First, welcome to BL! We don't do the SWIM/pet thing here. Please review the
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In terms of U-47700, its user is so new on the scene that we don't really know anything about long term effects on one's health. Considering you only used it for a month however, it is safe to assume until otherwise that you probably haven't done any serious damage. However, if you were to continue using it the chance of problems arising down the road increases exponentially.
Personally I don't think three weeks of even daily ketamine use (I have used the stuff fairly extensively, along with other dissociatives) would be super likely to cause kidney issues. Perhaps if you had some predisposition to them (particularly if you yourself have had them before), but otherwise I wouldn't be too concerned.
If you're able to take a good long break and use it more responsibly in the future (assuming you want to use it again), I imagine you'll be fine. However just like the above, the more you use it the greater the risks involved. I image continued use of ketamine, although ideally not daily, would be less costly in terms of risks involved than prolonged use of an RC opioid.
You'll have a much better idea of what, if any, short term issues you'll have once you have a few solid weeks of time away from ketamine. If there were any short term issues associated with U-47700, I think they'd at least be already beginning to become apparent, so you sound okay here.
