Ketamine: a new look at an old drug

Effects of intra-operative administration of subanesthetic s-ketamine on emergence from sevoflurane anesthesia: a randomized double-blind placebo-controlled study

BACKGROUND

Ketamine is administered in the perioperative period for its benefits in analgesia, anti-agitation and anti-depression when administered at a small dose. However, it is not clear whether the intra-operative administration of ketamine would affect emergence under sevoflurane anesthesia. To investigate this effect, we designed this trial.

METHODS

In this randomized, double-blind, placebo-controlled study, we enrolled 44 female patients aged 18-60 who were scheduled to elective laparoscopic gynecological surgeries. All patients were randomly assigned to saline or s-ketamine group. In s-ketamine group, patients received 0.125 mg/kg s-ketamine 30 min after the start of surgery. In saline group, patients were administered the same volume of saline. Sevoflurane and remifentanil were used to maintain general anesthesia. The primary outcome was emergence time. We also assessed postoperative agitation, cognitive function, and delirium. In addition, we collected and analyzed prefrontal electroencephalogram (EEG) during and after general anesthesia.

RESULTS

There were no significant differences in emergence time between s-ketamine group and saline group (10.80 ± 3.77 min vs. 10.00 ± 2.78 min, P = 0.457). Neither postoperative agitation (4 [3, 4] vs. 4 [3, 4], P = 0.835) nor cognitive function (25.84 ± 2.69 vs. 25.55 ± 2.19, P = 0.412) differed between groups. No postoperative delirium was observed in either group. Subanesthetic s-ketamine resulted in active EEG with decreased power of slow (-0.35 ± 1.13 dB vs. -1.63 ± 1.03 dB, P = 0.003), delta (-0.22 ± 1.11 dB vs. -1.32 ± 1.09 dB, P = 0.011) and alpha (-0.31 ± 0.71 dB vs. -1.71 ± 1.34 dB, P = 0.0003) waves and increased power of beta-gamma bands (-0.30 ± 0.89 dB vs. 4.20 ± 2.08 dB, P < 0.0001) during sevoflurane anesthesia, as well as an increased alpha peak frequency (-0.16 ± 0.48 Hz vs. 0.31 ± 0.73 Hz, P = 0.026). EEG patterns did not differ during the recovery period after emergence between groups.

CONCLUSION

Ketamine administered during sevoflurane anesthesia had no apparent influence on emergence time in young and middle-aged female patients undergoing laparoscopic surgery. Subanesthetic s-ketamine induced an active prefrontal EEG pattern during sevoflurane anesthesia but did not raise neurological side effects after surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2100046479 (date: 16/05/2021).

Efficacy and Safety of Ketamine in the Treatment of Neuropathic Pain: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Purpose

Ketamine is a N-methyl-D-aspartate (NMDA) antagonist with strong analgesic properties. Its addition to the treatment of neuropathic pain may reduce pain intensity and improve overall quality of life. A systematic review and meta-analysis of randomized controlled trials was performed to investigate the addition of ketamine to the treatment of patients with neuropathic pain.

Patients and Methods

GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to rate the overall certainty of the evidence for each outcome. Eighteen (18) randomized controlled trials including 706 participants were included for further analysis.

Results

Ketamine addition to standard treatment of neuropathic pain (NP) resulted in a statistically significant reduction of pain intensity at one week after the end of treatment with ketamine (MD −2.14, 95% CI −2.65 to −1.63; p<0.00001) and after 30 days after the end of treatment with ketamine (MD −1.68, 95% CI −2.25 to −1.12; p<0.00001) and a statistically significant increase in discomfort (RR 4.06; 95% CI 1.18 to 13.95; p=0.03), and psychedelic effects (RR 4.94; 95% CI 2.76 to 8.84; p<0.00001).

Conclusion

There is a statistically significant pain reduction by adding ketamine to the treatment of chronic NP when compared to the standard treatment. However, such pain reduction comes at the expense of adverse outcomes, especially psychedelic effects related to the administration of ketamine. However, the overall quality of certainty of evidence is low due to the clinical heterogeneity among the intervention characteristics of the trials analyzed (different administration routes, dosing regimen, therapy durations, different clinical characteristics of the population investigated). Future large multi-centered trials are necessary to confirm or not the results of the present review.

Ketamine Sedation for Patients With Acute Behavioral Disturbance During Aeromedical Retrieval: A Retrospective Chart Review

OBJECTIVE

The aim of this study was to determine the prevalence, safety (as measured by the incidence of adverse events), and effectiveness (as measured by the incidence of intubations) of ketamine sedation in patients with acute behavioral disturbance (ABD) during air medical retrieval.

METHODS

This was a retrospective observational study. Eligible patients were identified by searching the electronic databases of 2 air medical retrieval services in Queensland, Australia, for adult patients with ABD transported between January 1, 2015, and June 30, 2016. Data abstraction was performed as per standard chart review criteria. The incidences of intubations and adverse reactions were the main outcomes.

RESULTS

One hundred twenty-two patients met the inclusion criteria. Thirty-one (25.4%) patients were intubated, 21 (17.2%) for airway protection/respiratory depression and 10 (8.1%) for persistent ABD. Twenty-one (17.2%) patients received ketamine, 3 of whom (14.3%) were intubated for persistent ABD. Nine (42.9%) patients developed hypertension after ketamine, 2 of whom needed intervention. One patient developed hypoxia after ketamine that resolved without intervention, and 1 patient developed increased secretions. No patients developed nausea, vomiting, emergence phenomena, apnea, or laryngospasm.

CONCLUSION

Our study suggests that ketamine is a safe and effective agent for sedating patients with ABD during air medical retrieval.

Deep sedation in GreenLight laser prostatectomy

Introduction:

Evaluation of ketamine and propofol combination for the performance of photoselective vaporization of prostate (PVP).

Patients and Methods:

Twenty-six patients undergoing PVP for benign prostatic hyperplasia were included in the study. Co-morbidities were present in 24 patients. Midazolam 2 mg intravenous was administered for the induction to anesthesia. Propofol (10 mg/ml) and ketamine (1 mg/ml) were administered with the use of two pumps. An initial bolus dose of 0.03 ml/kg of propofol and 5 mg of ketamine was administered intravenously. The anesthesia was maintained by continuous infusion of 0.01 ml/kg/min of propofol and 2 ml/min of ketamine. Fentanyl was administered when deemed necessary. The level of sedation, peri-operative parameters and side-effects were recorded.

Results:

The average periods from the induction of anesthesia and intraoperative infusion were 12.38 ± 5.84 min and 59.5 ± 22.15 min, respectively. Average propofol and total ketamine dose were 85.5 ± 10.62 μg/kg/min and 144.9 ± 45.62 mg, respectively. The average dose of fentanyl administered was 29.81 ± 27.40 μcg. An average period between the end of the infusion and the discharge to the urology clinic was 34.62 ± 22.89 min. Ten patients experienced nausea and five eventually vomited. Hallucinations were observed in five cases while visual disturbances in two patients.

Conclusion:

The combined use of ketamine and propofol for the performance of PVP proved to be an efficient method for anesthesia. The “deep sedation” provided by these drugs was not associated with significant side-effects. Moreover, the use of the above method is indicated in patients with significant co-morbidities that should undergo PVP.

The effect of ketamine on hypoventilation during deep sedation with midazolam and propofol: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Hypoventilation is a major cause of morbidity and mortality in patients having procedures under sedation. Few clinical strategies have been evaluated to reduce intraoperative hypoventilation during surgical procedures under deep sedation.

OBJECTIVE

The primary objective of this investigation was to examine the effect of ketamine on hypoventilation in patients receiving deep sedation for surgery with midazolam and propofol.

DESIGN

The study was a randomised, placebo-controlled, double-blind clinical trial.

SETTING

Intraoperative.

PATIENTS

Healthy women undergoing breast surgery.

INTERVENTION

Randomised to receive ketamine (0.5 mg kg bolus, followed by an infusion of 1.5 μg kg min) or isotonic saline.

MAIN OUTCOME MEASURE

Duration of hypercapnia measured continuously with a transcutaneous carbon dioxide (TCO2) monitor.

RESULTS

Fifty-four participants were recruited. Patient and surgical characteristics were similar between the study groups. The median percentage of the sedation time with TCO2 more than 6.7 kPa in participants in the ketamine group, 1.2% (95% confidence interval, CI, 0 to 83), was less than that in the isotonic saline group (65%, 95% CI, 0 to 88; P = 0.01). Severe hypoventilation (TCO2 >8.0 kPa) was also less in the ketamine group, median 0% (95% CI, 0 to 11.7) compared with 28% (95% CI, 0 to 79.3; P = 0.0002) for the isotonic saline group. The ketamine group required less airway manoeuvres (chin lift) to keep the SaO2 greater than 95% median (95% CI) [0 (0 to 3) compared with 3 (0 to 16) in the isotonic saline group] (P = 0.004).

CONCLUSION

Ketamine decreased the duration and severity of hypercapnia in patients undergoing deep sedation with propofol. The addition of ketamine may reduce hypoventilation and adverse effects in patients having procedures under sedation.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01535976.

A review of ketamine in affective disorders: current evidence of clinical efficacy, limitations of use and pre-clinical evidence on proposed mechanisms of action

INTRODUCTION

Recent research has seen low-dose ketamine emerge as a novel, rapid-acting antidepressant. Ketamine, an N-methy-d-aspartate (NMDA) receptor antagonist, leads to effects on the glutamatergic system and abnormalities in this neurotransmittor system are present in depression. This article aims to (1) review the clinical literature on low-dose ketamine as a rapid-acting antidepressant in affective disorders, (2) provide a critical overview of the limitations of ketamine and research attempts to overcome these (3) discuss the proposed mechanisms of action of ketamine and (4) point towards future research directions.

METHOD

The electronic database Pubmed, Web of Science and sciencedirect were searched using the keywords: ketamine, N-methyl-d-aspartate receptor antagonist, rapid-acting antidepressant, depression, treatment-resistant depression, bipolar depression, suicidal ideation, electroconvulsive therapy, mechanism of action.

RESULT

The literature demonstrates evidence supporting a rapid-acting antidepressant effect of low-dose intravenous ketamine in major depressive disorder, in bipolar depression and in depression with suicidal ideation. There are mixed results as to whether ketamine leads to a reduction in time to remission in patients undergoing electroconvulsive therapy (ECT). Efforts to unravel ketamine's therapeutic mechanism of action have implicated the mammalian target of rapamycin (mTOR)-dependent synapse formation in the rat prefrontal cortex, eukaryotic elongation factor 2 phosphorylation (p-eEF2) and glycogen synthase kinase (GSK-3). Ketamine's limiting factors are the transient nature of its antidepressant effect and concerns regarding abuse, and research efforts to overcome these are reviewed.

CONCLUSION

Current and future research studies are using ketamine as a promising tool to evaluate the glutamatergic neurotransmittor system to learn more about the pathophysiology of depression and develop more specific rapid-acting antidepressant treatments.

Effects of anesthetics, sedatives, and opioids on ventilatory control

This article provides a comprehensive, up to date summary of the effects of volatile, gaseous, and intravenous anesthetics and opioid agonists on ventilatory control. Emphasis is placed on data from human studies. Further mechanistic insights are provided by in vivo and in vitro data from other mammalian species. The focus is on the effects of clinically relevant agonist concentrations and studies using pharmacological, that is, supraclinical agonist concentrations are de-emphasized or excluded.

Rapid-acting antidepressant strategies: mechanisms of action

Current antidepressants are ineffective in many depressed patients. Thus there is an urgent need to develop treatment strategies which have significantly faster response, can be sustained and have minimal side-effects. This paper reviews clinical data, potential biomarkers, mechanisms of action and future research directions for two proven strategies that produce marked improvement in severe depressive symptoms within 48 h, ketamine and sleep deprivation therapy (SDT). These treatments provide unequivocal evidence that the depressive process can be rapidly reversed in a subgroup of patients. Seventeen ketamine studies in over 150 patients showed a rapid response. Low-dose intravenous ketamine produced mild psychotomimetic effects but response has not been effectively sustained. SDT has been investigated in over 60 studies with a 40-60% response rate within 48 h. Although SDT is often used in Europe to initiate a rapid response, it is less utilized within the USA, in part, because it has a short duration when administered alone. We review data concerning chronotherapeutic strategies of bright-light therapy (BLT) and sleep-phase advance (SPA) which successfully sustain the antidepressant efficacy of SDT. Evidence is further discussed that a significant group of mood disorders have abnormal circadian rhythms which are known to be controlled by clock genes. It is hypothesized that chronotherapeutic manipulations can reset clock genes and thus, abnormalities in circadian rhythms. Further findings are reviewed that ketamine, in addition to its role as an NMDA antagonist, can also alter circadian rhythms. Thus, ketamine may share a critical mechanism with SDT.

The effect of ketamine administration on nocturnal sleep architecture

Substantial evidence exists in the acute, rehabilitative and outpatient settings demonstrating the presence of significant sleep pattern disturbances after burn injury. Although the etiology is multifactorial and includes environmental, injury, and treatment mediators, previous clinical studies have not analyzed the critically important relationship of various medications to sleep architecture. The purpose of this investigation was to describe the after-effect of ketamine on sleep patterns in seriously ill burn patients. Forty pediatric patients with a mean TBSA burn of 50.1 ± 2.9% (range, 22-89%) and full-thickness injury of 43.2 ± 3.6% (range, 24-89%) were enrolled in this sleep study. Twenty-three of the 40 patients received ketamine on the day of polysomnography testing. Standard polysomnographic sleep variables were measured from 10:00 pm until 7:00 am. Chi-square test and t-test were used for comparison of descriptive variables between the ketamine and nonketamine groups. A logarithmic transformation was used for analysis when necessary. Ketamine administration was associated with reduced rapid eye movement (REM) sleep when compared with patients who did not receive ketamine on the day of the sleep study (P < 0.04). Both ketamine and nonketamine groups were clearly REM deficient when compared with nonburn norms. There was no relationship between ketamine use and effect on nocturnal total sleep time, number of awakenings, or percent of time awake or in stage 1, 2, or 3 + 4 sleep. In conclusion, ketamine was associated with altered sleep architecture as evidenced by a reduction in REM sleep. This finding does not seem to be clinically significant when considering the magnitude of overall REM sleep pattern disturbance observed in both the ketamine and nonketamine groups compared with nonburn norms. Further research is required to identify potential mechanisms of disturbed sleep so that appropriate interventions can be developed.

Assessment of serum enzymatic markers of cardiomyocytes injury in female dogs submitted to ketamine S(+), atropin and xylazine association

PURPOSE

To assessment of the aspartate aminotransferase (AST), creatine kinase (CK) and creatine kinase isoenzyme fraction MB (CK-MB) serum activity in female dogs anesthetized with ketamine S (+), atropine and xylazine in several associations.

METHODS

Twenty three healthy female dogs randomly distributed in four groups named as GI (n=6), GII (n=6), GIII (n=6) and GIV (n=5) were treated respectively with atropine and ketamine S(+) (0.04 mg/kg; 10 mg/kg); ketamine S(+) (10 mg/kg); atropine, xylazine and ketamine S(+) (0.04 mg/kg; 1.1 mg/kg; 10 mg/kg) and xylazine and ketamine S(+) (1.1 mg/kg; 10 mg/kg). AST, CK and CK-MB serum activity measurement before pre-medication (M0) and one, two, three, six, 12, 24, 36 hours after.

RESULTS

There was no significant change in AST, CK e CK-MB serum activity among groups. However, CK serum activity in relation to moments within the groups was increased in all groups over the time in spite of treatment, except GI. In relation to CK-MB activity, in the moments within the group, it was observed an increase compared to baseline in all groups.

CONCLUSION

Creatine kinase and creatine kinase fraction MB isoenzyme showed changes in their mean values remained higher than baseline for a longer time in GIII and GIV.

Comparison of racemic ketamine and S-ketamine in treatment-resistant major depression: report of two cases

Recent studies with intravenous infusion of the NMDA receptor antagonist ketamine showed robust and rapid antidepressant effects within hours after treatment. Ketamine is a racemic mixture consisting of two enantiomers, R- and S-ketamine. In contrast to ketamine, S-ketamine is reported to be less prone to psychomimetic side effects, such as derealisation and hallucinations. In this report we describe the effect of ketamine and S-ketamine infusion therapy, respectively, in two patients with treatment-resistant major depression. Severity of depression was rated using the Hamilton Depression Rating Scale (HAMD) and the Beck Depression Inventory (BDI). While one patient did not respond to either treatment, in the other patient intravenous administration of ketamine as well as S-ketamine showed an antidepressant effect as assessed by a decrease in HAMD-21 and BDI at days 1 and 3 after infusion which faded until day 6. Both patients experienced psychomimetic side effects during ketamine infusion which were absent during treatment with S-ketamine. We conclude that S-ketamine might exert similar antidepressant effects as ketamine in drug-resistant depression but may be better tolerated by the patients.

Analgo-sedation of patients with burns outside the operating room

Following the initial resuscitation of burn patients, the pain experienced may be divided into a 'background' pain and a 'breakthrough' pain associated with painful procedures. While background pain may be treated with intravenous opioids via continuous infusion or patient-controlled analgesia (PCA) and/or less potent oral opioids, breakthrough pain may be treated with a variety of interventions. The aim is to reduce patient anxiety, improve analgesia and ensure immobilization when required. Untreated pain and improper sedation may result in psychological distress such as post-traumatic stress disorder, major depression or delirium. This review summarizes recent developments and current techniques in sedation and analgesia in non-intubated adult burn patients during painful procedures performed outside the operating room (e.g. staple removal, wound-dressing, bathing). Current techniques of sedation and analgesia include different approaches, from a slight increase in background pain therapy (e.g. morphine PCA) to PCA with rapid-onset opioids, to multimodal drug combinations, nitrous oxide, regional blocks, or non-pharmacological approaches such as hypnosis and virtual reality. The most reliable way to administer drugs is intravenously. Fast-acting opioids can be combined with ketamine, propofol or benzodiazepines. Adjuvant drugs such as clonidine or NSAIDs and paracetamol (acetaminophen) have also been used. Patients receiving ketamine will usually maintain spontaneous breathing. This is an important feature in patients who are continuously turned during wound dressing procedures and where analgo-sedation is often performed by practitioners who are not specialists in anaesthesiology. Drugs are given in small boluses or by patient-controlled sedation, which is titrated to effect, according to sedation and pain scales. Patient-controlled infusion with propofol has also been used. However, we must bear in mind that burn patients often show an altered pharmacokinetic and pharmacodynamic response to drugs as a result of altered haemodynamics, protein binding and/or increased extracellular fluid volume, and possible changes in glomerular filtration. Because sedation and analgesia can range from minimal sedation (anxiolysis) to general anaesthesia, sedative and analgesic agents should always be administered by designated trained practitioners and not by the person performing the procedure. At least one individual who is capable of establishing a patent airway and positive pressure ventilation, as well as someone who can call for additional assistance, should always be present whenever analgo-sedation is administered. Oxygen should be routinely delivered during sedation. Blood pressure and continuous ECG monitoring should be carried out whenever possible, even if a patient is undergoing bathing or other procedures that may limit monitoring of vital pulse-oximetry parameters.

Randomised, cross-over comparison of sevoflurane and ketamine-midazolam anaesthesia in children undergoing extracorporeal shock-wave lithotripsy

INTRODUCTION

The aim of this study was to assess the haemodynamic responses, adverse events and recovery characteristics associated with sevoflurane and ketamine-midazolam anaesthesia for paediatric extracorporeal shock-wave lithotripsy.

METHODS

Twenty children aged 2-11 years, who were undergoing two consecutive lithotripsy sessions at an interval of 4 weeks were enrolled and randomised to receive either inhalation or dissociative anaesthesia at their first session. The alternative anaesthesia protocol was used at their second session. Inhalation anaesthesia was induced with 8% sevoflurane and 70% N(2)O in oxygen; 10 microg/kg atropine and 2 microg/kg fentanyl were then administered. Anaesthesia was maintained with 2%-3% end-tidal sevoflurane and 70% N(2)O in oxygen via a laryngeal mask airway. Dissociative anaesthesia was induced intravenously with 10 mug/kg atropine, 0.05 mg/kg midazolam, 1.5 mg/kg ketamine and maintained with 0.5-1.0 mg/kg ketamine. Haemodynamic parameters were recorded before and after induction, after the start of the procedure, and every 10 minutes thereafter. Postoperatively, the times to responding to command, sitting, ambulating, achieving an Aldrete score > or = 9, and achieving a post-anaesthetic discharge score > or = 9 were recorded.

RESULTS

Systolic and diastolic arterial pressures at all measurements throughout the procedure were higher with ketamine-midazolam than with sevoflurane (P<0.05). Heart rates were comparable between groups, except after induction and after start of the procedure in which they were higher with ketamine-midazolam (P<0.05). All recovery endpoints were achieved earlier with sevoflurane than with ketamine-midazolam (P<0.05). Nausea-vomiting incidences were similar in both groups.

CONCLUSION

Sevoflurane and ketamine-midazolam both provided effective anaesthesia for paediatric lithotripsy. The recovery and discharge times were shorter after anaesthesia with sevoflurane compared with ketamine-midazolam in children undergoing lithotripsy.

The pediatric cardiac patient presenting for noncardiac surgery

PURPOSE OF REVIEW

To summarize results of recent papers and discuss current trends concerning anesthesia in children with congenital heart disease presenting for noncardiac surgery.

RECENT FINDINGS

Children with congenital heart disease have a significant incremental risk when presenting for minor or major surgery. It is a current trend that noncardiac surgery should be performed in pediatric centers, which have anesthesiologists and pediatricians familiar with the multiple specialties of children with congenital heart disease. A careful preoperative evaluation using a multidisciplinary approach is of great importance. In recent studies and case reports, the safe use of newer anesthetic agents, such as sevoflurane or desflurane, was reported in combination with opioids or regional blocks. In addition to standard monitors, invasive monitoring should be considered liberally perioperatively in patients with limited hemodynamic reserve and with major surgery. Several case reports reported that laparoscopic surgery was successfully performed even in high-risk patients with congenital heart disease.

SUMMARY

Careful preoperative evaluation, experienced anesthesiologists, suitable anesthetic agents and techniques, and the liberal use of invasive monitoring are integral parts of safe and effective anesthetic care in children with congenital heart disease. Future studies have to show whether laparoscopic surgery may be beneficial in this special subgroup of patients.

Single-dose ketamine administration induces apoptosis in neonatal mouse brain

The activity of N-methyl-D-aspartate (NMDA) receptors is critical for neuronal survival in the immature brain. Studies have reported that chronic blockage of these receptors mediates apoptosis in neonatal animals. We investigated the apoptotic effect of a clinically relevant single dose of ketamine, an NMDA receptor antagonist, in the brain of neonatal mice. Seven-day-old ICR mice were injected with ketamine (1.25, 2.5, 5, 10, 20, and 40 mg/kg body weight, subcutaneously in 0.9% NaCl) or with 0.9% NaCl alone as control. Righting reflex testing was performed and mouse brains were examined at 24, 48, and 72 h and 7 days after injection. The number of degenerating neurons was measured using silver staining. Apoptosis was confirmed by DNA fragmentation (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling). We observed in the sensorimotor cortex and cerebellum of ketamine-treated mice extensive apoptosis, which was clearly dose-dependent and present even after a low dose of ketamine (5 mg/kg). The most prominent apoptotic damage was detected 72 h post-injection (P < 0.001 vs control), at doses ranging from 10 to 40 mg/kg. After 7 d the number of neurodegenerative neurons, at doses ranging from 5 to 40 mg/kg, remained significantly high. The brain weight was comparable to that of untreated control mice and no gross neurobehavioral effects in the righting reflex test or alteration in the pattern of behavior was observed. The results indicate that the administration of ketamine in a clinically relevant single dose triggers long-lasting neuronal apoptosis in certain brain areas of neonatal mice.

IMPLICATIONS

The administration of ketamine in a clinically relevant single dose to 7-d-old mice induced apoptosis in the sensorimotor cortex and cerebellum. This effect was dose-dependent and long lasting.

Anaesthetic management in a neonate with congenital complete heart block

We present the case of a neonate undergoing surgery on the first day of life for the installation of a permanent pacemaker because of the existence of congenital complete heart block (CCHB) with a basal heart rate of 43 b.min(-1) and minimal elevation after initiating an isoproterenol perfusion. The intervention was under general anaesthesia with laryngeal mask airway (LMA) and spontaneous ventilation. The principal anaesthetic goals were to assure adequate anaesthesia, with haemodynamic and respiratory stability, to maintain the best possible heart rate and to avoid postoperative respiratory depression or apnoea.

Oral ketamine: a promising treatment for restless legs syndrome

IMPLICATIONS

Oral Ketamine, an NMDA receptor antagonist, can be used to treat restless legs syndrome. A mechanism for the efficacy of this treatment is discussed.

Ketamina, da anestesia ao uso abusivo

Objetivo. Realizar uma revisão bibliográfica sobre a ketamina, enfocando aspectos químicos e farmacocinéticos, seus mecanismos de ação, efeitos farmacológicos, usos terapêuticos, bem como aborda o uso da ketamina como droga de abuso. Ketamina. Método. Estudo de revisão bibliográfica através das bases de dados Pubmed, SciELO, Lilacs e Medline, na qual foram selecionados estudos clássicos e recentes relevantes para a discussão do tema abordado. Resultados. Após análise dos artigos selecionados, conclui-se que a ketamina apresenta perspectivas promissoras. Alguns estudos demonstraram propriedades analgésicas em relação à dor pós-operatória e outros revelaram uma ação antidepressiva rápida. Além disto, a ketamina também apresentou efeitos neuroprotetores em vários estudos animais. Embora a ketamina seja um campo promissor, essas ações precisam ser melhor investigadas. Atualmente, observou-se que o seu uso não se restringe apenas à prática clínica ou pesquisa, sendo frequentemente utilizada como droga de abuso pelos jovens em festas como um potente alucinógeno. Conclusão. Pesquisas sobre o uso recreacional da ketamina também são necessárias, especialmente no Brasil, assim como dados que mostrem a morbidade e mortalidade pelo uso desta substância como droga de abuso.