If you look at any list of side effects for the FDA-approved version of s-ketamine (Spravato), you see things like urinary tract problems, bladder problems, pain on urination, feeling of urgency to urinate. You can find a bunch of papers like Ketamine: An Important Drug With A Serious Adverse Effect, where they say that ketamine is potentially really great for depression, but that the risk of bladder injury needs to be taken really seriously.
When I first considered prescribing ketamine, the bladder injury stories scared me so much that I asked a bunch of veteran ketamine prescribers how I should monitor it. They all gave me weird non-commital answers like "I've prescribed ketamine to thousands of patients and never had a problem with this, so I guess don't worry". But why not? There are all these papers saying we should worry, and all these reports in the literature of ketamine-induced bladder injury!
A standard psychiatric dose of ketamine might be 0.5 mg/kg IV, 2x/week, for four weeks. So a 70 kg patient would get about 280 mg over the course of a month. This Chinese study and this UK study analyze recreational ketamine users, and both find they take about 3g daily, every day. That's 90,000 mg over the course of a month. Again, that's 280 mg for the psych patients and 90,000 mg for the recreational users (and you wouldn't believe how many hoops the psych patients have to jump through to get their 280, or how terrified their doctors are that something could go wrong). Drug users use a lot of drugs! So why don't psychiatric patients get bladder injuries? It's because you get bladder injuries when you're taking more like 90,000 mg of ketamine a month, and not when you're taking 280 mg.