Not nightmares, but it is indeed one HELL of a powerful oneirogen. At few boxes of strong valerian extract, 2-3 boxes (forget how many pills), not exactly nice to get down, but I've had worse by far. Harmala infusion for instance, or the thiazolethanol that one gets as an intermediate in the synthesis routes to chlormethiazole from vitamin B1/thiamine, that stuff fucking stinks something vile, and it hangs around too. Both of those had to go up the arse, too foul to swallow)
Then after taking the large doses of valerian wow...just....damn. It isn't what I'd describe as nightmarish unless theres already a cause in operation which will result in the taker having nightmares. Such as, potentially, opioid withdrawal. But its intense as fucking hell, like taking DMT whilst conscious in some ways. Not in terms of character or 'flavor' but certainly intensity, although while asleep. Its one of my absolute favourite drugs. Another impressive one for such uses is fly agaric in moderate or low-medium doses. This will, since the active in cured fly agaric, muscimol is an orthosteric agonist (that is to say it binds to the GABA recognition site itself, whilst valerian actives at least some thereof bind allosterically to the loreclezole binding site (betagamma subunit interface, beta2 IIRC but might be others, cbf looking it up right now as I'm in the middle of a game on my laptop, an oldie but a goodie.
As for the potential for clonidine-esque effects upon kratom withdrawal, this would modulate the severity of the withdrawal to an extent although how pronounced the effect is I don't know. Clonidine and other adrenergic autoreceptor agonists have been frequently used to combat and help alleviate the effects of opioid withdrawal.
What I do not know though is what withdrawal from a delta agonist is like. Since delta agonism (subtype dependent afaik) is actually involved in tolerance inductiin it stands to reason that kratom, if mitragynine pseudindoxyl is binds that DOR subtype then tolerance might drop off quicker than MOR-selective or mixed KOR/MOR agonists. This however should be remembered as being pure speculation k
Even galantamine and other cholinesterase inhibitors, without or even WITH betahistine taken alongside it shortly before going to sleep cannot even hope to beg for permission to get down on its knees and plead most humbly for the honor of wiping the toilet seat that valerian extract is about to squat down upon and bust a fudge. autoinduction of the very mildest of opioid withdrawal is another thing that does work and CAN almost equal that effect of valerian but the timing of dosage of last opioid intake pre-sleep and the dose must be precise so it wears off MOSTLY, but not in its entirety, just enough to kick the brakes off that oneirogenic rollercoaster.
If you ever try combining the two, its REALLY intense, and it takes away, being a GABAa-PAM, most any anxiety from the just-beginnings-of-first-hints-of-MOR agonist withdrawal. This I have done only with full MOR agonists, and before I was dependent, the selective MOR1 agonist meptazinol plus its benzoyl phenolic ester. I had made the propionyl, the acetyl and IIRC, the salicylic acid ester, but forgot the propionyl and acetyl were there as they had been stashed somewhere to protect them from the fucking pig filth cunts when they came to trash the house, the fucking shiteating whoreson gutterborn mingemongers.
Not sure about shivers, etc. as I've only used kratom either whilst nondependent on other MOR agonists, or whilst dependent to cover me for a few hours walking around the city center shopping, after popping into a headshop or two and buying some alkaloid extract of kratom. Two forms of it, one a tan, fine powder of flour-like consistency, the other a darker but crystalline extract that was obviously at least some form of crystallizable alkaloidal matter, just looked like it hadn't been bothered to be rextylized by whatever company manufactured the extract. A couple of vials of that stuff were STRONG, one rectally one per os, even with a fair tolerance, although nothing at all like the damnable gorilla on my back now. Said shoulder-ape seems to be on a diet, in that it can be kept from yowling its anger from the treetops with lesser doses but can be made pretty happy with a >1g IV dose of morphine.
Be aware that mitragynine pseudindoxyl is IIRC a delta opioid agonist (subtype unknown to me) and there is afaik an alpha2 adrenoreceptor antagonist in there too, so withdrawal leading to reversal of that latter property IF the physical dependency is to kratom only, or to other opioids with regular use of kratom in addition, will when its doing the opposite in withdrawal will act like clonidine, an alpha2 adrenergic autoreceptor agonist often used as an adjunctive med for opioid detox, to help combat physical w/d symptoms, especially the adrenergic hyperactivity and overstimulation, tachycardia, chest pains etc.
