One-stop clinic for ketamine-associated uropathy: report on service delivery model, patients' characteristics and non-invasive investigations at baseline by a cross-sectional study in a prospective cohort of 318 teenagers and young adults

Ketamine uropathy: Clinical experience in a high prevalence center

OBJECTIVES

Ketamine uropathy causes inflammatory changes to the urothelium, manifesting as significant lower urinary tract symptoms, small bladder capacity, and pelvic pain. Upper tract involvement and hydronephrosis can occur. Data from UK centers are limited, and no formal treatment guidelines exist.

PATIENTS AND METHODS

All patients with ketamine uropathy presenting to our unit over an 11-year period were identified through operative and clinic lists, emergency presentations, and a prospectively collected local database. Demographic data, biochemical findings, imaging techniques, and both medical and surgical management were recorded.

RESULTS

A total of 81 patients with ketamine uropathy were identified from 2011 to 2022; however, a large proportion presented from 2018 onwards. The average age at presentation was 26 years (interquartile range [IQR]: 27-34), 72.8% were male, and average follow-up time was 34 months (IQR: 8-46). Therapeutic interventions included anticholinergic medication, cystodistension, and intravesical sodium hyaluronate. Hydronephrosis was present in 20 (24.7%) patients and nephrostomy insertion was required in six. One patient underwent bladder augmentation surgery. Serum gamma-glutamyl transferase and length of follow-up were significantly higher in patients with hydronephrosis. Adherence to follow-up was poor.

CONCLUSIONS

We present a large cohort of patients with ketamine uropathy from a small town in the UK which is unusual. The incidence appears to be rising, in-keeping with increasing recreational ketamine use and should be of concern to urologists. Abstinence is a key aspect of management, and a multi-disciplinary approach works best particularly as many patients are lost to follow-up. The development of formal guidance would be helpful.

Current approaches for the treatment of ketamine-induced cystitis

AIMS

Ketamine is a dissociative anesthetic, historically used in a clinical setting for the induction and maintenance of anesthesia. Ketamine usage can produce undesirable psychological manifestations including hallucinations and long-term psychotomimetic effects. As a results of its fast onset and short period of action, ketamine is widely used as a recreational drug. Chronic abuse of ketamine can lead to significant urinary system complications including ketamine-induced cystitis (KIC). Common side effects of chronic ketamine abuse are urinary pain and discomfort and decreased bladder compliance and voiding pressure. Cessation of ketamine use is associated with improvement of symptoms however the exact pathophysiology of KIC remains unknown, complicating the ability of clinicians to treat this condition.

METHOD

A literature search was performed using the National Center for Biotechnology Information (NCBI) Pubmed database up to May 2021.

RESULTS

Animal models of KIC are necessary to further our understanding of KIC pathophysiology and explore potential treatment options. In all cases, cessation of ketamine use is the first line of treatment and is most effective in managing KIC. In addition to cessation, treatment plans must be tailored to the individual, based on the severity of symptoms and disease progression, and include options such as: oral anti-inflammatories, intravesical treatment and in the most severe cases, surgical intervention.

CONCLUSION

KIC is a painful condition that currently lacks standardized treatment methods. Both animal models of KIC and clinical trials to further elucidate the mechanism of KIC pathophysiology must be explored to create targeted treatment plans.

Disruption of Cav1.2-mediated signaling is a pathway for ketamine-induced pathology

The general anesthetic ketamine has been repurposed by physicians as an anti-depressant and by the public as a recreational drug. However, ketamine use can cause extensive pathological changes, including ketamine cystitis. The mechanisms of ketamine's anti-depressant and adverse effects remain poorly understood. Here we present evidence that ketamine is an effective L-type Ca2+ channel (Cav1.2) antagonist that directly inhibits calcium influx and smooth muscle contractility, leading to voiding dysfunction. Ketamine prevents Cav1.2-mediated induction of immediate early genes and transcription factors, and inactivation of Cav1.2 in smooth muscle mimics the ketamine cystitis phenotype. Our results demonstrate that ketamine inhibition of Cav1.2 signaling is an important pathway mediating ketamine cystitis. In contrast, Cav1.2 agonist Bay k8644 abrogates ketamine-induced smooth muscle dysfunction. Indeed, Cav1.2 activation by Bay k8644 decreases voiding frequency while increasing void volume, indicating Cav1.2 agonists might be effective drugs for treatment of bladder dysfunction.

What urologists need to know about ketamine-induced uropathy: A systematic review

AIMS

Ketamine is a general anesthetic. Dissociative effects and low cost led ketamine becoming an illegal recreational drug in young adults. Ketamine-induced uropathy (KIU) is one of the complications observed in abusers. This study aimed to provide a systematic literature review on KIU clinical presentation, pathophysiology, and treatments.

METHODS

We performed the literature search in PubMed, Web of Science, Scopus, and Embase using the terms ketamine and bladder. English papers on human and animal studies were accepted.

RESULTS

A total of 75 papers were selected. Regular ketamine users complain about severe storage symptoms and pelvic pain. Hydronephrosis may develop in long-term abusers and is correlated to the contracted bladder, ureteral stenosis, or vesicoureteral reflux due to ureteral involvement and/or bladder fibrosis. Cystoscopy shows ulcerative cystitis. Ketamine in urine might exert direct toxicity to the urothelium, disrupting its barrier function and enhancing cell apoptosis. The presence of ketamine/ions in the bladder wall result in neurogenic/IgE-mediated inflammation, stimulation of the inducible nitric oxide synthase-cytokines-cyclooxygenase pathway with persistent inflammation and fibrosis. Abstinence is the first therapeutic step. Anti-inflammatory drugs, analgesics and anticholinergics, intravesical instillation of hyaluronic acid, hydrodistension and intravesical injection of botulin toxin-A were helpful in patients with early-stage KIU. In patients with end-stage disease, the control of intractable symptoms and the increase of bladder capacity were the main recommendations to perform augmentation enterocystoplasty.

CONCLUSIONS

KIU is becoming a worldwide health concern, which should be taken into account in the differential diagnosis of ulcerative cystitis.

Esketamine for treatment resistant depression

Introduction: Treatment Resistant Depression (TRD) is a common and burdensome condition with poor outcomes and few treatment options. Esketamine is the S-enantiomer of ketamine and has recently been FDA approved in the United States for treating depression that has failed to respond to trials of two or more antidepressants. Areas covered: This review will briefly discuss current treatment options for TRD, then review esketamine. Relevant literature was identified through online database searches, and clinical trial data were provided by Janssen Pharmaceuticals. Pharmacology, including kinetics and dynamics, is discussed, then clinical data regarding efficacy and safety for esketamine from Phase 2-3 trials are reviewed. Expert opinion: In the expert opinion, the authors discuss multiple factors including patient, physician, and social factors that will influence the use of esketamine. While the efficacy of esketamine compared to off-label use of racemic ketamine remains unclear, both esketamine's approval for use in TRD and longer-term safety data may position it preferentially above racemic ketamine, although factors such as cost and monitoring requirements may limit its use. While questions remain regarding duration and frequency of treatment, as well as addictive potential, esketamine is a novel treatment option offering new hope for TRD.

Magnetic resonance cholangiogram patterns and clinical profiles of ketamine-related cholangiopathy in drug users

BACKGROUND & AIMS

Recreational ketamine use has emerged as an important health and social issue worldwide. Although ketamine is associated with biliary tract damage, the clinical and radiological profiles of ketamine-related cholangiopathy have not been well described.

METHODS

Chinese individuals who had used ketamine recreationally at least twice per month for six months in the previous two years via a territory-wide community network of charitable organizations tackling substance abuse were recruited. Magnetic resonance cholangiography (MRC) was performed, and the findings were interpreted independently by two radiologists, with the findings analysed in association with clinical characteristics.

RESULTS

Among the 343 ketamine users referred, 257 (74.9%) were recruited. The mean age and ketamine exposure duration were 28.7 (±5.8) and 10.5 (±3.7) years, respectively. A total of 159 (61.9%) had biliary tract anomalies on MRC, categorized as diffuse extrahepatic dilatation (n = 73), fusiform extrahepatic dilatation (n = 64), and intrahepatic ductal changes (n = 22) with no extrahepatic involvement. Serum alkaline phosphatase (ALP) level (odds ratio [OR] 1.007; 95% CI 1.002-1.102), lack of concomitant recreational drug use (OR 1.99; 95% CI 1.11-3.58), and prior emergency attendance for urinary symptoms (OR 1.95; 95% CI 1.03-3.70) had high predictive values for biliary anomalies on MRC. Among sole ketamine users, ALP level had an AUC of 0.800 in predicting biliary anomalies, with an optimal level of ≥113 U/L having a positive predictive value of 85.4%. Cholangiographic anomalies were reversible after ketamine abstinence, whereas decompensated cirrhosis and death were possible after prolonged exposure.

CONCLUSIONS

We have identified distinctive MRC patterns in a large cohort of ketamine users. ALP level and lack of concomitant drug use predicted biliary anomalies, which were reversible after abstinence. The study findings may aid public health efforts in combating the growing epidemic of ketamine abuse.

LAY SUMMARY

Recreational inhalation of ketamine is currently an important substance abuse issue worldwide, and can result in anomalies of the biliary system as demonstrated by magnetic resonance imaging. Although prolonged exposure may lead to further clinical deterioration, such biliary system anomalies might be reversible after ketamine abstinence. Clinical trial number: NCT02165488.

Mini review: Ketamine and the urinary tract

The use of ketamine as a recreational drug has become increasingly widespread, particularly amongst teenagers and young men. Its side-effects on the central nervous system and cardiovascular are well established and documented, although it is now clear that ketamine also has significant toxic effects on the genitourinary system. Increasing numbers of patients are presenting to urologists and healthcare professionals with debilitating symptoms attributable to ketamine use, with many clinicians having very little experience of managing patients with this condition. This mini-review aims to provide a contemporary outline of the clinical aspects of ketamine-associated genitourinary toxicity and a summary of management options for treating patients with this often chronic and debilitating condition.

Outcome Evaluation of a Short-Term Hospitalization and Community Support Program for People Who Abuse Ketamine

Ketamine is a popular recreational drug among young people in Hong Kong. Long-term abuse of ketamine can lead to acute urological and medical issues, which often require immediate care at emergency rooms. Many patients require short-term hospitalization for medical management. This opens a brief time window, within which mental health professionals could engage young people who abuses ketamine in psychosocial, functional, and lifestyle interventions. The Crisis Accommodation Program (CAP) is a short-term hospitalization and community support program that addresses the health care needs of young people who abuse ketamine. During short-term hospitalization, the patient participates in a range of cognitive and psychosocial assessments, motivational interviewing, emotions management, and lifestyle re-design interventions. Upon discharge, social work professionals of non-government agencies continue to work with the patients on their action plans in the community. This evaluation study uses a quasi-experimental non-equivalent group design, in which the outcomes of the treatment group (n = 84) are compared with a comparison group (n = 34) who have a history of ketamine abuse but who have not joined the treatment program. The results confirm that the treatment group showed significant increases in motivation for treatment, reduction in drug use, improvement in cognitive screening tests, healthy lifestyle scores, and self-efficacy in avoidance of drugs over 13 weeks. When compared with the comparison group, the treatment group had significant decreases in anxiety and treatment needs and had moved from pre-contemplation to the contemplation or preparation stage. However, there were no significant changes in outcome measures covering lifestyle or self-efficacy in drug avoidance. Overall, the CAP is effective in reducing drug use, anxiety, and helping patients to move from pre-contemplation to the contemplation or preparation stage of change. The study results suggest that health care professionals can successfully engage young people who abuse ketamine to participate in a package of psychosocial interventions, motivational interviewing, and lifestyle re-design during their hospital stay for management of urological problems. The CAP also highlights the importance of collaboration between hospitals and community social services in the management of addiction.

Clinical significance of interleukin‑6 and inducible nitric oxide synthase in ketamine‑induced cystitis

Ketamine is an ionotropic glutamatergic N-methyl-D-aspartate receptor antagonist, which is widely used among recreational drug abusers. Ketamine abusers exhibit substantially reduced bladder capacity, which can lead to urinary frequency. The molecular pathogenesis of ketamine-induced cystitis has been scarcely reported. Given previous clinical findings, it may be hypothesized that pathological alterations in smooth muscle cells (SMCs) of the urinary bladder serve a crucial role in the mechanism underlying cystitis. In the present study, two lineages of SMCs, one from differentiated foreskin-derived fibroblast-like stromal cells and the other from cultured normal aortic SMCs, were used to study ketamine-induced molecular alterations. Polymerase chain reaction was used to study the effects of ketamine on oxidative stress. The effects of adjuvant chemo-therapy with cyclophosphamide (CTX) were also investigated. The results indicated that the expression levels of interleukin-6 and inducible nitric oxide synthase (iNOS) were decreased, whereas collagen expression and deposition were increased in ketamine-treated SMCs. Conversely, treatment with CTX restored the expression of iNOS, which may prevent or limit oxidative damage. In conclusion, the present study demonstrated that ketamine may induce several molecular alterations in SMCs and these changes may be associated with the clinical symptoms observed in ketamine abusers. In addition, the specific chemotherapeutic agent CTX may reverse these ketamine-induced aberrations.

Clinical pattern and prevalence of upper gastrointestinal toxicity in patients abusing ketamine

OBJECTIVE

Evaluations of upper gastrointestinal toxicity from ketamine abuse are uncommon. This study investigated the clinical pattern of upper gastrointestinal symptoms in patients inhaling ketamine.

METHODS

In a cross-sectional study of 611 consecutive patients who were seeking treatment for ketamine uropathy in a tertiary hospital setting between August 2008 and June 2016, their clinical pattern of upper gastrointestinal symptoms was evaluated and compared with a control population of 804 non-users.

RESULTS

A total of 168 (27.5%) patients abusing ketamine (mean age 26.3 years, 58.9% female) reported the presence of upper gastrointestinal symptoms. These symptoms were significantly more prevalent in patients inhaling ketamine than in those who were not (27.5% vs 5.2%, P < 0.001). Their mean duration of ketamine abuse before symptom presentation was 5.0 ± 3.1 years. The presenting symptoms included epigastric pain (n = 155, 25.4%), recurrent vomiting (n = 48, 7.9%), anemia (n = 36, 5.9%) and gastrointestinal bleeding (n = 20, 3.3%). Uropathy symptoms were preceded by upper gastrointestinal symptoms for 4.4 ± 3.0 years in 141 (83.9%) patients. Logistic regression showed that elder age (odds ratio [OR] 1.06, P = 0.04), active abuser status (OR 1.60, P = 0.04) and longer duration of ketamine abuse (OR 1.00, P = 0.04) were independent factors associated with upper gastrointestinal toxicity.

CONCLUSIONS

Although epigastric symptoms are unusual in the young population, upper gastrointestinal toxicity was highly prevalent in those inhaling ketamine. Enquiries about ketamine abuse are recommended when assessing young patients with epigastric symptoms.

The Risk of Upper Urinary Tract Involvement in Patients With Ketamine-Associated Uropathy

Purpose

The aims of this study were to investigate the prevalence of upper tract involvement in ketamine-associated uropathy, and to determine the predictors of hydronephrosis in patients with a history of ketamine abuse.

Methods

This was a cross-sectional study of a prospective cohort of patients with ketamine-associated uropathy. Data including demographics, pattern of ketamine abuse, pelvic pain and urgency or frequency (PUF) symptom score, uroflowmetry (UFM) parameters, serum renal function, and liver function tests were collected. Upon consultation, ultrasonography was performed to assess the function of the urinary system.

Results

From December 2011 to October 2015, we treated 572 patients with ketamine-associated uropathy. Of these patients, 207 (36.2%) had managed to achieve abstinence at the time of their first consultation. Ninety-six patients (16.8%) in the cohort were found to have hydronephrosis on ultrasonography. Univariate analysis identified age, duration of ketamine abuse, PUF symptom score, voided volume on UFM, serum creatinine levels >100 μmol/L, and an abnormal serum liver enzyme profile as factors associated with hydronephrosis. Logistic regression revealed the following parameters to be statistically related to hydronephrosis: age (adjusted odds ratio [OR], 1.090; 95% confidence interval [CI], 1.020–1.166; P=0.012), functional bladder capacity (adjusted OR, 0.997; 95% CI, 0.995–0.999; P=0.029), serum creatinine >100 μmol/L (adjusted OR, 3.107; 95% CI, 1.238–7.794; P=0.016, and an abnormal serum liver enzyme profile (adjusted OR, 1.967; 95% CI, 1.213–3.187; P=0.006).

Conclusions

Ketamine-associated uropathy can involve the upper urinary tract. Patient demographics as well as investigations of UFM, renal function tests, and liver function tests may allow us to identify at-risk patients.

Analysis of print news media framing of ketamine treatment in the United States and Canada from 2000 to 2015

OBJECTIVES

There are multifaceted views on the use of ketamine, a potentially addictive substance, to treat mental health problems. The past 15 years have seen growing media coverage of ketamine for medical and other purposes. This study examined the print news media coverage of medical and other uses of ketamine in North America to determine orientations and trends over time.

METHODS

Print newspaper coverage of ketamine from 2000 to 2015 was reviewed, resulting in 43 print news articles from 28 North American newspapers. A 55-item structured coding instrument was applied to assess news reports of ketamine. Items captured negative and positive aspects, therapeutic use of ketamine, and adverse side effects. Chi-squares tested for changes in trends over time.

RESULTS

In the 15-year reviewed period, the three most frequent themes related to ketamine were: abuse (68.2%), legal status (34.1%), and clinical use in anesthesia (31.8%). There was significant change in trends during two periods (2000-2007 and 2008-2015). In 2008-2015, print news media articles were significantly more likely to encourage clinical use of ketamine to treat depression (p = 0.002), to treat treatment resistant depression (p = 0.043), and to claim that ketamine is more effective than conventional antidepressants (p = 0.043).

CONCLUSIONS

Our review found consistent positive changes in the portrayals of ketamine by the print news media as a therapeutic antidepressant that mirror the recent scientific publications. These changes in news media reporting might influence the popularity of ketamine use to treat clinical depression. Guidance is required for journalists on objective reporting of medical research findings, including limitations of current research evidence and potential risks of ketamine.

Risks Associated with Misuse of Ketamine as a Rapid-Acting Antidepressant

Major depression is a serious psychiatric disorder and remains a leading cause of disability worldwide. Conventional antidepressants take at least several weeks to achieve a therapeutic response and this lag period has hindered their ability to attain beneficial effects in depressed individuals at high risk of suicide. The non-competitive N-methyl-D-aspartate glutamate receptor antagonist ketamine has been shown to have rapid antidepressant effects in both rodents and humans. The emergence of ketamine as a fast-acting antidepressant provides promising new insights into the development of a rapid treatment response in patients with clinical depression. However, its safety and toxicity remain a concern. In this review, we focus on the limitations of ketamine, including neurotoxicity, cognitive dysfunction, adverse events associated with mental status, psychotomimetic effects, cardiovascular events, and uropathic effects. Studies have shown that its safety and tolerability profiles are generally good at low doses and with short-term treatment in depressed patients. The adverse events associated with ketamine usually occur with very high doses that are administered for prolonged periods of time and can be relieved by cessation. The antidepressant actions of its two enantiomers, S-ketamine (esketamine) and R-ketamine, are also discussed. R-ketamine has greater antidepressant actions than S-ketamine, without ketamine-related side-effects. Future treatment strategies should consider using R-ketamine for the treatment of depressed patients to decrease the risk of adverse events associated with long-term ketamine use.

Practical application of the neuroregenerative properties of ketamine: real world treatment experience

While controversial, ketamine has emerged as an effective treatment for refractory depression. Serial infusions have been performed 3 times per week, but our practical experience has challenged this precept concerning infusion frequency. Depression is associated with neuron loss, reduced synapse numbers, and dearborization of dendrites. Ketamine appears to potently induce mechanisms which reverse these neurodegenerative processes. Ketamine not only blocks the glutamate receptor, it activates eukaroyotic elongation factor 2 (eEF2). This, in turn, activates brain-derived neurotrophic factor (BDNF) protein synthesis. This is thought to underlie ketamine's enduring benefits. In addition, ketamine alters glycogen synthase kinase-3 (GSK-3) phosphorylation, probably responsible for its rapid antidepressant effect. Notably, inhibition of the BDNF receptor does not block the immediate benefits of ketamine, but does prevent the enduring effects. Neuro-Luminance Ketamine Infusion Centers have been treating patients with serial ketamine infusions for over three years. Our methods differ from what is often reported, as we perform infusions only once per week and generally do not perform more than five infusions. Data from 100 patients showed that 80% of the patients responded. The baseline Quick Inventory of Depressive Symptomatology-Self Report (QIDS-SR) score was 17.8 ± 2.8. Responders to ketamine showed a drop in QIDS-SR score of 10.8 ± 3.5, while non-responders showed a 0.8 ± 1.8 change. Moreover, they often had persistent benefits over several months. Recently, it was proposed that psychotomimetic effects are necessary during a ketamine infusion to yield effective antidepressant benefits. Yet, only one patient in our clinic has experienced hallucinations in three years. Nevertheless, 80% of our patients show clinical improvement. Further studies of clinical methods for ketamine infusion therapy are encouraged.

Intact urothelial barrier function in a mouse model of ketamine-induced voiding dysfunction

Ketamine is a popular choice for young drug abusers. Ketamine abuse causes lower urinary tract symptoms, with the underlying pathophysiology poorly understood. Disruption of urothelial barrier function has been hypothesized to be a major mechanism for ketamine cystitis, yet the direct evidence of impaired urothelial barrier function is still lacking. To address this question, 8-wk-old female C57BL/6J mice were injected intraperitoneally with 30 mg·kg(-1)·day(-1) ketamine for 12 wk to induce ketamine cystitis. A spontaneous voiding spot assay showed that ketamine-treated mice had increased primary voiding spot numbers and smaller primary voiding spot sizes than control mice (P < 0.05), indicating a contracted bladder and bladder overactivity. Consistently, significantly increased voiding frequency was observed in ketamine-treated mice on cystometrograms. These functional experiments indicate that ketamine induces voiding dysfunction in mice. Surprisingly, urothelial permeability in ketamine-treated mice was not changed when measured using an Ussing chamber system with isotopic urea and water. Mouse urothelial structure was also not altered, and intact umbrella cell structure was observed by both transmission and scanning electron microscopy. Furthermore, immunostaining and confocal microscopy confirmed the presence of a well-defined distribution of zonula occuldens-1 in tight junctions and uroplakin in umbrella cells. In conclusion, these data indicate that ketamine injection induces voiding dysfunction in mice but does not necessarily disrupt mouse bladder barrier function. Disruption of urothelial barrier function may not be the major mechanism in ketamine cystitis.

Clinical staging of ketamine-associated urinary dysfunction: a strategy for assessment and treatment

PURPOSE

To describe a clinical staging method linked to stepwise treatment indications for ketamine-associated urinary dysfunction (KAUD) based on review of our experience in management of KAUD patients and analysis of their clinical features.

METHODS

The eighty-one KAUD patients hospitalized from January 2008 to June 2014 were studied retrospectively. According to ketamine history, renal and liver function, bladder change and up urinary tract involvement, patients were categorized into a described model of three stages. Discriminant analysis was applied to validate the model. The void volume, micturition interval, nocturnal void frequency and pelvic pain and urgency/frequency (PUF) questionnaire score were, respectively, compared after treatments.

RESULTS

There were, respectively, 24, 47 and 10 patients in three stages. The duration of abuse varied (p = 0.047) correlated with clinical stages (p = 0.015, r = 0.268). The severity of LUTS was not significant. The creatinine, estimated glomerular filtration rate and liver function were worse in higher stages (p < 0.01), and the incidence of ureteral change and hydronephrosis was greater (p < 0.001). Based on the model, cross-validation confirmed 83.1 % cases were classified correctly. Twenty-four patients in stage I were treated with behavioral modification and pharmacotherapy, thirty-five patients in stage II with hydrodistention and six patients in stage III with surgical intervention due to rapid progression after conservative therapy. All patients in three stages demonstrated improvements in void volume, micturition interval, nocturnal void frequency and PUF score (all p < 0.05) after treatment.

CONCLUSION

Clinical staging could serve for assessment of progression, and the staging-based treatment is effective. This model still awaits further validation.

Clinical Outcome of a Prospective Case Series of Patients With Ketamine Cystitis Who Underwent Standardized Treatment Protocol

OBJECTIVE

To assess the outcome of a prospective cohort of patients with ketamine-associated uropathy after standardized treatment.

METHODS

This is a prospective case series of patients with ketamine-related urologic problems. Management for the patients includes a 4-tier approach, namely anti-inflammatory or anti-cholinergic drugs, opioid analgesics or pregabalin, intravesical hyaluronic acid, and finally, surgical intervention including hydrodistension and augmentation cystoplasty. Outcome was assessed with functional bladder capacity, pelvic pain and urgency or frequency (PUF) symptom scale, and the EuroQol visual analog scale.

RESULTS

Between December 2011 and June 2014, 463 patients presented with ketamine-associated uropathy. All were managed by the same standardized protocol. Among these patients, 319 patients came back for follow-up assessment. Overall mean follow-up duration was 10.7 ± 8.5 months. For those patients who received first-line treatment (290 patients), there was a significant improvement in PUF scores, the EuroQol visual analog scale, and functional bladder capacity. Both abstinence from ketamine usage and the amount of ketamine consumed were factors predicting the improvement of PUF scores. For those patients who required second-line oral therapy (62 patients), 42 patients (67.7%) reported improvement in symptoms. Eight patients have completed intravesical therapy. There was a significant improvement in voided volume for the patients after treatment.

CONCLUSION

The study demonstrated the efficacy of managing ketamine-associated uropathy using a 4-tier approach. Both anti-inflammatory drugs and analgesics could effectively alleviate symptoms. Being abstinent from ketamine abuse and the amount of ketamine consumed have bearings on treatment response.

Possible pathophysiology of ketamine-related cystitis and associated treatment strategies

Ketamine-related cystitis is characterized by ketamine-induced urinary frequency and bladder pain. It has become a serious problem in recent years. The most typical grossly pathological bladder change with ketamine related cystitis is a contracted bladder and bladder wall thickening. Ulcerative cystitis with an easily bleeding mucosa is a common cystoscopic finding. Microscopically, the urothelium is denuded and is infiltrated by inflammatory cells, such as mast cells and eosinophils. The pathogenesis of ketamine-related cystitis is complicated and involves many different pathways. Past evidence suggests a direct toxic effect, bladder barrier dysfunction, neurogenic inflammation, immunoglobulin-E-mediated inflammation, overexpression of carcinogenic genes, abnormal apoptosis and nitric oxide synthase-mediated inflammation contribute to the pathogenesis of ketamine-related cystitis. The first step to managing ketamine-related cystitis is always asking patients to cease ketamine. Medical treatment might be helpful in patients with early ketamine-related cystitis and abstinence from ketamine. Several case studies showed that the intravesical installation of hyaluronic acid and intravesical injection of botulinum toxin type A were effective for symptom relief in selected patients. For patients with irreversible pathological change, such as contracted bladder, augmentation enterocystoplasty might be the only solution to increase bladder capacity and relieve intractable bladder pain.

Ketamine: promising path or false prophecy in the development of novel therapeutics for mood disorders?

Large 'real world' studies demonstrating the limited effectiveness and slow onset of clinical response associated with our existing antidepressant medications has highlighted the need for the development of new therapeutic strategies for major depression and other mood disorders. Yet, despite intense research efforts, the field has had little success in developing antidepressant treatments with fundamentally novel mechanisms of action over the past six decades, leaving the field wary and skeptical about any new developments. However, a series of relatively small proof-of-concept studies conducted over the last 15 years has gradually gained great interest by providing strong evidence that a unique, rapid onset of sustained, but still temporally limited, antidepressant effects can be achieved with a single administration of ketamine. We are now left with several questions regarding the true clinical meaningfulness of the findings and the mechanisms underlying the antidepressant action. In this Circumspectives piece, Dr Sanacora and Dr Schatzberg share their opinions on these issues and discuss paths to move the field forward.