Dr Des Corrigan gets down and dirty to analyse the increased detection of ketamine in sewage wastewater
The most recent report on drugs in wastewater by the EU’s Drugs Agency (EUDA) reminded me of an occasion some years ago, during my term as co- chair of a European scientific committee drafting clinical use monographs on herbal medicines. The committee had a tradition of everyone eating together, which successfully broke down national barriers. The Portuguese delegation were especially welcome, as they invariably brought several bottles of port for the after-dinner tipple.
On one occasion my English co-chair asked colleagues if they knew how the English passed the port, referring to the Royal Navy-inspired tradition of passing the bottle to the left, etc. The Swiss delegate, a medical doctor, looked confused at first, thought for a few moments, and replied to general hilarity: “Through the kidneys, like everyone else.”
This raises the question of what other substances, medicinal or otherwise, we pass through our kidneys into our sewage system. The answer comes from the work of the SCORE Group — the acronym stands for Sewage analysis CORE group Europe, whose 2025 study involved 115 cities from 25 countries in the EU, along with Norway and Türkiye. It included wastewater from the Ringsend waste treatment plant in Dublin collected over a single week between March and May of last year. The samples were then analysed for either the parent drug in the case of amphetamines and ketamine, or the main urinary metabolites for cocaine and cannabis.
From an Irish perspective, a notable and perhaps surprising feature of the results is that Dublin is not one of the drug capitals of Europe, in that it does not feature among the cities with the highest reported levels of any of the drugs. For example, the highest levels of cocaine metabolites were found in cities in Belgium, the Netherlands and Spain. In fact, the results from Dublin were stable for cannabis and methamphetamine, while those for amphetamine, MDMA and cocaine declined between 2024 and 2025. The sole exception was for ketamine, where there was a 42 per cent increase since 2024.
At one stage ketamine was considered very much a niche drug used in ‘chemsex’, especially by
men who have sex with men. The wastewater data and recent large- scale seizures suggest that its use is becoming more common as a party drug. This undoubtedly explains the HSE alert before the St Patrick’s Holiday about pink powders found to contain ketamine, along with five other substances, including MDMA and a drug new to Ireland called 2-FMA or 2-fluoromethamphetamine.
The latter has actually been around since 2007 and there are reports of it being used to self-medicate ADHD, according to a 2023 paper in the International Journal of Drug Policy. Little is known about its
effects in humans but a 2025 paper in the Journal of Pharmacology and Experimental Therapeutics states that fluorinated amphetamines produce methamphetamine-like stimulant effects and so may have abuse potential comparable to crystal meth based on experiments in rodents. These pink powders are sold under a variety of names, including Pink Cocaine (even if it has never contained any cocaine), Tuci, Tusi or Tucibi. The latter three are a play on the name of a hallucinogenic stimulant 2-CB commonly found in the powders, although the exact composition is highly variable. For example, the 2024 Annual Report from Forensic Science Ireland described a sample of pink powder as containing ketamine, amphetamine, MDMA and caffeine, while yet another sample was found to contain benzocaine, presumably to fool consumers into thinking there was cocaine present.
Ketamine is mainly snorted recreationally for its dissociative and hallucinatory effects (‘going down or through the K-hole’), which gives a feeling of floating outside one’s body. There is a certain irony about the increased detection of ketamine in sewage wastewater, since the major concern about its non-medical use is severe and irreversible bladder complications.
While the overall prevalence of non- medical use is low in Ireland (lifetime use of 2.1 per cent generally in the 2023 Healthy Ireland Survey, but rising to 6.6 per cent in males aged 15-to- 34), there is increasing concern at European level about its use in very young people in nightlife settings, according to a special EUDA Report from March of this year. This highlights the increasing demand for treatment, as reports of chronic urological and psychological harms are on the rise. This has led in some countries to the opening of specialist clinics in order to respond to the severe ulcerative cystitis and long-term bladder dysfunction that occurs in chronic users despite their perception that ketamine is less risky than other drugs.
The impact of ketamine and its analogues on the urinary tract was described in more detail in a 2026 update on ketamine-related harms for the UK government. Among the effects are increased urinary frequency both during the day and at night (nocturia); urgency and incontinence; painful urination; haematuria and bladder pain. Urologists here and in the UK report a recent upsurge in referrals of both teenagers and adults with ketamine- related uropathy and about 25 per cent of regular users report at least one urinary symptom.
Anecdotally, when I discuss ketamine with groups of drug users in a Tallaght-based rehab project, a number will describe their own issues and others will know of friends who have to wear nappies because of the bladder damage. Apart from the urinary issues, other adverse effects have been reported by the EUDA and the ACMD, including psychotic emergence reactions as the effects wear off. Withdrawal symptoms after prolonged use point to its addiction potential and large doses may impair
Urologists here and in the UK report a recent upsurge in referrals of both teenagers and adults with ketamine- related uropathy
cognitive functioning due to partially
reversible neurotoxicity. Chronic abdominal pain, known as ‘k-cramps’, are more likely in women and older people, while liver damage progressing in some cases to fibrosis and cirrhosis has also been described.
A worrying aspect of the increased use of ketamine from a pharmaceutical perspective is that EUDA and EUROPOL believe that the black market is predominantly supplied by diversion from legitimate imports from India into Germany rather than illicit production. However, illicit synthesis has been reported from Asia involving clandestine labs that can also produce the required precursors.
If your pharmacy (community or hospital) stocks ketamine for human or veterinary anaesthetic/analgesic use, then you should be aware of the risks of diversion. I would also be cautious about stocks of esketamine for use as an anti-depressant, although the EUDA suggests that there is minimal diversion of the nasal spray.
Dr Des Corrigan, Best Contribution in Pharmacy Award (winner), GSK Medical Media Awards
2014, is an Adjunct Associate Professor at the School of Pharmacy and Pharmaceutical Sciences at TCD where he was previously Director and won the Lifetime Achievement Award at the 2009 Pharmacist Awards. He was chair of the Government’s National Advisory Committee on Drugs from 2000 to 2011, having previously chaired the Scientific and Risk Assessment Committees at the EU’s Drugs Agency in Lisbon. He chaired the Advisory Subcommittee on Herbal Medicines and was a member of the Advisory Committee on Human Medicines at the HPRA from 2007 to 2024. He has been a National Expert on Committee 13B (Phytochemistry) at the European Pharmacopoeia in Strasbourg and served on the editorial boards of a number of scientific journals on herbal medicine.
