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Loperamide & Methadone affinities for receptors

jasoncrest

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From what I read on a post in Other Drugs about Opiate Potentiation, Loperamide potentiates Methadone because it binds to some opiate receptors located in the body (gut, intestines, etc... ), but not the receptors in the brain, so Methadone doesn't bind to these receptors, as Loperamide is already on them, and so more Methadone will make an effect to the brain...

Is it the right theory? Did I understand it correctly?

So if I take a lot of Loperamide a few hours before taking Methadone, it will bind to many of the opiate receptors located elsewhere than in the brain, and taking Methadone after that will make it more potent, because more of it will have a central action?

But what if the Methadones affinity for these receptors is higher than the affinity of Loperamide, and it takes the Lopermide off the receptors and takes its place?

Does anyone know which of these Opioids (Loperamide & Methadone) has the higher afinity for these receptors?

(and last question, if Methadone has a higher affinity, will it still be a usefull way to potentiate it to take Loperamide before taking it?)

I hope everyone understands what I mean...
 
From what I read on a post in Other Drugs about Opiate Potentiation, Loperamide potentiates Methadone because it binds to some opiate receptors located in the body (gut, intestines, etc... ), but not the receptors in the brain, so Methadone doesn't bind to these receptors, as Loperamide is already on them, and so more Methadone will make an effect to the brain...

Is it the right theory? Did I understand it correctly?
That might be someone's theory, but it's completely fucking bullshit.

Why is a more plausible theory is that the transporters that pump loperamide out of the brain (and hence make it inactive) also pump methadone out. Loperamide occupies those pumps, and potentiates morphine.

As I find myself saying more and more often, affinity and concentration are the factors that decide the amount of drug that is bound to a receptor (occupancy). i.e. just cause drug A has higher affinity than drug B, doesn't mean that drug A will have higher receptor occupancy.
 
BilZ0r said:
That might be someone's theory, but it's completely fucking bullshit.

Why is a more plausible theory is that the transporters that pump loperamide out of the brain (and hence make it inactive) also pump methadone out. Loperamide occupies those pumps, and potentiates morphine.

As I find myself saying more and more often, affinity and concentration are the factors that decide the amount of drug that is bound to a receptor (occupancy). i.e. just cause drug A has higher affinity than drug B, doesn't mean that drug A will have higher receptor occupancy.

Thank you bilZ0r.
 
I've had a lot of experience with loperamide. Also with opiates, including 11 years of methadone use.

The last few times I had to kick heroin, I used very high-dose loperamide to great effect. (By high-dose, I mean app. 60 2mg tablets).

When you don't have access to centrally acting opiates, like methadone, a nice, potent, peripherally acting opiate like loperamide is almost as good. It snuffs out all withdrawal symptoms of the physical nature -- and anyone who has truly withdrawn from opiate addiction will tell you that after a few days it is the physical symptoms of withdrawal that are the hardest to deal with.

I've read aritcles that discuss receptor affinity of loperamide, and if memory serves me it is the kappa receptor that loperamide most strongly binds to, and whatever affinity it has for the mu receptors doesn't matter since it doesn't cross the blood-brain barrier (which is of course why you can buy it over-the-counter).

So, yeah, don't kick without a few hundred of those little beauties.
 
Ahhh, wrong, BilOrz.

With respect, you need to look up...... well that's more than I want to get into... Look, loperamide is very quickly and efficiently pumped out of CNS (that's another way of saying it doesn't cross the BBB, and more accurate too since it does cross it before it gets thrown out).

Methadone is just like other opiates, where the blood-brain barrier isn't even an issue...that's why in my above post I differentiate between physical side-effects of withdrawal and central side-effects of withdrawal.

THe guy who started this thread asks an interesting question: since loperamide and methadone both bind to peripheral receptors, will more methadone become available for CNS activity (since loperamide may already be occupying peripheral receptors). I can't say I know for sure but I would bet money that it would [cause more methadone to be available] -- especially with a large dose of loperamide.
 
The issue is, loperamide can extend the physical elements of methadone withdrawal.......I know this intimately, having gone through this....

Large doses (50-100mg) do have the ability to suppress many withdrawal symptoms, but again, can extend the process, so use it accordingly.....
 
^agreed. loperamide by itself has it's own kind of withdrawal, which is very very unpleasant, so take it into account please.....the op's idea sounds interesting to me, but trying to mix lope with meth for a purpose of gettin better high can result in some bad complications...unless you don't give a fuck what's going to happen.
 
wow thank you. its nice when people actually know what they are talking about
 
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