Ketamine is a dissociative anaesthetic that was made a class C substance under the Misuse of Drugs Act in 2006.

In recent years its popularity as a recreational drug has been increasing, not only in clubs but also in the home.

In a 2007 survey, only 0.8% of individuals aged 16-24 reported using ketamine in the previous year.1 However, the lifetime prevalence of ketamine misuse in those involved in the UK dance scene is 42%, with self-reported use increasing by around 50% per year over a five-year period from 1999 to 2003.^1-3 Ketamine is a cheap and widely available drug, and may be easier for teenagers to obtain than alcohol or cigarettes.

In the past two years, 11 patients have been referred to urologists in the South West with severe symptoms related to chronic ketamine misuse.⁴ In May 2008 an online survey of UK urologists revealed similar cases across all regions.

Patients are typically under the age of 30 and may present with suprapubic pain, haematuria, urgency, frequency and incontinence. These patients are often investigated for a UTI as the symptoms mimic cystitis, however they have no evidence of infection on urine culture and their symptoms persist after antimicrobial therapy.

At a recent workshop for individuals who misuse ketamine, half the patients reported urinary symptoms, with the majority having presented to their GP. However, only a minority of these patients were referred for urological investigation. Few patients actively divulge ketamine misuse. Therefore, it is worth asking young patients with cystitis-like symptoms, but no laboratory evidence of infection, specific questions about illicit drug use.

Patients should be referred to a urologist and may undergo renal function tests, ultrasound scans, cystoscopy and bladder biopsies. Chronic ketamine misuse may lead to hydronephrosis and acute renal failure, and percutaneous drainage may be necessary.

Suprapubic pain, frequency and urgency may be temporarily relieved by the insertion of a catheter. If the symptoms become intractable, surgical intervention may be necessary and our centre has performed cystectomy and neobladder formation operations for patients with pain refractory to analgesia.

Unfortunately, pain may be difficult to control. Patients may increase ketamine use in order to relieve symptoms and a vicious circle of progressive disease may arise. Anecdotally, two patients who presented at our centre started misusing heroin (from which they have withdrawn) in order to control their pain.

Patients who misuse ketamine should be encouraged to cut down or stop. Our survey of UK urologists found that following cessation one-third of cases may resolve, one-third stay the same and one-third progress, potentially leading to upper tract damage, acute renal failure and retroperitoneal inflammation.⁵ Ketamine cessation may be difficult and requires a multidisciplinary approach.⁶ We have formed a close collaboration with local drug services to provide a harm reduction strategy and detoxification programme for patients.

We are concerned that this little known phenomenon is increasing and the cases we have seen are simply the tip of the iceberg. By increasing awareness, not only among GPs but also urologists and drug services, ketamine misusers with urinary problems may be identified early and referral may be made before complications and disease progression occur.

We are trying to establish the scale of the problem in the UK and are planning to set up an online database. We would be grateful if GPs could contact us at [email protected] if they have seen a patient with urinary symptoms caused by ketamine misuse.