• N&PD Moderators: Skorpio | thegreenhand

Mirfentanil

Limpet_Chicken

Bluelighter
Joined
Oct 13, 2005
Messages
6,323
I'l expand more when I'm not sleep deprived and about to go to bed.


But, I was looking through some stuff, and mirfentanil amongst all the fents jumped out at me, due to in particular its lack of propensity to cause respiratory depression.

800px-Mirfentanil.png


I read a study paper where they infused what for a fentanyl seemed like humongous doses over 30 minutes into volunteers, some of the lucky buggers got upwards of 400mg (not mg/kg, mg total dose)

Also what is the half life/effective duration of activity with mir-fent, has anybody actually tried it, and does anybody know of any similar analogs bearing the pyrazin-2-yl group, or n-furamido moiety on the piperidine ring?
 
On the wiki entry it says it's interchangable with naloxone in morphine-dependent monkeys, while also stopping naloxone-induced withdrawls, so does that mean it can cause withdrawls as well as stop them? That sounds extremely counterintuitive so I believe I'm missing something here
 
It has analgesic effects that are seperable from its opioidergic ones, it apparently substituted for fentanyl in non opioid dependent lab animals.

Sounds to me like it is a partial agonist, but with a damned high binding affinity, efficacy to the side for a moment, if its still a partial agonist, but binds tightly enough to displace naloxone, then bobs your uncle, one has a ligand with somewhat funky pharmacokinetics.
 
It has analgesic effects that are seperable from its opioidergic ones, it apparently substituted for fentanyl in non opioid dependent lab animals.

Sounds to me like it is a partial agonist, but with a damned high binding affinity, efficacy to the side for a moment, if its still a partial agonist, but binds tightly enough to displace naloxone, then bobs your uncle, one has a ligand with somewhat funky pharmacokinetics.

Im not sure what you mean by this part. Are you suggesting that it is odd for something to be a partial agonist while having a strong enough affinity to displace naloxone? Because buprenorphine fits that description (partial agonist but extremely high affinity).-DG
 
It has analgesic effects that are seperable from its opioidergic ones

This probably implies something about your original comment, which was "mirfentanil amongst all the fents jumped out at me, due to in particular its lack of propensity to cause respiratory depression." Possible affinity for DAT or NET?
 
No, daddysgone, I wasn't suggesting it was odd.

Does this one have delta opioid agonist activity? AFAIK delta agonists reduce respiratory depression caused by mu agonists, although some cause siezures, in the paper I was reading there was one report of a fit in one of the test subjects that was terminated with (I think) thiopental.
 
isn't mirfentanyl supposed to have high delta affinity and relatively low mu?
not my field of interest but I just vaguely remember that being the case, and it would explain the low respiratory depression.
 
isn't mirfentanyl supposed to have high delta affinity and relatively low mu?
not my field of interest but I just vaguely remember that being the case, and it would explain the low respiratory depression.

I don't believe so. Im not sure about about delta but all 3 sources I've consulted state that it has a strong affinity at mu.-DG
 
It has analgesic effects that are seperable from its opioidergic ones, it apparently substituted for fentanyl in non opioid dependent lab animals.

Sounds to me like it is a partial agonist, but with a damned high binding affinity, efficacy to the side for a moment, if its still a partial agonist, but binds tightly enough to displace naloxone, then bobs your uncle, one has a ligand with somewhat funky pharmacokinetics.

It sounds like a mu-agonist (not partial agonist) that simply has a higher binding affinity than Naloxone and the most commonly prescribed/abused opioids. I wonder if it would out-compete Buprenorphine.*

*That would give it a very useful niche to fill in emergency medicine. I've posted the NAMA white paper on the proper protocol for treating severe/acute pain in Buprenorphine maintained patients before on Bluelight- it is lacking to the say the very least.

With the large population of Buprenorphine dependant patients out there, it would be useful for hospitals to have on hand an opioid analgesic that can be used to effectively (and reliably) work as an analgesic in this population in circumstances that warrant immediate pain relief (surgery, car accident, workplace accident, etc). In such a situation there isn't enough time to wait for the Buprenorphine to leave their system (1 NAMA recommendation), the dose of Buprenorphine cannot be raised or if it were to be raised it wouldn't provide adequate analgesia (2nd NAMA recommendation) and would be much more effective than using a non-opioid analgesic like Toradol (3rd NAMA recommendation).
 
Idk bout the suffocation side effect you mention but that N-furfuryl functional group placement looks positively delicious to me right now.

It would be a great swap for the R-CO2Me of both mph and cocaine.

because i can read
 
It sounds like a mu-agonist (not partial agonist) that simply has a higher binding affinity than Naloxone and the most commonly prescribed/abused opioids. I wonder if it would out-compete Buprenorphine.*

*That would give it a very useful niche to fill in emergency medicine. I've posted the NAMA white paper on the proper protocol for treating severe/acute pain in Buprenorphine maintained patients before on Bluelight- it is lacking to the say the very least.

With the large population of Buprenorphine dependant patients out there, it would be useful for hospitals to have on hand an opioid analgesic that can be used to effectively (and reliably) work as an analgesic in this population in circumstances that warrant immediate pain relief (surgery, car accident, workplace accident, etc). In such a situation there isn't enough time to wait for the Buprenorphine to leave their system (1 NAMA recommendation), the dose of Buprenorphine cannot be raised or if it were to be raised it wouldn't provide adequate analgesia (2nd NAMA recommendation) and would be much more effective than using a non-opioid analgesic like Toradol (3rd NAMA recommendation).

I completely understand your point here, and agree for the most part, but what concerns me is the prospect of using a potent opioid as an analgesic when there is no known antagonist which could effectively reverse this particular opioid in the case of an overdose. However if it is true that this opioid does carry a very low level of respiratory depression, then this concern is offset to a degree.
Still, I have to imagine that this opioid still carries some level of respiratory depression. This whole issue really gets complicated when dealing with patients on buprenorphine. Presumably a high dosage of this opioid would have to be administered (due to the patient's tolerance), and this coupled with the absence of an effective antagonist for this particular opioid, could really be dangerous.-DG
 
I have a couple of questions about this:

1. What would happen if one were to use both this and bupe together? Would precipitated withdrawals occur? Would they potentiate one another and increase the high?

2. (I know this isn't ADD specific, but I am not starting a new thread for this one question.) I can't seem to find any info on the scheduling of this substance, anyone know where it falls?
 
I was just about to enquire the same thing, the MODA text that I can find online (I live in the UK) is completely fucking useless, and it looks like it was the result of the conceptual thousand monkeys, thousand typewriters=works of shakespeare experiment, only conducted with the monkeys feet, in an atmosphere of N2O containing just barely sufficient O2 to support life, whilst the monkeys were dosed on PCP, and spun around at high speed in a centrifuge.

I am beginning to become curious enough to try mirfent myself, it looks quite worthwhile.
 
It has analgesic effects that are seperable from its opioidergic ones, it apparently substituted for fentanyl in non opioid dependent lab animals.

Sounds to me like it is a partial agonist, but with a damned high binding affinity, efficacy to the side for a moment, if its still a partial agonist, but binds tightly enough to displace naloxone, then bobs your uncle, one has a ligand with somewhat funky pharmacokinetics.

That's not really that strange at all... LSD has a hugely high affinity at 5HT2A/2C yet is compared to serotonin a relatively weak agonist.

I wouldn't be surprised if this is a partial agonist at the mu receptor, considering it antagonizes the analgesic effects of alfentanil at low doses (thanks wikipedia) and does not antagonize the immune system (at least according to NK splenic cells).
 
That would make for a hell of a trip. ^

If this actually does cause very little respiratory depression then I can see a whole new group of potent opioid OTC analgesic without the risk of overdosing.
 
Top