• Journal of Trauma and Injury
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• v.30 no.1
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• pp.1-5
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• 2017

Purpose: Nefopam is a centrally acting non-narcotic analgesic that has mostly been used for postoperative pain. We examined the efficacy of nefopam analgesia (alone and in combination with ketorolac) for trauma patients in the emergency department. Methods: We performed a retrospective chart review to select trauma patients who received nefopam at the emergency department of Korea University Medical Center Guro Hospital between January 2012 and December 2012. Patients younger than 15 years were excluded. The primary outcome measure was change of pain score (numeric rating scale) from baseline (before medication) to 30 min after medication. The secondary outcome measure was requirement for additional analgesia (pethidine). Results: Records of 1465 trauma patients who received analgesics in the emergency department from January 2012 to December 2012 were examined. Patients were classified into five groups according to initial analgesic: nefopam (n=112), ketorolac (n=867), pethidine (n=365), nefopam+ketorolac (92), and nefopam+pethidine (22). There were no significant differences in pain score reductions among the five groups. Twenty-two patients in the nefopam group, 141 in the ketorolac group, and 29 in the nefopam+ketorolac group required rescue analgesia with pethidine; these rates were not significantly different. Conclusion: The efficacy of nefopam analgesia for trauma patients in the emergency department is comparable to that of more commonly used agents, including ketorolac and pethidine.

• The Korean Journal of Pain
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• v.29 no.3
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• pp.164-171
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• 2016

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.

• The Korean Journal of Pain
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• v.27 no.1
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• pp.23-29
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• 2014

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.

• Journal of Korean Neurosurgical Society
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• v.56 no.5
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• pp.448-450
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• 2014

Nefopam, a centrally acting analgesic, has been used to control postoperative pain. Reported adverse effects are anticholinergic, cardiovascular or neuropsychiatric. Neurologic adverse reactions to nefopam are confusion, hallucinations, delirium and convulsions. There are several reports about fatal convulsive seizures, presumably related to nefopam. A 71-year-old man was admitted for surgery for a lumbar spinal stenosis. He was administered intravenous analgesics : ketorolac, tramadol, orphenadrine citrate and nefopam HCl. His back pain was so severe that he hardly slept for several days; he even needed morphine and pethidine. At 4 days of administration of intravenous analgesics, the patient suddenly started generalized tonic-clonic seizures for 15 seconds, and subsequently, status epilepticus; these were not responsive to phenytoin and midazolam. After 3 days of barbiturate coma therapy the seizures were controlled. Convulsive seizures related to nefopam appear as focal, generalized, myoclonic types, or status epilepticus, and are not dose-related manifestations. In our case, the possibility of convulsions caused by other drugs or the misuse of drugs was considered. However, we first identified the introduced drugs and excluded the possibility of an accidental misuse of other drugs. Physicians should be aware of the possible occurrence of unpredictable and serious convulsions when using nefopam.

• The Korean Journal of Pain
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• v.27 no.4
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• pp.326-333
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• 2014

Background: Nefopam is a centrally acting non-opioid analgesic agent. Its analgesic properties may be related to the inhibitions of monoamine reuptake and the N-methyl-D-aspartate (NMDA) receptor. The antinociceptive effect of nefopam has been shown in animal models of acute and chronic pain and in humans. However, the effect of nefopam on diabetic neuropathic pain is unclear. Therefore, we investigated the preventive effect of nefopam on diabetic neuropathic pain induced by streptozotocin (STZ) in rats. Methods: Pretreatment with nefopam (30 mg/kg) was performed intraperitoneally 30 min prior to an intraperitoneal injection of STZ (60 mg/kg). Mechanical and cold allodynia were tested before, and 1 to 4 weeks after drug administration. Thermal hyperalgesia was also investigated. In addition, the transient receptor potential ankyrin 1 (TRPA1) and TRP melastatin 8 (TRPM8) expression levels in the dorsal root ganglion (DRG) were evaluated. Results: Pretreatment with nefopam significantly inhibited STZ-induced mechanical and cold allodynia, but not thermal hyperalgesia. The STZ injection increased TRPM8, but not TRPA1, expression levels in DRG neurons. Pretreatment with nefopam decreased STZ-induced TRPM8 expression levels in the DRG. Conclusions: These results demonstrate that a nefopam pretreatment has strong antiallodynic effects on STZ-induced diabetic rats, which may be associated with TRPM8 located in the DRG.

• The Korean Journal of Pain
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• v.26 no.1
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• pp.14-20
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• 2013

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 $ED_{50}$ 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 $ED_{50}$, or $ED_{50}$ 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 $30{\mu}g$ in phase 1 (39.8% of control) and $10{\mu}g$ 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.

• The Korean Journal of Pain
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• v.26 no.4
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• pp.361-367
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• 2013

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 ${\mu}g$, 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 ${\mu}g$ is injected with nefopam 20 mg.

• The Korean Journal of Pain
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• v.31 no.2
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• pp.102-108
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• 2018

Background: Nefopam is a non-opioid, non-steroidal analgesic drug with fewer adverse effects than narcotic analgesics and nonsteroidal anti-inflammatory drugs, and is widely used for postoperative pain control. Because nefopam sometimes causes side effects such as nausea, vomiting, somnolence, hyperhidrosis and injection-related pain, manufacturers are advised to infuse it slowly, over a duration of 15 minutes. Nevertheless, pain at the injection site is very common. Therefore, we investigated the effect of warmed carrier fluid on nefopam injection-induced pain. Methods: A total of 48 patients were randomly selected and allocated to either a control or a warming group. Warming was performed by diluting 40 mg of nefopam in 100 ml of normal saline heated to $31-32^{\circ}C$ using two fluid warmers. The control group was administered 40 mg of nefopam dissolved in 100 ml of normal saline stored at room temperature ($21-22^{\circ}C$) through the fluid warmers, but the fluid warmers were not activated. Results: The pain intensity was lower in the warming group than in the control group (P < 0.001). The pain severity and tolerance measurements also showed statistically significant differences between groups (P < 0.001). In the analysis of vital signs before and after the injection, the mean blood pressure after the injection differed significantly between the groups (P = 0.005), but the heart rate did not. The incidence of hypertension also showed a significant difference between groups (P = 0.017). Conclusions: Use of warmed carrier fluid for nefopam injection decreased injection-induced pain compared to mildly cool carrier fluid.

• The Korean Journal of Pain
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• v.25 no.1
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• pp.7-15
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• 2012

Background: Neuropathic pain is a chronic pain due to disorder in the peripheral or central nervous system with different pathophysiological mechanisms. Current treatments are not effective. Analgesic drugs combined can reduce pain intensity and side effects. Here, we studied the analgesic effect of nimesulide, nefopam, and morphine with different mechanisms of action alone and in combination with other drugs in chronic constriction injury (CCI) model of neuropathic pain. Methods: Male Wistar rats (n = 8) weighing 150-200 g were divided into 3 different groups: 1- Saline-treated CCI group, 2- Saline-treated sham group, and 3- Drug-treated CCI groups. Nimesulide (1.25, 2.5, and 5 mg/kg), nefopam (10, 20, and 30 mg/kg), and morphine (1, 3, and 5 mg/kg) were injected 30 minutes before surgery and continued daily to day 14 post-ligation. In the combination strategy, a nonanalgesic dose of drugs was used in combination such as nefopam + morphine, nefopam + nimesulide, and nimesulide + morphine. Von Frey filaments for mechanical allodynia and acetone test for cold allodynia were, respectively, used as pain behavioral tests. Experiments were performed on day 0 (before surgery) and days 1, 3, 5, 7,10, and 14 post injury. Results: Nefopam (30 mg/kg) and nimesulide (5 mg/kg) blocked mechanical and thermal allodynia; the analgesic effects of morphine (5 mg/kg) lasted for 7 days. Allodynia was completely inhibited in combination with nonanalgesic doses of nefopam (10 mg/kg), nimesulide (1.25 mg/kg), and morphine (3 mg/kg). Conclusions: It seems that analgesic drugs used in combination, could effectively reduce pain behavior with reduced adverse effects.

• Korean Journal of Clinical Pharmacy
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• v.28 no.4
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• pp.279-284
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• 2018

Objective: To compare the analgesic effects and adverse drug reactions (ADRs) of fentanyl intravenous patient-controlled analgesia (ivPCA) with nefopam, a centrally acting analgesic agent with demonstrated opioid sparing activity, as compared to ketorolac in a tertiary teaching hospital. Methods: A retrospective evaluation of electronic medical records was conducted on patient records including either nefopam or ketorolac with opioid ivPCA for post-operative pain management in general surgery department from January to December 2014. The status of pain control and ADRs were collected. Results: Out of 6,330 general surgery cases, nefopam was given in 153 prescriptions (6.9%) and ketorolac in 81 prescriptions (3.6%). The level of pain control was not different between two groups (70.9% vs. 75.3%; p = 0.51), but ADRs were more frequently reported in nefopam group (9.8% vs. 2.5%; p < 0.05). New ADRs of hot flushes (n = 1) and paresthesia in hands (n = 1) were reported in nefopam group and they were unlisted in the approved package insert. No serious ADRs were reported in both groups. Conclusion: Our findings presented that nefopam showed a similar analgesic effect and higher ADR rates compared to ketorolac as an adjuvant to fentanyl iv PCA for post-operative pain management in general surgery patients in South Korea.