Rediscovery of nefopam for the treatment of neuropathic pain

Efficacy of Oral Nefopam on Multimodal Analgesia in Total Knee Arthroplasty: A Prospective, Double-Blind, Placebo-Controlled, Randomized Trial

BACKGROUND

Multimodal analgesia is central to pain management after total knee arthroplasty (TKA). This study aimed to evaluate the efficacy of adding oral nefopam to multimodal analgesia for post-TKA pain management.

METHODS

In this prospective, double-blind, placebo-controlled, randomized trial, 100 patients who underwent TKA at our hospital were randomized to either the nefopam or the control group. After surgery, patients in the nefopam group received 200 mg of celecoxib, 150 mg of pregabalin, and 40 mg of nefopam twice daily to control postoperative pain. Patients in the control group received 200 mg of celecoxib, 150 mg of pregabalin, and a placebo. Oxycodone hydrochloride (10 mg) was used as the rescue analgesic. If the pain remained poorly controlled, 10 mg of morphine hydrochloride was injected subcutaneously as a secondary rescue analgesic. The primary outcome was the postoperative consumption of oxycodone and morphine as rescue analgesics. Secondary outcomes were postoperative pain assessed using the visual analogue scale (VAS), functional recovery assessed by the range of knee motion and ambulation distance, time until hospital discharge, indicators of liver function, and complication rates.

RESULTS

Patients in the nefopam group had significantly lower postoperative oxycodone and morphine consumption within 24 hours after surgery and during hospitalization, lower VAS pain scores at rest and during motion within 24 h after surgery, better functional recovery on postoperative days 1 and 2, and a shorter hospital stay. However, the absolute reduction in 0 to 24 h opioid consumption, VAS pain scores, and knee range of motion did not exceed the reported minimal clinically important difference. Both groups had similar indicators of liver function and complication rates.

CONCLUSIONS

Adding oral nefopam to multimodal analgesia resulted in statistically significant improvements in opioid consumption, VAS pain scores, and functional recovery. However, the amount of improvement may not be clinically important.

Efficacy of Multimodal Analgesia with Transversus Abdominis Plane Block in Comparison with Intrathecal Morphine and Intravenous Patient-Controlled Analgesia after Robot-Assisted Laparoscopic Partial Nephrectomy

Background: Robot-assisted laparoscopic partial nephrectomy (RAPN) for renal tumor treatment provides ergonomic advantages to surgeons and improves surgical outcomes. However, moderate-to-severe pain is unavoidable even after minimally invasive surgery. Despite the growing interest in multimodal analgesia, few studies have directly compared its efficacy with intrathecal morphine, a traditional opioid-based analgesic. Methods: We retrospectively investigated the efficacy of multimodal analgesia compared with that of intrathecal analgesia and intravenous patient-controlled analgesia (IV-PCA) in patients who underwent transperitoneal RAPN at our institute between 2020 and 2022. Among the 334 patients who met the inclusion criteria, intrathecal analgesia using morphine 200 µg was performed in 131 patients, and multimodal analgesia, including transversus abdominis plane block and intraoperative infusion of paracetamol 1 g and nefopam 20 mg, was administered to 105 patients. The remaining 98 patients received postoperative IV-PCA alone. Results: As the primary outcome, the area under the curve of pain scores over 24 h was significantly lower in the intrathecal analgesia and multimodal analgesia groups than in the IV-PCA group (89 [62-108] vs. 86 [65-115] vs. 108 [87-126] h, p < 0.001). Cumulative opioid requirements were also significantly lower in the intrathecal analgesia and multimodal analgesia groups at 24 h after surgery (p < 0.001). However, postoperative nausea and vomiting were significantly increased in the intrathecal analgesia group (27.5% vs. 13.3% vs. 13.3%, p = 0.005). Conclusions: Multimodal analgesia with a transversus abdominis plane block is an efficient analgesic method with fewer adverse effects compared to other analgesic methods. Our findings suggest the efficacy and safety of a multimodal approach for opioid-sparing analgesia after RAPN in the current opioid epidemic.

Nefopam as a multimodal analgesia in thoracoscopic surgery: a randomized controlled trial

Background

Video-assisted thoracoscopic surgery (VATS) is a minimally invasive procedure. However, some patients still experience severe pain after VATS. Pain after VATS can disturb deep breathing and coughing, and can increase postoperative pulmonary complications. Therefore, multidisciplinary pain management is emphasized for enhanced recovery after VATS. Nefopam is a centrally-acting, non-opioid, non-steroidal analgesic drug, and its pain reduction effect in many surgeries has been reported. We sought to determine whether administration of nefopam is effective as multimodal analgesia in VATS.

Methods

This study enrolled patients aged 19 years or older, and scheduled for elective VATS lobectomy with American Society of Anesthesiologists (ASA) physical class I-III. Forty-six participants were randomly divided into a group receiving nefopam (group N), and a control group (group O) in a 1:1 ratio. The study participants, and the researcher collecting the data were blinded to the group allocation. For the group N, nefopam 20 mg was administered before surgical incision and also at the end of surgery while chest tube was inserted. For the group O, normal saline 100 mL was administered. The primary outcome of this study was the pain score, by verbal numerical rating scale, at rest and upon coughing.

Results

Forty-five participants (group N =22, group O =23) were involved in the statistical analysis. Nefopam reduced pain at rest at 0 h [8 (IQR, 5-10) vs. 4 (IQR, 2-7), P=0.01], and at 0-1 h [5 (IQR, 5-8) vs. 3 (IQR, 2-5), P=0.001]. Pain upon coughing decreased with nefopam at 0 h [9 (IQR, 6-10) vs. 6 (IQR, 2-8), P=0.009], 0-1 h [6 (IQR, 5-8) vs. 5 (IQR, 2-6), P=0.001], and at 12-24 h [4 (IQR, 3-7) vs. 3 (IQR, 1-4), P=0.03]. Injection of 20 mg of nefopam before incision and at the end of surgery relieved postoperative pain at 0 h, 1 h at rest and at 0 h, 1 h, 12-24 h with coughing after VATS.

Conclusions

Therefore, nefopam can serve as a useful component of multimodal analgesia for pain management after VATS.

Trial Registration

ClinicalTrials.gov (NCT05173337).

Impact of Intraoperative Nefopam on Postoperative Pain, Opioid Use, and Recovery Quality with Parietal Pain Block in Single-Port Robotic Cholecystectomy: A Prospective Randomized Controlled Trial

Background and Objectives: This study explored how nefopam, a non-opioid analgesic in a multimodal regimen, impacts postoperative pain, opioid use, and recovery quality in single-port robot-assisted laparoscopic cholecystectomy (RALC) patients with a parietal pain block, addressing challenges in postoperative pain management. Materials and Methods: Forty patients scheduled for elective single-port RALC were enrolled and randomized to receive either nefopam or normal saline intravenously. Parietal pain relief was provided through a rectus sheath block (RSB). Postoperative pain was assessed using a numeric rating scale (NRS) in the right upper quadrant (RUQ) of the abdomen, at the umbilicus, and at the shoulder. Opioid consumption and recovery quality, measured using the QoR-15K questionnaire, were also recorded. Results: The 40 patients had a mean age of 48.3 years and an average body mass index (BMI) of 26.2 kg/m2. There were no significant differences in the pre- or intraoperative variables between groups. Patients receiving nefopam reported significantly lower RUQ pain scores compared to the controls, while the umbilicus and shoulder pain scores were similar. Rescue fentanyl requirements were lower in the nefopam group in both the PACU and ward. The QoR-15K questionnaire scores for nausea and vomiting were better in the nefopam group, but the overall recovery quality scores were comparable between the groups. Conclusions: Nefopam reduces RUQ pain and opioid use post-single-port RALC with a parietal pain block without markedly boosting RSB's effect on umbilicus or shoulder pain. It may also better manage postoperative nausea and vomiting, underscoring its role in analgesia strategies for this surgery.

Evaluating the Efficacy of Methocarbamol and Nefopam in Orthopedic Surgical Pain

Introduction Pain after orthopedic surgeries represents a special concern in patients with fractures. The use of multimodal analgesia significantly reduced the opioid need and reduced the risk of their side effects. Objectives This study compared the effectiveness and safety of methocarbamol and nefopam in the reduction of post-operative pain for patients undergoing orthopedic surgeries. Method This prospective, double-blind, randomized controlled trial took place at Al-Sader Teaching Hospital in Basrah, Iraq, from the first of February 2022 to the end of October 2023. The study aimed to assess the post-operative pain relief efficacy and safety of intramuscular nefopam (20 mg) and intravenous methocarbamol (1 g) in 110 adults (aged 18-65) undergoing elective orthopedic surgeries. Exclusions were made for allergies to the drugs, substance abuse history, and severe hepatic or renal impairment. Participants were randomized into two groups, with pain intensity measured at one hour, six hours, and 12 hours post-operation using the visual analog scale (VAS). Side effects were also evaluated. Statistical analysis was done using SPSS 27, with a significance level set at p<0.05 and a 95% confidence interval (CI). Results  In this study, we conducted a rigorous comparison between two groups, methocarbamol and nefopam, to evaluate their efficacy and safety in post-operative pain management. We started by ensuring that the groups were well-matched in terms of age, gender distribution, and body mass index (BMI). The results showed remarkable similarities in mean age, gender distribution, and BMI, supported by robust p-values, affirming the effective matching of the two groups. Moving to pain management, we observed a significant advantage in favor of methocarbamol. At all-time intervals (one hour, six hours, and 12 hours post-operation), methocarbamol consistently demonstrated lower mean VAS scores compared to nefopam. These differences were highly statistically significant, underscoring the superior pain relief efficacy of methocarbamol. Exploring side effects, we found no statistically significant disparities in the occurrence of nausea and vomiting between the two groups. However, there was a noticeable trend toward higher tachycardia incidence in the nefopam group, though it did not reach statistical significance. Conclusion The present study showed a higher efficacy of methocarbamol in post-operative pain reduction in comparison to nefopam. No serious side effects were observed with both drugs.

Antinociceptive effects of nefopam activating descending serotonergic modulation via 5-HT2 receptors in the nucleus raphe magnus

BACKGROUND

Nefopam is a centrally acting antinociceptive drug; however, the underlying mechanisms are not fully understood. This study investigated the supraspinal mechanisms of nefopam.

METHODS

The effects of intraperitoneally administered nefopam were assessed in rats using the formalin test, and the mechanisms were investigated by intrathecal or intra-nucleus raphe magnus (NRM) pre-treatment with the serotonin (5-HT) receptor antagonist or 5-HT2 receptor antagonist. The change in extracellular 5-HT levels was measured by spinal cord microdialysis.

RESULTS

Intraperitoneally administered nefopam showed antinociceptive effects in the rat formalin test, which were reversed by intrathecal pre-treatment with 5-HT receptor antagonist dihydroergocristine. Microdialysis study revealed that systemic nefopam significantly increased 5-HT level in the spinal dorsal horn. Pretreatment of cinanserin, a 5-HT2 receptor antagonist, into the NRM blocked the antinociceptive effects of intraperitoneally delivered nefopam. Direct injection of nefopam into the NRM mimicked the effects of systemic nefopam, and this effect was reversed by intra-NRM cinanserin pre-treatment. The increase in spinal level of 5-HT by systemic nefopam was attenuated by intra-NRM cinanserin pre-treatment.

CONCLUSION

The antinociceptive effects of systemically administered nefopam are mediated by 5-HT2 receptors in the NRM, which recruit the descending serotonergic fibres to increase the release of 5-HT into the spinal dorsal horn.

SIGNIFICANCE

This study revealed supraspinal mechanisms of nefopam-produced analgesia mediated by 5-HT2 receptors in the NRM recruiting the descending serotonergic fibres to increase the release of 5-HT into the spinal dorsal horn. These observations support a potential role for nefopam in multimodal analgesia based on its distinct mechanisms of action that are not shared by the other analgesics.

The Year in Thoracic Anesthesia: Selected Highlights from 2022

This article reviews research highlights in the field of thoracic anesthesia. The highlights of this year included new developments in the preoperative assessment and prehabilitation of patients requiring thoracic surgery, updates on the use of devices for one-lung ventilation (OLV) in adults and children, updates on the anesthetic and postoperative management of these patients, including protective OLV ventilation, the use of opioid-sparing techniques and regional anesthesia, and outcomes using enhanced recovery after surgery, as well as the use of expanding indications for extracorporeal membrane oxygenation, specialized anesthetic techniques for airway surgery, and nonintubated video-assisted thoracic surgery.

Perioperative Intravenous Nefopam on Pain Management and Ambulation after Open Spine Surgery: A Randomized Double-Blind Controlled Study

STUDY DESIGN

This was a randomized double-blind controlled study.

PURPOSE

This study was designed to evaluate the effects of intravenous nefopam regarding its ability to reduce morphine consumption and postoperative pain and improve recovery in patients undergoing open spine surgery.

OVERVIEW OF LITERATURE

Multimodal analgesia, including nonopioid medications, is essential for pain management in spine surgery. Evidence regarding the use of intravenous nefopam in open spine surgery as part of enhanced recovery after surgery is lacking.

METHODS

In this study, 100 patients undergoing lumbar decompressive laminectomy with fusion were randomized into two groups. The nefopam group received 20-mg intravenous nefopam diluted in 100-mL normal saline intraoperatively, followed by 80-mg nefopam diluted in 500-mL normal saline, administered as a continuous infusion postoperatively for 24 hours. The control group received an identical volume of normal saline. Postoperative pain was managed using intravenous morphine via patient-controlled analgesia. Morphine consumption in the first 24 hours was recorded as the primary outcome. Secondary outcomes, including postoperative pain score, postoperative function, and length of hospital stay (LOS), were assessed.

RESULTS

No statistically significant differences in the total morphine consumption and postoperative pain score in the first 24 hours postoperatively between the two groups. At the post-anesthesia care unit (PACU), the nefopam group demonstrated lower pain scores while at rest (p =0.03) and upon movement (p =0.02) than the normal saline group. However, the severity of postoperative pain between the two groups was similar from postoperative day 1 to day 3. LOS was significantly shorter in the nefopam group than in the control group (p <0.01). The time to first sitting and walking and PACU discharge between the two groups were comparable.

CONCLUSIONS

Perioperative intravenous nefopam demonstrated significant pain reduction during the early postoperative period and shortened LOS. Nefopam is considered safe and effective as a part of multimodal analgesia in open spine surgery.

Dynamic intermittent compression cryotherapy with intravenous nefopam results in faster pain recovery than static compression cryotherapy with oral nefopam: post-anterior cruciate ligament reconstruction

PURPOSE

To evaluate the effectiveness of dynamic intermittent compression cryotherapy (DICC) (CryoNov®) with an intravenous nefopam-based pain management protocol (DCIVNPP) in reducing post-operative pain following anterior cruciate ligament reconstruction (ACLR) compared to static compression cryotherapy (SCC) (Igloo®) and oral Nefopam.

METHODS

This was a retrospective analysis of prospectively collected data including 676 patients who underwent primary ACLR in 2022. Patients were either in the DCIVNPP group or in the SCC (control group), and were matched for age, sex, and Lysholm and Tegner scores (338 per arm). The primary outcome was pain on the visual analogue scale (VAS), analyzed in relation to the minimal clinically important difference (MCID) and the Patient Acceptable Symptom State (PASS) thresholds for VAS. The secondary outcome was side effects.

RESULTS

Postoperative pain in the DCIVNPP group was less severe on the VAS than in the control group (p < 0.05). The maximum difference in the VAS between groups was 0.57, which is less than the MCID threshold for VAS. The DCIVNPP group crossed the PASS threshold for VAS on Day 3, sooner than the control group. The side effect profiles were similar in both groups except for higher rates of dizziness and malaise in the DCIVNPP group, and higher rates of abdominal pain in the control group. Most of the side effects decreased over time in both groups, with no significant side effects after Day 3.

CONCLUSION

DCIVNPP effectively allows for faster pain recovery than in the control group. The difference in side effects between the protocols may be due to mode of administration of nefopam.

LEVEL OF EVIDENCE

III.

Intravenous lidocaine bolus for reducing nefopam-induced venous pain: A randomized, intrasubject comparison trial

Background and Aims

Intravenous nefopam reduces postoperative pain and opioid consumption but can cause infusion-related pain. We aimed to investigate whether lidocaine can effectively reduce this pain.

Material and Methods

This prospective, randomized, double-blind, controlled, intrasubject comparison trial included 42 patients (20-60 years) undergoing elective surgery under regional or peripheral anesthesia. In the postanesthesia care unit, two 50 mL syringes containing nefopam (20 mg) diluted in saline (100 mL) were sequentially infused in 15 min into venous catheters in the left and right arms. Patients were randomly assigned to the "left side" or "right side" group based on the arm in which a bolus of 1% lidocaine (2 mL) (study group) was administered before nefopam infusion. Normal saline (2 mL) was administered on the control side. Numerical Rating Scale scores and the incidence of pain (scores > 3) and nausea or vomiting were recorded at 1, 5, 10, and 15 min.

Results

The analysis included 42 patients (84 infusions). Compared with the placebo, lidocaine lowered the mean infusion-related pain at 1 (0.07 vs. 2.21, P < 0.001), 5 (2 vs. 4.21, P < 0.001), 10 (2.02 vs. 3.95, P < 0.001), and 15 min (1.62 vs. 3.16, P = 0.003). At 5 min, significantly higher percentages of infusion sites with moderate and higher pain scores (> 3) were observed on the control side (30.95% vs. 14.29%, P = 0.000). Seven patients exhibited nausea or vomiting (16.7%).

Conclusion

For the nefopam infusion rate and concentration that we used, a 20 mg lidocaine pretreatment bolus significantly reduces infusion-related pain.

Comparative effectiveness of interventions for managing urological postoperative catheter-related bladder discomfort: a systematic review and network meta-analysis

BACKGROUND

Catheter-related bladder discomfort (CRBD) is a common postoperative bladder pain syndrome. Many drugs and interventions for managing CRBD have been studied, but their comparative effectiveness remains controversial. We made a study to assess the comparative effectiveness of interventions included Ketorolac, Lidocaine, Chlorpheniramine, Gabapentin, Magnesium, Nefopam, Oxycodone, Parecoxib, Solifenacin, Tolterodine, Bupivancaine, Dexmedetomidine, Hyoscine N-butyl bromide, Ketamine, Penile nerve block on urological postoperative CRBD.

METHODS

We performed a network meta-analysis via Aggregate Data Drug Inormation System software included 18 studies with 1816 patients and assessed the risk of bias by Cochrane Collaboration tool. The incidence of moderate to severe CRBD at 0, 1, and 6 h after surgery and the incidence severe CRBD at 1 h after surgery were compared.

RESULT

The number of best rank is 0.48(Nefopam) and 0.22(Nefopam) in the incidence of moderate to severe CRBD at 1 h and incidence severe CRBD at 1 h. More than half of studies at unclear or high risk of bias.

CONCLUSION

Nefopam reduced the incidence of CRBD and prevented severe events, but limited by the small number of studies for each intervention and heterogeneous patients.

Single-dose intravenous nefopam on postoperative catheter-related bladder discomfort in patients undergoing transurethral resection of prostate: a randomized, double-blind placebo-controlled trial

PURPOSE

Transurethral resection of prostate (TURP) with postoperative catheter traction can lead to significant catheter-related bladder discomfort (CRBD). This condition causes many postoperative complications and low patient satisfaction. This study aimed to evaluate the effectiveness of preoperative single-dose intravenous nefopam on the incidence and severity of CRBD and its adverse effects.

METHODS

This randomized, controlled, double-blind study included patients who underwent TURP under spinal anesthesia with postoperative urinary catheter traction. Patients were allocated into nefopam (NF) and normal saline (NS) groups. Twenty mg of nefopam in normal saline solution (NSS) 100 mL or NSS 100 mL were given intravenously before TURP. The primary outcome was the incidence of CRBD.

RESULTS

Seventy-three patients were randomized into NF (n = 37) and NS (n = 36) groups. There were 35 and 33 patients in the NF and NS groups, respectively, in the final analysis. The incidences of CRBD were 45.71% and 84.85% in the NF and NS groups at 6 h after operation, respectively, OR 0.54 (95% CI 0.36, 0.73), while before the end of catheter traction, the corresponding incidences were 37.14% and 75.76%, respectively, OR 0.49 (95% CI 0.28, 0.84). The CRBD scores were statistically significantly lower in the NF group at both time points. Morphine consumptions and adverse effects were not different between groups. Patient satisfaction was higher in the NF group.

CONCLUSIONS

Single-dose nefopam significantly reduced the incidence and severity of CRBD in patients undergoing TURP with urinary catheter traction at 6 h after the procedure and before the end of catheter traction without increasing the adverse effects.

Neuropathic pain: Mechanisms and therapeutic strategies

The physiopathology and neurotransmission of pain are of an owe inspiring complexity. Our ability to satisfactorily suppress neuropathic or other forms of chronic pain is limited. The number of pharmacodynamically distinct and clinically available medications is low and the successes achieved modest. Pain Medicine practitioners are confronted with the ethical dichotomy imposed by Hippocrates: On one hand the mandate of primum non nocere, on the other hand, the promise of heavenly joys if successful divinum est opus sedare dolorem. We briefly summarize the concepts associated with nociceptive pain from nociceptive input (afferents from periphery), modulatory output [descending noradrenergic (NE) and serotoninergic (5-HT) fibers] to local control. The local control is comprised of the "inflammatory soup" at the site of pain origin and synaptic relay stations, with an ATP-rich environment promoting inflammation and nociception while an adenosine-rich environment having the opposite effect. Subsequently, we address the transition from nociceptor pain to neuropathic pain (independent of nociceptor activation) and the process of sensitization and pain chronification (transient pain progressing into persistent pain). Having sketched a model of pain perception and processing we attempt to identify the sites and modes of action of clinically available drugs used in chronic pain treatment, focusing on adjuvant (co-analgesic) medication.

A Comprehensive Review: Chronic Pain Sequelae in the Presence of Ehlers-Danlos Syndrome

PURPOSE OF REVIEW

Patients diagnosed with Ehlers-Danlos syndromes (EDS), and especially those with the hypermobility subtype, often experience a diverse range of acute and chronic pain conditions throughout their lifetime. These can present in a variety of different phenotypes and comorbidities, making it difficult to develop structured treatment protocols. This review seeks to summarize the current literature to address old and novel treatments for EDS.

RECENT FINDINGS

Historically, medications and surgery have been used to treat patients with EDS but with low efficacy. Newer therapies that have shown promising effects for both decreasing pain and increasing quality of life include physical/occupational therapy, transcutaneous electrical nerve stimulation units, trigger point injections, low-dose naltrexone, and laser therapy. In addition, addressing the psychosocial aspects of pain with EDS through methods like cognitive behavioral therapy and patient education has shown to be vital in minimizing pain. Most research also emphasizes that pain management should not only focus on pain reduction, but on helping reduce symptoms of hypermobility, central sensitization, and fatigue to make an impactful difference. Research on pain in EDS is still limited with good clinical practice guidelines often limited by poor sample size and lack of clinical studies. Treatment options should be structured based on the specific type of pain pathology and presenting symptoms of each patient and their comorbidities. Future research should attempt to prioritize larger sample sizes, clear definitions of EDS subtypes, randomized trials for treatment efficacy, and more studies dedicated to non-musculoskeletal forms of pain.

Postoperative analgesia of intraoperative nefopam in patients undergoing anterior cervical spine surgery: A prospective randomized controlled trial

BACKGROUND

Nefopam is a non-opioid, non-nonsteroidal anti-imflammatory drug, analgesic drug that inhibits the reuptake of serotonin, norepinephrine, and dopamine. It is widely used as an adjuvant for pain. This study investigated whether the intraoperative, intravenous infusion of nefopam (20 mg) reduces postoperative morphine consumption, pain scores, and alleviates neuropathic pain in patients undergoing cervical spine surgery.

METHODS

A prospective, paralleled design, randomized study was conducted on 50 patients (aged 18-75 years) in a university-based hospital. The patients were assigned to an intervention or a control group (25 patients in each). The intervention group received a 1-hour infusion of nefopam (20 mg) before the end of surgery. The control group received normal saline (NSS). The outcome measures were morphine consumption during the first 24 postoperative hours, numerical rating scale (NRS) pain scores, and scores for the Thai version of the Neuropathic Pain Symptom Inventory (NPSI-T) in patients with neuropathic pain and adverse drug reactions. The NPSI-T scores were assessed on the preoperative day, postoperative day 1, 3, 15, and 30. The outcome assessors were blinded to group allocation.

RESULTS

Fifty patients were analyzed. During the first 24 postoperative hours, morphine consumption was 8 mg (nefopam) and 12 mg (NSS; P = .130). The intervention and control groups demonstrated no significant differences in the median NRS scores or total NPSI-T scores or adverse drug reactions.

CONCLUSIONS

A single, intraoperative infusion of 20 mg of nefopam did not significantly reduce postoperative (24 hours) morphine consumption in patients undergoing anterior cervical spine surgery.

The Lack of Analgesic Efficacy of Nefopam after Video-Assisted Thoracoscopic Surgery for Lung Cancer: A Randomized, Single-Blinded, Controlled Trial

Nefopam is a centrally acting non-opioid analgesic, and its efficacy in multimodal analgesia has been reported. This study aimed to assess the analgesic efficacy of intraoperative nefopam on postoperative pain after video-assisted thoracoscopic surgery (VATS) for lung cancer. Participants were randomly assigned to either the nefopam or the control group. The nefopam group received 20 mg of nefopam after induction and 15 min before the end of surgery. The control group received saline. The primary outcome was cumulative opioid consumption during the 6 h postoperatively. Pain intensities, the time to first request for rescue analgesia, adverse events during the 72 h postoperatively, and the incidence of chronic pain 3 months after surgery were evaluated. Ninety-nine patients were included in the analysis. Total opioid consumption during the 6 h postoperatively was comparable between the groups (nefopam group [n = 50] vs. control group [n = 49], 19.8 [13.5–25.3] mg vs. 20.3 [13.9–27.0] mg; median difference: −1.55, 95% CI: −6.64 to 3.69; p = 0.356). Pain intensity during the 72 h postoperatively and the incidence of chronic pain 3 months after surgery did not differ between the groups. Intraoperative nefopam did not decrease acute postoperative opioid consumption or pain intensity, nor did it reduce the incidence of chronic pain after VATS.

Micro- and nanocarriers for pain alleviation

Acute or chronic pain is a major source of impairment in quality of life and affects a substantial part of the population. To date, pain is alleviated by a limited range of treatments with significant toxicity, increased risk of misuse and inconsistent efficacy, owing, in part, to lack of specificity and/or unfavorable pharmacokinetic properties. Thanks to the unique properties of nanoscaled drug carriers, nanomedicine may enhance drug biodistribution and targeting, thus contributing to improved bioavailability and lower off-target toxicity. After a brief overview of the current situation and the main critical issues regarding pain alleviation, this review will examine the most advanced approaches using nanomedicine of each drug class, from the preclinical stage to approved nanomedicines.

Does Nefopam Provide Analgesic Effect and Reduce Morphine Consumption After Primary Total Knee Arthroplasty? A Prospective, Double-Blind, Randomized Controlled Trial

BACKGROUND

One of the most undesirable results after total knee arthroplasty (TKA) is severe immediate postoperative pain, resulting in patient dissatisfaction. We aimed to evaluate nefopam's analgesic efficacy after primary TKA along with related outcomes, including morphine consumption and adverse events.

METHODS

We conducted a double-blind, randomized controlled trial of patients undergoing unilateral primary TKA, comparing 24 hours of 80 mg of continuous intravenous nefopam to placebo infusion. A 100-mm Visual Analog Scale (VAS) for pain-at-rest and in-motion ≤48 hours was the primary outcome measure. Secondary outcomes were morphine and antiemetic consumption, adverse events, and functional outcomes: time-to-walk, timed up-and-go test, postoperative knee range of motion at 24 and 48 hours, time-to-discharge, and patient satisfaction scores.

RESULTS

Patients in the nefopam group had significantly lower VAS at rest 6 hours postop (20.3 ± 27.3 vs 35 ± 24.3, P = .01). Other timepoints and in-motion VAS did not significantly differ. Total morphine consumption (0-48 hours) was 37% less, significantly lower, in the nefopam group (5.3 ± 4.5 vs 8.4 ± 7.5 mg, P = .03). Antiemetic consumption was also 61% lower in the nefopam group but not statistically significant (0.8 ± 2.3 vs 2.0 ± 3.8 mg, P = .08). There were no variations in adverse events, functional outcomes, and satisfaction scores between groups.

CONCLUSION

Continuous nefopam administration as part of multimodal analgesia for 24 hours post-TKA produced a significant analgesic effect but only within the first 6 hours. However, there was a notable reduction in morphine use 48 hours postop. Nefopam is a useful agent for contemporary pain control after TKA.

LEVEL OF EVIDENCE

Therapeutic Level I.

A case report of percutaneous endoscopic debridement for treating lumbar tuberculous spondylitis with large psoas abscess

Introduction and importance

Case presentation

Discussion

Conclusion

•

Early diagnosis and management of spondylitis tuberculosis have special importance in preventing complications

•

We reviewed the evaluation of clinical outcome, laboratory findings, and radiological post-minimal invasive endoscopic debridement in spinal tuberculosis with psoas abscess

•

Post percutaneous endoscopic debridement, patients had a good response in eradicating germs with clinical, laboratory, and radiology findings improvement with resorption of psoas abscess

•

This study is concerned that a combination of the administration of anti-tuberculous drugs and surgical treatment is the best choice for patients with spondylitis tuberculous with large psoas abscess

Analgesic Effect of Intravenous Nefopam for Postoperative Pain in Minimally Invasive Spine Surgery: A Randomized Prospective Study

Study Design

Randomized double-blind control study.

Purpose

To evaluate the effects of nefopam on reducing morphine consumption and postoperative pain in patients undergoing minimally invasive spine surgery (MISS) and to evaluate its effects on enhanced recovery after spine surgery.

Overview of Literature

Enhanced recovery after surgery (ERAS) has become a major goal for spine surgery. Multimodal pain management combining non-opioid analgesics is a key element of this. However, there is little evidence regarding the use of nefopam in spine surgery as part of an ERAS protocol.

Methods

One hundred patients undergoing MISS were randomized into two groups. Patients in the nefopam group received 20 mg of intravenous nefopam diluted in 100 mL of normal saline intraoperatively, followed by 80 mg of nefopam diluted in 500 mL of normal saline, given as a continuous infusion postoperatively for 24 hours. The control group received an identical volume of normal saline. Postoperative pain was managed by patient-controlled analgesia in the form of intravenous morphine. Morphine consumption in the first 24 hours was recorded as a primary outcome. Secondary outcomes regarding ERAS were also collected.

Results

There were no significant differences in either total morphine consumption or postoperative pain score in the first 24 hours postoperatively between patients receiving nefopam and the control group. Morphine consumption in patients receiving nefopam was 13.54±10.64 mg compared with 15.86±16.2 mg in the control group (p=0.41). Time to postanesthetic care unit discharge, times to first sitting and walking, length of hospital stay, as well as duration of Foley catheter use and time until drain removal were also similar. There were no serious adverse effects of nefopam compared with normal saline.

Conclusions

Nefopam did not significantly reduce opioid consumption or postoperative pain score. Adding nefopam as part of multimodal analgesia did not show beneficial effects for enhancing recovery after spine surgery.

Effect of Nefopam-Based Patient-Controlled Analgesia with and without Fentanyl on Postoperative Pain Intensity in Patients Following Laparoscopic Cholecystectomy: A Prospective, Randomized, Controlled, Double-Blind Non-Inferiority Trial

Background and Objectives: We investigated the non-inferiority of patient-controlled analgesia (PCA), using either nefopam alone or combined nefopam-fentanyl for postoperative analgesia in patients undergoing laparoscopic cholecystectomy. Materials and Methods: In this prospective, randomized, controlled study, 78 patients were allocated to receive nefopam 240 mg (Group N240) or nefopam 120 mg with fentanyl 600 μg (Group NF), equivalent to fentanyl 1200 μg, with a total PCA volume of 120 mL. Patients were given a loading dose (0.1 mL/kg) from the PCA device along with ramosetron (0.3 mg) and connected to a PCA device with a background infusion rate of 2 mL/h, bolus dose amount set at 2 mL, and lockout interval set at 15 min. Pain scores were obtained using the numeric rating scale (NRS) at 30 min after recovery room (RR) admission, as well as 8 and 24 h postoperatively. The primary outcome was analgesic efficacy evaluated using NRS-rated 8 h postoperatively. Other evaluated outcomes included the incidence rate of bolus demand, rescue analgesic and antiemetic requirements, and postoperative adverse effects. Results: NRS scores were not significantly different between the groups throughout the postoperative period (p = 0.539). NRS scores of group N240 were not inferior to those of group NF at 30 min after RR admission, or at 8 and 24 h postoperatively (mean difference [95% CI], -0.05 [-0.73 to 0.63], 0.10 [-0.29 to 0.50], and 0.28 [-0.06 to 0.62], respectively). Postoperative adverse effects were not significantly different between the two groups (p = 1.000) and other outcomes were also not significantly different between the two groups (p ≥ 0.225). Conclusions: PCA using nefopam alone has a non-inferior and effective analgesic efficacy and produces a lower incidence of postoperative adverse effects compared to a combination of fentanyl and nefopam after laparoscopic cholecystectomy.

Antinociceptive effects of nefopam modulating serotonergic, adrenergic, and glutamatergic neurotransmission in the spinal cord

The present study investigated the effects of intrathecal nefopam on the pain behavior and on the extracellular levels of serotonin (5-HT), norepinephrine (NE), and glutamate in the spinal cord, in a rat model of pain induced by formalin. Nefopam was intrathecally administered 10 min prior to the formalin test to assess its antinociceptive effects. In another cohorts of animals, dihydroergocristine, yohimbine, or (RS)-α-Methylserine-O-phosphate (MSOP), a serotonergic, α-2 adrenergic receptor, or group III metabotropic glutamate receptor antagonist, respectively, were administered prior to the application of nefopam in the formalin test. Microdialysis studies were conducted to measure the extracellular levels of 5-HT, NE, and glutamate in the spinal cord following nefopam administration. Intrathecal nefopam reduced formalin-induced behavior in both phases of the test. The blockade of serotonergic or adrenergic receptors partially reversed the analgesic effects of nefopam in the first phase of the formalin test whereas MSOP reversed these effects in both phases. The microdialysis results revealed that intrathecal nefopam significantly increased 5-HT and NE levels and attenuated the formalin-induced release of glutamate in the spinal cord. Thus, the present data suggest that the increase in the extracellular levels of 5-HT and NE, and reductions in glutamate release in the spinal cord, may have contributed to the analgesic effects of nefopam.

Nefopam hydrochloride as a component of multimodal analgesia in the postoperative period

The modern approach to the multimodal scheme of postoperative analgesia includes the mandatory use of drugs that have a small number of side effects and at the same time have a polymodal effect on the pathogenetic links of pain development. Nefopam hydrochloride is able to prevent the development of: opioid hyperalgesia, stop pain stimuli without respiratory depression, affect platelet aggregation and the condition of the mucous membrane and motility of the gastrointestinal tract, which distinguishes it from classical NSAIDs. Nefopam hydrochloride is characterized by a low risk of addiction with prolonged use, a pronounced anti-sensory effect, especially significant at the stage of awakening and in the early postoperative period. Postoperative analgesia based on nefopam hydrochloride as a component of multimodal analgesia is effective and safe in the absence of absolute contraindications. The planned use of nefopam hydrochloride for the correction of pain reduces complications in the postoperative period and improves the quality of life of patients. Nefopam hydrochloride is one of the most effective drugs for the correction of postoperative tremor syndrome. The use of nefopam hydrochloride as a drug, which is a part of premedication before surgical interventions and a component of multimodal analgesia, improves the quality of the postoperative period due to: reduction of pain syndrome, planned correction of postoperative tremor syndrome and correction of complications arising from inadequate treatment of pain syndrome.

Analgesic efficacy of nefopam for cancer pain: a randomized controlled study

Background: Nefopam is a non-opioid, non-steroidal, central acting drug used effectively for postoperative pain. The efficacy of nefopam for cancer pain remains unclear. We aimed to evaluate the analgesic efficacy of nefopam for cancer pain in a randomized controlled trial. Methods: Patients with moderate to severe cancer pain (n=40) were randomly divided into two groups. The nefopam group (n=20) received three 20 mg doses of nefopam every 8 hours. The placebo group (n=20) received normal saline. Intravenous patient-controlled analgesia with morphine was given for breakthrough pain for 48 hours. The primary outcome was significant pain reduction. Secondary outcomes were morphine consumption over 48 hours and incidence of side effects. Results: The nefopam group showed pain reduction at 12 hours (65% of patients), 24 hours (80%), 36 hours (85%), and 48 hours (65%). The placebo group showed pain reduction at 12 hours (70%), 24 hours (75%), 36 hours (80%), and 48 hours (60%). However, there were no statistically significant differences between the groups (p>0.05). The median dosage of morphine consumption in 48 hours was lower in the nefopam group (25.5 mg) compared with the placebo group (37 mg), but this was not statistically significant (p=0.499). There were no statistically significant differences in blood pressure and heart rate between the groups. Side effects in both groups were comparable. Conclusions: At dosage of 60 mg in 24 hours, nefopam did not provide significant pain reduction in moderate to severe cancer pain patients. However, there was a trend of reduced opioid consumption. Further studies with larger sample sizes, longer duration, or higher doses of nefopam are warranted. Registration: Thai Clinical Trail Registry (TCTR) ID TCTR20181016001; registered on 12 October 2018.

All about pain pharmacology: what pain physicians should know

From the perspective of the definition of pain, pain can be divided into emotional and sensory components, which originate from potential and actual tissue damage, respectively. The pharmacologic treatment of the emotional pain component includes antianxiety drugs, antidepressants, and antipsychotics. The anti-anxiety drugs have anti-anxious, sedative, and somnolent effects. The antipsychotics are effective in patients with positive symptoms of psychosis. On the other hand, the sensory pain component can be divided into nociceptive and neuropathic pain. Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are usually applied for somatic and visceral nociceptive pain, respectively; anticonvulsants and antidepressants are administered for the treatment of neuropathic pain with positive and negative symptoms, respectively. The NSAIDs, which inhibit the cyclo-oxygenase pathway, exhibit anti-inflammatory, antipyretic, and analgesic effects; however, they have a therapeutic ceiling. The adverse reactions (ADRs) of the NSAIDs include gastrointestinal problems, generalized edema, and increased bleeding tendency. The opioids, which bind to the opioid receptors, present an analgesic effect only, without anti-inflammatory, antipyretic, or ceiling effects. The ADRs of the opioids start from itching and nausea/vomiting to cardiovascular and respiratory depression, as well as constipation. The anticonvulsants include carbamazepine, related to sodium channel blockade, and gabapentin and pregabalin, related to calcium blockade. The antidepressants show their analgesic actions mainly through inhibiting the reuptake of serotonin or norepinephrine. Most drugs, except NSAIDs, need an up-dose titration period. The principle of polypharmacy for analgesia in case of mixed components of pain is increasing therapeutic effects while reducing ADRs, based on the origin of the pain.

Emergence agitation: current knowledge and unresolved questions

Emergence agitation (EA), also referred to as emergence delirium, can have clinically significant consequences. The mechanism of EA remains unclear. The proposed risk factors of EA include age, male sex, type of surgery, emergency operation, use of inhalational anesthetics with low blood-gas partition coefficients, long duration of surgery, anticholinergics, premedication with benzodiazepines, voiding urgency, postoperative pain, and the presence of invasive devices. If preoperative or intraoperative objective monitoring could predict the occurrence of agitation during emergence, this would help to reduce its adverse consequences. Several tools are available for assessing EA. However, there are no standardized clinical research practice guidelines and its incidence varies considerably with the assessment tool or definition used. Total intravenous anesthesia, propofol, μ-opioid agonists, N-methyl-D-aspartate receptor antagonists, nefopam, α2-adrenoreceptor agonists, regional analgesia, multimodal analgesia, parent-present induction, and preoperative education for surgery may help in preventing of EA. However, it is difficult to identify patients at high risk and apply preventive measures in various clinical situations. The risk factors and outcomes of preventive strategies vary with the methodologies of studies and patients assessed.This review discusses important outcomes of research on EA and directions for future research.

Analgesic Effect of Low Dose Nefopam Hydrochloride after Arthroscopic Rotator Cuff Repair: A Randomized Controlled Trial

Arthroscopic rotator cuff repair causes acute postoperative hyperalgesia. Multimodal analgesia is preferable to opioid-based intravenous patient-controlled analgesia (IV-PCA) due to postoperative nausea and vomiting (PONV). We evaluated the effect of nefopam as a postoperative non-opioid analgesic after shoulder surgeries. A total of 180 adult patients were enrolled for arthroscopic rotator cuff repair. They were randomly assigned to nefopam (N) or control (C) groups and each group was reclassified according to the interscalene block (B) into NB, CB and NX, CX. Nefopam was applied at a constant dose intravenously during recovery. Pain scores were measured with a Visual Analogue Scale (VAS) before (T0), immediately after (T1), 30 min (T2) and 12 h (T3), 24 h (T4) and 48 h (T5) after surgery. There was no significant difference in demographic data. The overall VAS scores did not differ with regard to nefopam use, except for the NB group at T4 in intention to treat (ITT) analysis (p < 0.05). PONV occurred more frequently in the N group than in the C group (p < 0.05). Neither individual nor all risk factors were associated with PONV occurrence (p > 0.10). In conclusion, nefopam alone did not show a definite decrease in postoperative pain. It instead increased PONV regardless of risk factors.

Effects on postoperative nausea and vomiting of nefopam versus fentanyl following bimaxillary orthognathic surgery: a prospective double-blind randomized controlled trial

Background

Postoperative nausea and vomiting (PONV) frequently occurs following bimaxillary orthognathic surgeries. Compared to opioids, Nefopam is associated with lower incidences of PONV, and does not induce gastrointestinal tract injury, coagulopathy, nephrotoxicity, or fracture healing dysfunction, which are common side effects of Nonsteroidal anti-inflammatory drugs. We compared nefopam- and fentanyl-induced incidence of PONV in patients with access to patient-controlled analgesia (PCA) following bimaxillary orthognathic surgeries.

Methods

Patients undergoing bimaxillary orthognathic surgeries were randomly divided into nefopam and fentanyl groups. Nefopam 120 mg or fentanyl 700 µg was mixed with normal saline to a final volume of 120 mL. Patients were given access to nefopam or fentanyl via PCA. Postoperative pain intensity and PONV were measured at 30 minutes and 1 hour after surgery in the recovery room and at 8, 24, 48, and 72 hours after surgery in the ward. The frequency of bolus delivery was compared at each time point.

Results

Eighty-nine patients were enrolled in this study, with 48 in the nefopam (N) group and 41 in the fentanyl (F) group. PONV occurred in 13 patients (27.7%) in the N group and 7 patients (17.1%) in the F group at 8 hours post-surgery (P = 0.568), and there were no significant differences between the two groups at any of the time points. VAS scores were 4.4 ± 2.0 and 3.7 ± 1.9 in the N and F groups, respectively, at 8 hours after surgery (P = 0.122), and cumulative bolus delivery was 10.7 ± 13.7 and 8.6 ± 8.5, respectively (P = 0.408). There were no significant differences in pain or bolus delivery at any of the remaining time points.

Conclusion

Patients who underwent bimaxillary orthognathic surgery and were given nefopam via PCA did not experience a lower rate of PONV compared to those that received fentanyl via PCA. Furthermore, nefopam and fentanyl did not provide significantly different postoperative pain control.

The efficacy and safety of first-line therapies for preventing chronic post-surgical pain: a network meta-analysis

Background

Due to conflicting evidence regarding first-line therapies for chronic post-surgical pain (CPSP), here we comparatively evaluated the efficacy and safety of first-line therapies for the prevention of CPSP.

Materials and Methods

MEDLINE, EMBASE, and Cochrane CENTRAL databases were searched for randomized, controlled trials (RCTs) of systemic drugs measuring pain three months or more post-surgery. Pairwise meta-analyses (a frequentist technique directly comparing each intervention against placebo) and network meta-analyses (a Bayesian technique simultaneously comparing several interventions via an evidence network) compared the mean differences for primary efficacy (reduction in all pain), secondary efficacy (reduction in moderate or severe pain), and primary safety (drop-out rate from treatment-related adverse effects). Ranking probabilities from the network meta-analysis were transformed using surface under the cumulative ranking analysis (SUCRA). Sensitivity analyses evaluated the impact of age, gender, surgery type, and outlier studies.

Results

Twenty-four RCTs were included. Mexiletine and ketamine ranked highest in primary efficacy, while ketamine and nefopam ranked highest in secondary efficacy. Simultaneous SUCRA-based rankings of the interventions according to both efficacy and safety revealed that nefopam and mexiletine ranked highest in preventing CPSP. Through the sensitivity analyses, gabapentin and ketamine remained the most-highly-ranked in terms of efficacy, while nefopam and ketamine remained the most-highly-ranked in terms of safety.

Conclusions

Nefopam and mexiletine may be considered as first-line therapies for the prevention of CPSP. On account of the paucity of evidence available on nefopam and mexiletine, gabapentin and ketamine may also be considered. Venlafaxine is not recommended for the prevention of CPSP.

Nefopam downregulates autophagy and c-Jun N-terminal kinase activity in the regulation of neuropathic pain development following spinal nerve ligation

Background

Neurodegeneration is associated with changes in basal cellular function due to the dysregulation of autophagy. A recent study introduced the involvement of autophagy during spinal nerve ligation (SNL). Nefopam has shown potential for reducing neuropathic pain, but the underlying mechanisms are unknown. Here, we investigated the effects of nefopam on neuropathic pain development following SNL, focusing on the involvement of autophagy.

Methods

The functional role of nefopam in capsaicin-induced autophagy was assessed by human glioblastoma M059 K cells. The neuropathic pain model was used to determine whether the effect of nefopam on pain control was mediated through autophagy control. Neuropathic pain was induced by L5 and L6 SNL in male rats randomized into three groups: Group S (sham-operated), Group C (received normal saline), and Group E (received nefopam). A behavioral test using a von Frey was examined. Expression changes of autophagy in response to nefopam was analyzed in spinal cord tissues (L4-L6) by immunoblotting and immunohistochemistry.

Results

The paw withdrawal threshold examined on days 3, 5, 7, and 14 post-SNL was significantly higher in Group E than in Group C. SNL increased the levels of microtubule-associated protein 1 light chain 3B (LC3B-1), with concomitant reduction of sequestosome 1 (SQTSM1/p62), compared with Group S, indicating that SNL induced autophagy. These effects were reversed by nefopam injection, and the results were confirmed by immunohistochemistry for LC3-I/II. Furthermore, SNL-mediated JNK activation was markedly decreased following nefopam injection. Hematoxylin and eosin staining on Day 14 post-SNL revealed that SNL caused lymphocyte infiltration and oligodendrocyte localization in the substantia gelatinosa of the dorsal gray horn, which were reduced by nefopam injection.

Conclusion

Collectively, the mode of action of nefopam on neuropathic pain appears to be associated with downregulation of phospho-JNK and autophagy, as well as modulation of the immune response.

Effects of nefopam on catheter-related bladder discomfort in patients undergoing ureteroscopic litholapaxy

BACKGROUND

Patients who undergo urinary catheterization may experience postoperative catheter-related bladder discomfort (CRBD). Previous studies have indicated that drugs with antimuscarinic effects could reduce the incidence and severity of CRBD. Accordingly, this study was carried out to investigate whether nefopam, a centrally acting analgesic with concomitant antimuscarinic effect, reduces the incidence and severity of CRBD.

METHODS

Sixty patients with American Society of Anesthesiologists physical status I and II and aged 18-70 years who were scheduled to undergo elective ureteroscopic litholapaxy participated in this double-blinded study. Patients were divided into control and nefopam groups, comprising 30 patients each. In the nefopam group, 40 mg nefopam in 100 ml of 0.9% saline was administered intravenously. In the control group, only 100 ml of 0.9% saline was administered. All patients had a urethral catheter and ureter stent inserted during surgery. The incidence and severity of CRBD, numerical rating scale (NRS) score of postoperative pain, rescue pethidine dose, and side effects were recorded in the post-anesthesia care unit after surgery.

RESULTS

The incidence (P = 0.020) and severity (P < 0.001) of CRBD were significantly different between the control group and the nefopam group. The NRS score of postoperative pain (P = 0.006) and rescue dose of pethidine (P < 0.001) were significantly higher in the control group than in the nefopam group.

CONCLUSIONS

Intravenous administration of nefopam in patients scheduled to undergo ureteroscopic litholapaxy reduced the incidence and severity of CRBD, NRS score of postoperative pain and analgesic requirements.

Effects of nefopam on emergence agitation after general anesthesia for nasal surgery: A prospective, randomized, and controlled trial

BACKGROUND

Emergence agitation (EA) occurs frequently after nasal surgery. N-methyl-D-aspartate (NMDA) receptor antagonists and analgesics, such as fentanyl, have been shown to prevent EA. Nefopam inhibits the NMDA receptor and shows a potent analgesic effect. We investigated the effects of nefopam on EA in patients undergoing nasal surgery.

METHODS

In this prospective, double-blind study, 100 adult patients were allocated randomly to 1 of 2 groups (each n = 50). Patients received 20 mg of nefopam in 98 mL of saline for 20 minutes immediately after induction of anesthesia (nefopam group) or 100 mL of saline (control group) in the same manner. After surgery, the incidence and degree of EA, time for extubation, hemodynamic parameters, and adverse events were evaluated by an observer blinded to the group allocation.

RESULTS

The overall incidence of EA was lower in the nefopam group than in the control group (34% [17/50] vs 54% [27/50], respectively; P = .044). The incidence of severe EA was also lower in the nefopam group than in the control group (8% [4/50] vs 38% [19/50], respectively; P = .001). Heart rate (HR) was higher in the nefopam group than in the control group from the end of surgery to 3 minutes after extubation (P = .008). Time for extubation and adverse events were similar between groups.

CONCLUSIONS

Nefopam infusion is effective in preventing and reducing the severity of EA after nasal surgery without a delay in extubation. However, caution is required regarding the increase in HR.

A Review of Adjunctive CNS Medications Used for the Treatment of Post-Surgical Pain

Inadequate post-operative pain management can have significant impacts on patients' quality of life. Effective management of acute pain after surgery is important for early mobilization and discharge from hospital, patient satisfaction, and overall well-being. Utilizing multimodal analgesic strategies has become the mainstay of acute post-operative pain management. A comprehensive search was performed, assessing the published or otherwise publically available literature on different central nervous system (CNS) drugs [excluding opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and acetaminophen] and their uses to treat acute post-surgical pain. Included among the drugs evaluated in this review are anticonvulsants, N-methyl-D-aspartic acid (NMDA) agonists, local anesthetics, α₂-agonists, cannabinoids, serotonin-noradrenaline reuptake inhibitors (SNRIs), and serotonin-noradrenaline-dopamine reuptake inhibitors (SNDRIs). Timing, dosing, routes of administration, as well as mechanisms of action are discussed for these CNS drugs.

Earlier treatment improves the chances of complete relief from postherpetic neuralgia

Background

As herpes zoster progresses via postherpetic neuralgia (PHN) to well-established PHN, it presents its recalcitrant nature to the treatment. At this point, the well-established PHN is fixed as a non-treatable, but manageable chronic painful neuropathic disorder. This study evaluated the incidence of complete relief from PHN according to PHN duration at their first visit, and the other factors influencing it.

Methods

A retrospective chart review was performed on patients with PHN at a university-based pain clinic over 7 years. The responders were defined as patients who had complete relief from pain after 1 year of active treatment. Age, sex, PHN duration at their first visit, dermatomal distribution, and underlying disorders were compared in the responder and non-responder groups. Responders were also compared according to these factors.

Results

Among 117 PHN patients (M/F = 48/69), 35 patients (29.9%) had complete relief from PHN. Mean ages were 64.3 ± 10.6 and 66.9 ± 10.7 years, numbers of male to female patients were 11/24 and 37/45, and mean durations of PHN at their first visit were 8.5 ± 6.3 and 15.3 ± 10.7 months in the responder and non- responder groups, respectively. In addition, PHN patients who visited the clinic before 9 months showed a better result. Dermatomal distribution and underlying disorders did not show significant differences.

Conclusions

Almost 30% of PHN patients received complete relief. Those who sought treatment in a pain clinic before 9 months received a better result.

Comparison of effect of electroacupuncture and nefopam for prevention of postanesthetic shivering in patients undergoing urologic operation under spinal anesthesia

Background

Shivering during spinal anesthesia is a frequent complication and is induced by the core-to-peripheral redistribution of heat. Nefopam has minimal side effects and prevents shivering by reducing the shivering threshold. Electroacupuncture is known to prevent shivering by preserving the core body temperature. We compared the efficacies of electroacupuncture and nefopam for the prevention of shivering during spinal anesthesia.

Methods

Ninety patients scheduled for elective urological surgery under spinal anesthesia were enrolled in the study. Patients were randomly divided into the control group (Group C, n = 30), the electroacupuncture group (Group A, n = 30), and the nefopam group (Group N, n = 30). Groups C and A received 100 ml of isotonic saline intravenously for 30 minutes before spinal anesthesia, while Group N received nefopam (0.15 mg/kg) mixed in 100 ml of isotonic saline. Group A received 30 minutes of electroacupuncture before receiving anesthesia. Shivering scores, mean arterial pressure, heart rate, body temperature and side effects were recorded before, and at 5, 15, 30, and 60 minutes after spinal anesthesia.

Results

The incidence of postanesthetic shivering was significantly lower in Group N (10 of 30) and Group A (4 of 30) compared with that in Group C (18 of 30)(P < 0.017). Body temperature was higher in Group N and Group A than in Group C (P < 0.05). Hemodynamic parameters were not different among the groups.

Conclusions

By maintaining body temperature during spinal anesthesia, electroacupuncture is as effective as nefopam in preventing postanesthetic shivering.

Development and statistical optimization of nefopam hydrochloride loaded nanospheres for neuropathic pain using Box-Behnken design

Nefopam hydrochloride (NFH) is a non-opioid centrally acting analgesic drug used to treat chronic condition such as neuropathic pain. In current research, sustained release nefopam hydrochloride loaded nanospheres (NFH-NS) were auspiciously synthesized using binary mixture of eudragit RL 100 and RS 100 with sorbitan monooleate as surfactant by quasi solvent diffusion technique and optimized by 35 Box-Behnken designs to evaluate the effects of process and formulation variables. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetric (DSC) and X-ray diffraction (XRD) affirmed absence of drug-polymer incompatibility and confirmed formation of nanospheres. Desirability function scrutinized by design-expert software for optimized formulation was 0.920. Optimized batch of NFH-NS had mean particle size 328.36 nm ± 2.23, % entrapment efficiency (% EE) 84.97 ± 1.23, % process yield 83.60 ± 1.31 and % drug loading (% DL) 21.41 ± 0.89. Dynamic light scattering (DLS), zeta potential analysis and scanning electron microscopy (SEM) validated size, charge and shape of nanospheres, respectively. In-vitro drug release study revealed biphasic release pattern from optimized nanospheres. Korsmeyer Peppas found excellent kinetics model with release exponent less than 0.45. Chronic constricted injury (CCI) model of optimized NFH-NS in Wistar rats produced significant difference in neuropathic pain behavior (p < 0.05) as compared to free NFH over 10 h indicating sustained action. Long term and accelerated stability testing of optimized NFH-NS revealed degradation rate constant 1.695 × 10-4 and shelf-life 621 days at 25 ± 2 °C/60% ± 5% RH.

The Role of Spinal Dopaminergic Transmission in the Analgesic Effect of Nefopam on Rat Inflammatory Pain

Background

Nefopam has been known as an inhibitor of the reuptake of monoamines, and the noradrenergic and/or serotonergic system has been focused on as a mechanism of its analgesic action. Here we investigated the role of the spinal dopaminergic neurotransmission in the antinociceptive effect of nefopam administered intravenously or intrathecally.

Methods

The effects of intravenously and intrathecally administered nefopam were examined using the rat formalin test. Then we performed a microdialysis study to confirm the change of extracellular dopamine concentration in the spinal dorsal horn by nefopam. To determine whether the changes of dopamine level are associated with the nefopam analgesia, its mechanism was investigated pharmacologically via pretreatment with sulpiride, a dopaminergic D2 receptor antagonist.

Results

When nefopam was administered intravenously the flinching responses in phase I of the formalin test were decreased, but not those in phase II of the formalin test were decreased. Intrathecally injected nefopam reduced the flinching responses in both phases of the formalin test in a dose dependent manner. Microdialysis study revealed a significant increase of the level of dopamine in the spinal cord by intrathecally administered nefopam (about 3.8 fold the baseline value) but not by that administered intravenously. The analgesic effects of intrathecally injected nefopam were not affected by pretreatment with sulpiride, and neither were those of the intravenous nefopam.

Conclusions

Both the intravenously and intrathecally administered nefopam effectively relieved inflammatory pain in rats. Nefopam may act as an inhibitor of dopamine reuptake when delivered into the spinal cord. However, the analgesic mechanism of nefopam may not involve the dopaminergic transmission at the spinal level.

Tapentadol: Can It Kill Two Birds with One Stone without Breaking Windows?

Tapentadol is a novel oral analgesic with a dual mode of action as an agonist of the µ-opioid receptor (MOR), and as a norepinephrine reuptake inhibitor (NRI) all in a single molecule. Immediate release (IR) tapentadol shows its analgesic effect quickly, at around 30 minutes. Its MOR agonistic action produces acute nociceptive pain relief; its role as an NRI brings about chronic neuropathic pain relief. Absorption is rapid, with a mean maximal serum concentration at 1.25-1.5 h after oral intake. It is present primarily in the form of conjugated metabolites after glucuronidation, and excretes rapidly and completely via the kidneys. The most common adverse reactions are nausea, dizziness, vomiting, and somnolence. Constipation is more common in use of the ER formulation. Precautions against concomitant use of central nervous system depressants, including sedatives, hypnotics, tranquilizers, general anesthetics, phenothiazines, other opioids, and alcohol, or use of tapentadol within 14 days of the cessation of monoamine oxidase inhibitors, are advised. The safety and efficacy have not been established for use during pregnancy, labor, and delivery, or for nursing mothers, pediatric patients less than 18 years of age, and cases of severe renal impairment and severe hepatic impairment. The major concerns for tapentadol are abuse, addiction, seeking behavior, withdrawal, and physical dependence. The presumed problem for use of tapentadol is to control the ratio of MOR agonist and NRI. In conclusion, tapentadol produces both nociceptive and neuropathic pain relief, but with worries about abuse and dependence.