Opioids Fentanyl and Methadone Affinity

[Nati]

I've been curious about something this week that I was hoping to maybe get some clarification on.


Since Fentanyl has a higher affinity than methadone does it also affect the half life as well? Or what effects does it have on my dose?


Basically, I've been relapsing a little lately and the days I take fent my dose will not hold me over as long. Which I was thinking could either be from the more potent fent creating more receptors which the done doesnt fill or from what I stated above somehow the affinity affects Half-Life? Elaboration? I tried searching relevant topics and nothing mentions the affects on half life. Thanks in advance.

 

[Coolwhip]

Its not the half life, you were on the right track although its nowhere near as simple as you put it. But yes, it's tachyphylaxis, the fent raises your tolerance to opiates through a variety of mechanisms and the amount of circulating m-done won't cut it anymore.

 

[kleinerkiffer]

Affinity and half life are different things, while fentanyl has a high affinity for the mu-opioid receptor it's half life is 0.2-7 hours (depending of ROA), while methadone has a half life of up to 55 hours
As coolwhip said, the fentanyl most likely increased your tolerance to opioids

 

[OntarioGuy]

I got effects from IV fentanyl while on methadone actually. Any other opioid is a waste. I Prepped and IV'd 4 x 30 mg hydromorph contin, while on 120 mgs of methadone and got only a slight warmth tingle "rush" is u can call it that, with virtually no high or withdrawal relief, I was craving my methadone dose. I'd been without methadone for about 56 hours at the time. Methadone jacks up ur tolerance to an insane degree.

But with fentanyl, I had skipped my dose so about 48-50 hours without methadone. I had 200 mcg blotters of fentanyl from a DNM. I cut up 10 of them into small pieces, then soaked them in warm water for a few
Minutes while mashing it up. I drew it up and IV'd it and was pleasantly surprised by the strong rush and a decent little high and withdrawal relief. I guess 2 mgs of fentanyl is a large dose though.

A friend of mine is on a similar dose of methadone as me, and the crazy guy told me about his experience vaporizing carfentanil. He said it completely broke through his dose, and I believe he vaped only micrograms of the carfent. Crazy potency.

That being said, be careful mixing fentanyl with methadone, and I'd advise ppl to avoid carfentanil all together. (They won't, but I have to say it)

 

[cj]

I got some effect from fent when I used on top of methadone but for the best result I had to wait 36 hours after my last dose of done. Even then the effect was very diminished