Something new about ketamine for pediatric anesthesia?

Improving pediatric magnetic resonance imaging safety by enhanced non-technical skills and team collaboration

BACKGROUND

Safe pediatric magnetic resonance imaging (MRI) ideally relies on non-sedative techniques, as avoiding risky sedation is inherently safer. However, in practice, sedation often becomes unavoidable, particularly for younger children or those with anxiety, to ensure motion-free, high-quality imaging. This narrative review explores the current practices and proposes strategies to enhance safety in pediatric MRI examinations.

METHODS

We identified and analyzed 247 studies addressing various aspects of pediatric MRI safety, including sedation protocols, patient monitoring, and team-based management approaches.

RESULTS

Safe sedation requires careful drug selection tailored to individual needs, continuous monitoring, and robust emergency preparedness. While efforts are underway to minimize sedation, safer drug protocols and improved monitoring technologies remain essential. Assembling dedicated MRI teams trained in both technical and non-technical skills-such as situational awareness, communication, and teamwork-supports these strategies. Structured team briefings covering monitoring procedures, emergency scenarios, response protocols, and specific resuscitation roles are also critical. Developing a strong organizational culture that promotes patient safety and continuous learning from incident reports helps ensure ongoing improvements.

CONCLUSIONS

Achieving safe pediatric MRI examinations requires balancing the need for sedation with the goal of minimizing its use. Strengthening collaboration, refining sedation protocols, and implementing advanced safety monitoring systems are essential steps. Further advancements in imaging technologies are also necessary to reliably obtain high-quality scans without sedation, reducing risks and improving patient outcomes.

Rethinking ketamine as a panacea: adverse effects on oxygenation and postoperative outcomes

Ketamine is receiving renewed interest in perioperative medicine as an anaesthetic adjunct and a treatment for chronic conditions, including depression. Ketamine's complex pharmacologic profile results not only in several desirable effects, such as anaesthesia and analgesia, but also multiple adverse effects affecting the central nervous, cardiovascular, and respiratory systems. In addition to defining patient-centred outcomes in future clinical studies on the perioperative uses of ketamine, careful monitoring for its numerous adverse effects will be paramount.

Predictive factors of success and failure for intravenous ketamine therapy in patients suffering from chronic neuropathic pain

Background

Intravenous (IV) ketamine is used for chronic neuropathic pain refractory to other treatments. Administration of such a medication requires high-cost services while the result is not always satisfactory with a significant percentage of failure. Success and failure are related to some factors.

Method

In this study, we aim to point the most responsive disease category to IV ketamine and the predictive factors for successful and failed treatment. Two hundred and sixty-nine patients out of 371 were included. Demographic, clinical, and therapy-related variables were retrospectively collected and then statistically analyzed using various descriptive and inferential methods. A few descriptive statistics are obtained for the variables depending on their nature (e.g., percentages for qualitative variables and means for quantitative variables). Furthermore, several inferential methods are considered to address some statistical points of interest, including, but not limited to, odds ratio interpretations via logistic regression as well as association and correlation analyses.

Results

A significant association was found between the presence of intermittent pain pattern as well as the pain of chronic primary category and favorable response to IV ketamine while the history of previous analgesic interventions was significantly associated with a negative response.

Conclusion

The identified factors can be used to prospectively study the efficacy of ketamine using selection criteria based on the observed results in our study to re-evaluate the percentage of responsiveness according to these new parameters.

The Effects of Dexmedetomidine on Children Undergoing Magnetic Resonance Imaging: A Systematic Review and Meta-Analysis

BACKGROUND

Magnetic Resonance Imaging (MRI) is a valuable diagnostic tool but often requires sedation to complete, especially in children. Dexmedetomidine (DEX) is an a2 agonist, for which there are experimental findings that support its potential neuroprotective effects. Given the potential risks of anesthetic drugs, we ran this study to examine DEX's effectiveness and cardiopulmonary safety as a sedative drug for children undergoing MRI.

MATERIAL AND METHODS

Systematic research was conducted in PubMed, Google Scholar, Scopus and Cochrane databases for randomized controlled trials published between 2010 and 6th/2022 and involving children undergoing MRI who received DEX as sedative medication. The records which met the including criteria, after indexing via the PRISMA chart and assessing for bias, were processed, and a meta-analysis was carried out with the random effects method.

RESULTS

Thirteen studies were included. Out of 6204 measurements obtained, in 4626, it was planned for the participants to only receive DEX (measure group) as an anesthetic drug throughout the procedure. The participants' mean age was 57 months (Ι² = 4%, τ² = 0.5317, p = 0.40). A total of 5.6% (95% CI: 0.6-14.1%, I² = 98%, p < 0.01) of the patients needed a second dose of DEX. In total, 6% (95% CI: 1-15%, I² = 93%, τ² = 0.0454, p < 0.01) required the administration of another drug, besides DEX, to complete the imaging (sedation failure). The effectiveness of the only-DEX method was 99% (95% CI: 97.5-100%, I² = 81%, τ² = 0.0107, p < 0.01). The whole rate of adverse events was 15% (95% CI: 9.3-21.5%, I² = 92%, p < 0.01). Hypotension was reported in 8.7% of the cases (95% CI: 3.1-16.4%, I² = 84%, p < 0.01), hypertension in 1.1% (95% CI: 0-5.4%, I² = 89%, p < 0.01), bradycardia in 10% (95% CI: 4-18%, I² = 95%, p < 0.01) and desaturation in 1.2% (95% CI: 0-4%, I² = 68%, p < 0.01). There was no statistically significant incidence in respiratory rate decrease (comparing the children who received DEX to their baseline). Five cases of vomiting and one of apnea were recorded.

CONCLUSIONS

Given that DEX seems to be an effective as well as respiratory and hemodynamically safe drug, it may be a future spotlight in (pediatric) sedation for imaging procedures such as MRI.

Arylcyclohexylamine Derivatives: Pharmacokinetic, Pharmacodynamic, Clinical and Forensic Aspects

Since the 2000s, an increasing number of new psychoactive substances (NPS) have appeared on the drug market. Arylcyclohexylamine (ACH) compounds such as ketamine, phencyclidine and eticyclidine derivatives are of particular concern, given their rapidly increasing use and the absence of detailed toxicity data. First used mainly for their pharmacological properties in anesthesia, their recreational use is increasing. ACH derivatives have an antagonistic activity against the N-methyl-D-aspartate receptor, which leads to dissociative effects (dissociation of body and mind). Synthetic ketamine derivatives produced in Asia are now arriving in Europe, where most are not listed as narcotics and are, thus, legal. These structural derivatives have pharmacokinetic and pharmacodynamic properties that are sometimes very different from ketamine. Here, we describe the pharmacology, epidemiology, chemistry and metabolism of ACH derivatives, and we review the case reports on intoxication.

General anesthesia and sleep: like and unlike

General anesthesia and sleep have long been discussed in the neurobiological context owingto their commonalities, such as unconsciousness, immobility, non-responsiveness to externalstimuli, and lack of memory upon returning to consciousness. Sleep is regulated bycomplex interactions between wake-promoting and sleep-promoting neural circuits. Anestheticsexert their effects partly by inhibiting wake-promoting neurons or activating sleep-promotingneurons. Unconscious but arousable sedation is more related to sleep-wake circuitries,whereas unconscious and unarousable anesthesia is independent of them. Generalanesthesia is notable for its ability to decrease sleep propensity. Conversely, increasedsleep propensity due to insufficient sleep potentiates anesthetic effects. Taken together, it isplausible that sleep and anesthesia are closely related phenomena but not the same ones.Further investigations on the relationship between sleep and anesthesia are warranted.

First-time offenders for recreational ketamine use under a new penalty system in Taiwan: incidence, recidivism and mortality in national cohorts from 2009 to 2017

BACKGROUND AND AIMS

Ketamine has become a new recreational drug of choice among young people in parts of Asia. Using national databases in Taiwan, this study aimed to (1) examine the yearly trend in the ketamine offence rate over time; (2) estimate the 3-year risk of drug-related re-offence and its correlates among the first-time offenders; and (3) estimate the 3-year standardized mortality ratio (SMR) among the first-time offenders.

DESIGN, SETTING AND PARTICIPANTS

Retrospective cohort studies of offenders for recreational ketamine use in a penalty system initiated in 2009. Offenders for recreational ketamine use were identified from the Administrative Penalty System for Schedule III/IV Substances database from 2009 to 2017, and the re-offence rate and mortality among first-time offenders were assessed via record-linkage within the database as well as with both the criminal drug offence database and the national mortality database. The cohort from 2009 to 2016 (n = 39 178) was used for the recidivism analysis and the cohort from 2009 to 2013 (n = 25 357) was used for the 3-year SMR analysis.

MEASUREMENTS

Recidivism was estimated using survival analysis of the event as re-arrest for using ketamine, more serious illicit drugs (Schedules I/II), or any illicit drugs (ketamine or Schedules I/II). SMRs were estimated for overall and cause-specific death within 3 years after the first offence for ketamine use.

FINDINGS

The age-standardized rates for both prevalent (1.38 per 1000) and first-time offenders (0.65 per 1000) peaked in 2013 and then decreased steadily. The 3-year risk of re-offence was 33.85% [95% confidence interval (CI) = 33.23-34.47%) for ketamine use and 39.52% (95% CI = 39.00-40.04%) for any illicit drug use. These first-time offenders had an SMR of 4.9 (95% CI = 4.3-5.4) for overall mortality, 2.1 (95% CI = 1.6-2.7) for natural deaths and 7.6 (95% CI = 6.7-8.6) for unnatural deaths.

CONCLUSIONS

Recreational ketamine use in Taiwan appears to lead not only to high risk for drug-related re-offence but also to excess mortality.

Ketamine for pain control of snake envenomation in Guinea: A case series

Snakebite envenomation is a global health crisis and is classified as a Category A neglected tropical disease by the World Health Organization (WHO). Snakebite envenomations account for a significant amount of morbidity and morbidity in tropical and subtropical regions. Recently, publications have illustrated the potential for snake envenomations causing post-traumatic stress disorder (PTSD) in a significant number of patients. Ketamine is on the WHO's list of essential medications and is used for a variety of pharmacologic applications including anesthesia and acute pain management. To date it has not been assessed for pain control in snakebite envenomations. Twelve patients who presented with severe pain secondary to Bitis, Causus, and Atractaspis envenomations were treated with low-dose intravenous ketamine. The patients included 7 males and 5 females with a median age of 37.5 (range 14-64) and a median presentation time of 5.75 h (range 5 min-96 h) after the initial bite occurred. Ten envenomations were presumed to have been caused by Bitis species resulting in extensive swelling and blistering of the affected extremities. One envenomation was presumedC. maculatus causing local swelling and pain. One envenomation was a presumed Atractaspis species causing significant local pain with minimal swelling. All patients expressed having significant pain but could not express the degree of their pain using an analogue pain scale. An initial median dose of 5 mg of ketamine (range 2.5-15 mg) was administered intravenously for pain control. Every patient expressed decreased pain and felt more comfortable within 1 min after administration of ketamine. Nine of the twelve patients only required a single dose. There were no adverse side effects. Ketamine appears to be an effective means of pain control for those suffering from painful envenomations. With minimal risk of significant side effects at acute pain management doses and the average cost per effective dose averaging between US$0.03-0.06, this may provide a cheap, safe, and effective solution for Sub-saharan Africa and other resource-limited settings. Controlled studies need to be done to critically assess our observations.

Prenatal Exposure to Ketamine Leads to Anxiety-Like Behaviors and Dysfunction in Bed Nucleus of Stria Terminalis

BACKGROUND

Both the clinical and preclinical studies have suggested embryonic or infant exposure to ketamine, a general anesthetic, pose a great threat to the developing brain. However, it remains unclear how ketamine may contribute to the brain dysfunctions.

METHODS

A mouse model of prenatal exposure to ketamine was generated by i.m. injection and continuous i.p. infusion of pregnant mice. Open field test and elevated plus maze test were used to analyze the behavioral alterations induced by ketamine. Immunostaining by c-Fos was used to map the neuron activity. Chemogenetic modulation of the neurons was used to rescue the abnormal neuron activity and behaviors.

RESULTS

Here we show that mice prenatally exposed to ketamine displayed anxiety-like behaviors during adulthood, but not during puberty. C-Fos immunostaining identified abnormal neuronal activity in Bed Nucleus of the Stria Terminalis, the silencing of which by chemogenetics restores the anxiety-like behaviors.

CONCLUSIONS

Taken together, these results demonstrate a circuitry mechanism of ketamine-induced anxiety-like behaviors.

Ketamine applications beyond anesthesia - A literature review

Ketamine's clinical use began in the 1970s. Physicians benefited from its safety and ability to induce short-term anesthesia and analgesia. The psychodysleptic effects caused by the drug called its further clinical use into question. Despite these unpleasant effects, ketamine is still applied in veterinary medicine, field medicine, and specialist anesthesia. Recent intensive research brought into light new possible applications of this drug. It began to be used in acute, chronic and cancer pain management. Most interesting reports come from research on the antidepressive and antisuicidal properties of ketamine giving hope for the creation of an effective treatment for major depressive disorder. Other reports highlight the possible use of ketamine in treating addiction, asthma and preventing cancer growth. Besides clinical use, the drug is also applied to in animal model of schizophrenia. It seems that nowadays, with numerous possible applications, the use of ketamine has returned; to its former glory. Nevertheless, the drug must be used with caution because still the mechanisms by which it executes its functions and long-term effects of its use are not fully known. This review aims to discuss the well-known and new promising applications of ketamine.

Ketamine-A Narrative Review of Its Uses in Medicine

One of the most fascinating drugs in the anesthesiologist's armament is ketamine, an N-methyl-D-aspartate receptor antagonist with a myriad of uses. The drug is a dissociative anesthetic and has been used more often as an analgesic in numerous hospital units, outpatient pain clinics, and in the prehospital realm. It has been used to treat postoperative pain, chronic pain, complex regional pain syndrome, phantom limb pain, and other neuropathic conditions requiring analgesia. Research has also demonstrated its efficacy as an adjunct in psychotherapy, as a treatment for both depression and posttraumatic stress disorder, as a procedural sedative, and as a treatment for respiratory and neurologic conditions. Ketamine is not without its adverse effects, some of which can be mitigated with certain efforts. Such effects make it necessary for the clinician to use the drug only in situations where it will provide the greatest benefit with the fewest adverse effects. To the best of our knowledge, none of the reviews regarding ketamine have taken a comprehensive look at the drug's uses in all territories of medicine. This review will serve to touch on its chemical data, pharmacokinetics and pharmacodynamics, medical uses, and adverse effects while focusing specifically on the drugs usage in anesthesia and analgesia.

Effects of NMDA antagonists on the development and expression of tolerance to diazepam-induced motor impairment in mice

The goal of the study was to investigate the effects of ketamine and memantine on the development and expression of tolerance to diazepam (DZ)-induced motor impairment in mice. DZ-induced motor incoordination was assessed by the rotarod and chimney tests. It was found that (a) ketamine, at the dose of 5mg/kg (but not 2.5mg/kg), decreased the expression, but not the development, of tolerance to the motor impairing effects of DZ, (b) memantine, at the doses of 5 and 10mg/kg decreased both the development and expression of DZ tolerance in the rotarod test (also in the chimney test but at the higher dose of 10mg/kg) and (c) ketamine and memantine alone had no effect, either in the rotarod or the chimney test in mice. Those findings provided behavioral evidence that the glutamatergic system could contribute an important role in the development and/or expression of tolerance to DZ in mice.

Perioperative low-dose ketamine improves postoperative analgesia following Cesarean delivery with general anesthesia

OBJECTIVE

In this study, the effect of perioperative uses of low dose ketamine on post-operative wound pain and analgesic consumption in patients undergoing elective Cesarean section was evaluated.

METHODS

In randomized, double blind clinical trial, 52 women with American Society of Anesthesiologists (ASA) class I-II identification undergoing elective Cesarean section in general anesthesia were enrolled. In the ketamine group (group K), a ketamine bolus of 0.5 mg kg(-1) IV was administered at the time of induction of general anesthesia. After induction, a ketamine infusion of 0.25 mg kg(-1) h(-1) was started and discontinued at the end of surgery. Patients allocated to the control group (group C) were given identical volumes of saline. The cumulative dose of morphine consumption after surgery was measured as the primary outcome of this study. Secondary outcomes were pain control assessed by numeric rating scale (NRS) and need for rescue analgesia and incidence of side effects.

RESULTS

The mean 24-h morphine consumption was lower in group K (p = 0,001). At 15 min postoperatively, NRS values were lower in group K than group C (p = 0,001). There was no difference among groups regarding the need for supplemental analgesia (rescue diclofenac doses) (p > 0.05).

CONCLUSIONS

Perioperative uses of low dose ketamine decreased post-operative opioid requirements, which was observed long after the normal expected duration of ketamine.

Ketamine in pain management

For ketamine's fiftieth birthday, a narrative review of this unique drug in pain management is presented. Its history is traced from its conception, and its heritage, as a phencyclidine offspring, delineated. The earliest roots of the conceptions concerning the mechanisms of action are sought, and then followed in preclinical as well as clinical research. The major proposed mechanisms in the literature are commented on and evaluated. The growth of the clinical evidence for perioperative pain, acute pain, and chronic pain is followed from early attempts to systematic reviews. Finally, an attempt is made to foresee what the next 50 years might hold in store for our 50 years old.

Neuraxial analgesia in neonates and infants: a review of clinical and preclinical strategies for the development of safety and efficacy data

Neuraxial drugs provide robust pain control, have the potential to improve outcomes, and are an important component of the perioperative care of children. Opioids or clonidine improves analgesia when added to perioperative epidural infusions; analgesia is significantly prolonged by the addition of clonidine, ketamine, neostigmine, or tramadol to single-shot caudal injections of local anesthetic; and neonatal intrathecal anesthesia/analgesia is increasing in some centers. However, it is difficult to determine the relative risk-benefit of different techniques and drugs without detailed and sensitive data related to analgesia requirements, side effects, and follow-up. Current data related to benefits and complications in neonates and infants are summarized, but variability in current neuraxial drug use reflects the relative lack of high-quality evidence. Recent preclinical reports of adverse effects of general anesthetics on the developing brain have increased awareness of the potential benefit of neuraxial anesthesia/analgesia to avoid or reduce general anesthetic dose requirements. However, the developing spinal cord is also vulnerable to drug-related toxicity, and although there are well-established preclinical models and criteria for assessing spinal cord toxicity in adult animals, until recently there had been no systematic evaluation during early life. Therefore, in the second half of this review, we present preclinical data evaluating age-dependent changes in the pharmacodynamic response to different spinal analgesics, and recent studies evaluating spinal toxicity in specific developmental models. Finally, we advocate use of neuraxial drugs with the widest demonstrable safety margin and suggest minimum standards for preclinical evaluation before adoption of new analgesics or preparations into routine clinical practice.

Pharmacology of sedative-analgesic agents: dexmedetomidine, remifentanil, ketamine, volatile anesthetics, and the role of peripheral Mu antagonists

In this article, the authors discuss the pharmacology of sedative-analgesic agents like dexmedetomidine, remifentanil, ketamine, and volatile anesthetics. Dexmedetomidine is a highly selective alpha-2 agonist that provides anxiolysis and cooperative sedation without respiratory depression. It has organ protective effects against ischemic and hypoxic injury, including cardioprotection, neuroprotection, and renoprotection. Remifentanil is an ultra-short-acting opioid that acts as a mu-receptor agonist. Ketamine is a nonbarbiturate phencyclidine derivative and provides analgesia and apparent anesthesia with relative hemodynamic stability. Volatile anesthetics such as isoflurane, sevoflurane, and desflurane are in daily use in the operating room in the delivery of general anesthesia. A major advantage of these halogenated ethers is their quick onset, quick offset, and ease of titration in rendering the patient unconscious, immobile, and amnestic.

Wherefore ketamine?

PURPOSE OF REVIEW

Ketamine has been repeatedly reviewed in this journal but novel developments have occurred in the last few years prompting an update. Interesting recent publications will be highlighted against a background of established knowledge.

RECENT FINDINGS

In the field of anesthesia, particularly in pediatrics, some contributions have been made concerning intramuscular versus intravenous induction. The need for anticholinergic adjuvants has also been clarified. Neuroapoptosis has been observed in animals and its implications for human subjects are discussed in a general context of neurotoxicity. The most important developments, however, are in the treatment of pain. Neurological and urological side effects strongly question long-term use. Other potentially beneficial effects have also been reported, such as anti-inflammatory and antidepressive effects. There are also indications that ketamine may attenuate postoperative delirium in coronary by-pass patients.

SUMMARY

More questions have arisen than have been answered. Some have very grave implications. The issue of neuroapoptosis must be clarified. The long-term effects must be further investigated. On the bright side the effects on postoperative delirium, as well as the anti-inflammatory and antidepressive effects, might open new vistas for an old drug.

Infant with in utero ketamine exposure: quantitative measurement of residual dosage in hair

BACKGROUND

The drug ketamine is frequently abused for recreational use in Asia, but few studies in humans have focused on the effects of ketamine exposure during pregnancy on the health of neonates. Here, we report a neonate whose mother was suspected of ketamine abuse during pregnancy. The case was confirmed by testing hair samples of the neonate.

METHODS

Hair samples of the neonate were taken on the first day of referral. Levels of common drugs of abuse in Asia were measured in the hair sample by gas chromatography-mass spectrometry using our previously reported method with modifications. This method was developed and validated to simultaneously quantify levels of amphetamine, ketamine and opiate in human hair.

RESULTS

The neonate was a female baby, born full term, with a low birth weight of 2250 g. Very high levels of ketamine were detected in the neonate's hair, even though the mother stated that she had stopped abusing ketamine during the early stage of pregnancy. The neonate suffered from general hypotonia; moderate cerebral dysfunction was found by electroencephalography. Fortunately, her hypotonia improved gradually within 21 days.

CONCLUSION

This is the first report of ketamine exposure during late pregnancy detected by hair testing. We noted several clinical features in this case, including the infant being small for gestational age, intrauterine growth retardation, remarkable hypotonia, and poor reflex responses. Although the mother denied the use of ketamine during the late stage of her pregnancy, significant amount of ketamine and norketamine was still found in hair samples (only 2 cm long and 25 mg) from the infant.

Effects of perioperative S (+) ketamine infusion added to multimodal analgesia in patients undergoing ambulatory haemorrhoidectomy

Background and objective

Perioperative low-dose ketamine has been useful for postoperative analgesia. In this study we wanted to assess the analgesic effect and possible side-effects of perioperative low-dose S (+) ketamine when added to a regime of non-opioid multimodal pain prophylaxis.

Methods

Seventy-seven patients scheduled for haemorrhoidectomy were enrolled in this randomized, double-blind, controlled study. They received oral paracetamol 1–2 g, total intravenous anaesthesia, intravenous 8 mg dexamethasone, 30 mg ketorolac and local infiltration with bupivacaine/epinephrine. Patients randomized to S (+) ketamine received an intravenous bolus dose of 0.35 mg kg−1 S (+) ketamine before start of surgery followed by continuous infusion of 5 μg kg−1 min−1 until 2 min after end of surgery. Patients in the placebo group got isotonic saline (bolus and infusion). BISTM monitoring was used. Pain intensity and side-effects were assessed by blinded nursing staff during PACU stay and by phone 1, 7 and 90 days after surgery.

Results

In patients randomized to S (+) ketamine emergence from anaesthesia was significantly longer (13.1 min vs. 9.3 min; p < 0.001). BIS values were significantly higher during anaesthesia (maximal value during surgery: 62 vs. 57; p = 0.01) and when opening eyes (81 vs. 70, p < 0.001). Pain scores (NRS and VAS) did not differ significantly between groups.

Conclusions

The addition of perioperative S (+) ketamine for postoperative analgesia after haemorrhoidectomy on top of multimodal non-opioid pain prophylaxis does not seem to be warranted, due to delayed emergence and recovery, more side-effects, altered BIS readings and absence of additive analgesic effect.

Upper gastrointestinal problems in inhalational ketamine abusers

OBJECTIVE

To study the association between upper gastrointestinal (GI) problems and inhalational ketamine abuse.

METHODS

This is a retrospective study of 64 ketamine abusers treated from 2001 to 2008. Variables studied included clinical presentations, findings of upper GI endoscopy, abstinence from ketamine and relief of epigastric pain.

RESULTS

The following patients with (i) a previous history of upper GI problem; (ii) a history of non-steroidal anti-inflammatory drug (NSAID), aspirin or other substance abuse; and (iii) a known history of Helicobacter pylori (H. pylori) infection were excluded. The study group thus consisted of 37 ketamine abusers, of whom 28 had upper GI symptoms. Overall 14 of these patients had an upper endoscopy performed. The endoscopic diagnoses were: 12 (85.7%) with gastritis, one (7.1%) with gastroduodenitis, and one (7.1%) normal finding. Test for H. pylori, infection was negative. Abstinence from ketamine was found to be associated significantly with relief of symptoms (P= 0.027). Logistic regression showed the odds ratio of symptomatic relief for abstinence versus continued use of ketamine is 12.5 (95% CI[1.20, 130.6], P= 0.035). In patients whom an upper GI endoscopy was performed, H. pylori negative gastritis was the commonest histopathological finding (78.6%). Despite the use of medications, symptoms are commonly not relieved and that is associated with the continued abuse of ketamine.

CONCLUSION

Ketamine abusers frequently presented with upper GI symptoms, the commonest of which is epigastric pain (73% of abusers). Abstinence from ketamine abuse can lead to the relief of symptoms, which is an important message for ketamine abusers.

Inhibitory effects of ketamine on lipopolysaccharide-induced microglial activation

Microglia activated in response to brain injury release neurotoxic factors including nitric oxide (NO) and proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Ketamine, an anesthetic induction agent, is generally reserved for use in patients with severe hypotension or respiratory depression. In this study, we found that ketamine (100 and 250 μM) concentration-dependently inhibited lipopolysaccharide (LPS)-induced NO and IL-1β release in primary cultured microglia. However, ketamine (100 and 250 μM) did not significantly inhibit the LPS-induced TNF-α production in microglia, except at the higher concentration (500 μM). Further study of the molecular mechanisms revealed that ketamine markedly inhibited extracellular signal-regulated kinase (ERK1/2) phosphorylation but not c-Jun N-terminal kinase or p38 mitogen-activated protein kinase stimulated by LPS in microglia. These results suggest that microglial inactivation by ketamine is at least partially due to inhibition of ERK1/2 phosphorylation.