Doctors at the UK's first dedicated clinic for ketamine-related bladder damage in under-16s are warning parents that they are seeing the injury in patients who started using the drug at 13.
Some cases are so advanced that children face major reconstructive surgery or dialysis to keep their kidneys working.
The clinic, at Alder Hey Children's NHS Foundation Trust in Liverpool, opened in May 2025 as referrals of teenagers with bladder problems linked to street ketamine climbed.
A new clinical letter in Archives of Disease in Childhood, published in September 2026, sets out what the first 60 young patients looked like.
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Their average age was 14, with a range of 13 to 15. Around two-thirds were girls, and roughly the same share lived in the most deprived neighborhoods in England.
On average, they had been using non-prescribed ketamine for one to two years before being referred.
What ketamine does to a young bladder
Ketamine is a dissociative anesthetic used in surgery and, more recently, in specialist mental-health care.
When it is taken repeatedly for recreational purposes, it can trigger a condition called ketamine-induced uropathy, sometimes shortened to KIU or nicknamed "ketamine bladder."
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The drug and its breakdown products irritate the lining of the bladder. Over months and years, that can lead to inflammation, ulcers, scarring and a bladder that shrinks and stiffens.
Warning signs include needing to pee constantly, pain or burning when urinating, sudden urgency, leaking, and blood in the urine.
In a review of the condition in the medical literature, doctors describe how continued use can push the damage up into the ureters and kidneys, and cause chronic kidney failure.
Stopping ketamine early can settle some of the symptoms. Once the bladder wall is heavily scarred, though, the changes may be permanent.
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What the Alder Hey team found
Harriet Corbett, a consultant pediatric urologist at Alder Hey and one of the authors, said the effects can be lasting. She said that it can lead to chronic bladder pain, incontinence and, in the most severe cases, the need for major surgery or dialysis.
Beyond the bladder itself, the study paints a picture of vulnerable children. Sixteen of the 60 patients had autism, ADHD or both.
Nearly three-quarters had experienced some form of emotional trauma in childhood, and one in five had been in the care system. Half were using other drugs alongside ketamine, 27 percent reported alcohol use and 48 percent used vapes.
Professor Rachel Isba, a consultant in pediatric public health medicine at Alder Hey and professor emerita at Lancaster University Medical School, said the picture is not just about the drug.
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She noted that ketamine use rarely occurs alone, and that the team's analysis is working to identify the range of factors that may contribute to young people developing serious health problems.
What parents should watch for
The most important message from the clinical letter is that these injuries are showing up in children, not just in long-term adult users.
Parents who notice a teenager going to the bathroom unusually often, holding themselves in pain, wetting the bed after years of being dry, or seeing blood in the toilet, should not dismiss it as a urinary tract infection that will pass.
Doctors treating ketamine-induced cystitis stress that cutting out the drug is the single most important step, and that early diagnosis gives the best chance of avoiding permanent damage.
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A pediatrician or family doctor is the right first stop, and they can arrange a urology referral if needed.
The Alder Hey team say the pattern in their first year is a signal that services for under-16s who use ketamine need to be built around the whole child. That means trauma support and easy access to care, not just a bladder clinic at the end of the pipeline.
This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.