information I've seen on a few threads when it comes to withdrawal I found rather concerning). And for new members: this information may be worth something (most only read the first two or three pages of topics on a forum and give up or move on and/or refuse to use the search function).

AdCare: Drug & Alcohol Rehab in Rhode Island and Massachusetts

Drug & alcohol rehab centers in Rhode Island and Massachusetts, providing both inpatient and outpatient addiction treatment services.

sunrisehouse.com

By the way: there's also some pretty interesting and useful links that show up on the top right hand corner of each page.

And of course for verification purposes there's the table from good 'ol Prof. Ashton's Manual:

Table 1

How strange. I can’t open these links.

 

[Shant]

Good morning.

That is strange. Just tested them both and they work fine this side (both from within the original post and your quote of the original post above).

Try them again?

They're nothing special or obscure or anything like that.

K let me try again. If not, just post the url I’m sure I can get to it that way.

 

[Shant]

This information needs to spread around the forums and other forums for heavens sakes. Unfortunately, the lowest Clonazepam dose is 0.5MG in my country.

But Clonazepam (that’s Ativan, right?) is so weak. I’ve got the 1mgs and I need to take 6 or 7 to do anything. Tonight I’ll be taking 6 Ativan and 3 Klonopins (2mg). Hopefully that’ll be enough to get some sleep. I inducted suboxone today. Successfully I may as well add.

 

[Shant]

Good morning.

That is strange. Just tested them both and they work fine this side (both from within the original post and your quote of the original post above).

Try them again?

They're nothing special or obscure or anything like that.

Huh! They work fine now. Wtf I hate that. But thanks again for posting those. And anything you have to say on fentanyl, I wanna know. Is there anyway I can be alerted every time you post, friend?