Effects of preoperative use of oral dextromethorphan on postoperative need for analgesics in patients with knee arthroscopy

The Effect of Intrathecal Injection of Dextromethorphan on the Experimental Neuropathic Pain Model

Background

Peripheral glucocorticoid receptors (GRs) are altered by peripheral nerve injury and may modulate the development of neuropathic pain. Two central pathogenic mechanisms underlying neuropathic pain are neuroinflammation and N-methyl-D-aspartate receptor (NMDAR)-dependent neural plasticity in the spinal cord.

Objectives

This study examined the effect of the non-competitive NMDAR antagonist dextromethorphan on partial sciatic nerve ligation (PSL)-induced neuropathic pain and the spinal expression of the glucocorticoid receptor (GR).

Methods

Male mice were randomly assigned into a sham group and two groups receiving PSL followed by intrathecal saline vehicle or dextromethorphan (iDMP). Vehicle or iDMP was administered 8 - 14 days after PSL. The hotplate paw-withdrawal latency was considered to measure thermal pain sensitivity. The spinal cord was then sectioned and immunostained for GR.

Results

Thermal hyperalgesia developed similarly in the vehicle and iDMP groups prior to the injections (P = 0.828 and 0.643); however, it was completely mitigated during the iDMP treatment (P < 0.001). GR expression was significantly higher in the vehicle group (55.64 ± 4.50) than in the other groups (P < 0.001). The iDMP group (9.99 ± 0.66) showed significantly higher GR expression than the sham group (6.30 ± 1.96) (P = 0.043).

Conclusions

The suppression of PLS-induced thermal hyperalgesia by iDMP is associated with the downregulation of GR in the spinal cord, suggesting that this analgesic effect is mediated by inhibiting GR-regulated neuroinflammation.

Perioperative nonopioid analgesia reduces postoperative opioid consumption in knee arthroscopy: a systematic review and meta-analysis

PURPOSE

The opioid epidemic has prompted an emphasis on investigating opioid-sparing alternatives for pain management following knee arthroscopy. This review evaluated the effects of perioperative nonopioid adjunct analgesia on postoperative opioid consumption and pain control in patients undergoing knee arthroscopy.

METHODS

A systematic review and meta-analysis was performed using the following databases: PubMed, Embase, Web of Science, MEDLINE, and SCOPUS. Prospective comparative studies assessing the efficacy of various perioperative nonopioid analgesic strategies in patients undergoing knee arthroscopy were included. Twenty-five studies (n = 2408) were included.

RESULTS

Pre-emptive nonopioid pain medications demonstrated a reduction in cumulative postoperative oral morphine equivalent (OME) consumption by 11.8 mg (95% CI - 18.3, - 5.4, p ≤ 0.0001) and VAS pain scores by 1.5 (95% CI - 2.3, - 0.7, p < 0.001) at 24 h compared to placebo. Postoperative nonopioid pain medications significantly reduced cumulative postoperative OME consumption by 9.7 mg (95% CI - 14.4, - 5.1, p < 0.001) and VAS pain scores by 1.0 (95% CI - 1.354, - 0.633, p < 0.001) at 24 h compared to placebo. Saphenous nerve blocks significantly reduced cumulative postoperative OME consumption by 6.5 mg (95% CI - 10.3, - 2.6, p = 0.01) and VAS pain scores by 0.8 (- 1.4, - 0.3, p = 0.03) at 24 h compared to placebo. Both preoperative patient education and postoperative cryotherapy reduced postoperative opioid consumption.

CONCLUSION

Perioperative nonopioid pharmacotherapy, saphenous nerve blocks, and cryotherapy for patients undergoing knee arthroscopy significantly reduce opioid consumption and pain scores when compared to placebo at 24 h postoperatively. These interventions should be considered in efforts to reduce opioid consumption in patients undergoing knee arthroscopy. More research is needed to determine which interventions can reduce pain outside of the immediate postoperative period and the potential synergistic effects of combining interventions.

LEVEL OF EVIDENCE

II.

Adjuvant Drugs for Peripheral Nerve Blocks: The Role of NMDA Antagonists, Neostigmine, Epinephrine, and Sodium Bicarbonate

The potential for misuse, overdose, and chronic use has led researchers to look for other methods to decrease opioid consumption in patients with acute and chronic pain states. The use of peripheral nerve blocks for surgery has gained increasing popularity as it minimizes peripheral pain signals from the nociceptors of local tissue sustaining trauma and inflammation from surgery. The individualization of peripheral nerve blocks using adjuvant drugs has the potential to improve patient outcomes and reduce chronic pain. The major limitations of peripheral nerve blocks are their limited duration of action and dose-dependent adverse effects. Adjuvant drugs for peripheral nerve blocks show increasing potential as a solution for postoperative and chronic pain with their synergistic effects to increase the duration of action and decrease the required dosage of local anesthetic. N-methyl-d-aspartate (NMDA) receptor antagonists are a viable option for patients with opioid resistance and neuropathic pain due to their affinity to the neurotransmitter glutamate, which is released when patients experience a noxious stimulus. Neostigmine is a cholinesterase inhibitor that exerts its effect by competitively binding at the active site of acetylcholinesterase, which prevents the hydrolysis of acetylcholine and subsequently retaining acetylcholine at the nerve terminal. Epinephrine, also known as adrenaline, can potentially be used as an adjuvant to accelerate and prolong analgesic effects in digital nerve blocks. The theorized role of sodium bicarbonate in local anesthetic preparations is to increase the pH of the anesthetic. The resulting alkaline solution enables the anesthetic to more readily exist in its un-ionized form, which more efficiently crosses lipid membranes of peripheral nerves. However, more research is needed to show the efficacy of these adjuvants for nerve block prolongation as studies have been either mixed or have small sample sizes.

Comparative Evaluation of Preemptive Analgesia of Dextromethorphan and Ibuprofen in Third Molar Surgeries

Introduction:

Postoperative pain following third molar removal is one of the most common and unpleasant complications encountered in routine surgical practice. Various methods have been advocated to minimize the postoperative pain: preemptive analgesia is one of those found to be effective.

Objective:

The aim of this study was to compare the preemptive analgesic efficacy of Dextromethorphan (DM) and Ibuprofen in the third molar surgeries.

Material and Methods:

Thirty-six patients reporting to our institution were included in the study. Patients were randomized into three groups of 12 patients each to receive either DM 30 mg, ibuprofen 100 mg, or placebo in the form of multivitamin syrup, 90 min before the procedure. The difficulty of removal of the teeth was assessed using Campbell difficulty score. The study objectives were to evaluate the time elapsed since surgery after which the patient took their first dose of aceclofenac, to evaluate the postoperative pain using visual analog scale score, and to record the number of aceclofenac tablets consumed postoperatively.

Results:

The results of the study revealed that preemptive DM was significantly better than ibuprofen and placebo in the duration of time that elapsed before the patients consumed their first analgesic postoperatively. Preemptive DM also reduced the total number of aceclofenac tablets consumed on the day of surgery and on the 1^st postoperative day, but the difference was not statistically significant. Between the two drugs, DM is better suited for providing preemptive analgesia. No side effects at a dose of 30 mg of DM were noted in any of the patients.

Conclusion:

DM premedication is a viable preemptive analgesic in reducing postoperative pain.

Efficacy of Preoperative Administration of Acetaminophen and Melatonin on Retrobulbar Block Associated Pain in Cataract Surgery

Background

Retrobulbar block is one of the chosen methods for local anesthesia in cataract surgery. Since it is a painful procedure, using analgesic and sedative drugs is recommended. Current medications have side effects and evaluating of new drugs or new uses of existing safer drugs is necessary.

Objectives

The aim of this study was to compare the administration of melatonin and acetaminophen on pain and hemodynamic changes during retrobulbar block.

Methods

In a double-blinded randomized trial, 180 patients undergoing cataract surgery were randomly divided into three groups: Melatonin group (received melatonin 6 mg), acetaminophen group (received acetaminophen 500 mg), and control group (received placebo). All drugs were administered orally 60 min before arrival to the operating room by nurses blinded to the drugs administered. All patients received fentanyl 0.5 μg/kg before retrobulbar block intravenously. Hemodynamic variables and pain score in each patient were evaluated on arrival in the operating room, during retrobulbar block, during surgery, 20 min after operation, at the end of surgery, and in the recovery room. In case of pain score more than three, additional fentanyl was administered. All data were recorded in structured data sheets.

Results

Data analysis indicated no significant differences among the groups at baseline on any of the demographic variables. Both acetaminophen and melatonin reduced the pain score significantly compared with control during retrobulbar block (P < 0.05 and P < 0.01, respectively). Administration of additional fentanyl was significantly lower in the melatonin group than the control group (P < 0.05). Hemodynamic changes were not significantly different among all groups.

Conclusions

For the first time, as far as we have studied, the analgesic effect of acetaminophen on the retrobulbar block was indicated. We also showed that melatonin can reduce pain during retrobulbar block leading to reduction of additional fentanyl during operation. It seems that both melatonin and acetaminophen may have a beneficial effect on pain control in the retrobulbar block.

Comparison of tramadol/acetaminophen fixed-dose combination, tramadol, and acetaminophen in patients undergoing ambulatory arthroscopic meniscectomy

OBJECTIVES

Preemptive analgesia is a technique in which analgesics are administered before a surgery to provide better postoperative pain relief with fewer side effects. In this study, we aimed to compare the preemptive efficacy of tramadol/acetaminophen fixed-dose combination, tramadol, and acetaminophen in patients undergoing ambulatory arthroscopic partial meniscectomy.

METHODS

We evaluated the patient records of 75 patients who underwent ambulatory arthroscopic partial meniscectomy. We divided the patients into three groups consisting of 20 patients each to equalize the groups. Group A comprised patients who were administered 37.5 mg tramadol/325 mg acetaminophen fixed-dose combination, Group B comprised patients who were administered 50 mg tramadol, and Group C comprised patients who were administered 500 mg acetaminophen. Premedication was not used in any group.

RESULTS

There were no significant differences between the groups in terms of age, sex, BMI, and duration of surgery and anesthesia. All patients in Group B and Group C and 17 patients in Group A required rescue analgesics in the first 6 h. Visual analog scale (VAS) was 4.75 ± 3.05 in Group B at time 0 and was 6.10 ± 1.86 in Group C in the first hour and was higher than the other groups with a statistically significance (p = 0.030 and 0.020, respectively). VAS at 24 h postoperatively was ≤3 (1.60 ± 1.63, 1.55 ± 1.84 and 1.70 ± 0.65 respectively in each group), and none of the patients in any group required rescue analgesics. No major side effects, except for slight nausea in one patient requiring no medication, were noted in any group.

CONCLUSION

The fixed-dose combination of tramadol/acetaminophen or tramadol alone is better than acetaminophen alone as a preemptive analgesic in patients undergoing ambulatory arthroscopic meniscectomy.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Perioperative Dextromethorphan as an Adjunct for Postoperative Pain: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

N-methyl-D-aspartate receptor antagonists have been shown to reduce perioperative pain and opioid use. The authors performed a meta-analysis to determine whether the use of perioperative dextromethorphan lowers opioid consumption or pain scores.

METHODS

PubMed, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Pubget, and EMBASE were searched. Studies were included if they were randomized, double-blinded, placebo-controlled trials written in English, and performed on patients 12 yr or older. For comparison of opioid use, included studies tracked total consumption of IV or intramuscular opioids over 24 to 48 h. Pain score comparisons were performed at 1, 4 to 6, and 24 h postoperatively. Difference in means (MD) was used for effect size.

RESULTS

Forty studies were identified and 21 were eligible for one or more comparisons. In 848 patients from 14 trials, opioid consumption favored dextromethorphan (MD, -10.51 mg IV morphine equivalents; 95% CI, -16.48 to -4.53 mg; P = 0.0006). In 884 patients from 13 trials, pain at 1 h favored dextromethorphan (MD, -1.60; 95% CI, -1.89 to -1.31; P < 0.00001). In 950 patients from 13 trials, pain at 4 to 6 h favored dextromethorphan (MD, -0.89; 95% CI, -1.11 to -0.66; P < 0.00001). In 797 patients from 12 trials, pain at 24 h favored dextromethorphan (MD, -0.92; 95% CI, -1.24 to -0.60; P < 0.00001).

CONCLUSION

This meta-analysis suggests that dextromethorphan use perioperatively reduces the postoperative opioid consumption at 24 to 48 h and pain scores at 1, 4 to 6, and 24 h.