Methadone dose reductions and blood serum levels

[Ethyl]

As most of you probably know methadone builds up on the body up to close to 200% of your daily dose.
It takes about 8 to 10 days to reach its maximum serum levels but the increase is greater in the first 3 to 5 days, then they gradually tend to stabilize in about 10 days time.

You can see bellow the increase in serum levels when a user takes 30mgs each day for about a month. It will build up from 30mgs to 55.38mgs over time.




But what many don't think of is the fact that dose reductions also make the serum levels decrease over a few days to 200% of what they were previous to reduction.
So lets see a 5mg reduction (11.5% of your daily dose) and how that will affect the serum levels until they stabilize again.
So lets see the reduction of 5mgs in the 30mgs daily dose.




As you can see the serum blood levels of methadone have decreased from 55.38mgs to 46.5mgs when the dose was reduced only 5mgs but led to an decrease of almost 10mgs (double of the reducted dose 5mgs, or 200% if you prefer).

So as you can see a reduction of "just" 5mgs in 30mgs leads to a reduction of 10mgs of the "real" quantity of methadone inside you.


So the reduction inside you is the double of the dose reduced, you should take that in consideration when reducing doses.
Also you should wait 15 days between reductions in order to give time to the serum levels of methadone stabilize again before you reduce again.


Hope you find this relevant and try to remember this next time you plan your reductions or increases.

EDIT:
NOTE: The source is my own, its calculated using the half-life for methadone and from there its easy to calculate this. Do it yourself and see that you come with the same results. The half-life that was used for making the calculations is 22hours, if you increase the half-life it will lead to an increase in serum levels.

Reputation Comments on this post:

	source please?If this is correct,swim salutes you and thanks you immensely for this info.
	Useful information, although why on earth you didn't take the half-life as 24 hours I'll never know! It makes calculatio...

[Ethyl]

Now...

Lets see how the serum levels react when you don't take your daily dose of methadone in 1 day.



As you can see it takes a long time to the serum levels to stabilize again, but the difference is more felt during the first 3 days but it only stabilizes 12 days after even tough the difference is pretty small after the first 3 days.


And if you miss 2 days...


There's isnt much difference in the time to recover from 1 day to 2 days of missing doses, the difference is pretty small.


And if you miss 3 days...


Also not much difference from 1 day or 2 days when compared to 3 days...

Reputation Comments on this post:

good info. it showed the effect of "missing Doses" very well!

[LiquidHandcuffs]

Interesting stuff there OP.

Since Swim highly doubts that Swiy took the time to post these graphs as a hoax (no sources), he trusts that they are legitimate.

Swim jumped MMT cold turkey from 65mgs/6months.

Today is Swim's 12th day (almost 13th) since jumping, and he is actually pretty much through the Acute Withdrawal stage.

Perhaps Swiy's information about the serum levels helps explain how Swim has gotten through the worst of it relatively quickly.

Either way, good, informative post.

[jloops]

Swim thinks that last graph explains why trying to wait for buprenorphine threw him off pretty badly for a few days. It also explains why methadone withdrawal drags on for so long -- in effect, ceasing methadone is like starting a taper with a short-acting opiate in which you reduce your daily dose by half every day. (So, if 30 mg methadone is [acute] equipotent with 30 mg morphine, and the morphine needs to be dosed 5 times per day to get a similar effect to the methadone, that's 5*30=150 mg morphine is like 30 mg methadone per day... So, ceasing 30 mg methadone is like going 75-32.5-16.25-8.125-4-2-1 with the morphine everyday. That means it's 3 days without the stuff until it gets below the equivalent of taking 3 percocets everyday, explaining why it takes those 3 days plus maybe a few more to hit the peak of withdrawal.)

Interesting stuff, ethyl.

[Ethyl]

Originally Posted by jloops

So, ceasing 30 mg methadone is like going 75-32.5-16.25-8.125-4-2-1 with the morphine everyday. That means it's 3 days without the stuff until it gets below the equivalent of taking 3 percocets everyday, explaining why it takes those 3 days plus maybe a few more to hit the peak of withdrawal.)

I'll show the graphic of stopping methadone altogether.




And because the graphic is hard to read the values so i'll show you the values bellow:

Originally Posted by LiquidHandcuffs

Today is Swim's 12th day (almost 13th) since jumping, and he is actually pretty much through the Acute Withdrawal stage.

Perhaps Swiy's information about the serum levels helps explain how Swim has gotten through the worst of it relatively quickly.

If you see the graphic above you can see that the 13th day after stopping the methadone is the first day with 0mgs inside you, until this day you still had methadone inside you.. Maybe that has something to do with why you still are in wd..

Reputation Comments on this post:

good stuff, helpful to understanding methadone

[LiquidHandcuffs]

Swim has found the above graph to be pretty accurate.

However, he must point out that the Half-Life of Methadone can vary greatly. Depending on factors such as Metabolism, Age, Duration of Use, Overall Health... etc...

Swim has also been cautioned about the effects of Hep C on Methadone Metabolization.

All in all, OP makes good, albeit generalized, points about the Serum Levels.