How Dangerous Is Ketamine ("K")? What It Does to the Bladder and Brain, and What Families Should Know

What Is Ketamine?

Ketamine is an anaesthetic used in human and veterinary medicine, but it has been misused as a recreational drug for decades, especially at nightclubs and festivals. The U.S. National Institute on Drug Abuse (NIDA) notes that illicit ketamine is usually sold as an off-white powder or a liquid.

Users experience distorted sights and sounds, a dreamlike feeling, or a sense of floating outside their body. At higher doses they can feel extremely detached from their body and surroundings, which users call a "K-hole".

Acute Danger: Breathing Can Stop, Especially When Mixed

Short-term effects include headache, dizziness, sleepiness, nausea, blurred vision, numbness and changes in blood pressure and heart rate. NIDA warns that unsupervised use can slow breathing dangerously, and in a NIDA-funded study the most serious problems occurred when ketamine was combined with other drugs.

In Thailand, ketamine is often sold mixed with other drugs as "K nom phong". Bangkok Hospital notes that the mix may contain heroin, methamphetamine (ice) or clonazepam-type sedatives, which together can suppress breathing, cause loss of consciousness or reduce blood flow to the heart; with alcohol it can be fatal, even on first use.

If someone who has used is very drowsy, cannot be woken, has bluish lips or is breathing abnormally slowly, call 1669 immediately, put them in the recovery position and stay with them until help arrives.

How Ketamine Damages the Bladder

A lesser-known harm is ketamine-induced cystitis. A 2022 review in Health Psychology Research found urinary symptoms in more than 25% of recreational users, rising with frequency of use: about 20% of frequent users reported cystitis-like symptoms, compared with 6.7% of infrequent users.

Symptoms include urgent and frequent urination, painful urination, blood in the urine, lower abdominal pain and waking at night to urinate. Left untreated, the bladder wall can scar and shrink, the ureters can narrow, and the kidneys can swell and fail. Some late-stage cases need surgery to enlarge or rebuild the bladder.

The good news is that in early cases, stopping usually lets the urinary tract recover close to normal. But some people's symptoms persist or worsen after stopping, and many relapse because they use ketamine to relieve the pain it caused. Stopping early matters.

Effects on the Brain, Mood and Addiction

NIDA links long-term heavy use with memory problems, depression and anxiety. High doses can cause psychosis, and frequent use can leave delusions lasting up to a month after stopping. Some long-term users get severe abdominal pain known as "K-cramps".

Ketamine can cause signs of addiction: continuing despite harm, using more than intended, spending a lot of time getting it, and tolerance, needing more to get the same effect.

Signs Families Should Watch For

Beyond the general signs of drug use, such as withdrawing, changing friends or unusual spending, signs more specific to ketamine include very frequent trips to the toilet, complaints of lower abdominal pain or painful urination, blood in the urine, bouts of stomach pain, and periods of seeming spaced out or absent.

If there are urinary symptoms and you suspect ketamine use, see a urologist and be honest with the doctor about drug use, as this helps them diagnose and treat correctly.

How It Is Treated

Treatment has two parts that go together. The first treats the physical damage, especially to the bladder and kidneys, under a doctor's care. The second treats the addiction, which decides whether the person can actually stop. There is no specific medication for ketamine addiction, so the mainstay is behavioural therapy, counselling and care for the depression and anxiety that often come with it.

For advice on treatment, call the Thai drug treatment hotline 1165, or contact the Petch Nava Hope Care team, who can assess and plan treatment together with your family in confidence.