Does long term use of naltrexone cause any withdrawal symptoms after quitting?
no griffin. Actually I'd imagine it would be quite the opposite.
It probably would feel good, as the opioid receptors have been clogged with Naltrexone for X years or months, and even the bodies natural opioids would've been getting blocked. Upon cessation of the antagonist (naltrexone) the natural opioids would be able to bind and have an effect.
Also, I'd imagine there would be some effect on the amount of natural opioids produced in the body, since they weren't binding for so long, the body may be prone to produce more of them, so there may be more available. Not sure about this, but it's basically the opposite of the effect that external opiates have, whereas if one takes heroin for a long period, the body quits producign opioids internally (endogenously) and thus there is a lack of those things when the external opiates (exogenous) are stopped. That is the idea here, why wouldn't the reverse be true? I don't know maybe someone with more biopharmacological understnading then me can chime in on that part.
So, in short, your answer is NO unpleasant withdrawls form stopping high dose naltrexone after a long period.