Pharmacologic management of chronic pain

Pain-Insomnia-Depression Syndrome: Triangular Relationships, Pathobiological Correlations, Current Treatment Modalities, and Future Direction

Pain-insomnia-depression syndrome (PIDS) is a complex triad of chronic pain, insomnia, and depression that has profound effects on an individual's quality of life and mental health. The pathobiological context of PIDS involves complex neurobiological and physiological mechanisms, including alterations in neurotransmitter systems and impaired pain processing pathways. The first-line therapeutic approaches for the treatment of chronic pain, depression, and insomnia are a combination of pharmacological and non-pharmacological therapies. In cases where patients do not respond adequately to these treatments, additional interventions such as deep brain stimulation (DBS) may be required. Despite advances in understanding and treatment, there are still gaps in knowledge that need to be addressed. To improve our understanding, future research should focus on conducting longitudinal studies to uncover temporal associations, identify biomarkers and genetic markers associated with PIDS, examine the influence of psychosocial factors on treatment responses, and develop innovative interventions that address the complex nature of PIDS. The aim of this study is to provide a comprehensive overview of these components and to discuss their underlying pathobiological relationships.

A Qualitative Exploration of Rural Older Adults' Experiences With Pain From Chronic Illnesses and Its Treatment

Pain is one of the most common concerns among chronically ill older adults. However, access to pain management is not equitable among certain populations, including rural residents. This qualitative study explored rural older adults' experiences with pain and its treatment. Eighteen participants were recruited from rural counties of Alabama, who were age 60+, cognitively intact, community-dwelling, had one or more chronic/serious illnesses, and experienced pain. Open-ended questions were asked in individual interviews, and inductive, thematic analysis was used for data analysis. Findings revealed the impact of pain (physical limitations, psychological distress, and coping strategies), the impact of COVID-19 (physical/mental health and pain management), challenges in pain management in rural areas (lack of provider and healthcare resources, transportation-related issues, mistrust, and limited insurance coverage) and suggestions to address these challenges. Program and policy-level interventions are crucial in improving the resources and education/training needed for effective pain management for rural older adults.

Effect of ABT-639 on Cav3.2 channel activity and its analgesic actions in mouse models of inflammatory and neuropathic pain

Cav3.2 T-type calcium channels are important targets for pain relief in rodent models of inflammatory and neuropathic pain. Even though many T-type channel blockers have been tested in mice, only one molecule, ABT-639, has been tested in phase II clinical studies and did not produce analgesic effects over placebo. Here we examined the effects of ABT-639 on Cav3.2 channel activity in tsA-201 cells and dorsal root ganglion (DRG) neurons, in comparison with another established Cav3.2 inhibitor Z944. These experiments revealed that Z944 mediated ∼100-fold more potent inhibition of Cav3.2 currents than ABT-639, with the latter blocking channel activity by less than 15 percent when applied at a concentration of 30 μM. A slight increase in ABT-639 potency was observed at more depolarized holding potentials, suggesting that this compound may act preferentially on inactivated channels. We tested the effects of both compounds in the Complete Freund's Adjuvant (CFA) model of chronic inflammatory pain, and in partial sciatic nerve injury model of neuropathic pain in mice. In the neuropathic pain model, both Z944 and ABT-639 reversed mechanical hypersensitivity to similar degrees when delivered systemically, but remarkably, when delivered intrathecally, only Z944 was effective. In the CFA model, both compounds reversed thermal hyperalgesia upon systemic delivery, but only Z944 mediated pain relief upon intrathecal delivery, indicating that ABT-639 acts primarily at peripheral sites. ABT-639 lost its analgesic effects in CFA treated Cav3.2 null mice, indicating that these channels are essential for ABT-639-mediated pain relief despite its poor inhibition of Cav3.2 currents.

Neuromodulation Techniques in Chronic Refractory Coccydynia: A Narrative Review

Refractory coccydynia is a condition characterized by severe coccygeal pain and poses a challenging management dilemma for clinicians. Advancements in neuromodulation (NM) technology have provided benefits to people experiencing chronic pain that is resistant to standard treatments. This review aims to summarize the spectrum of current NM techniques employed in the treatment of refractory coccydynia along with their effectiveness. A review of studies in the scientific literature from 2012 to 2023 was conducted, revealing a limited number of case reports. Although the available evidence at this time suggests significant pain relief with the utilization of NM techniques, the limited scope and nature of the studies reviewed emphasize the need for large-scale, rigorous, high-level research in this domain in order to establish a comprehensive understanding of the role of NM and its effectiveness in the management of intractable coccydynia.

The effect of perineural injection therapy on neuropathic pain: a retrospective study

Background

Among the various pain-related diseases that can be encountered at the clinic, there is a neuropathic pain that is difficult to treat. Numerous methods have been proposed to treat neuropathic pain, such as taking medication, nerve block with lidocaine, or neurolysis with alcohol or phenol. Recently, a method of perineural injection using dextrose instead of lidocaine was proposed. This study was designed to compare the effects of perineural injection therapy (PIT) with buffered 5% dextrose or 0.5% lidocaine on neuropathic pain.

Methods

The data were collected from the database of pain clinic from August 1st, 2019 to December 31st, 2022 without any personal information. The inclusion criteria were patients diagnosed with postherpetic neuralgia (PHN), trigeminal neuralgia (TN), complex regional pain syndrome (CRPS), or peripheral neuropathy (PN), and patients who had undergone PIT with buffered 5% dextrose (Dextrose group) or 0.5% lidocaine (Lidocaine group) for pain control. The data of patients, namely sex, age, and pain score (numerical rating scale, NRS) were collected before PIT. The data of NRS, side effects, and satisfaction grade (excellent, good, fair, or poor) were collected one week after each of the four PIT, and two weeks after the last PIT.

Results

Overall, 112 subjects were enrolled. The Dextrose group included 89 and Lidocaine group included 23 patients. Because the number of patients in the Lidocaine group was too small to allow statistical analysis, the trend in Lidocaine group was just observed in each disease. There were no significant side effects except for a few bruise cases on the site of injection in all groups. The NRS in most Dextrose groups except CRPS were reduced significantly; however, the Lidocaine group showed a trend of pain reduction only in PHN. The Dextrose group except CRPS showed increased satisfaction two weeks after the final PIT.

Conclusion

From the results, it is suggested that PIT with buffered 5% dextrose may have a good effect for neuropathic pain without any side effect except for patients with CRPS. This may offer a window into a new tool that practitioners can employ in their quest to help patients with neuropathic pain.

Circulating Polyunsaturated Fatty Acids and Pain Intensity in Five Chronic Pain Conditions

Pain intensity is well-known to be influenced by a wide range of biobehavioral variables. Nutritional factors, however, have not been generally considered for their potential importance. This cross-sectional study examined associations between erythrocyte omega-6 (n-6) and omega-3 (n-3) polyunsaturated fatty acids (PUFAs) and pain intensity in 605 adults. Pain intensity was computed on a 0 to 100 numeric rating scale from questions about 5 chronic pain conditions: orofacial pain, headache, low back pain, irritable bowel syndrome, and bodily pain. For each pain condition, multiple linear regression tested the hypothesis that a higher ratio of n-6 arachidonic acid to the sum of n-3 eicosapentaenoic acid and docosahexaenoic acid (AA/(EPA+DHA) was associated with greater pain intensity. In covariate-adjusted analysis, orofacial pain intensity increased 5.7 points (95% CI: 1.4, 9.9) per unit increase in n-6/n-3 PUFA ratio. Likewise, a 1 unit increase in n-6/n-3 PUFA ratio was associated with significant increases in pain intensity (range 5-8 points) of headache pain, low back pain, and bodily pain, but not abdominal pain. Separate multiple linear regression models investigated the independent strength of association of individual PUFAs to the intensity of each pain condition. Overall, n-3 docosahexaenoic acid was most strongly, and inversely, associated with pain intensity. PERSPECTIVE: A higher ratio of n-6/n-3 long-chain polyunsaturated fatty acids was associated greater pain intensity for orofacial pain, headache, low back pain, and bodily pain, but not abdominal pain. The n-6/n-3 PUFA ratio was more consistently associated with pain intensity than any individual constituent of the long-chain PUFA ratio.

Sex-specific differences in alcohol-induced pain sensitization

Pain sensitization is a phenomenon that occurs to protect tissues from damage and recent studies have shown how a variety of non-noxious stimuli included in our everyday lives can lead to pain sensitization. Consumption of large amounts of alcohol over a long period of time invokes alcohol use disorder (AUD), a complex pathological state that has many manifestations, including alcohol peripheral neuropathy (neuropathic pain). We asked if 'non-pathological' alcohol consumption can cause pain sensitization in the absence of other pathology? Studies have pointed to glia and other immune cells and their role in pain sensitization that results in cell and sex-specific responses. Using a low-dose and short-term ethanol exposure model, we investigated whether this exposure would sensitize mice to a subthreshold dose of an inflammatory mediator that normally does not induce pain. We observed female mice exhibited specific mechanical and higher thermal sensitivity than males. We also observed an increase in CD68⁺ macrophages in the ipsilateral dorsal root ganglia (DRG) and Iba1⁺ microglia in the ipsilateral spinal dorsal horn of animals that were exposed to ethanol and injected with subthreshold inflammatory prostaglandin E2. Our findings suggest that short-term ethanol exposure stimulates peripheral and central, immune and glial activation, respectively to induce pain sensitization. This work begins to reveal a possible mechanism behind the development of alcoholic peripheral neuropathy.

High-impact chronic pain: evaluation of risk factors and predictors

Background

The concept of high-impact chronic pain (HICP) has been proposed for patients with chronic pain who have significant limitations in work, social life, and personal care. Recognition of HICP and being able to distinguish patients with HICP from other chronic pain patients who do not have life interference allows the necessary measures to be taken in order to restore the physical and emotional functioning of the affected persons. The aim was to reveal the risk factors and predictors associated with HICP.

Methods

Patients with chronic pain without life interference (grade 1 and 2) and patients with HICP were compared. Significant data were evaluated with regression analysis to reveal the associated risk factors. Receiving operating characteristic (ROC) analysis was used to evaluate predictors and present cutoff scores.

Results

One thousand and six patients completed the study. From pain related cognitive processes, fear of pain (odds ratio [OR], 0.92; 95% confidence interval [CI], 0.87-0.98; P = 0.007) and helplessness (OR, 1.06; 95% CI, 1.01-1.12; P = 0.018) were found to be risk factors associated with HICP. Predictors of HICP were evaluated by ROC analysis. The highest discrimination value was found for pain intensity (cut-off score > 6.5; 83.8% sensitive; 68.7% specific; area under the curve = 0.823; P < 0.001).

Conclusions

This is the first study in our geography to evaluate HICP with measurement tools that evaluate all dimensions of pain. Moreover, it is the first study in the literature to evaluate predictors and cut-off scores using ROC analysis for HICP.

Risk of cardiovascular events according to the tricyclic antidepressant dosage in patients with chronic pain: a retrospective cohort study

PURPOSE

We aimed to examine the risk of cardiovascular adverse events by tricyclic antidepressant (TCA) dosage among patients with chronic pain.

METHODS

A retrospective cohort study was conducted using a nationwide sample cohort. Among patients aged ≥ 18 years with a chronic pain diagnosis and no history of cardiovascular events, we extracted users and non-users of TCAs through 1:1 propensity score matching. TCA users were categorized into three groups according to the mean defined daily dose (DDD): very low doses (< 0.15 DDD), low doses (0.15-0.34 DDD), and traditional doses (≥ 0.34 DDD). A 6-month follow-up was conducted with an intention-to-treat approach. We examined the hazard ratio of cardiovascular adverse events using Cox proportional hazards analysis.

RESULTS

In total, 16,660 matched patients were followed up (8330 TCA users and 8330 non-users). TCA use did not significantly increase cardiovascular adverse events (hazard ratio [HR] 1.12, 95% confidence interval [CI] 0.94-1.33). Low-dose (0.15-0.34 DDD) TCAs (HR 1.37, 95% CI 1.08-1.74), particularly low-dose (0.15-0.34 DDD) nortriptyline (HR 2.11, 95% CI 1.44-3.08), was associated with an increased risk of cardiovascular adverse events. Administration of TCAs at the traditional dose (≥ 0.34 DDD) increased the risk of ischemic stroke (HR 2.08, 95% CI 1.11-3.88).

CONCLUSION

Close monitoring of patients on long-term, low-dose use of TCAs should be conducted to avoid an increase in the cumulative dose, which increases the risk of cardiovascular adverse events.

SR 57227A, a serotonin type-3 receptor agonist, as a candidate analgesic agent targeting nociplastic pain

Pain is influenced by various factors, such as fear, anxiety, and memory. We previously reported that pain-like behaviors in mice can be induced by environmental cues in which a pain stimulus was previously presented, and that pain was reduced using fentanyl (an opioid). Although opioid analgesics are currently used to treat persistent pain, their inappropriate use causes a significant number of deaths in the United States. Thus, alternative medicines to opioids are needed. Here, we reported that SR 57227A, a serotonin type-3 receptor agonist, significantly reduced pain-like behaviors. The number of c-Fos positive cells increased by environmental cues in PFC was decreased by SR 57227A. Moreover, SR 57227A reduced pain-like behaviors of the formalin test, and restored reductions in paw withdrawal thresholds by acidic saline intramuscular injection and sciatic nerve ligation. Unlike opioids, SR 57227A induced no preference behaviors as measured by the conditioned place preference test. These data suggested that SR 57227A is an effective alternative pain reliever to opioids that targets chronic pain.

A prospective, multicenter, open-label study of the clinical efficacy of tapentadol extended-release in the treatment of cancer-related pain and improvement in the quality of life of opioid-naïve or opioid-resistant patients

Purpose

This study aimed to investigate the clinical efficacy of tapentadol extended-release (ER) on pain control and the quality of life (QoL) of patients with moderate to severe chronic cancer pain in clinical practice in Korea.

Methods

In this prospective, open-label, multicenter trial, patients with sustained cancer pain as well as chronic pain, who were or were not using other analgesics were enrolled. Thirteen centers recorded a total of 752 patients during the 6-month observation period, based on the tapentadol ER dose and tolerability, prior and concomitant analgesic treatment, pain intensity, type of pain, adverse effects, and clinical global impression change (CGI-C). Of those 752 patients, 688 were enrolled, and 650 completed the study for efficacy and adverse drug reactions; among them, 349 were cancer patients.

Results

Tapentadol ER significantly reduced the mean pain intensity including neuropathic pain during the observation period by 2.9 points (from a mean 7 ± 0.87 to 4.1 ± 2.02). Furthermore, QoL was observed to be significantly improved based on the CGI-C, an objective measure.

Conclusion

This study showed that tapentadol ER was effective for treating patients with moderate to severe cancer pain and neuropathic pain, and therefore it significantly improved the patients’ QoL.

Conolidine: A Novel Plant Extract for Chronic Pain

: Pain, the most common symptom reported among patients in the primary care setting, is complex to manage. Opioids are among the most potent analgesics agents for managing pain. Since the mid-1990s, the number of opioid prescriptions for the management of chronic non-cancer pain (CNCP) has increased by more than 400%, and this increased availability has significantly contributed to opioid diversion, overdose, tolerance, dependence, and addiction. Despite the questionable effectiveness of opioids in managing CNCP and their high rates of side effects, the absence of available alternative medications and their clinical limitations and slower onset of action has led to an overreliance on opioids. Conolidine is an indole alkaloid derived from the bark of the tropical flowering shrub Tabernaemontana divaricate used in traditional Chinese, Ayurvedic, and Thai medicine. Conolidine could represent the beginning of a new era of chronic pain management. It is now being investigated for its effects on the atypical chemokine receptor (ACK3). In a rat model, it was found that a competitor molecule binding to ACKR3 resulted in inhibition of ACKR3’s inhibitory activity, causing an overall increase in opiate receptor activity. Although the identification of conolidine as a potential novel analgesic agent provides an additional avenue to address the opioid crisis and manage CNCP, further studies are necessary to understand its mechanism of action and utility and efficacy in managing CNCP.

Ketamine for the Treatment of Chronic Pain: A Comprehensive Review

Background

Chronic pain significantly worsens the quality of life. Unlike neuropathic, musculoskeletal, postoperative pain, and cancer pain, chronic primary pain cannot be explained by an underlying disease or condition, making its treatment arduous.

Objectives

This manuscript intends to provide a comprehensive review of the use of ketamine as a treatment option for specific chronic pain conditions.

Study Design

A review article.

Setting

A review of the literature.

Methods

A search was done on PubMed for relevant articles.

Results

A comprehensive review of the current understanding of chronic pain and the treatment of specific chronic pain conditions with ketamine.

Limitations

Literature is scarce regarding the use of ketamine for the treatment of chronic pain.

Conclusion

First-line treatment for many chronic pain conditions includes NSAIDs, antidepressants, anticonvulsants, and opioids. However, these treatment methods are unsuccessful in a subset of patients. Ketamine has been explored in randomized controlled trials (RCTs) as an alternative treatment option, and it has been demonstrated to improve pain symptoms, patient satisfaction, and quality of life. Conditions highlighted in this review include neuropathic pain, fibromyalgia, complex regional pain syndrome (CRPS), phantom limb pain (PLP), cancer pain, and post-thoracotomy pain syndrome. This review will discuss conditions, such as neuropathic pain, fibromyalgia, complex regional pain syndrome, and more and ketamine's efficacy and its supplementary benefits in the chronic pain patient population. As the opioid crisis in the United States continues to persist, this review aims to understand better multimodal analgesia, which can improve how chronic pain is managed.

A Glra3 phosphodeficient mouse mutant establishes the critical role of protein kinase A-dependent phosphorylation and inhibition of glycine receptors in spinal inflammatory hyperalgesia

ABSTRACT

Glycinergic neurons and glycine receptors (GlyRs) exert a critical control over spinal nociception. Prostaglandin E2 (PGE2), a key inflammatory mediator produced in the spinal cord in response to peripheral inflammation, inhibits a certain subtype of GlyRs (α3GlyR) that is defined by the inclusion of α3 subunits and distinctly expressed in the lamina II of the spinal dorsal horn, ie, at the site where most nociceptive nerve fibers terminate. Previous work has shown that the hyperalgesic effect of spinal PGE2 is lost in mice lacking α3GlyRs and suggested that this phenotype results from the prevention of PGE2-evoked protein kinase A (PKA)-dependent phosphorylation and inhibition of α3GlyRs. However, direct proof for a contribution of this phosphorylation event to inflammatory hyperalgesia was still lacking. To address this knowledge gap, a phospho-deficient mouse line was generated that carries a serine to alanine point mutation at a strong consensus site for PKA-dependent phosphorylation in the long intracellular loop of the GlyR α3 subunit. These mice showed unaltered spinal expression of GlyR α3 subunits. In behavioral experiments, they showed no alterations in baseline nociception, but were protected from the hyperalgesic effects of intrathecally injected PGE2 and exhibited markedly reduced inflammatory hyperalgesia. These behavioral phenotypes closely recapitulate those found previously in GlyR α3-deficient mice. Our results thus firmly establish the crucial role of PKA-dependent phosphorylation of α3GlyRs in inflammatory hyperalgesia.

Prospective Cross-Sectional Study of the Uses of Non-prescription Analgesics among Hail Residents

<p>The aim of this paper was to describe the general status of the use of non-prescription analgesics (NPA) among the residents of Hail city to ensure the safe use of non-prescription analgesics.  One hundred participants with different diseases were studied consecutively from January to March 2020. Data were collected with an online, semi-structured questionnaire; the obtained data were converted into statistical data using Microsoft Excel 2013. Most participants were taking a single, non-prescription analgesic (87.5%), while combination analgesic products were used by only 12.5% of participants. Using over-the-counter analgesics is common among residents of Hail, and most of those studied use these products in moderation and do not exceed the recommended dose. Acetaminophen is the most widely used product, but people also use NSAIDs and amphetamine-like products. The use of over-the-counter analgesics is common among residents of Hail, and most of the participants in this study use these products in moderation and do not exceed the recommended dose; therefore, exposure of patients to an increased risk of adverse effects of these products is out of the question, and this indicates that a large group of people in this region knows the risk of analgesics overuse. New studies are needed to help improve the approaches to the use of NPA drugs</p>

Topical Capsaicin for the Treatment of Neuropathic Pain

BACKGROUND

Neuropathic pain (NP) is an egregious problem worldwide. Due to the side-effects of oral drugs, drugs delivered directly to the affected area of pain are preferred.

OBJECTIVE

Capsaicin, a chemical compound isolated from chili peppers, is used as an analgesic in topical ointments and dermal patches to alleviate pain. Objective of the study is to review the application and functionality of topical capsaicin in treatment of neuropathic pain.

DATA SOURCES

To systematically review capsaicin's functions on NP, we retrieved articles from the PubMed database published in the last ten years.

STUDY ELIGIBILITY CRITERIA

The inclusion criteria were capsaicin and the use of capsaicin for the treatment of NP; on the other hand, articles were excluded according to the mentioned criteria such as abstracts, articles written in any language other than English, incomplete articles, and conference papers.

PARTICIPANTS AND INTERVENTIONS

Out of 265 articles, 108 articles were selected after filtering through the inclusion and exclusion criteria. The data and knowledge currently existing for capsaicin treatment in NP are summarized.

RESULTS

This review indicates that capsaicin effectively improves NP treatment without affecting the motor and large nerve fibres involved in sensory function. Transient receptor potential channel vanilloid type 1 (TRPV1) is the capsaicin receptor expressed in central and peripheral terminals of a sensitive primary nerve cell. Conclusions and implications of key findings: Topical capsaicin has a sensible safety profile and is effective in reducing NP. Therefore, studies over the last decade suggest that capsaicin might be a potential drug for NP treatment.

Serotonin syndrome in a patient with chronic pain taking analgesic drugs mistaken for psychogenic nonepileptic seizure

Serotonin syndrome (SS) is a potentially life-threatening condition that is caused by the administration of drugs that increase serotonergic activity in the central nervous system. We report a case of serotonin syndrome in a patient with chronic pain who was taking analgesic drugs. A 36-year-old female with chronic pain in the lower back and right buttock area had been taking tramadol hydrochloride 187.5 mg, acetaminophen 325 mg, pregabalin 150 mg, duloxetine 60 mg, and triazolam 0.25 mg daily for several months. After amitriptyline 10 mg was added to achieve better pain control, the patient developed SS, which was mistaken for psychogenic nonepileptic seizure. However, her symptoms completely disappeared after discontinuation of the drugs that were thought to trigger SS and subsequent hydration with normal saline. Various drugs that can increase serotonergic activity are being widely prescribed for patients with chronic pain. Clinicians should be aware of the potential for the occurrence of SS when prescribing pain medications to patients with chronic pain.

Optimal Sedation and Pain Management: A Patient- and Symptom-Oriented Paradigm

In the critically ill patient, optimal pain and sedation management remains the cornerstone of achieving comfort, safety, and to facilitate complex life support interventions. Pain relief, using multimodal analgesia, is an integral component of any orchestrated approach to achieve clinically appropriate goals in critically ill patients. Sedative management, however, remains a significant challenge. Subsequent studies including most recent randomized trials have failed to provide strong evidence in favor of a sedative agent, a mode of sedation or ancillary protocols such as sedative interruption and sedative minimization. In addition, clinical practice guidelines, despite a comprehensive evaluation of relevant literature, have limitations when applied to individual patients. These limitations have been most apparent during the coronavirus disease 2019 pandemic. As such, there is a need for a mindset shift to a practical and achievable sedation strategy, driven by patients' characteristics and individual patient needs, rather than one cocktail for all patients. In this review, we present key principles to achieve patient-and symptom-oriented optimal analgesia and sedation in the critically ill patients. Sedative intensity should be proportionate to care complexity with due consideration to an individual patient's modifiers. The use of multimodal analgesics, sedatives, and antipsychotics agents-that are easily titratable-reduces the overall quantum of sedatives and opioids, and reduces the risk of adverse events while maximizing clinical benefits. In addition, critical considerations regarding the choice of sedative agents should be given to factors such as age, medical versus operative diagnosis, and cardiovascular status. Specific populations such as trauma, neurological injury, and pregnancy should also be taken into account to maximize efficacy and reduce adverse events.

Medicolegal Consideration to Prevent Medical Malpractice Regarding Opioid Administration: An Analysis of Judicial Opinion in South Korea

PURPOSE

Although the use of opioids is increasing in South Korea, there have been no studies on the serious complications caused by the opioids. The aim of this study was to investigate the rare but serious complications through medicolegal analysis.

MATERIALS AND METHODS

From January 1994 to December 2019, we retrospectively reviewed the closed cases of lawsuits involving the complications of opioids using the database of judgments of the Supreme Court of Korea. General characteristics, opioid-induced complications, and judicial characteristics were analyzed.

RESULTS

Of the 46 cases, 31 cases of complications were finally included in the analysis. There were 28 (90.3%) cases of opioid administration for acute pain and 3 (9.7%) cases for chronic pain. The most commonly prescribed opioid was pethidine (n = 13, 41.9%), and the most common complication was respiratory depression (n = 17, 54.8%). All except two cases were associated with permanent injuries, including 18 (58%) deaths. Twelve (38.7%) cases were ruled in favor of the plaintiff in the claims for damages, with a median payment of United States dollar (USD) 126,346 (IQR: USD 77,275-379,219). Of these cases, the most frequently admitted complaint by the court was the neglect of observation (n = 10, 32.3%), followed by the inappropriate drug choice (n = 4, 12.9%). Eleven (36.7%) cases were plaintiffs' claims for violating explanation obligations, of which 2 (6.7%) were recognized in the court.

CONCLUSION

Our results suggest that physicians must be aware of the serious complications related to opioids and health policies to prevent such complications and malpractice should be adopted.

Non-Opioid Perioperative Pain Strategies for the Clinician: A Narrative Review

Alternative and non-opioid options for pain management are necessary in perioperative patient care. Opioids are no longer touted as cure-all medications, and furthermore, there have been tremendous advances in alternative therapies such as in interventional pain, physical therapy, exercise, and nutritional counseling that have proven benefits to combat pain. The center for disease control now strongly recommends the use of multimodal analgesia and multidisciplinary approaches based on the individual needs of patients: personalized medicine. In this manuscript, the specifics of non-opioid pharmacological and non-pharmacological analgesic approaches will be discussed as well as their possible indications and uses to reduce the need for excessive use of opioids for adequate pain control.

Associations between chronic pain, analgesic use and physical therapy among adults living with HIV in Atlanta, Georgia: a retrospective cohort study

Chronic pain - widely classified as pain lasting longer than 3 months - has emerged as a treatment priority among people living with HIV (PLHIV), and has been associated with decreased patient retention in HIV primary care. This retrospective cohort study evaluated the changes in self-reported pain scores and analgesic usage for HIV-positive adults with chronic pain enrolled at a large, urban HIV clinic in Atlanta, Georgia, USA who received a physical therapy (PT) intervention compared with a demographically matched cohort who did not receive PT. Retrospective data was collected from patients' charts who received PT, and from patients' charts who did not receive PT during the time period. Patients who had received PT were referred by their primary HIV providers at the clinic, but were not recruited specifically for study purposes. Results revealed that among patients who received PT interventions, the majority (93.5%) reported a decrease or total elimination of pain. In addition, all of the patients who received PT reported decreased analgesic use, with the exception of opioids, which remained unchanged. Among patients who did not receive PT intervention, there was an overall increase in analgesic usage in all medication categories including opioids. The majority of the non-PT group (74%) reported increased or unchanged pain over the study period. In a non-randomized sample of HIV-positive adults at one HIV clinic, PT intervention appears to be an effective, non-pharmacological method to decrease chronic pain and analgesic use in selected persons living with HIV.

Transdermal Ketoprofen Patch in Comparison to Eutectic Mixture of Local Anesthetic Cream and Subcutaneous Lidocaine to Control Pain Due to Venous Cannulation

Background:

This study was established to compare the analgesic and side effects between transdermal ketoprofen patch 30 mg and eutectic mixture of local anesthetic (EMLA) cream applied to the peripheral venous cannulation site and lidocaine injection before cannulation.

Patients and Methods:

One hundred and five adult patients who had been scheduled for elective general surgery with patients' physical status American Society of Anesthesiologists classes I and II were randomly divided into three groups: Group I (EMLA group) received EMLA cream, Group II (lidocaine group) received subcutaneous infiltration of 1 ml of 2% lidocaine HCl 10 min before cannulation, and Group III (ketoprofen group) received a transdermal ketoprofen patch 30 mg. Groups I and III received their cream or patch 60 min before cannulation. The pain resulting from cannulation by an 18G cannula was assessed by a visual analog scale (VAS) at the time of cannulation and every 2 h for another 6 h for all groups. Signs of inflammation at the site of cannulation (erythema, induration, edema, and blanching) were observed at the site of cannulation for 24 h.

Results:

Ketoprofen patch, EMLA cream, and lidocaine injection were found to be equal in controlling pain caused by venous cannulation with no significant difference in VAS. Signs of inflammation at the site of cannulation (blanching, erythema, and induration) were very evident in Group I (EMLA) which showed significant difference than in other two groups.

Conclusions:

EMLA cream, ketoprofen patch, and lidocaine injection have equal ability to alleviate pain due to cannulation when applied before the procedure, but ketoprofen patch is more superior as it had less local inflammatory effect in comparison to EMLA cream and without double puncture as with lidocaine injection.

Therapeutic alternatives in painful diabetic neuropathy: a meta-analysis of randomized controlled trials

Background

One of the most frequent problems caused by diabetes is the so called painful diabetic neuropathy. This condition can be treated through numerous types of therapy. The purpose of this study was to analyze, as a meta-analysis, different treatments used to alleviate painful diabetic neuropathy, with the aim of generating results that help making decisions when applying such treatments to tackle this pathology.

Methods

A search was conducted in the main databases for Health Sciences, such as PUBMED, Web of Science (WOS), and IME biomedicina (Spanish Medical Reports in Biomedicine), to gather randomized controlled trials about treatments used for painful diabetic neuropathy. The analyzed studies were required to meet the inclusion criteria selected, especially those results related to pain intensity.

Results

Nine randomized controlled trials were chosen. The meta-analysis shows significant positive effects for those treatments based on tapentadol [g: -1.333, 95% CI (-1.594; -1.072), P < 0.05], duloxetine [g: -1.622, 95 % CI (-1.650; -1.594), P < 0.05], pregabalin [g: -0.607, 95% CI (-0.980; -0.325), P < 0.05], and clonidine [g: -0.242, 95 % CI (-0.543; -0.058), P < 0.05].

Conclusions

This meta-analysis indicates the effectiveness of the treatments based on duloxetine, gabapentin and pregabalin, as well as other drugs, such as tapentadol and topic clonidine, whose use is better prescribed in more specific situations. The results provided can help increase the knowledge about the treatment of painful diabetic neuropathy and also in the making of clinical practice guidelines for healthcare professionals.

Analgesic Efficacy and Safety of Prolonged-Release Oxycodone/Naloxone in Korean Patients with Chronic Pain from Spinal Disorders

Background

A prolonged-release formulation of oxycodone/naloxone has been shown to be effective in European populations for the management of chronic moderate to severe pain. However, no clinical data exist for its use in Korean patients. The objective of this study was to assess efficacy and safety of prolonged-release oxycodone/naloxone in Korean patients for management of chronic moderate-to-severe pain.

Methods

In this multicenter, single-arm, open-label, phase IV study, Korean adults with moderate-to-severe spinal disorder-related pain that was not satisfactorily controlled with weak opioids and nonsteroidal anti-inflammatory drugs received prolonged-release oral oxycodone/naloxone at a starting dose of 10/5 mg/day (maximum 80/40 mg/day) for 8 weeks. Changes in pain intensity and quality of life (QoL) were measured using a numeric rating scale (NRS, 0–10) and the Korean-language EuroQol-five dimensions questionnaire, respectively.

Results

Among 209 patients assessed for efficacy, the mean NRS pain score was reduced by 25.9% between baseline and week 8 of treatment (p < 0.0001). There was also a significant improvement in QoL from baseline to week 8 (p < 0.0001). The incidence of adverse drug reactions was 27.7%, the most common being nausea, constipation, and dizziness; 77.9% of these adverse drug reactions had resolved or were resolving at the end of the study.

Conclusions

Prolonged-release oxycodone/naloxone provided significant and clinically relevant reductions in pain intensity and improved QoL in Korean patients with chronic spinal disorders. (ClinicalTrials.gov identifier: NCT01811238)

Double blind randomized control trial to evaluate the efficacy of ketoprofen patch to attenuate pain during venous cannulation

Background

Venipuncture pain is an uncomfortable suffering to the patient. It creates anxiety, fear and dissatisfaction. The ketoprofen transdermal patch is a proven treatment for musculoskeletal and arthritic pain. We planned this study to evaluate the efficacy of the ketoprofen patch to reduce venipuncture pain.

Methods

Two hundred adult patients, aged 18–60 years, of either sex, ASA grade I or II, were enrolled. Presuming that therapy would decrease venipuncture pain by 30%, a power calculation with α = 0.05 and β = 0.80 required enrollment of at least 24 patients into each group. However, 100 patients in each group were recruited. Group I (Control) received a placebo patch; Group II (Ketoprofen) received a 20 mg ketoprofen patch. A selected vein on the dorsum of the patient's non-dominant hand was cannulated with 18 g intravenous cannula 1 h after the application of the respective patch. Assessment of pain was done by a 10 cm visual analogue scale (VAS) of 0–10, where 0 depicts “no pain” and 10 is “the worst imaginable pain”. The venipuncture site was assessed for the presence of skin erythema, swelling and rashes at 12 h, 24 h and at the time of decannulation.

Results

Incidence of pain was 100% (94/94) in the control group as compared to 93% (85/91) in the ketoprofen group. The severity of the venipuncture pain was 6 (2) and 2 (2) for control and ketoprofen groups respectively (P < 0.05).

Conclusions

Application of a ketoprofen patch at the proposed site of venipuncture one hour before the attempt is effective and safe for attenuating venipuncture pain.

Management of chronic neuropathic pain with single and compounded topical analgesics

The goal of our review was to emphasize important aspects that physicians should take into consideration when prescribing topical analgesics as part of chronic neuropathic pain treatment. We discuss the dermatopharmacokinetics and microstructural components of the skin, differences between topical and transdermal drug delivery, and topical medication effects on peripheral neuropathy and central sensitization. Even though the US FDA approved topical analgesics are 8%-capsaicin and 5%-lidocaine patches for treating postherpetic neuralgia, there are many other studies conducted on the efficacy of topical ketamine cream, clonidine gel, topical gabapentin, topical baclofen and topical phenytoin for peripheral neuropathic pain, either alone or in combination with other formulations. Furthermore, we discuss new compounded topical analgesics that are becoming more popular and that are showing promising results in the management of chronic peripheral neuropathies. However, more studies are needed for elucidation of the role of topical analgesics and their effects, especially when combined with other treatments.

Tapentadol in neuropathic pain cancer patients: a prospective open label study

Many chemotherapy treatments induce peripheral neuropathy (CIPN). These patients often experience neuropathic pain (NP) that reduces the quality of life. The aim of this prospective, open label study was to evaluate the efficacy and tolerability of tapentadol (TP) in patients affected by CIPN. CIPN were consecutively enrolled in a prospective open label study at the Neuro-Oncology Unit of the Regina Elena National Cancer Institute in Rome. During the titration phase, each patient initially received doses of TP 50 mg twice a day. All patients underwent pain intensity (NRS) and DN4. For evaluation of quality of life, patients underwent EORTC QLQ-C30 and EORTC QLQ-CIPN2 QLQ-CIPN20. We enrolled 31 patients, 19 were females with a median age of 60 years. After 3 months of treatment with TP, 22 patients completed the statistical package for social sciences (SPSS). Nineteen patients out of 22 showed a response to treatment (86%). We also observed that TP reduced the NRS and DN4 values from baseline to the last visit in a significant way (p < 0.001, respectively). Seven patients (22.5%) discontinued the TP therapy after the first week of occurrence of side effects. Furthermore, we observed that TP improved also the global health status measured by EORT QLQ-C30. TP is well tolerated and efficacy in the treatment of NP. The important reduction of neuropathic pain, the improvement in NRS and QoL scores after therapy with TP makes it a candidate in the management of patients suffering from neuropathic pain of CIPN also as a first line of therapy.

Low doses of amitriptyline, pregabalin, and gabapentin are preferred for management of neuropathic pain in India: is there a need for revisiting dosing recommendations?

Background

Current therapy for the treatment of neuropathic pain is often unsatisfactory. Considerable variation in treatment pattern still exists in spite of availability of sufficient literature from various guidelines. Recent Indian market data suggested that the utilization (sale) of drugs such as amitriptyline, pregabalin, and gabapentin was more for low-dose unit packs than that of the high-dose unit packs, raising the belief that these drugs are prescribed at a lower dose than is actually recommended in the guidelines. To test this hypothesis, a survey was conducted across speciality throughout the country to observe the prescription pattern of these drugs amongst the health care providers in India.

Methods

Three hundred fifty survey forms were distributed of which 281 forms were included for analysis.

Results

It was observed that the commonly used initiation and maintenance dose for amitriptyline, pregabalin, and gabapentin was 5–10 mg/day, 50–75 mg/day, and 100–300 mg/day, respectively. The reason to select the lower dosages was to have a balancing effect to achieve good efficacy with minimum side effects. Care-givers reported no side effects/not many side effects as a reason in 22.2%, 16.88%, and 23.86% patients with amitriptyline, pregabalin, and gabapentin, respectively. Sedation and giddiness were commonly reported with all three drugs.

Conclusions

Commonly prescribed drugs for management of neuropathic pain, such as amitriptyline, pregabalin, and gabapentin are preferred at lower doses in Indian clinical settings. Acceptable efficacy and low tolerance to the standard dosage is believed to be the reason behind the prescribed dose.

Opioids Resistance in Chronic Pain Management

Chronic pain management represents a serious healthcare problem worldwide. Chronic pain affects approximately 20% of the adult European population and is more frequent in women and older people. Unfortunately, its management in the community remains generally unsatisfactory and rarely under the control of currently available analgesics. Opioids have been used as analgesics for a long history and are among the most used drugs; however, while there is no debate over their short term use for pain management, limited evidence supports their efficacy of long-term treatment for chronic non-cancer pain. Therapy with opioids is hampered by inter-individual variability and serious side effects and some opioids often result ineffective in the treatment of chronic pain and their use is controversial. Accordingly, for a better control of chronic pain a deeper knowledge of the molecular mechanisms underlying resistance to opiates is mandatory.

Different electrophysiological effects of the levo- and dextro-rotatory isomers of mexiletine in isolated rabbit cardiac muscle

Racemic mexiletine is a widely used antiarrhythmic agent that blocks sodium channels. The effects of R-(-) and S-(+) mexiletine stereoisomers on maximum rate of depolarization ([Formula: see text]), conduction time, and repolarization have not yet been investigated in isolated cardiac preparations. We studied the effect of the R-(-) and S-(+) mexiletine on rabbit cardiac action potential parameters by using the conventional microelectrode technique. Both enantiomers at 20 μmol/L of therapeutically and experimentally relevant concentration, significantly depressed the [Formula: see text] at fast heart rates (BCLs 300-700 ms). R-(-) mexiletine has more potent inhibitory effect than S-(+) mexiletine. Both R-(-) and S-(+) mexiletine significantly inhibited the [Formula: see text] of early extrasystoles measured at 70 ms diastolic interval induced by S1-S2 stimuli. R-(-) mexiletine has more pronounced inhibitory effect than S-(+) mexiletine. Both R-(-) and S-(+) mexiletine increased significantly the ERP/APD₉₀ ratio. The time constant (τ) of recovery of [Formula: see text] was found to be τ = 376.0 ± 77.8 ms for R-(-) mexiletine and τ = 227.1 ± 23.4 ms for S-(+) mexiletine, which indicates a slower offset kinetics for R-(-) mexiletine from sodium channels than that of the S-(+) enantiomer. These data suggest that R-(-) mexiletine might be a more potent antiarrhythmic agent than S-(+) mexiletine.

Guidelines for prescribing opioids for chronic non-cancer pain in Korea

As the treatment of chronic non-cancer pain gradually increases, clinicians have more opportunities to encounter opioid prescription. However, guidelines for prescribing opioids for chronic non-cancer pain have never been published in Korea. The present guidelines were prepared by reviewing various research data. In cases in which the data were insufficient, recommendations were presented following discussion among experts affiliated with the Opioids Research Group in the Korean Pain Society. The present guidelines may need to be continuously revised and amended as more clinical evidence is acquired.

The Effectiveness and Safety of Topical Capsaicin in Postherpetic Neuralgia: A Systematic Review and Meta-analysis

In particular, neuropathic pain is a major form of chronic pain. This type of pain results from dysfunction or lesions in the central and peripheral nervous system. Capsaicin has been traditionally utilized as a medicine to remedy pain. However, the effectiveness and safety of this practice is still elusive. Therefore, this systematic review aimed to investigate the effect of topical capsaicin as a pain-relieving agent that is frequently used in pain management. In brief, all the double-blinded, randomized placebo- or vehicle-controlled trials that were published in English addressing postherpetic neuralgia were included. Meta-analysis was performed using Revman^® version 5.3. Upon application of the inclusion and exclusion criteria, only six trials fulfilled all the criteria and were included in the review for qualitative analysis. The difference in mean percentage change in numeric pain rating scale score ranges from -31 to -4.3. This demonstrated high efficacy of topical capsaicin application and implies that capsaicin could result in pain reduction. Furthermore, meta-analysis was performed on five of the included studies. All the results of studies are in favor of the treatment using capsaicin. The incidence of side effects from using topical capsaicin is consistently higher in all included studies, but the significance of safety data cannot be quantified due to a lack of p-values in the original studies. Nevertheless, topical capsaicin is a promising treatment option for specific patient groups or certain neuropathic pain conditions such as postherpetic neuralgia.

Ultrasound-Guided Nerve Block with Botulinum Toxin Type A for Intractable Neuropathic Pain

Neuropathic pain includes postherpetic neuralgia (PHN), painful diabetic neuropathy (PDN), and trigeminal neuralgia, and so on. Although various drugs have been tried to treat neuropathic pain, the effectiveness of the drugs sometimes may be limited for chronic intractable neuropathic pain, especially when they cannot be used at an adequate dose, due to undesirable severe side effects and the underlying disease itself. Botulinum toxin type A (BoNT-A) has been known for its analgesic effect in various pain conditions. Nevertheless, there are no data of nerve block in PHN and PDN. Here, we report two patients successfully treated with ultrasound-guided peripheral nerve block using BoNT-A for intractable PHN and PDN. One patient had PHN on the left upper extremity and the other patient had PDN on a lower extremity. Due to side effects of drugs, escalation of the drug dose could not be made. We injected 50 Botox units (BOTOX^®, Allergan Inc., Irvine, CA, USA) into brachial plexus and lumbar plexus, respectively, under ultrasound. Their pain was significantly decreased for about 4–5 months. Ultrasound-guided nerve block with BoNT-A may be an effective analgesic modality in a chronic intractable neuropathic pain especially when conventional treatment failed to achieve adequate pain relief.

Low Level Laser Therapy Versus Pharmacotherapy in Improving Myofascial Pain Disorder Syndrome

INTRODUCTION

Temporomandibular disorders (TMD) lead to masticatory muscle pain, jaw movement disability and limitation in mouth opening. Pain is the chief complaint in 90% of the TMD patients which leads to disability and severe socioeconomic costs. The purpose of this study was to evaluate the therapeutic effects of low level laser therapy (LLLT) compared to pharmacotherapy with NSAIDs (naproxen) in myofascial pain disorder syndrome (MPDS).

METHODS

In this randomized controlled clinical trial, 40 MPDS patients were divided into two groups. One group received naproxen 500 mg bid for 3 weeks as treatment modality and also had placebo laser sessions. The other group received active laser (diode 810 nm CW) as treatment and placebo drug. Pain intensity was measured by visual analogue scale (VAS) and maximum painless mouth opening was also measured as a functional index every session and at 2 months follow up. Data was collected and analyzed with SPSS software. Independent t test was used to analyze the data. A P < 0.05 was considered significant.

RESULTS

Low level laser caused significant reduction in pain intensity (P < 0.05) and a significant increase in mouth opening. In naproxen group neither pain intensity nor maximum mouth opening had significant improvement. Pain relief, in subjective VAS was observed in third session in LLLT group, but did not occur in naproxen group. Maximum mouth opening increased significantly in laser group compared to the naproxen group from the eighth session.

CONCLUSION

Treatment with LLLT caused a significant improvement in mouth opening and pain intensity in patients with MPDS. Similar improvement was not observed in naproxen group.

An Overview of Pharmacologic Management of Chronic Pain

Patients with chronic pain can be challenging to manage and historically providers have relied on opiates to treat pain. Recent studies have brought into question the safety and efficacy of chronic opiate therapy in the noncancer population. There is a vast amount of literature to support the use of nonsteroidal anti-inflammatory medications, antidepressants, anticonvulsants, topical agents, cannabinoids, and botulinum toxin either in conjunction with or in lieu of opioids. Intrathecal drug delivery systems can deliver some of these medications directly to their primary site of action while minimizing the side effects seen with systemic administration.

Chronic Pain and Cognitive Behavioral Therapy

Cognitive behavioral therapy (CBT) is often used to treat chronic pain; however, more information is needed about what are the most efficacious dose and delivery methods. The aims of this review were to determine (a) which CBT doses, delivery methods, strategies, and follow-up periods have been explored in recent intervention studies of individuals with chronic pain and (b) whether the outcomes described in the selected studies were consistent with recommendations by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials. The CINAHL, EMBASE, PubMed, PsycInfo, and SCOPUS databases were searched for randomized controlled trials published from 2009 to 2015 testing CBT for adults with chronic pain. Thirty-five studies were included in this review. Results revealed that CBT reduced pain intensity in 43% of trials, the efficacy of online and in-person formats were comparable, and military veterans and individuals with cancer-related chronic pain were understudied.

Peroxisome proliferator-activated receptor agonists modulate neuropathic pain: a link to chemokines?

Chronic pain presents a widespread and intractable medical problem. While numerous pharmaceuticals are used to treat chronic pain, drugs that are safe for extended use and highly effective at treating the most severe pain do not yet exist. Chronic pain resulting from nervous system injury (neuropathic pain) is common in conditions ranging from multiple sclerosis to HIV-1 infection to type II diabetes. Inflammation caused by neuropathy is believed to contribute to the generation and maintenance of neuropathic pain. Chemokines are key inflammatory mediators, several of which (MCP-1, RANTES, MIP-1α, fractalkine, SDF-1 among others) have been linked to chronic, neuropathic pain in both human conditions and animal models. The important roles chemokines play in inflammation and pain make them an attractive therapeutic target. Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear receptors known for their roles in metabolism. Recent research has revealed that PPARs also play a role in inflammatory gene repression. PPAR agonists have wide-ranging effects including inhibition of chemokine expression and pain behavior reduction in animal models. Experimental evidence suggests a connection between the pain ameliorating effects of PPAR agonists and suppression of inflammatory gene expression, including chemokines. In early clinical research, one PPARα agonist, palmitoylethanolamide (PEA), shows promise in relieving chronic pain. If this link can be better established, PPAR agonists may represent a new drug therapy for neuropathic pain.

Acute systemic infusion of bupropion decrease formalin induced pain behavior in rat

Background

The chronic pain can disturb physical, psychological, and social performances. Analgesic agents are widely used but some antidepressants (ADs) showed analgesia also. Bupropion is using for smoke cessation but it can change morphine withdrawal signs such as pain. This study tested the acute systemic effect of bupropion on formalin induced pain behavior in rats.

Methods

Wistar male healthy rats were divided into 7 groups (control, sham, and 5 treated groups with 10, 30, 90, 120, and 200 mg/kg of bupropion, i.p.). The bupropion injected 3 hours prior to formalin induced pain behavior. Formalin (50 µl, 2.5%) was injected subcutaneously in dorsal region of right hindpaw in all animals. Nociceptive signs were observed continuously on-line and off-line each minute. Common pain scoring was used for pain assessment.

Results

The analysis of data by one-way ANOVA showed that bupropion can reduce pain scores in the second phase but not in first phase. Bupropion decreased the licking/biting duration significantly in first and second phase of formalin test.

Conclusions

The results showed that bupropion has analgesic effects at systemic application. The change of second phase of the pain behavior was significant and it revealed that central mechanisms involve in bupropion analgesia.

[Pain management in patients with liver cirrhosis]

Pain management in patients with liver cirrhosis is a real challenge and is often inadequate due to a lack of therapeutic efficacy or the high incidence of adverse effects. The focus of treatment differs depending on whether the pain is acute or chronic and involves understanding the causative pathophysiological mechanism. Analgesics should be started with the minimum effective dose and should be titrated slowly with avoidance of polypharmacy. Adverse effects must be monitored, especially sedation and constipation, which predispose the patient to the development of hepatic encephalopathy. The first-line drug is paracetamol, which is safe at doses of 2-3g/day. Non-steroidal anti-inflammatory agents are contraindicated because they can cause acute renal failure and/or gastrointestinal bleeding. Tramadol is a safe option for moderate-severe pain. The opioids with the best safety profile are fentanyl and hydromorphone, with methadone as an alternative. Topical treatment can reduce oral drug consumption. In neuropathic pain the first-line therapeutic option is gabapentin. The use of antidepressants such as amitriptyline can be considered in some patients. Interventional techniques are a valuable tool in moderate to severe pain, since they allow a reduction in drug therapy and consequently its adverse effects. Psychological treatment, physical therapy and rehabilitation should be considered as part of multimodality therapy in the management of chronic pain.

Anti-allodynic effects of levodopa in neuropathic rats

PURPOSE

Levodopa is the most effective anti-Parkinsonian agent. It has also been known to exhibit analgesic properties in laboratory and clinical settings. However, studies evaluating its effects on neuropathic pain are limited. The aim of the present study was to examine the anti-allodynic effects of levodopa in neuropathic rats.

MATERIALS AND METHODS

Sprague-Dawley male rats underwent the surgical procedure for L5 and L6 spinal nerves ligation. Sixty neuropathic rats were randomly divided into 6 groups for the oral administration of distilled water and levodopa at 10, 30, 50, 70, and 100 mg/kg, respectively. We co-administered carbidopa with levodopa to prevent peripheral synthesis of dopamine from levodopa, and observed tactile, cold, and heat allodynia pre-administration, and at 15, 30, 60, 90, 120, 150, 180, and 240 min after drug administration. We also measured locomotor function of neuropathic rats using rotarod test to examine whether levodopa caused side effects or not.

RESULTS

Distilled water group didn't show any difference in all allodynia. For the levodopa groups (10-100 mg/kg), tactile and heat withdrawal thresholds were increased, and cold withdrawal frequency was decreased dose-dependently (p<0.01). In addition, levodopa induced biphasic analgesia. Different dosage of levodopa did not impact on the rotarod time (p>0.05).

CONCLUSION

Levodopa reversed tactile, cold and heat allodynia in neuropathic rat without any side effects.

Chronic Pain and Its Determinants: A Population-based Study in Southern Iran

Background

Prevalence of chronic pain and its association with demographic characteristics have been reported by different studies from different geographical regions in the world. However, data from many Middle East countries including Iran (especially southern Iran) are scare. The aim of the present study was to demonstrate the prevalence of chronic pain and its association with demographic, psychological and socioeconomic factors in an Iranian population.

Methods

In this population-based survey, the target population was comprised of subjects aged 20 to 85 years residing in Jahrom, southern Iran during 2009-2011. All eligible subjects were invited to participate in the study. Before a detailed questionnaire was given; face to face interviews were done for each individual.

Results

There were 719 men and 874 women with an average age of 40.5 years at the onset of the study. Among the study population, 38.9% (620/1,593) complained of chronic pain, of whom 40.8% (253/620) were men and 59.2% (367/620) were women. Foot and joint pain were observed in 31.9%. Hip and spine pain, migraine and tension headaches, heart pain, and abdomen pain were observed in 21.5%, 15.5%, 9.5%, and 8.0% of chronic pain cases, respectively. There was a significant association among the covariables age, sex, overweight, educational level, income, and type of employment with chronic pain as the dependent variable (P < 0.0001).

Conclusions

Our findings show the prevalence of chronic pain and its association with demographic, psychological and socioeconomic factors. Individuals with low incomes and less education became accustomed to pain due to a lack of knowledge.