• Journal of Oral Medicine and Pain
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• v.36 no.2
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• pp.139-146
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• 2011

Neuropathic pain is defined by "pain is initiated or caused by primary lesion or dysfunction in the nervous system" and several etiologic conditions can induce the neuropathic pains. Various groups of drugs are used to treat the neuropathic pains. Not depending on anecdotal case or habitual choice, to obtain the more effective pharmacotherapy, relative-comparison index is suggested through multiple analyses of clinical trials. Depending on relative-comparison index, first-line medications and second-line medications for neuropathic pain are recommended. To support the Quality of life in patients, selection of medication is made on such recommendations.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.6
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• pp.387-392
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• 2012

In this study, we examined the antinociceptive effect of Cyperi rhizoma (CR) and Corydalis tuber (CT) extracts using a chronic constriction injury-induced neuropathic pain rat model. After the ligation of sciatic nerve, neuropathic pain behavior such as mechanical allodynia and thermal hyperalgesia were rapidly induced and maintained for 1 month. Repeated treatment of CR or CT (per oral, 10 or 30 mg/kg, twice a day) was performed either in induction (day 0~5) or maintenance (day 14~19) period of neuropathic pain state. Treatment of CR or CT at doses of 30 mg/kg in the induction and maintenance periods significantly decreased the nerve injury-induced mechanical allodynia. In addition, CR and CT at doses of 10 or 30 mg/kg alleviated thermal heat hyperalgesia when they were treated in the maintenance period. Finally, CR or CT (30 mg/kg) treated during the induction period remarkably reduced the nerve injury-induced phosphorylation of NMDA receptor NR1 subunit (pNR1) in the spinal dorsal horn. Results of this study suggest that extracts from CR and CT may be useful to alleviate neuropathic pain.

• Hip & pelvis
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• v.30 no.4
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• pp.226-232
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• 2018

Purpose: Pain caused by osteoarthritis is primarily nociceptive pain; however, it is considered that a component of this pain is due to neuropathic pain (NP). We investigated the effects of total hip arthroplasty (THA) in patients with NP diagnosed by the PainDETECT questionnaire. Materials and Methods: One hundred sixty-three hips (161 patients) were evaluated. All patients were asked to complete the PainDETECT questionnaire based on their experience with NP, and clinical scores were evaluated using the Japanese Orthopaedic Association (JOA) Hip Score before and after THA. Results: The patients of 24.5% reported NP before THA; 5.5% reported NP 2 months after THA. Prior to THA, there was no significant correlation between the PainDETECT score and the radiographic severity; however, there was a significant correlation between the PainDETECT score and JOA score. NP at 2 months after THA was not significantly correlated with pain scores at 1 week after THA; however, a significant correlation was observed between the preoperative pain score and NP at 2 months after THA. Conclusion: THA was useful for relieving nociceptive pain and for relieving NP in patients with hip osteoarthritis. Preoperative pain was a risk factor for NP after THA. Controlling preoperative pain may be effective for reducing postoperative NP.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.201-209
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• 1998

Background: Tricyclic antidepressants (TCA) have been used for various pain syndromes for their analgesic effects. They, however, often have anticholinergic side effects and therefore search for more selective drugs with fewer side effects is justified. Paroxetine, a selective serotonin reuptake inhibitor devoid of autonomic side effects, was evaluated for its role as an analgesic adjuvant in the management of neuropathic pain. Method: According to individual diagnostic group as diabetic neuropathy, postherpetic neuralgia, central pain syndrome and cancer related plexopathy, 10 patients per each group were equally accumulated. Patients have been stabilized in their analgesic regimen at least four weeks prior to enrollment into study. TCA, if taken, was discontinued for two weeks for wash out period. Baseline four point verbal pain intensity score was obtained and oral administration of paroxetine 20 mg was initiated. At two weeks follow-up visit, pain intensity scores, pain improvement scores judged by family, drug efficacy, tolerability and overall evaluation were assessed. The incidence of side effects were also obtained. Result: After two weeks of treatment, pain intensity scores decreased in 77.5% of patients and no patients experienced aggravation. These findings were objectively reflected in pain improvement scores judged by family members. But, the number of nonresponders was different among groups. In drug efficacy, tolerability and overall evaluation, the proportions of patients who scored as excellent or good were 75%, 80% and 80% respectively. Incidence of side effects was 27.5%, but the side effects spontaneously disappeared after discontinuation of medication. Conclusion: Paroxetine, a selective serotonin reuptake inhibitor, appears to be effective as adjuvant analgesic for the management of various neuropathic pain syndromes.

• Journal of Korean Academy of Nursing
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• v.41 no.4
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• pp.520-527
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• 2011

Purpose: The purpose of this study was to examine effects of nitric oxide synthase (NOS) inhibitor on muscle weight and myofibrillar protein content of affected and unaffected hindlimb muscles in rats with neuropathic pain induced by unilateral peripheral nerve injury. Methods: Neuropathic pain was induced by ligation and cutting of the left L5 spinal nerve. Adult male Sprague-Dawley rats were randomly assigned to one of two groups: The NOSI group (n=19) had NOS inhibitor (L-NAME) injections daily for 14 days, and the Vehicle group (n=20) had vehicle injections daily for 14 days. Withdrawal threshold, body weight, food intake and activity were measured every day. At 15 days all rats were anesthetized and soleus, plantaris and gastrocnemius muscles were dissected from hindlimbs. Muscle weight and myofibrillar protein content of the dissected muscles were determined. Results: The NOSI group showed significant increases as compared to the Vehicle group for body weight at 15 days, muscle weight and myofibrillar protein content of the unaffected soleus and gastrocnemius. The NOSI group demonstrated a higher pain threshold than the vehicle group. Conclusion: NOSI for 14 days attenuates unaffected soleus and gastrocnemius muscle atrophy in neuropathic pain model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.4
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• pp.895-897
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• 2009

Lonicera japonica has been widely used for chronic inflammatory diseases in many Asian countries. Its analgesic effect has not been explored yet. This study aimed to test the analgesic potential of methanol extracts from Lonicera japonica (MELJ) in rat neuropathic mctel. Neuropathic pain was pacts ed by partial sciatic nerve injury. Two weeks after surgery, neuropathic rats received oral administration of MELJ at doses of either 0.0 g/kg, 0.2 g/kg or 0.4 g/kg. At dose of 0.0 g, rats were administered with saline only and used as conracl. The behavioral tests for f 0.0 g, raand ccld hs were adma were weformed up to 2 hours after treatment. The MELJ at the dose 0.4 g/kg dmg gfg, ntly alleviated f 0.0 g, rahyperalgesia, but not cold hyperalgesia. These results showed that the MELJ had, although transient, analgesic effect on mechanical hyperalgesia in the rat neuropathic model.

• Biomolecules & Therapeutics
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• v.24 no.3
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• pp.252-259
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• 2016

Neuropathic pain is a complex state showing increased pain response with dysfunctional inhibitory neurotransmission. The TREK family, one of the two pore domain $K^+$ (K2P) channel subgroups were focused among various mechanisms of neuropathic pain. These channels influence neuronal excitability and are thought to be related in mechano/thermosensation. However, only a little is known about the expression and role of TREK-1 and TREK-2, in neuropathic pain. It is performed to know whether TREK-1 and/or 2 are positively related in dorsal root ganglion (DRG) of a mouse neuropathic pain model, the chronic constriction injury (CCI) model. Following this purpose, Reverse Transcription Polymerase Chain Reaction (RT-PCR) and western blot analyses were performed using mouse DRG of CCI model and compared to the sham surgery group. Immunofluorescence staining of isolectin-B4 (IB4) and TREK were performed. Electrophysiological recordings of single channel currents were analyzed to obtain the information about the channel. Interactions with known TREK activators were tested to confirm the expression. While both TREK-1 and TREK-2 mRNA were significantly overexpressed in DRG of CCI mice, only TREK-1 showed significant increase (~9 fold) in western blot analysis. The TREK-1-like channel recorded in DRG neurons of the CCI mouse showed similar current-voltage relationship and conductance to TREK-1. It was easily activated by low pH solution (pH 6.3), negative pressure, and riluzole. Immunofluorescence images showed the expression of TREK-1 was stronger compared to TREK-2 on IB4 positive neurons. These results suggest that modulation of the TREK-1 channel may have beneficial analgesic effects in neuropathic pain patients.

• The Korean Journal of Pain
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• v.30 no.1
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• pp.51-58
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• 2017

Background: Recently symptoms-based screening questionnaires have gained attention for screening for a neuropathic pain component (NePC) in various chronic pain conditions. The present study assessed the usefulness of four commonly used NePC screening questionnaires including the Self-completed douleur neuropathique 4 (S-DN4), the ID Pain, the painDETECT questionnaire (PDQ), and the Self-completed Leeds Assessment of neuropathic Symptoms and Signs (S-LANSS) questionnaire in patients with chronic low back pain (CLBP) to assess the presence of NePC. Methods: This is a single-center cross-sectional study where patients with CLBP, with or without leg pain, were included. Participants were initially screened for NePC presence by a physician according to the regular practice, and later assessed using screening questionnaires. The diagnostic accuracy of these questionnaires was compared assuming the physician-made diagnosis as the gold standard. Results: A total of 215 patients with CLBP of which 164 (76.3%, 95% CI, 70.2-81.5) had a NePC were included. S-DN4, ID Pain, and PDQ have an area under the curve (AUC) > 0.8 indicating excellent discrimination. However, S-LANSS has an AUC of 0.69 (0.62-0.75), indicating low discrimination. S-DN4 has a significantly higher AUC as compared to ID Pain (d(AUC) = 0.063, P < 0.01) and S-LANSS (d(AUC) = 0.197, P < 0.01). But the AUC of S-DN4 does not significantly differ from that of PDQ (d(AUC) = 0.013, P = 0.62). Conclusions: S-DN4, ID Pain, and PDQ, but not S-LANSS, have good discriminant validity to screen for NePCs in patients with CLBP. Despite using all the tests, 20-30% of patients with an NePC were missed. Thus, these questionnaires can only be used as an initial clue in screening for NePCs, but do not replace clinical judgment.

• The Korean Journal of Pain
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• v.36 no.2
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• pp.253-267
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• 2023

Background: Cancer-induced bone pain (CIBP) is considered to have both nociceptive and neuropathic components. However, the prevalence, risk factors, and impact of the neuropathic components are yet poorly understood. Methods: We estimate the prevalence of neuropathic pain (NP) features in patients with CIBP at a tertiary care pain clinic setting using the Douleur Neuropathique 4 questionnaire and evaluate their associated factors and their impact after 4 weeks of treatment using the Brief Pain Inventory questionnaire and the Edmonton Symptom Assessment System. Results: A total of 133 patients were recruited. The estimated prevalence of NP was 30.8% (95% confidence interval: 23.6%-39.1%). Initially, the patients with NP had significantly higher average pain scores (6.00 vs. 5.05, P = 0.006), higher total interference scores (5.84 vs. 4.89, P = 0.033), and symptom distress scores (35.88 vs. 26.52, P = 0.002). After 4 weeks of treatment, patients in both groups reported significantly decreased pain intensity and improved quality of life. However, the patients with NP still reported significantly higher average pain (4.61 vs. 3.58, P = 0.048), trending toward higher total interference scores (3.52 vs. 2.99, P = 0.426), and symptom distress scores (23.30 vs. 20.77, P = 0.524). From multivariate analysis, the independent risk factors for NP were younger age, pain in the extremities, and higher average pain scores. Conclusions: NP are common in patients with CIBP. These conditions negatively affect pain intensity and the patient's quality of life before and after treatment.

• The Korean Journal of Pain
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• v.33 no.2
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• pp.121-130
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• 2020

Background: Transcutaneous electrical nerve stimulation (TENS), manual acupuncture (MA), and spinal cord stimulation (SCS) are used to treat a variety of pain conditions. These non-pharmacological treatments are often thought to work through similar mechanisms, and thus should have similar effects for different types of pain. However, it is unclear if each of these treatments work equally well on each type of pain condition. The purpose of this study was to compared the effects of TENS, MA, and SCS on neuropathic, inflammatory, and non-inflammatory pain models. Methods: TENS 60 Hz, 200 ㎲, 90% motor threshold (MT), SCS was applied at 60 Hz, an intensity of 90% MT, and a 0.25 ms pulse width. MA was performed by inserting a stainless-steel needle to a depth of about 4-5 mm at the Sanyinjiao (SP6) and Zusanli (ST36) acupoints on a spared nerve injury (SNI), knee joint inflammation (3% carrageenan), and non-inflammatory muscle pain (intramuscular pH 4.0 injections) in rats. Mechanical withdrawal thresholds of the paw, muscle, and/or joint were assessed before and after induction of the pain model, and daily before and after treatment. Results: The reduced withdrawal thresholds were significantly reversed by application of either TENS or SCS (P < 0.05). MA, on the other hand, increased the withdrawal threshold in animals with SNI and joint inflammation, but not chronic muscle pain. Conclusions: TENS and SCS produce similar effects in neuropathic, inflammatory and non-inflammatory muscle pain models while MA is only effective in inflammatory and neuropathic pain models.