Efficacy of Venlafaxine in Neuropathic Pain: A Narrative Review of Optimized Treatment

Pathophysiology and Management of Chest Wall Pain after Surgical and Non-Surgical Local Therapies for Lung Cancer

Chest wall pain syndromes can emerge following local therapies for lung cancer and can adversely affect patients' quality-of-life. This can occur after lung surgery, radiation therapy, or percutaneous image-guided thermal ablation. This review describes the multifactorial pathophysiology of chest wall pain syndromes that develop following surgical and non-surgical local therapies for lung cancer and summarizes evidence-based management strategies for inflammatory, neuropathic, myofascial, and osseous pain. It discusses a step-wise approach to treating chest wall pain that begins with non-opioid oral analgesics and includes additional pharmacologic treatments as clinically indicated, such as anticonvulsants, serotonin and norepinephrine reuptake inhibitors, tricyclic antidepressants, and various topical treatments. For myofascial pain, physical medicine techniques, such as acupuncture, trigger point injections, deep tissue massage, and intercostal myofascial release can also offer pain relief. For severe or refractory cases, opioid analgesics, intercostal nerve blocks, or intercostal nerve ablations may be indicated. Fortunately, palliation of treatment-related chest wall pain syndromes can be managed by most clinical providers, regardless of the type of local therapy utilized for a patient's lung cancer treatment. In cases where a patient's pain fails to respond to initial medical management, clinicians can consider referring to a pain specialist who can tailor a more specific pharmacologic approach or perform a procedural intervention to relieve pain.

Efficacy of electro-acupuncture versus sham acupuncture for diabetic peripheral neuropathy: study protocol for a three-armed randomised controlled trial

INTRODUCTION

Specific treatment for diabetic peripheral neuropathy (DPN) is still lacking, and acupuncture may relieve the symptoms. We intend to investigate the efficacy and safety of electro-acupuncture (EA) in alleviating symptoms associated with DPN in diabetes.

METHODS AND ANALYSIS

This multicentre, three-armed, participant- and assessor-blind, randomised, sham-controlled trial will recruit 240 eligible participants from four hospitals in China and will randomly assign (1:1:1) them to EA, sham acupuncture (SA) or usual care (UC) group. Participants in the EA and SA groups willl receive either 24-session EA or SA treatment over 8 weeks, followed by an 8-week follow-up period, while participants in the UC group will be followed up for 16 weeks. The primary outcome of this trial is the change in DPN symptoms from baseline to week 8, as rated by using the Total Symptom Score. The scale assesses four symptoms: pain, burning, paraesthesia and numbness, by evaluating the frequency and severity of each. All results will be analysed with the intention-to-treat population.

ETHICS AND DISSEMINATION

The protocol has been approved by the Ethics Committee of the Beijing University of Chinese Medicine (Identifier: 2022BZYLL0509). Every participant will be informed of detailed information about the study before signing informed consent. The results of this trial will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200061408.

Treatment of Persistent Idiopathic Dentoalveolar Pain with Venlafaxine: A Multicentric Retrospective Study on Its Effectiveness and Safety

Purpose

To determine the effectiveness and safety of venlafaxine in treating persistent idiopathic dentoalveolar pain (PIDP).

Patients and Methods

A retrospective analysis was conducted on a cohort comprising 129 patients with a definite diagnosis of PIDP, who were treated with venlafaxine between May 2020 and December 2022 at three different institutions. Baseline characteristics were statistically described, and visual analog scale (VAS) scores before and during treatment were collected. The percentage of pain relief was calculated. Differences in baseline characteristics between responsive and unresponsive patients were evaluated. Additionally, side effects experienced during treatment were also summarized.

Results

Among the included patients, 4 suffered immediate side effects following the initial dose of venlafaxine and the treatment was discontinued. 104 (80.6%) patients achieved pain relief. VAS scores of responsive patients at weeks 2, and months 1, 2, and 3 were significantly lower than baseline (p<0.001). Duration of pain was the only factor related to responsiveness (Wilcoxon rank sum test p<0.001, logistic regression p=0.001). 64 patients (49.6%) suffered from mild side effects. No serious side effects were observed during the study.

Conclusion

Venlafaxine is potentially effective and safe in the management of PIDP. Early application of venlafaxine following the diagnoses of PIDP can result in a higher possibility of pain relief.

The Spectrum of Extraglandular Manifestations in Primary Sjögren's Syndrome

Extraglandular manifestations (EGMs) in primary Sjogren's syndrome (pSS) represent the clinical expression of the systemic involvement in this disease. EGMs are characterized by a wide heterogeneity; virtually any organ or system can be affected, with various degrees of dysfunction. The existing gaps of knowledge in this complex domain of extraglandular extension in pSS need to be overcome in order to increase the diagnostic accuracy of EGMs in pSS. The timely identification of EGMs, as early as from subclinical stages, can be facilitated using highly specific biomarkers, thus preventing decompensated disease and severe complications. To date, there is no general consensus on the diagnostic criteria for the wide range of extraglandular involvement in pSS, which associates important underdiagnosing of EGMs, subsequent undertreatment and progression to severe organ dysfunction in these patients. This review article presents the most recent basic and clinical science research conducted to investigate pathogenic mechanisms leading to EGMs in pSS patients. In addition, it presents the current diagnostic and treatment recommendations and the trends for future therapeutic strategies based on personalized treatment, as well as the latest research in the field of diagnostic and prognostic biomarkers for extraglandular involvement in pSS.

Red Ginger Extract Prevents the Development of Oxaliplatin-Induced Neuropathic Pain by Inhibiting the Spinal Noradrenergic System in Mice

Oxaliplatin is a well-known chemotherapeutic drug that is widely used to treat colorectal cancer. However, it can induce acute side effects in up to 90% of patients. Serotonin and norepinephrine reuptake inhibitors (SNRIs) are used as first-choice drugs; however, even SNRIs are known to be effective only in treatment and not for prevention. Therefore, finding a drug that can prevent the development of cold and mechanical forms of allodynia induced by oxaliplatin is needed. This study demonstrated that multiple oral administrations of 100 mg/kg and 300 mg/kg of red ginger extract could significantly prevent pain development in mice. The role of the noradrenergic system was investigated as an underlying mechanism of action. Both the spinal α1- and α2-adrenergic receptors were significantly downregulated after treatment. Furthermore, the noradrenaline levels in the serum and spinal cord were upregulated and downregulated after treatment with paclitaxel and red ginger, respectively. As the active sub-component of red ginger, ginsenoside Rg3 (Rg3) was identified and quantified using HPLC. Moreover, multiple intraperitoneal injections of Rg3 prevented the development of pain in paclitaxel-treated mice, suggesting that RG3 may induce the effect of red ginger extract.

Electrical stimulus combined with venlafaxine and mirtazapine improves brain Ca2+ activity, pre-pulse inhibition, and immobility time in a model of major depressive disorder in schizophrenia

BACKGROUND

The prevalence of major depressive disorder in patients with schizophrenia (SZ-MDD) has been reported to be about 32.6 %, but it varies considerably depending on the stage (early or chronic) and state (acute or post-psychotic) of schizophrenia. The exploration of ideal strategies for the treatment of major depressive disorder in the context of schizophrenia is urgently needed. Thus, the present study was conducted to investigate the treatment effects of clozapine, electrical stimulation (ECS; the mouse model equivalent of electroconvulsive therapy for humans), venlafaxine, and mirtazapine for SZ-MDD.

METHODS

A mouse model of SZ-MDD was established with MK801 administration and chronic unpredictable mild stress exposure. Clozapine and ECS, alone and with mirtazapine and/or venlafaxine, were used as treatment strategies. In-vivo two-photon imaging was performed to visualize Ca²⁺ neural activity in the prefrontal cortex (PFC). Mouse performance on behavioral assays was taken to reflect acute treatment effects.

RESULTS

ECS + venlafaxine + mirtazapine performed significantly better than other treatments in alleviating major depressive disorder, as reflected by PFC Ca²⁺ activity and behavioral assay performance. Clozapine + venlafaxine + mirtazapine did not have an ideal treatment effect. Brain Ca²⁺ activity alterations did not correlate with behavioral expression in any treatment group.

CONCLUSIONS

In this mouse model of SZ-MDD, ECS + venlafaxine + mirtazapine improved brain Ca2+ activity, pre-pulse inhibition, and immobility time. These findings provide useful information for the further exploration of treatment methods for patients with SZ-MDD, although the mechanisms underlying this comorbidity needed to be investigated further.

A Look at Commonly Utilized Serotonin Noradrenaline Reuptake Inhibitors (SNRIs) in Chronic Pain

Purpose of Review

Chronic pain continues to be one of the leading healthcare cost burdens in the United States and is typically defined as ongoing pain, lasting longer than six months. Various treatment options exist for chronic pain, including physical therapy, medical management, pain psychology, and interventional therapies. Pain medications have been the mainstay of treatment for chronic pain conditions with an increasing use of membrane stabilizers and antidepressants to treat neuropathic pain conditions. Specifically, serotonin noradrenaline reuptake inhibitors (SNRIs) have been used to treat a range of pain conditions expanding from everyday use for depressive disorders.

Recent Findings

SNRIs, including duloxetine, venlafaxine, and milnacipran, have demonstrated efficacy in reducing pain in musculoskeletal pain (chronic low back pain and osteoarthritis), fibromyalgia, and neuropathic pain conditions (peripheral diabetic neuropathy).

Summary

The article describes the function, role, and use of SNRIs to treat chronic and neuropathic pain by altering the noradrenergic descending inhibitory pathways.

The State-of-the-art Pharmacotherapeutic Options for the Treatment of Chronic Non-Cancer Pain

INTRODUCTION

Pharmacotherapeutic options continue to expand for the treatment of chronic non-cancer pain. There has been an increasing emphasis on multimodal analgesia. This strategy employs use of multiple analgesic medications each with a distinct mechanism of action, which when administered concomitantly may provide profound analgesia.

AREAS COVERED

The authors describe evidence from randomized controlled trials and systematic reviews on a variety of established medications including anti-inflammatory agents, opioids, anti-convulsants, anti-depressants, N-methyl-D-aspartate receptor antagonists, sodium channel blockers, cannabinoids, and alpha-2-receptor blockers. Furthermore, they provide developing evidence on more novel pharmacotherapeutics including alpha lipoic acid, acetyl-L-carnitine, low dose naltrexone, calcitonin gene-related peptide antagonists, targeted toxin therapy, Nav1.7 inhibitors, neurotensin agonists, purinoceptor antagonists, and sigma-1 receptor antagonists. Furthermore, the authors review the safety and adverse effect profile for these agents.

EXPERT OPINION

In this era of the opioid epidemic, clinicians should first offer non-opioid analgesics and employ a multimodal analgesic strategy. Current guidelines recommend a personalized approach to the chronic pain treatment, in each case accounting for type, location, severity, and chronicity of pain. Clinicians should also carefully consider the risk-to-benefit ratio to the patient based on the drug side effect profile, patient age, and comorbidities.

Venlafaxine Caffeic Acid Salt: Synthesis, Structural Characterization, and Hypoglycemic Effect Analysis

Depression is a recurrent and chronic mental disorder requiring long-term treatment. Major depressive disorder is present in 15-20% of patients with type 1 or type 2 diabetes. Large-scale evidence revealed that depression and depressive symptoms are independent risk factors for the development of type 2 diabetes, and they may contribute to hyperglycemia and even accelerate the premature onset of diabetes complications. Venlafaxine is a clinical first-line antidepressant used for more than 30 years. Recently, clinical reports showed that venlafaxine overdose might cause hypoglycemia. Venlafaxine is insoluble and salt formation technology is the most appropriate method to improve the physicochemical properties and the pharmacokinetic profile of the drug. In the present work, the use of the solvent evaporation method, slurry, and the liquid-assisted grinding method resulted in the crystalline salt venlafaxine-caffeic acid (1:1). The compounds were characterized using a series of solid-state techniques, viz., powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and solid-state nuclear magnetic resonance, and the crystal structure was determined by single-crystal X-ray diffraction. Besides, a comparative study of solubility, dissolution, and hypoglycemic activity of the parent drug and the new salt has been carried out. The tested venlafaxine-caffeic acid salt showed about 16-fold higher solubility than the pure drug. Moreover, the glucose consumption assay results showed that the novel salt possesses potent hypoglycemic activity in vitro, suggesting that it is a promising candidate effective for major depressive disorder patients with type 2 diabetes.

Beyond Amitriptyline: A Pediatric and Adolescent Oriented Narrative Review of the Analgesic Properties of Psychotropic Medications for the Treatment of Complex Pain and Headache Disorders

Children and adolescents with recurrent or chronic pain and headache are a complex and heterogenous population. Patients are best served by multi-specialty, multidisciplinary teams to assess and create tailored, individualized pain treatment and rehabilitation plans. Due to the complex nature of pain, generalizing pharmacologic treatment recommendations in children with recurrent or chronic pains is challenging. This is particularly true of complicated patients with co-existing painful and psychiatric conditions. There is an unfortunate dearth of evidence to support many pharmacologic therapies to treat children with chronic pain and headache. This narrative review hopes to supplement the available treatment options for this complex population by reviewing the pediatric and adult literature for analgesic properties of medications that also have psychiatric indication. The medications reviewed belong to medication classes typically described as antidepressants, alpha 2 delta ligands, mood stabilizers, anti-psychotics, anti-sympathetic agents, and stimulants.

Long-Lasting and Additive Analgesic Effects of Combined Treatment of Bee Venom Acupuncture and Venlafaxine on Paclitaxel-Induced Allodynia in Mice

Paclitaxel, a primary chemotherapeutic agent used to treat numerous solid malignancies, is commonly associated with debilitating peripheral neuropathy. However, a satisfactory gold-standard monotherapy for this neuropathic pain is not currently available. A combination strategy of two or more medications with different properties may achieve more beneficial effects than monotherapy. Thus, we investigated the analgesic efficacies and spinal mechanisms of the combination strategy, including bee venom acupuncture (BVA) and venlafaxine (VLX) against paclitaxel-induced allodynia in mice. Four intraperitoneal infusions of paclitaxel on alternating days (2 mg/kg/day) induced cold and mechanical allodynia for at least 1 week as assessed using acetone and the von Frey hair test, respectively. Co-treatment of BVA (1.0 mg/kg, s.c., ST36) with VLX (40 mg/kg, i.p.) at the medium dose produced a longer-lasting and additive effect than each monotherapy at the highest dose (BVA, 2.5 mg/kg; VLX, 60 mg/kg). Spinal pre-administration of idazoxan (α₂-adrenergic receptor antagonist, 10 μg), methysergide (mixed 5-HT₁/5-HT₂ receptor antagonist, 10 μg), or MDL-72222 (5-HT₃ receptor antagonist, 10 μg) abolished this analgesia. These results suggest that the combination therapy with BVA and VLX produces long-lasting and additive analgesic effects on paclitaxel-induced allodynia, via the spinal noradrenergic and serotonergic mechanism, providing a promising clinical strategy.

State-of-the-art pharmacotherapy for diabetic neuropathy

INTRODUCTION

The global epidemic of diabetes has led to an epidemic of diabetes complications. Diabetic neuropathy is the most common microvascular complication, of which diabetic peripheral neuropathy (DPN) and autonomic neuropathy (AN) are the most prevalent, affecting ~50% of patients. DPN results in pain with a poor quality of life and a loss of sensation with an increased risk of foot ulceration. Autonomic neuropathy can cause significant morbidity in a minority and is associated with increased mortality. The cornerstone of treatment to prevent or limit the progression of DPN/AN is multifactorial risk factor modification including treatment of glycemia, lipids and blood pressure. Whilst, there are no FDA-approved disease-modifying therapies, there are a number of therapies to relieve symptoms in DPN and AN.

AREAS COVERED

The authors discuss current approved therapies for painful diabetic neuropathy and autonomic neuropathy. They also address the potential role of improving risk factors to limit the development and progression of diabetic neuropathy and new pathogenetic and pain-relieving treatments.

EXPERT OPINION

The FDA-approved Pregabalin and Duloxetine over 25 years ago and Tapentadol, 6 years ago for painful diabetic neuropathy. There are currently no FDA-approved disease-modifying treatments for diabetic neuropathy which has been attributed to inappropriate models of the disease with limited translational capacity and major limitations of trial designs and endpoints in clinical trials.

The use of antineuropathic medications for the treatment of chronic pain

Chronic pain syndromes cost the US healthcare system over $600 billion per year. A subtype of chronic pain is neuropathic pain (NP), which is defined as "pain caused by a lesion or disease of the somatosensory system," according to the International Association for the Study of Pain (IASP). The pathophysiology of neuropathic pain is very complex, and more research needs to be done to find the exact mechanism. Patients that have preexisting conditions such as cancer and diabetes are at high-risk of developing NP. Many NP patients are misdiagnosed and receive delayed treatment due to a lack of a standardized classification system that allows clinicians to identify, understand, and utilize pain management in these patients. Medications like tricyclic antidepressants, serotonin-norepinephrine reuptake Inhibitor (SNRIs), and gabapentinoids are first-line treatments followed by opioids, cannabinoids, and other drugs. There are limited studies on the treatment of NP.

Challenges of neuropathic pain: focus on diabetic neuropathy

Neuropathic pain is a frequent condition caused by a lesion or disease of the central or peripheral somatosensory nervous system. A frequent cause of peripheral neuropathic pain is diabetic neuropathy. Its complex pathophysiology is not yet fully elucidated, which contributes to underassessment and undertreatment. A mechanism-based treatment of painful diabetic neuropathy is challenging but phenotype-based stratification might be a way to develop individualized therapeutic concepts. Our goal is to review current knowledge of the pathophysiology of peripheral neuropathic pain, particularly painful diabetic neuropathy. We discuss state-of-the-art clinical assessment, validity of diagnostic and screening tools, and recommendations for the management of diabetic neuropathic pain including approaches towards personalized pain management. We also propose a research agenda for translational research including patient stratification for clinical trials and improved preclinical models in relation to current knowledge of underlying mechanisms.

Non-Adherence to Pharmacotherapy: A Prospective Multicentre Study About Its Incidence and Its Causes Perceived by Chronic Pain Patients

OBJECTIVE

Pharmacological interventions remain the cornerstone of chronic pain treatment; however, nearly 40% of the prescription medicines are not taken as prescribed. The present study aims at understanding and describing non-adherence from the perspective of chronic pain patients during a 1-year follow-up study.

METHODS

A cohort of 950 consecutive patients referred to a first consultation in Multidisciplinary Chronic Pain Clinics was followed with a standardized protocol for 1 year. This included assessment of pain characteristics; prescribed medication; therapeutic adherence; effectiveness of treatment, non-adherence and its perceived reasons; clinical outcomes and quality of life. We used a mixed methods approach, including qualitative and quantitative analyses.

RESULTS

Forty-nine percent of the 562 patients who responded to all assessments during follow-up were adherent after 1 year of chronic pain treatment. The core associations between each "non-adherence reason" and Anatomical Therapeutic Chemical Code (ATC) group were perceived side effects (p=0.019) and delayed start (p=0.022) for narcotic analgesics (opioids); perceived non-efficacy (p=0.017) and delayed start (p=0.004) for antiepileptics and anticonvulsants; perceived low necessity (p=0.041) and delayed start (p=0.036) for analgesics antipyretics; change in prescriptions because of a new clinical condition for antidepressants (p=0.024); high concerns (p=0.045) and change in prescriptions because of a new clinical condition (p<0.001) for non-steroidal anti-inflammatory drugs; delayed start (p=0.016) and financial constraints (p=0.018) for other medications.

DISCUSSION

This study emphasizes the patient's perspective regarding non-adherence to pharmacological treatment of chronic pain, providing valuable and novel information to be used in future interventions to help patients make an informed choice about their adherence behavior.

Treatment of diabetic peripheral neuropathy: a review

OBJECTIVES

This review surveys current pharmacotherapies available for the treatment of diabetic peripheral neuropathy (DPN), emphasising their mechanisms of action.

METHODS

A comprehensive literature review focusing on the 'pharmacotherapy and treatment of diabetic peripheral neuropathy' was conducted. The Database of International Pharmaceutical Abstracts, EMBASE, PubMed, OVID, Scopus, Google and Google Scholar were searched, and reference lists of relevant articles were also included.

KEY FINDINGS

Diabetic peripheral neuropathy is often inadequately treated, and the role of improving glycaemic control specifically in type-2 diabetes remains unclear. It is crucial to explore the mechanisms of action and effectiveness of available therapies. Major international clinical guidelines for the management of DPN recommend several symptomatic treatments. First-line therapies include tricyclic antidepressants, serotonin-noradrenaline reuptake inhibitors, and anticonvulsants that act on calcium channels. Other therapies include opioids and topical agents such as capsaicin and lidocaine. The objectives of this paper are to review current guidelines for the pharmacological management of DPN and to discuss research relevant to the further development of pharmacological recommendations for the treatment of diabetic neuropathy.

SUMMARY

Diabetic neuropathy is a highly prevalent, disabling condition, the management of which is associated with significant costs. Evidence supports the use of specific anticonvulsants and antidepressants for pain management in patients with diabetic peripheral neuropathy. All current guidelines advise a personalised approach with a low-dose start that is tailored to the maximum response having the least side effects or adverse events.

The Analgesic Effect of Venlafaxine and Its Mechanism on Oxaliplatin-Induced Neuropathic Pain in Mice

The analgesic effect of venlafaxine (VLX), which is a selective serotonin and noradrenaline reuptake inhibitor (SNRI), has been observed on oxaliplatin-induced neuropathic pain in mice. Significant allodynia was shown after oxaliplatin treatment (6 mg/kg, i.p.); acetone and von Frey hair tests were used to assess cold and mechanical allodynia, respectively. Intraperitoneal administration of VLX at 40 and 60 mg/kg, but not 10 mg/kg, significantly alleviated these allodynia. Noradrenaline depletion by pretreatment of N-(2-Chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4, 50 mg/kg, i.p.) blocked the relieving effect of VLX (40 mg/kg, i.p.) on cold and mechanical allodynia. However, serotonin depletion by three consecutive pretreatments of para-chlorophenylalanine (PCPA, 150 mg/kg/day, i.p.) only blocked the effect of VLX on mechanical allodynia. In cold allodynia, the α₂-adrenergic antagonist idazoxan (10 μg, i.t.), but not the α₁-adrenergic antagonist prazosin (10 μg, i.t.), abolished VLX-induced analgesia. Furthermore, idazoxan and 5-HT₃ receptor antagonist bemesetron (MDL-72222, 15 μg, i.t.), but not prazosin or mixed 5-HT_{1, 2} receptor antagonist methysergide (10 μg, i.t.), abolished VLX-induced analgesia in mechanical allodynia. In conclusion, 40 mg/kg of VLX treatment has a potent relieving effect against oxaliplatin-induced neuropathic pain, and α₂-adrenergic receptor, and both α₂-adrenergic and 5-HT₃ receptors are involved in this effect of VLX on cold and mechanical allodynia, respectively.

An update on the diagnosis and treatment of diabetic somatic and autonomic neuropathy

Diabetic peripheral neuropathy (DPN) is the most common chronic complication of diabetes. It poses a significant challenge for clinicians as it is often diagnosed late when patients present with advanced consequences such as foot ulceration. Autonomic neuropathy (AN) is also a frequent and under-diagnosed complication unless it is overtly symptomatic. Both somatic and autonomic neuropathy are associated with increased mortality. Multiple clinical trials have failed because of limited efficacy in advanced disease, inadequate trial duration, lack of effective surrogate end-points and a lack of deterioration in the placebo arm in clinical trials of DPN. Multifactorial risk factor reduction, targeting glycaemia, blood pressure and lipids can reduce the progression of DPN and AN. Treatment of painful DPN reduces painful symptoms by about 50% at best, but there is limited efficacy with any single agent. This reflects the complex aetiology of painful DPN and argues for improved clinical phenotyping with the use of targeted therapy, taking into account co-morbid conditions such as anxiety, depression and sleep disturbance.

rTMS effects in patients with co-morbid somatic pain and depressive mood disorders

BACKGROUND

Pain is a common co-morbidity among clinically depressed individuals. We investigated a group of patients who were treated with repetitive transcranial magnetic stimulation (rTMS) for treatment resistant depression (TRD) and who were assessed for severity of both depression and pain at baseline and throughout treatment.

METHODS

Records of 71 patients treated for TRD with rTMS from 2008 to 2017 were reviewed. Primary outcome measures including depression severity using the Quick Inventory of Depressive Symptomatology (QIDS) and a 0-10 numeric pain rating scale were assessed at baseline and after every 5 sessions throughout the course of 30 treatments.

RESULTS

In the total sample, pain improved significantly over the course of treatment. Changes within subjects in QIDS were associated with the changes in pain (p = 0.011). TRD patients with higher pain scores at baseline tended to be older, experienced a longer duration of illness, and showed significant differences in QIDS over treatment time as compared with the low baseline pain group. Patients who had failed a serotonin norepinephrine reuptake inhibitor (SNRI) (venlafaxine or duloxetine) trial in the past had less pain at baseline and showed a group difference in pain scores at all time points, which was significant at treatments 20, 25 and 30, compared to patient groups who had never taken these medications or were currently taking these medications.

LIMITATIONS

Limitations include the potential impact of the discomfort over the treatment site on the scalp, as it is unclear whether patients' assessment of pain included this side effect, and the lack of a control group due to the naturalistic design of this study.

CONCLUSION

Our data show that pain and depression respond well to rTMS in a TRD population. Pain and depression severity in rTMS patients may be associated over the course of rTMS treatment time-points in individuals with higher levels of baseline pain.

Medications for alcohol use disorders: An overview

Patients who suffer from alcohol use disorders (AUDs) usually go through various socio-behavioral and pathophysiological changes that take place in the brain and other organs. Recently, consumption of unhealthy food and excess alcohol along with a sedentary lifestyle has become a norm in both developed and developing countries. Despite the beneficial effects of moderate alcohol consumption, chronic and/or excessive alcohol intake is reported to negatively affect the brain, liver and other organs, resulting in cell death, organ damage/failure and death. The most effective therapy for alcoholism and alcohol related comorbidities is alcohol abstinence, however, chronic alcoholic patients cannot stop drinking alcohol. Therefore, targeted therapies are urgently needed to treat such populations. Patients who suffer from alcoholism and/or alcohol abuse experience harmful effects and changes that occur in the brain and other organs. Upon stopping alcohol consumption, alcoholic patients experience acute withdrawal symptoms followed by a protracted abstinence syndrome resulting in the risk of relapse to heavy drinking. For the past few decades, several drugs have been available for the treatment of AUDs. These drugs include medications to reduce or stop severe alcohol withdrawal symptoms during alcohol detoxification as well as recovery medications to reduce alcohol craving and support abstinence. However, there is no drug that completely antagonizes the adverse effects of excessive amounts of alcohol. This review summarizes the drugs which are available and approved by the FDA and their mechanisms of action as well as the medications that are under various phases of preclinical and clinical trials. In addition, the repurposing of the FDA approved drugs, such as anticonvulsants, antipsychotics, antidepressants and other medications, to prevent alcoholism and treat AUDs and their potential target mechanisms are summarized.

Diabetic Peripheral Neuropathy: Epidemiology, Diagnosis, and Pharmacotherapy

PURPOSE

Diabetic peripheral neuropathy (DPN) is the commonest cause of neuropathy worldwide, and its prevalence increases with the duration of diabetes. It affects approximately half of patients with diabetes. DPN is symmetric and predominantly sensory, starting distally and gradually spreading proximally in a glove-and-stocking distribution. It causes substantial morbidity and is associated with increased mortality. The unrelenting nature of pain in this condition can negatively affect a patient's sleep, mood, and functionality and result in a poor quality of life. The purpose of this review was to critically review the current literature on the diagnosis and treatment of DPN, with a focus on the treatment of neuropathic pain in DPN.

METHODS

A comprehensive literature review was undertaken, incorporating article searches in electronic databases (EMBASE, PubMed, OVID) and reference lists of relevant articles with the authors' expertise in DPN. This review considers seminal and novel research in epidemiology; diagnosis, especially in relation to novel surrogate end points; and the treatment of neuropathic pain in DPN. We also consider potential new pharmacotherapies for painful DPN.

FINDINGS

DPN is often misdiagnosed and inadequately treated. Other than improving glycemic control, there is no licensed pathogenetic treatment for diabetic neuropathy. Management of painful DPN remains challenging due to difficulties in personalizing therapy and ascertaining the best dosing strategy, choice of initial pharmacotherapy, consideration of combination therapy, and deciding on defining treatment for poor analgesic responders. Duloxetine and pregabalin remain first-line therapy for neuropathic pain in DPN in all 5 of the major published guidelines by the American Association of Clinical Endocrinologists, American Academy of Neurology, European Federation of Neurological Societies, National Institute of Clinical Excellence (United Kingdom), and the American Diabetes Association, and their use has been approved by the US Food and Drug Administration.

IMPLICATIONS

Clinical recognition of DPN is imperative for allowing timely symptom management to reduce the morbidity associated with this condition.

Cancer-Related Neuropathic Pain: Review and Selective Topics

Neuropathic pain is the result of neuroplastic and neuroinflammatory changes from trauma or diseases that damage the somatosensory system. Cancer-related neuropathic pain is caused by treatment, cancer, or paraneoplastic reactions to cancer. Approximately 30% of patients with cancer have neuropathic pain, mostly mixed nociceptive and neuropathic pain. History, physical examination, quantitative sensory testing, skin punch biopsies, and functional MRIs help to divide pain into phenotypes that may facilitate analgesic choices. Guidelines for treating cancer-related neuropathic pain are not consistent and are highly dependent on trials in patients without cancer. Combinations of analgesics are promising, whereas evidence for cannabinoids is meager.

Serotonin and Norepinephrine Reuptake Inhibitors

This chapter covers antidepressants that fall into the class of serotonin (5-HT) and norepinephrine (NE) reuptake inhibitors. That is, they bind to the 5-HT and NE transporters with varying levels of potency and binding affinity ratios. Unlike the selective serotonin (5-HT) reuptake inhibitors (SSRIs), most of these antidepressants have an ascending rather than a flat dose-response curve. The chapter provides a brief review of the chemistry, pharmacology, metabolism, safety and adverse effects, clinical use, and therapeutic indications of each antidepressant. Venlafaxine, a phenylethylamine, is a relatively weak 5-HT and weaker NE uptake inhibitor with a 30-fold difference in binding of the two transporters. Therefore, the drug has a clear dose progression, with low doses predominantly binding to the 5-HT transporter and more binding of the NE transporter as the dose ascends. Venlafaxine is metabolized to the active metabolite O-desmethylvenlafaxine (ODV; desvenlafaxine) by CYP2D6, and it therefore is subject to significant inter-individual variation in blood levels and response dependent on variations in CYP2D6 metabolism. The half-life of venlafaxine is short at about 5 h, with the ODV metabolite being 12 h. Both parent compound and metabolite have low protein binding and neither inhibit CYP enzymes. Therefore, both venlafaxine and desvenlafaxine are potential options if drug-drug interactions are a concern, although venlafaxine may be subject to drug-drug interactions with CYP2D6 inhibitors. At low doses, the adverse effect profile is similar to an SSRI with nausea, diarrhea, fatigue or somnolence, and sexual side effects, while venlafaxine at higher doses can produce mild increases in blood pressure, diaphoresis, tachycardia, tremors, and anxiety. A disadvantage of venlafaxine relative to the SSRIs is the potential for dose-dependent blood pressure elevation, most likely due to the NE reuptake inhibition caused by higher doses; however, this adverse effect is infrequently observed at doses below 225 mg per day. Venlafaxine also has a number of potential advantages over the SSRIs, including an ascending dose-antidepressant response curve, with possibly greater overall efficacy at higher doses. Venlafaxine is approved for MDD as well as generalized anxiety disorder, social anxiety disorder, and panic disorder. Desvenlafaxine is the primary metabolite of venlafaxine, and it is also a relatively low-potency 5-HT and NE uptake inhibitor. Like venlafaxine it has a favorable drug-drug interaction profile. It is subject to CYP3A4 metabolism, and it is therefore vulnerable to enzyme inhibition or induction. However, the primary metabolic pathway is direct conjugation. It is approved in the narrow dose range of 50-100 mg per day. Duloxetine is a more potent 5-HT and NE reuptake inhibitor with a more balanced profile of binding at about 10:1 for 5HT and NE transporter binding. It is also a moderate inhibitor of CYP2D6, so that modest dose reductions and careful monitoring will be needed when prescribing duloxetine in combination with drugs that are preferentially metabolized by CYP2D6. The most common side effects identified in clinical trials are nausea, dry mouth, dizziness, constipation, insomnia, asthenia, and hypertension, consistent with its mechanisms of action. Clinical trials to date have demonstrated rates of response and remission in patients with major depression that are comparable to other marketed antidepressants reviewed in this book. In addition to approval for MDD, duloxetine is approved for diabetic peripheral neuropathic pain, fibromyalgia, and musculoskeletal pain. Milnacipran is marketed as an antidepressant in some countries, but not in the USA. It is approved in the USA and some other countries as a treatment for fibromyalgia. It has few pharmacokinetic and pharmacodynamic interactions with other drugs. Milnacipran has a half-life of about 10 h and therefore needs to be administered twice per day. It is metabolized by CYP3A4, but the major pathway for clearance is direct conjugation and renal elimination. As with other drugs in this class, dysuria is a common, troublesome, and dose-dependent adverse effect (occurring in up to 7% of patients). High-dose milnacipran has been reported to cause blood pressure and pulse elevations. Levomilnacipran is the levorotary enantiomer of milnacipran, and it is pharmacologically very similar to the racemic compound, although the side effects may be milder within the approved dosing range. As with other NE uptake inhibitors, it may increase blood pressure and pulse, although it appears to do so less than some other medications. All medications in the class can cause serotonin syndrome when combined with MAOIs.

Small fiber neuropathy: Diagnosis, causes, and treatment

Small fiber neuropathy, which affects the sensory Aδ and C fibers, is now a major diagnostic and therapeutic challenge. Nearly 7% of the general population have chronic neuropathic pain responsible for severe quality-of-life impairments. Awareness must therefore be raised among clinicians of the somatosensory and autonomic symptoms that can reveal small fiber neuropathy, appropriate diagnostic investigations, most common causes, and best treatment options for each patient profile. To help achieve this goal, the present review article discusses the clinical presentation of neuropathic pain and paresthesia and/or autonomic dysfunction due to involvement of nerves supplying exocrine glands and smooth muscle; normal findings from standard electrophysiological investigations; most informative diagnostic tests (epidermal nerve fiber density in a skin biopsy, laser-evoked potentials, heat- and cold-detection thresholds, electrochemical skin conductance); main causes, which consist chiefly of metabolic diseases (diabetes mellitus, glucose intolerance), dysimmunity syndromes (Sjögren's syndrome, sarcoidosis, monoclonal gammopathy), and genetic abnormalities (familial amyloidosis due to a transthyretin mutation, Fabry disease, sodium channel diseases); and the available symptomatic and etiological treatments.