Discussions that mention imitrex

Pain Management board


Jon,

When I get some time I'll try to research this for you.

But it seems that maybe the info I got is not totally accurate. I would have thought that a person on 100mcg/hr fentanyl would react badly to Stadol. The fact that your friend does not is surprising. But I wouldn't doubt his experience for a minute.

What I do know for sure is that buprenorphine will antagonize fentanyl and bring on instant withdrawal to one dependent on fentanyl.

So, it would seem that Stadol and buprenorphine are more dissimilar than I thought. A competitive antagonist is one that is supposed to kick out any other opioids present and then fully occupy the receptor. So, the mu receptor is the main opioid receptor for the full mu agonists like morphine, oxycodone, fentanyl, and the like. These meds have a "high affinity" for the mu receptor, meaning they are highly attracted to it and bind strongly to it. The "potency" of an opioid is related to an opioid's level of attraction to and ability to bind to a mu receptor. There's a little more to it than that, but that's the basics.

There are two other opioid receptors that make up the main three - the delta receptor and the kappa receptor. So you have the mu, the delta and the kappa receptors. The "full agonists" (morphine and the like) go mainly for the mu receptor, with some limited attraction to the other two receptors as well. Then there are partial agonists, antagonists and partial agonists/antagonists (at the mu receptor). Most of these are highly potent meds. Buprenorphine is a partial agonist/antagonist involving all three receptors. It is an agonist to the mu receptor at levels stronger than nearly every other opioid. I understand it is up to 100 times stronger than morphine, which is why it is dosed at less than a milligram per. However, because it is so strongly attracted to the mu receptor, it will "kick out" any other opioids present, including the morphine type opioids. Then it binds to the mu receptor for all it's worth and nothing else is gonna replace it until it weakens its hold about 3-6 hours later. Because it also has antagonist properties it fully reverses the "agonist" effects of the morphine type drugs including pain relief, sedation, anxyolysis, tolerance and dependence. In this sense it's a lot like naloxone, a full antagonist at the mu receptor, which will take someone ODed on heroin and not breathing, to someone who is bright eyed and wide awake in literally seconds.

Now, the literature I read indicated that Stadol was similar to buprenorphine as described above. But, if that were the case, then your friend would certainly know it. The only thing I can guess is that either Stadol is dosed so low that it can't fully antagonize fentanyl, or it is less attracted to and binds less tightly to the mu receptor than it was claimed to in my reading material.

I will look into this more closely and let you know. You've really got me interested now. I have also used Stadol for migraines but had little success. And it always made me feel uneasy. Now that I have Imitrex I don't need anything else. The stuff is magic and not even narcotic.

steve
Dear [SIZE="5"]Steve,

Thank you for explaining that to me! These combinations of receptors are complicated, and I can see why the prescriber must be careful when deciding which medications to give a patient.

My friend, Paul, uses the Stadol NS and the fentanyl patch (Sandoz brand). I have placed a call into the answering service of his cell phone. I'll try to get the most updated information on his usage.

Back in 1994, I was Rx'd Imitrex in a Nasal Spray form. I had to order it from a particular pharmacy that formulated it for me. Maybe it comes in a standardized Nasal Spray form now, but I never felt that Imitrex did much for me. Also, I was on a study for nearly a year, about that same time, with Imitrex Injections--for free! Still, the Imitrex never helped me very much. I'm glad that it works for you because it is comforting to know that non-opiates can still work on pain--particularly the pain of migraine headaches!!

Back in 1992 or so, my doctor gave me 5--yes, f-i-v-e--sample bottles of Stadol NS. At the time, I had no idea how expensive this medicine would regularly cost. Fortunately, I had good insurance when I was teaching school. So, I could easily afford it then. Five bottles of Stadol NS--given to me as samples--was practically a Biblical experience!

Steve, I have some other questions. I have seen the buprenorphine mentioned by you and several others over the last few years. What form does this come in? Are they pills, shots, or what? And, do I understand you correctly that this is an agonist-antagonist like Stadol? Is buprenorphine a C-IV like Stadol NS is? For what kind of pain does a physician Rx buprenorphine?

Thank you for explaining the receptor issue to me. I've seen several others discuss it, but it didn't mean as much to me at those times. I'm going to print out what you've explained.

Steve, thank you for your help!

Sincerely,
Jon (Conductor)