Sweating in opiate withdrawal is probably caused by rebound overproduction of Noradrenaline, the neurotransmitter responsible for the 'fight or flight' response. Note lots of posters above have recommended Cloinidine, not all of them understanding why.
But it is not just too much norepinephrine. This would also cause other ugly symptoms. I think during withdrawal it is only too much norepinephrine in the locus coeruleus in the brain...
I asked my doctor about clonidine and she nearly knew nothing. She even did not know that is can be used to alleviate opioid withdrawal symptoms. (And actually she is the doctor who started the methadone programme in the city were I live.)
She looked in her computer and told me that it seems that the stuff could help with sweating.
Methadone patient who have a problem with excessive sweating usually get polamidone instead of methadone.
If this does not change anything then the patients will get a "sormodren" prescription. It's a medicine for Parkinson's disease. The active ingredient is called "bornaprin" (probably "bornaprine" in English).
It's an anticholinergic and is said that it may have some bad side effects.
But strange thing - a Parkinson medicament. Parkinson medicaments also help for other opioid withdrawal symptoms although some of them work on different neurotransmitters.
Apomorphine is said to reduce nearly all opiate withdrawal symptoms. (dopamine agonist)
L-dopa is used to treat Parkinson but also RLS. It shall help with withdrawal RLS, too. (increases dopamine)
And it seems that in Russia, Parkinson patients will get phenibut and picamilon for Parkinson (Although this has effect on GABA and not on dopamine, it is said to help. At least I read this somewhere.)
Some of those GABA-drugs can also help with opiate withdrawal. GHB/GBL can reduce nearly all withdrawal symptoms. Baclofen, gabapentin and pregabalin seem to help some people during opiate withdrawal (but I never tried it by myself.)
Maybe there is a connection?
It seems that there is a lack of dopamine during opioid withdrawal. Parkinson patients have a lack of dopamine, too.
Parkison patients often have problems with excessive sweating. The same during opiate withdrawal.
And then there is the RLS problem. It seems that it also is a dopamine problem (at least for the opiate withdrawal RLS).
Maybe opiate withdrawal is something like temporarily Parkison's disease?
I don't know what causes excessive sweating in Parkinson patients. Maybe it's the lack of dopamine but maybe it is something else...
But perhaps the same thing triggers excessive sweating during opiate withdrawal, too.
Has anyone ever tried sage for the excessive sweatings?