Ketamine combined with morphine for the management of pain in an opioid addict

Novel uses of ketamine in the emergency department

INTRODUCTION

: Ketamine is gaining renewed interest among healthcare providers due to its novel clinical applications in the emergency department (ED) setting.

AREAS COVERED

: This article provides a comprehensive discussion of ketamine's pharmacological properties, including safety profile and adverse effects, in addition to an overview of current evidence for ketamine (racemic formulation) in the management of ED patients with acute agitation, pain, and depression/suicide ideation.

EXPERT OPINION

: Ketamine is an effective adjunct to opioids, providing greater pain relief than morphine alone. As an analgesic agent, administration of ketamine (0.1-0.3 mg/kg IV) alone can provide analgesia similar to that of morphine in patients with acute visceral and musculoskeletal pain. Moreover, ketamine provides equal analgesic efficacy to morphine in a variety of chronic painful conditions including pain associated with cancer, vaso-occlusive pain crisis associated with sickle cell disease, and in patients with high opioid tolerance and/or opioid dependency. Available literature shows that ketamine (1-2mg/kg IV or 4-5 mg/kg IM) is a safe, rapid (<5 minutes) and effective tranquilization agent for ED patients with acute agitation. Finally, there is growing evidence that suggests ketamine may have a potential utility in the management of patients with self-harm ideation or acute depressive episodes. Intravenous infusion of ketamine (0.5 mg/kg over 40 mins) has been shown to produce an antidepressant effect and decrease in suicidal ideation within 4 hours with effects lasting up to one week.

Comparison of Perioperative Systemic Lidocaine or Systemic Ketamine in Acute Pain Management of Patients With Opioid Use Disorder After Orthopedic Surgery

INTRODUCTION AND AIMS

Patients with opioid use disorder experience great challenges during acute pain management due to opioid tolerance or withdrawal symptoms. Previous studies have recommended the use of adjuvant drugs in these patients. In this study, we compared the effect of intraoperative lidocaine with ketamine in postoperative pain management of these patients.

DESIGN AND METHODS

In this randomized clinical trial, 180 patients with opioid use disorder who underwent orthopedic surgery under general anesthesia were randomly allocated into 3 groups. Patients in groups A, B, and C received intravenous lidocaine, ketamine, or normal saline, respectively, during the operation. Then, postoperative pain scores, analgesic requirements, patient satisfaction, and patient sleepiness were recorded and compared among the 3 groups.

RESULTS

Numerical rating scales during the first hour postoperation were significantly lower in the lidocaine group than in the ketamine or control group (P < 0.001). The mean total amount of morphine consumption during the first 24-hour postoperation was 14.49 ± 26.89, 16.59 ± 30.65, and 21.72 ± 43.29 mg in the lidocaine, ketamine, and control group, respectively, being significantly lower in the lidocaine group in comparison with the other groups (P < 0.001). Patients in the lidocaine group were less restless, calmer, and less drowsy than patients in the ketamine and control group (P < 0.001).

DISCUSSION AND CONCLUSION

According to these findings, systemic lidocaine is more effective than systemic ketamine to improve the quality of acute pain management without causing any significant complications in patients with opioid use disorder.

Perioperative Management of Patients on Buprenorphine and Methadone: A Narrative Review

The opioid epidemic has emerged as a major health and social problem over the last few decades. An increasing number of patients with opioid use disorder are presenting for perioperative management. These patients are either on buprenorphine or methadone for the maintenance and treatment of opioid addiction or chronic pain. In the settings of acute pain, the optimal management of patients with opioid use disorder is challenging, and recovery can be jeopardized secondary to the unique pharmacology of these agents. The purpose of this narrative review is to summarize the existing studies on the perioperative management of patients who are using buprenorphine and methadone and provide guidance for the management of patients with opioid use disorder during the perioperative period.

The Use of Continuous Ketamine for Analgesia and Sedation in Critically Ill Patients with Opioid Abuse: A Case Series

Managing pain and agitation in patients with opioid abuse is becoming more common in intensive care units. Tolerance to commonly used agents is often observed, leading to inadequate pain control and increased agitation. Ketamine's unique mechanism of action and opioid-sparing effects make it an ideal agent for patients with suboptimal response to opioid therapy. This report describes our experience using continuous ketamine infusions for analgesia and sedation in four mechanically ventilated patients with histories of opioid abuse that had suboptimal response to standard therapy. Ketamine was successful in improving analgesia and sedation in three patients while reducing the need for other analgesics and sedatives with minimal adverse effects. Continuous ketamine infusions may be useful to facilitate mechanical ventilation in patients with histories of opioid abuse with minimal toxicity. More information is needed on the optimal dose and titration parameters.

Perioperative management of the opioid tolerant patient for orthopedic surgery

The prevalence of opioid use in the North America and some countries of the European Union has resulted in an increase in the number of patients who may exhibit opioid tolerance when requiring postoperative pain management. The approach to postoperative pain control in these patients is different from the strategies used in opioid-naïve patients. Better understanding of the cellular mechanisms of opioid tolerance in animals has resulted in the transfer of these concepts from the basic research to the clinical arena. This article presents new developments in opioid tolerance and how this knowledge can be applied to clinical practice.

Intra- and postoperative very low dose intravenous ketamine infusion does not increase pain relief after major spine surgery in patients with preoperative narcotic analgesic intake

OBJECTIVE

This study aims to demonstrate the analgesic efficacy and opioid-sparing effect of low dose ketamine in patients with preoperative narcotic intake undergoing major spine surgery.

DESIGN

The study used a prospective, randomized, double-blinded, and placebo-controlled clinical trial.

SETTINGS AND PATIENTS

We evaluated the analgesic efficacy and safety of low dose IV ketamine infusion after major spine surgery in patients with preoperative narcotic analgesic intake. Ketamine group received IV ketamine infusion (2 µg/kg/min) and saline group received saline intraoperatively and the first 24 hours postoperatively. In addition, all patients received IV patient-controlled hydromorphone and epidural bupivacaine.

OUTCOME MEASURES

Pain scores, narcotic requirement, and side effects were compared between the groups for 48 hours postoperatively.

RESULTS

Thirty patients completed the study (N = 15 in each group). No difference in pain scores at rest and movement was noted between the groups (P > 0.05). Patients in ketamine group received 40.42 ± 32.86 mg IV hydromorphone at 48 hours compared with 38.24 ± 26.19 mg in saline group (P = 0.84). Central nervous system side effects were observed in five (33%) ketamine group patients compared with nine (60%) in saline group (P = 0.29).

CONCLUSION

The addition of IV very low dose ketamine infusion regimen did not improve postoperative analgesia. Side effects were not increased with low dose ketamine.

Low-dose ketamine for analgesia in the ED: a retrospective case series

OBJECTIVES

The aim of this study was to describe the use and effect of low-dose ketamine (LDK) for analgesia in the emergency department (ED).

METHODS

A chart review was performed to identify all adult patients who received LDK for analgesia in our ED. Cases were identified by pharmacy record of ketamine administration. Low-dose ketamine was defined as the administration of 0.1 to 0.6 mg/kg of ketamine for pain control. Use of ketamine during procedural sedation was excluded. Data were analyzed descriptively.

RESULTS

Thirty-five cases in which patients received LDK in the ED for a 2-year period were identified. Doses ranged from 5 to 35 mg. Administration was intravenous in 30 (86%) of 35 cases and intramuscular in 5 (14%) of 35 cases. Opioids were administered before or coadministered with LDK in 32 (91%) of 35 cases, and in the remaining 3 cases, opioids were used before the patient came to the ED. Improvement in pain was observed in 19 (54%) of 35 cases in which patients received LDK. Pain scores did not improve in 8 (23%) of 35 cases. Insufficient data were available to determine LDK effect for 8 (23%) of 35 cases. No significant adverse events were identified in any of the 35 cases.

CONCLUSIONS

The administration of LDK in the ED may be a safe and effective adjunct for analgesia in some patients. However, prospective randomized controlled trials are needed before widespread use of LDK for analgesia in the ED can be recommended.

The clinical role of NMDA receptor antagonists for the treatment of postoperative pain

Recent advances in the understanding of postoperative pain have demonstrated its association with sensitization of the central nervous system (CNS) which clinically elicits pain hypersensitivity. N-methyl-D-aspartate (NMDA) receptors play a major role in synaptic plasticity and are specifically implicated in CNS facilitation of pain processing. Therefore, NMDA receptor antagonists, and specifically ketamine commonly used in clinical practice, have been implicated in perioperative pain management. At subanesthetic (i.e. low) doses, ketamine exerts a specific NMDA blockade and hence modulates central sensitization induced both by the incision and tissue damage and by perioperative analgesics such as opioids. However, the mechanisms underlying ketamine anti-hyperalgesic effect are not totally understood, and neither is the relationship between central sensitization and the risk of developing residual pain after surgery. This chapter examines the role of low doses of ketamine as an adjuvant drug in current perioperative pain management and questions the anti-hyperalgesic mechanisms involved.

Anästhesie und Analgesie bei Suchtpatienten

Addicts have an exaggerated organic and psychological comorbidity and in cases of major operations or polytrauma they are classified as high-risk patients. Additional perioperative problems are a higher analgetics requirement, craving, physical and/or psychological withdrawal symptoms, hyperalgesia and tolerance. However, the clinical expression depends on the substance abused. For a better understanding of the necessary perioperative measures, it is helpful to classify the substances into central nervous system depressors (e.g. heroin, alcohol, sedatives, hypnotics), stimulants (e.g. cocaine, amphetamines, designer drugs) and other psychotropic substances (e.g. cannabis, hallucinogens, inhalants). The perioperative therapy should not be a therapy for the addiction, as this is senseless. On the contrary, the characteristics of this chronic disease must be accepted. Anesthesia and analgesia must be generously stress protective and sufficiently analgesically effective. Equally important perioperative treatment principles are stabilization of physical dependence by substitution with methadone (for heroin addicts) or benzodiazepines/clonidine (for alcohol, sedatives and hypnotics addiction), avoidance of stress and craving, thorough intraoperative and postoperative stress relief by using regional techniques or systematically higher than normal dosages of anesthetics and opioids, strict avoidance of inadequate dosage of analgetics, postoperative optimization of regional or systemic analgesia by non-opioids and coanalgetics and consideration of the complex physical and psychological characteristics and comorbidities. Even in cases of abstinence (clean) an inadequate dosage must be avoided as this, and not an adequate pain therapy sometimes even with strong opioids, can potentially activate addiction. A protracted abstinence syndrome after withdrawal of opioids can lead to increased response to administered opioids (e.g. analgesia, side-effects).

Acute pain management for opioid dependent patients

Patients requiring acute pain management may be opioid dependent as a result of either recreational or therapeutic opioid use, including those in opioid addiction programmes. Pain in these patients is often under-estimated and under-treated. In addiction, drug-seeking behaviour differentiates it from simple dependence. With few randomised controlled trials, current evidence predominantly consists of guidelines based on case reports, retrospective studies and expert opinion. Consensus recommendations include maintaining regular provision of the patient's pre-existing opioid requirement, with additional analgesia, ideally multimodal, in appropriate combinations of short-acting opioid (as required), local anaesthesia, and adjuvant anti-inflammatory analgesics and paracetamol. Patient controlled analgesia with higher bolus doses and shorter lock-out intervals is a recommended strategy. Transdermal opioid patches and implantable pumps will continue to deliver opioid, to which non-opioid and short-acting opioids may be added. Re-exposure to opioid is ideally avoided in previously addicted patients, but if not feasible, opioid therapy should be prescribed.

Cellular mechanisms of opioid tolerance and the clinical approach to the opioid tolerant patient in the post-operative period

The high prevalence of opioid use for recreational purposes in the USA and the European Union, as well as the use of opioids for the treatment of chronic non-malignant pain, has resulted in an increase in the number of patients with opioid tolerance who undergo surgery and require post-operative pain management. The approach to post-operative pain control in these patients is significantly different to the strategies used in opioid naïve patients. Fortunately, better understanding of the cellular mechanisms of opioid tolerance in animals has resulted in the transfer of concepts from the 'bench' to the clinical arena. This chapter describes the new developments in opioid tolerance and how this knowledge can be applied to clinical practice.

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.