Morphine-sparing effect of nefopam by continuous intravenous injection after abdominal surgery by laparotomy

The Analgesic Efficacy of Nefopam in Patient-Controlled Analgesia after Laparoscopic Gynecologic Surgery: A Randomized, Double-Blind, Non-Inferiority Study

Opioid-sparing effects of nefopam during patient-controlled analgesia (PCA) are well demonstrated. We hypothesized that postoperative pain control with an opioid-equivalent dose of nefopam as a single analgesic agent for PCA would not be inferior to fentanyl in laparoscopic gynecologic surgery. In total, 135 patients were randomly assigned to the N (nefopam 200 mg), NF (fentanyl 500 mcg + nefopam 100 mg), and F (fentanyl 1000 mcg) groups (n = 45 patients per group). The primary outcome was the numerical rating scale (NRS) score at rest at 6 h postoperatively, and the non-inferiority limit was set to 1. Secondary outcomes were pain severity and incidence of nausea and vomiting for 48 h postoperatively. Mean differences (MD) in primary outcome between the N and F groups were 0.4 (95% confidence interval (CI) −0.5 to 1.3). The upper limit of 95% CI exceeded the non-inferiority limit. The N group showed higher pain scores than the NF group (MD, 1.1; 95% CI, 0.3–1.9) in pairwise comparisons. No significant intergroup differences were observed in the cumulative dose of PCA usage and incidence of postoperative nausea and vomiting (PONV). In laparoscopic gynecological surgery, nefopam alone showed limited efficacy for postoperative pain control.

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.

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.

Median effective dose of nefopam to treat postoperative pain in patients who have undergone laparoscopic cholecystectomy

Objective

Nefopam is thought to reduce postoperative pain; however, the evidence is insufficient. The recommended dose is 20 mg, and the median effective dose (ED50) in the surgical setting reportedly ranges from 17 to 28 mg. However, nefopam frequently produces inadequate postoperative analgesia. We evaluated the ED50 of nefopam as a single agent in patients undergoing laparoscopic cholecystectomy.

Methods

Twenty-nine patients were scheduled for laparoscopic cholecystectomy. Postoperative pain was evaluated using a numerical pain scale (NPS). When the NPS score was >3, patients were administered a predetermined dose of nefopam. The dose was calculated using the up-and-down allocation technique based on the previous response. The initial dose was 28 mg, with adjustment intervals of 5 mg. An effective response was defined as a decrease in the NPS score to <3 at 30 minutes after infusion.

Results

The ED50 of nefopam was 62.1 mg (95% confidence interval, 52.9–72.9 mg). Eight patients reported pain upon injection, and three were excluded due to severe injection pain and phlebitis.

Conclusions

The estimated ED50 was higher than the predetermined dose based on previous studies. We recommend that the dose of nefopam be chosen after careful consideration of individual variations and clinical settings.

Opioid sparing effect and safety of nefopam in patient controlled analgesia after laparotomy: A randomized, double blind study

OBJECTIVES

A double-blind randomised study to evaluate the opioid sparing effect and safety of nefopam when administered via intravenous patient controlled analgesia (PCA) with fentanyl.

METHODS

Patients planned for elective open laparotomy, were randomly assigned to receive into fentanyl 25 µg/ml (SF group) or nefopam 2.4 mg/ml plus fentanyl 25 µg/ml (NF group). Patients were assessed before surgery and for 24 h postoperatively.

RESULTS

Total PCA fentanyl consumption was significantly lower in the NF group (n = 35) than the SF group (n = 36). Pain scores were significantly lower and patients' satisfaction with treatment significantly better in the NF group than the SF group. Dry mouth and dizziness were significantly more frequent in the NF group than the SF group. There were no other statistically significant between-group differences in the incidence of adverse events.

CONCLUSIONS

Intravenous PCA using nefopam + fentanyl following laparotomy has an opioid sparing effect and is associated with a low incidence of some of the typical opioid related adverse events.

TRIAL REGISTRY

Clinicaltrials.gov Registration No: NCT02596269.

Post-operative intravenous patient-controlled analgesic efficacy of morphine with ketorolac versus nefopam after laparoscopic gynecologic surgery: a randomized non-inferiority trial

Background

Nefopam is a non-opioid non-steroidal centrally acting analgesic. This study was conducted to assess the analgesic efficacy of intravenous patient-controlled analgesia (IV-PCA) using nefopam alone, compared with a combination of morphine and ketorolac, after laparoscopic gynecologic surgery.

Methods

Sixty patients undergoing laparoscopic gynecologic surgery received IV-PCA. Group A (n = 30) received IV-PCA with a combination of morphine 60 mg and ketorolac 180 mg, while group B (n = 30) received nefopam 200 mg (basal rate 1 ml/h, bolus 1 ml, and lockout time 15 min for both). The primary outcome evaluated was analgesic efficacy using the visual analogue scale (VAS). Other evaluated outcomes included the incidence rate of postoperative nausea and vomiting (PONV), patient satisfaction of pain control, percentage of patients requiring additional opioids, and incidence rate of postoperative adverse effects.

Results

Group B was not inferior to group A in relation to the VAS in the post-anesthesia care unit, and at 12, 24, and 48 h after surgery (mean difference [95% confidence interval], 0.50 [–0.43 to 1.43], -0.30 [-1.25 to 0.65], -0.05 [-0.65 to 0.55], and 0.10 [-0.55 to 0.75], respectively). The incidence rate of nausea was lower in group B than in group A at 12 and 24 h after surgery (P = 0.004 and P = 0.017, respectively). There were no significant differences in the other outcomes between groups.

Conclusions

IV-PCA using nefopam alone has a non-inferior analgesic efficacy and produces a lower incidence of PONV in comparison with IV-PCA using a combination of morphine and ketorolac after laparoscopic gynecologic surgery.

Spinal noradrenergic modulation and the role of the alpha-2 receptor in the antinociceptive effect of intrathecal nefopam in the formalin test

BACKGROUND

Nefopam has shown an analgesic effect on acute pain including postoperative pain. The reuptake of monoamines including serotonin and noradrenaline has been proposed as the mechanism of the analgesic action of nefopam, but it remains unclear. Although alpha-adrenergic agents are being widely used in the perioperative period, the role of noradrenergic modulation in the analgesic effect of nefopam has not been fully addressed.

METHODS

Changes in the antinociceptive effect of intrathecal (i.t.) nefopam against formalin-elicited flinching responses were explored in Sprague-Dawley rats pretreated with i.t. 6-hydroxydopamine (6-OHDA), which depletes spinal noradrenaline. In addition, antagonism to the effect of nefopam by prazosin and yohimbine was evaluated to further elucidate the antinociceptive mechanism of i.t. nefopam.

RESULTS

Pretreatment with i.t. 6-OHDA alone did not alter the flinching responses in either phase of the formalin test, while it attenuated the antinociceptive effect of i.t. nefopam significantly during phase 1, but not phase 2. The antagonist of the alpha-2 receptor, but not the alpha-1 receptor, reduced partially, but significantly, the antinociceptive effect of i.t. nefopam during phase 1, but not during phase 2.

CONCLUSIONS

This study demonstrates that spinal noradrenergic modulation plays an important role in the antinociceptive effect of i.t. nefopam against formalin-elicited acute initial pain, but not facilitated pain, and this action involves the spinal alpha-2 but not the alpha-1 receptor.

The analgesic effect of nefopam with fentanyl at the end of laparoscopic cholecystectomy

BACKGROUND

Nefopam is a centrally acting analgesic that is used to control pain. The aim of this study was to find an appropriate dose of nefopam that demonstrates an analgesic effect when administered in continuous infusion with fentanyl at the end of laparoscopic cholecystectomy.

METHODS

Ninety patients scheduled for laparoscopic cholecystectomy were randomly assigned to receive analgesia with fentanyl alone (50 µg, Group 1, n = 30), or with fentanyl in combination with nefopam 20 mg (Group 2, n = 30) or in combination with nefopam 40 mg (Group 3, n = 30) at the end of surgery. Pain and side effects were evaluated at 10 minutes, 30 minutes, 1 hour, 2 hours, 6 hours, and 12 hours after arrival in the post-anesthesia care unit (PACU).

RESULTS

Pain was statistically significantly lower in Groups 2 and 3 than in Group 1 at 10 minutes, 2 hours, and 6 hours after arrival in the PACU. Nausea was statistically significantly lower in Group 2 than in Groups 1 and 3 at 10 minutes after arrival in the PACU. Shivering was statistically significantly lower in Groups 2 and 3 than in Group 1 at 10 minutes after arrival in the PACU.

CONCLUSIONS

Nefopam is a drug that can be safely used as an analgesic after surgery, and its side effects can be reduced when fentanyl 50 µg is injected with nefopam 20 mg.

Antinociceptive effect of intrathecal nefopam and interaction with morphine in formalin-induced pain of rats

Background

Nefopam, a non-opiate analgesic, has been regarded as a substance that reduces the requirement for morphine, but conflicting results have also been reported. The inhibition of monoamine reuptake is a mechanism of action for the analgesia of nefopam. The spinal cord is an important site for the action of monoamines however, the antinociceptive effect of intrathecal nefopam was not clear. This study was performed to examine the antinociceptive effect of intrathecal (i.t.) nefopam and the pattern of pharmacologic interaction with i.t. morphine in the formalin test.

Methods

Male Sprague-Dawley rats were implanted with an i.t. catheter, and were randomly treated with a vehicle, nefopam, or morphine. Formalin was injected into the hind-paw 10 min. after an i.t. injection of the above experiment drugs. After obtaining antinociceptive ED₅₀ of nefopam and morphine, the mixture of nefopam and morphine was tested for the antinociceptive effect in the formalin test at a dose of 1/8, 1/4, 1/2 of ED₅₀, or ED₅₀ of each drug followed by an isobolographic analysis.

Results

Intrathecal nefopam significantly reduced the flinching responses in both phases of the formalin test in a dose-dependent manner. Its effect, however, peaked at a dose of 30 µg in phase 1 (39.8% of control) and 10 µg during phase 2 (37.6% of control). The isobolograhic analysis indicated an additive interaction of nefopam and morphine during phase 2, and a synergy effect in antinociception during phase 1.

Conclusions

This study demonstrated that i.t. nefopam produces an antinociceptive effect in formalin induced pain behavior during both phases of the formalin test, while interacting differently with i.t. morphine, synergistically during phase 1, and additively during phase 2.

Recent advances in the pharmacological management of pain

Pain is an unpleasant sensation that originates from ongoing or impending tissue damage. Management of different types of pain (acute, postoperative, inflammatory, neuropathic or cancer) is the most frequent issue encountered by clinicians and pharmacological therapy is the first line of approach for the treatment of pain. This review presents and discusses recent clinical advances regarding both the improvements in delivery of analgesic drugs and improvements in the design of analgesic molecules. The new modalities of administration of analgesics used in the clinic are reviewed, including skin patches, oral and mucosal sprays, transdermal delivery systems and intranasal administration. New insights are then presented on standard drugs used to relieve pain, such as opioids (including tramadol), NSAIDs including selective cyclo-oxygenase-2 inhibitors, paracetamol (acetaminophen), local anaesthetics and adjuvant analgesics such as antidepressants, anticonvulsants (gabapentin and pregabalin), cannabinoids, ketamine and others (e.g. nefopam). Although the understanding of pain mechanisms has improved significantly recently, much more is yet to be discovered and awaited. Broadening of our knowledge is needed to improve basic and clinical research in this field in order to better alleviate pain in millions of people.