Enantiomeric separation of nefopam and cathinone derivatives using a supramolecular deep eutectic solvent as a chiral selector in capillary electrophoresis.

The present study investigates the utilization of a supramolecular deep eutectic solvent (SUPRADES), consisting of sulfated-ß-cyclodextrin (S-ß-CD) and citric acid (CA), as a chiral selector (CS) in capillary electrophoresis for the enantiomeric separation of nefopam (NEF) and five cathinone derivatives (3-methylmethcathinone [3-MMC], 4-methylmethcathinone [4-MMC], 3,4-dimethylmethcathinone [3,4-DMMC], 4-methylethcathinone [4-MEC], and 3,4-methylendioxycathinone [MDMC]). A significant improvement in enantiomeric separation of the target analytes was observed upon the addition of S-ß-CD-CA to the background electrolyte (BGE), leading to a baseline separation of all analytes. In particular, the optimum percentage of S-ß-CD-CA, added to the BGE, was determined to be 0.075% v/v for NEF (Rs = 1.5) and 0.050% v/v for three out of five cathinone derivatives (Rs = 1.5, 1.6, and 2.4 for 3-MMC, 4-MEC, and 3,4-DMMC, respectively). In the case of 4-MMC and MDMC, a higher percentage of the CS, equal to 0.075% and 0.10% v/v, respectively, was required to achieve baseline separation (Rs = 1.5, 1.9 for MDMC and 4-MMC, respectively). The outcomes of the present study highlight the potential effectiveness of using SUPRADES as a CS in electrophoretic enantioseparations.

Comparison of analgesic effectiveness between nefopam and propacetamol in living kidney donors following rectus sheath block after hand-assisted living donor nephrectomy: a prospective, randomized controlled trial.

BACKGROUND: Nefopam and propacetamol are the most commonly used analgesics in postoperative multimodal analgesic regimens. Distinct mechanisms are involved in each drug's anti-nociceptive effects. No studies have compared pain relief efficacy between the two drugs in patients undergoing transplantation surgery. Here, we investigated whether the administration of nefopam or propacetamol to healthy living kidney donors who underwent rectus sheath block (RSB) for parietal pain could reduce the subsequent opioid dose necessary to produce adequate analgesia. METHODS: This prospective, randomized controlled trial included 72 donors undergoing elective hand-assisted living donor nephrectomy into two groups: propacetamol (n = 36) and nefopam (n = 36). Intraoperative RSB was performed in all enrolled donors. The primary outcome was the total volume of intravenous opioid-based patient-controlled analgesia (PCA) used on postoperative day 1 (POD 1). Additionally, the Numeric Rating Scale scores for flank (visceral) and umbilicus (parietal) pain at rest and during coughing were compared, and the Korean adaptation of the Quality of Recovery-15 Questionnaire (QoR-15 K) was evaluated on POD 1. RESULTS: Both groups had similar preoperative and intraoperative characteristics. On POD 1, the total amount of PCA infusion was significantly lower in the nefopam group than in the propacetamol group (44.5 ± 19.3 mL vs. 70.2 ± 29.0 mL; p < 0.001). This group also reported lower pain scores at the flank and umbilical sites and required fewer rescue doses of fentanyl in the post-anesthesia care unit. However, pain scores and fentanyl consumption in the ward were comparable between groups. The QoR-15 K scores were similar between groups; there were substantial improvements in breathing, pain severity, and anxiety/depression levels in the nefopam group. The incidences of postoperative complications, including sweating and tachycardia, were similar between groups. CONCLUSION: Compared with propacetamol, nefopam provides a greater analgesic effect for visceral pain and enhances the effects of blocks that reduce the opioid requirement in living kidney donors with parietal pain managed by RSB. TRIAL REGISTRATION: The trial was registered prior to patient enrollment in the clinical trial database using the Clinical Research Information Service (registration no. KCT0007351 , Date of registration 03/06/2022).

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.

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.

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.

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.

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.

Multimodal oral analgesia strategy after ambulatory arthroscopic shoulder surgery: case series using adaptive therapeutic approaches by sequential analysis.

BACKGROUND: Pain control and quality of recovery (QoR) at home remains a challenge after ambulatory shoulder arthroscopy. This study aims to assess the QoR and pain relief using a sequential implementation strategy for rescue analgesic drugs. METHODS: After institutional review board approval, patients (>18 years, American Society of Anesthesiology [ASA] score 1-3 stable) scheduled for ambulatory surgery under general anesthesia with a single-shot interscalene nerve block were enrolled. After discharge, patients received standard information regarding the postoperative recovery and care consisting of a multimodal analgesic regime (acetaminophen and ketoprofen for 5 days). The first 48 postoperative hours allowed us to compare 3 different rescue drug regimes with a control group, in sequential order: tramadol (control group), tramadol + nefopam, immediate-release oxycodone (IR), and extended-release oxycodone (ER). The primary endpoint was the QoR 40 score at 48 hours after surgery. Secondary endpoints were pain relief and adverse events over a 7-day period. An intention-to-treat statistical analysis was performed with sequential analysis (as an interim analysis) every 20 patients. Results were recorded as medians and interquartiles (25-75). RESULTS: We analyzed 109 patients with similar characteristics among groups. The QoR 40 scores were similar for the tramadol group (168 [161-172]), the tramadol + nefopam group (161 [151-173], P = .09), and the IR group (164 [153-169], P = .17), but higher for the ER group (176 [167-181], P = .03). Concerning adverse events, drugs were interrupted more frequently in the tramadol + nefopam group (36 %). In the ER group, a higher quality of postoperative relief was attained in the domains of pain and sleep. CONCLUSION: The present study shows that a combination of IR and ER oxycodone over a short period of time (<48 hours) is associated with a better QoR at home after ambulatory shoulder 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.

Multicentre, prospective, double-blind, randomised controlled clinical trial comparing different non-opioid analgesic combinations with morphine for postoperative analgesia: the OCTOPUS study.

BACKGROUND: Head-to-head comparisons of combinations of more than one non-opioid analgesic (NOA) with morphine alone, for postoperative analgesia, are lacking. The objective of this multicentre, randomised, double-blind controlled trial was to compare the morphine-sparing effects of different combinations of three NOAs-paracetamol (P), nefopam (N), and ketoprofen (K)-for postoperative analgesia. METHODS: Patients from 10 hospitals were randomised to one of eight groups: control (C) received saline as placebo, P, N, K, PN, PK, NK, and PNK. Treatments were given intravenously four times a day during the first 48 h after surgery, and morphine patient-controlled analgesia was used as rescue analgesia. The outcome measures were morphine consumption, pain scores, and morphine-related side-effects evaluated 24 and 48 h after surgery. RESULTS: Two hundred and thirty-seven patients undergoing a major surgical procedure were included between July 2013 and November 2016. Despite a failure to reach a calculated sample size, 24 h morphine consumption [median (inter-quartile range)] was significantly reduced in the PNK group [5 (1-11) mg] compared with either the C group [27 (11-42) mg; P<0.05] or the N group [21 (12-29) mg; P<0.05]. Results were similar 48 h after surgery. Patients experienced less pain in the PNK group compared with the C, N, and P groups. No difference was observed in the incidence of morphine-related side-effects. CONCLUSIONS: Combining three NOAs with morphine allows a significant morphine sparing for 48 h after surgery associated with superior analgesia the first 24 h when compared with morphine alone. CLINICAL TRIAL REGISTRATION: EudraCT: 2012-004219-30; NCT01882530.

[The effect of various multimodal analgesia regimens during surgical treatment of patients with spinal stenosis on the rate of failed back surgery syndrome]. / Vliianie razlichnykh mul'timodal'nykh skhem analgezii pri khirurgicheskom lechenii patsientov so stenozom pozvonochnogo kanala na chastotu sindroma neudachnoi operatsii na pozvonochnike.

OBJECTIVE: To determine the effect of various methods of perioperative analgesia on the rate of failed back surgery syndrome in patients operated on for spinal stenosis. MATERIAL AND METHODS: A total of 122 patients were operated on for spinal stenosis in 2010-2016. The patients were assigned to groups according to the type of received analgesia: Group K (n=19) underwent analgesia on-demand. Patients in the PMA group (n=21) received preventive multimodal analgesia (PMA) with ketoprofen, paracetamol and morphine. Patients in the PMA+PG (n=20) and PMA+N (n=20) groups additionally received pregabalin and nefopam, respectively. Patients in the PMA+E group (n=22) received continuous epidural analgesia with a combination of ropivacaine and morphine. In patients in the PMA+I group (n=20), the wound was infiltrated with ropivacaine and ketorolac. RESULTS AND CONCLUSION: In Group K, analgesia was not adequate during five postoperative days. Analgesia with PMA resulted in significant pain reduction during three postoperative days compared to Group K. Wound infiltration in addition to PMA was followed by more significant pain relief during six postoperative hours (compared to the PMA group). Administration of pregabalin or nefopam, as well as epidural analgesia, did not improve quality of postoperative analgesia. Five to seven months after the surgery, 66% (57; 75%) of patients had low back and/or leg pain; 41% (32; 50%) of patients had leg pain. Among patients suffering from pain, 32-41% patients had the severe chronic pain syndrome that resulted in sleep disorder, disability and significant deterioration of quality of life. The rate of failed back surgery syndrome did not depend on the perioperative analgesia regimen.

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.

The Effect of Nefopam Infusion during Laparascopic Cholecystectomy on Postoperative Pain.

Background: While recovery from remifentanil is fast due to its rapid metabolism, it can induce hyperalgesia by activation of N-methyl-D-aspartic acid (NMDA) receptors. Therefore, administration of NMDA receptor antagonists such as ketamine is effective in relieving hyperalgesia caused by remifentanil. A previous study showed that nefopam administration before anesthesia combined with low-dose remifentanil reduced pain and analgesic consumption during the immediate postoperative period. We hypothesized that intraoperative infusion of nefopam during laparoscopic cholecystectomy would be as effective as ketamine in controlling pain during the acute postoperative period after sevoflurane and remifentanil based anesthesia. Methods: Sixty patients scheduled to undergo laparoscopic cholecystectomy were randomly divided into three groups. General anesthesia was maintained with sevoflurane and effect-site target concentration of remifentanil (4 ng/ml) in all patients. An intravenous bolus of nefopam (0.3 mg/kg) was given, followed by continuous infusion (65 µg/kg/h) in Group N (n=20). An intravenous bolus of ketamine (0.3 mg/kg) was administered, followed by continuous infusion (180 µg/kg/h) in Group K (n=20), and Group C received a bolus and subsequent infusion of normal saline equal to the infusion received by Group K (n=20). We compared postoperative Visual Analogue Scale (VAS) scores and analgesic requirements over the first 8 postoperative hours between groups. Results: The pain scores (VAS) and fentanyl requirements for 1 h after surgery were significantly lower in the nefopam and ketamine groups compared with the control group (p<0.05). There were no differences between the nefopam and ketamine groups. The three groups showed no differences in VAS scores and number of analgesic injections from 1 to 8 h after surgery. Conclusion: Intraoperative nefopam infusion during laparoscopic cholecystectomy reduced opioid requirements and pain scores (VAS) during the early postoperative period after remifentanil-based anesthesia.

Nefopam, a non-opioid analgesic, does not alleviate experimental work/effort dyspnoea in healthy humans: A randomised controlled trial.

BACKGROUND: Dyspnoea is a distressing and debilitating symptom with a major impact on quality of life. Alleviation of dyspnoea therefore constitutes a major clinical challenge. When causative physiological disorders cannot be corrected ("persistent dyspnoea"), nonspecific treatment must be considered. Morphine alleviates dyspnoea but has numerous side-effects including ventilatory depression, which justifies looking for alternatives. Certain forms of dyspnoea involve C-fibres, and can be attenuated by C-fibres blockade. We hypothesised that nefopam, a non-sedative benzoxazocine analgesic known to block the transient receptor potential vanilloid subtype 1 abundantly present on C-fibres, would attenuate dyspnoea. METHODS: We conducted a randomised, double-blind, placebo-controlled crossover study of nefopam in healthy subjects submitted to experimental work/effort dyspnoea by inspiratory threshold loading (15 healthy male volunteers; age 23-41). We studied a perceptual outcome (dyspnoea visual analogue scale -D-VAS-) and a neurophysiological outcome (effect of nefopam on dyspnoea-pain counter-irritation as assessed by laser-evoked potentials; an effect of nefopam on dyspnoea was hypothetised to reduce the ability of dyspnoea to inhibit pain). Somaesthetic evoked potentials (SEPs) were studied as a control. RESULTS: A statistically significant decrease in LEP amplitude was observed in response to loading with nefopam (F = 19.1; p < 0.001) and placebo (F = 5.73 and p < 0.001), with no significant difference between nefopam and placebo and no change in SEP characteristics. CONCLUSIONS: In this study, nefopam did not exhibit any effects on dyspnoea.

Nefopam analgesia and its role in multimodal analgesia: A review of preclinical and clinical studies.

Nefopam is a non-opioid, non-steroidal, centrally acting analgesic drug used to prevent postoperative pain, primarily in the context of multimodal analgesia. This paper reviews preclinical and clinical studies in which nefopam has been combined with opioids, non-steroidal anti-inflammatory compounds, and paracetamol. This report focuses on the literature during the last decade and discusses the translational efforts between animal and clinical studies in the context of multimodal or balanced analgesia. In preclinical rodent models of acute and inflammatory pain, nefopam combinations including opioids revealed a synergistic interaction or enhanced morphine analgesia in six out of seven studies. Nefopam combinations including non-steroidal anti-inflammatory drugs (NSAIDs) (aspirin, ketoprofen or nimesulide) or paracetamol likewise showed enhanced analgesic effects for the associated compound in all instances. Clinical studies have been performed in various types of surgeries involving different pain intensities. Nefopam combinations including opioids resulted in a reduction in morphine consumption in 8 out of 10 studies of severe or moderate pain. Nefopam combinations including NSAIDs (ketoprofen or tenoxicam) or paracetamol also demonstrated a synergic interaction or an enhancement of the analgesic effect of the associated compound. In conclusion, this review of nefopam combinations including various analgesic drugs (opioids, NSAIDs and paracetamol) reveals that enhanced analgesia was demonstrated in most preclinical and clinical studies, suggesting a role for nefopam in multimodal analgesia based on its distinct characteristics as an analgesic. Further clinical studies are needed to evaluate the analgesic effects of nefopam combinations including NSAIDs or paracetamol.

Pharmacokinetics, metabolism, and excretion of nefopam, a dual reuptake inhibitor in healthy male volunteers.

1. The disposition of nefopam, a serotonin-norepinephrine reuptake inhibitor, was characterized in eight healthy male volunteers following a single oral dose of 75 mg [(14)C]-nefopam (100 µCi). Blood, urine, and feces were sampled for 168 h post-dose. 2. Mean (± SD) maximum blood and plasma radioactivity concentrations were 359 ± 34.2 and 638 ± 64.7 ngEq free base/g, respectively, at 2 h post-dose. Recovery of radioactive dose was complete (mean 92.6%); a mean of 79.3% and 13.4% of the dose was recovered in urine and feces, respectively. 3. Three main radioactive peaks were observed in plasma (metabolites M2 A-D, M61, and M63). Intact [(14)C]-nefopam was less than 5% of the total radioactivity in plasma. In urine, the major metabolites were M63, M2 A-D, and M51 which accounted for 22.9%, 9.8%, and 8.1% of the dose, respectively. An unknown entity, M55, was the major metabolite in feces (4.6% of dose). Excretion of unchanged [(14)C]-nefopam was minimal.

Pharmacokinetics, distribution, metabolism, and excretion of the dual reuptake inhibitor [(14)C]-nefopam in rats.

1. This study examined the pharmacokinetics, distribution, metabolism, and excretion of [(14)C] nefopam in rats after a single oral administration. Blood, plasma, and excreta were analyzed for total radioactivity, nefopam, and metabolites. Metabolites were profiled and identified. Radioactivity distribution was determined by quantitative whole-body autoradiography. 2. The pharmacokinetic profiles of total radioactivity and nefopam were similar in male and female rats. Radioactivity partitioned approximately equally between plasma and red blood cells. A majority of the radioactivity was excreted in urine within 24 hours and mass balance was achieved within 7 days. 3. Intact nefopam was a minor component in plasma and excreta. Numerous metabolites were identified in plasma and urine generated by multiple pathways including: hydroxylation/oxidation metabolites (M11, M22a and M22b, M16, M20), some of which were further glucuronidated (M6a to M6c, M7a to M7c, M8a and M8b, M3a to M3d); N-demethylation of nefopam to metabolite M21, which additionally undergoes single or multiple hydroxylations or sulfation (M9, M14, M23), with some of the hydroxylated metabolites further glucuronidated (M2a to M2d). 4. Total radioactivity rapidly distributed with highest concentrations found in the urinary bladder, stomach, liver, kidney medulla, small intestine, uveal tract, and kidney cortex without significant accumulation or persistence. Radioactivity reversibly associated with melanin-containing tissues.

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 effect of modulated electro-hyperthermia on the pharmacokinetic properties of nefopam in healthy volunteers: A randomised, single-dose, crossover open-label study.

PURPOSE: Nefopam is a widely available analgesic for the management of pain. The aim of this study was to reveal the effect of regional hyperthermia of the abdominal area on the pharmacokinetics of nefopam. MATERIALS AND METHODS: A randomised, single-dose, crossover, open-label study was conducted to reveal the effect of hyperthermia using modulated electro-hyperthermia on the pharmacokinetics of nefopam. The pharmacokinetics of orally administered nefopam without hyperthermia was studied in 12 healthy volunteers and then 7 days later they were treated with nefopam plus modulated electro-hyperthermia to the abdominal area for 1 h. Blood samples were collected up to 24 h after the drug administration. From the blood concentration-time curve, the maxinum plasma concentration (C(max)), time to C(max) (T(max)) and the area under the curve (AUC) were obtained. The safety and tolerability of these treatments were also assessed. RESULTS: The geometric mean ratios (GMRs) ((nefopam + modulated electro-hyperthermia)/nefopam) and the associated 90% confidence intervals (CIs) for C(max), AUC(last) and AUC(inf) were 1.2804 (1.1155∼1.4696), 1.0512 (0.9555∼1.1566) and 1.0612 (0.9528∼1.1819), respectively. The increase in C(max) was statistically significant, and T(max) was significantly shortened. CONCLUSIONS: The significant increase in C(max) and decrease in T(max) indicated that modulated electro-hyperthermia increased the absorption of the orally administered nefopam, thereby transitionally increasing the blood concentration of the drug. The AUC is an important parameter that contributes to the therapeutic effect of drugs. The lack of significant change in AUC suggests that modulated electro-hyperthermia may increases the absorption of orally administered drugs without increasing the systemic adverse effect of the drugs.