ross tolerance between Tramadol and Codeine?

[ThHardMotherfucker]

I've used the fucking search engine, Googled it on my phone, haven't come across any information. I'm guessing since tramadol isn't converted into morphine, unlike codeine does, that it targets a different opioid receptor, therefor a lack of cross tolerance between Tramadol (which is practically an SNRI) and codeine (natural opium alkaloid).

 

[Mr Blonde]

that it targets a different opioid receptor,

That's not how it works. Can't be bothered to go in depth, but yes there is cross-tolerance but because tramadol has other major mechanisms of action (through serotonin, norepinephrine) it is not to the same extent as say codeine and hydrocodone or other opioids.

 

[spacejunk]

ross tolerance? no, i don't know him - sorry. i hear he's a laid back guy though.

 

[Divine Moments]

There isn't a unique receptor for every drug - drugs of the same family (e.g. opioids) tend to interact with the same receptors, just in slightly different ways. As Mr Blonde said, there is some cross tolerance between tramadol and codeine.

 

[ThHardMotherfucker]

How come, then, a tramadol 'high' versus a codeine 'high' feels nothing like a 10 mg oxycodone dose?

They target the same opioid receptors, in all different amounts, I'm guessing?

 

[Mr Blonde]

^ Morphine (the main active metabolite of codeine) and oxycodone bind very similarly to the opioid receptors, with a slightly different profile. There are three main opioid receptors, mu, delta and kappa. Mu is the main euphoric receptor but all opioids bind to these receptors to varying degrees. The potency, binding profile and pharmacokinetics of each drug will affect how you subjectively appreciate the high. Also, consider that codeine is a pro-drug and must first be converted into morphine before having an effect, whereas oxycodone will work without being metabolized first. This will also have an effect on the subjective experience.

As for tramadol... it binds to opioid receptors, it's main metabolite O-desmethyltramadol binds a lot stronger though and tramadol also has major effects on serotonin and norepinephrine that are very important to it's pharmacology. It is by no means a typical opioid, hence why it is very different to the others.