Current Status of the New Antiepileptic Drugs in Chronic Pain

TRPV1 channel in the pathophysiology of epilepsy and its potential as a molecular target for the development of new antiseizure drug candidates

Identification of transient receptor potential cation channel, subfamily V member 1 (TRPV1), also known as capsaicin receptor, in 1997 was a milestone achievement in the research on temperature sensation and pain signalling. Very soon after it became evident that TRPV1 is implicated in a wide array of physiological processes in different peripheral tissues, as well as in the central nervous system, and thereby could be involved in the pathophysiology of numerous diseases. Increasing evidence suggests that modulation of TRPV1 may also affect seizure susceptibility and epilepsy. This channel is localized in brain regions associated with seizures and epilepsy, and its overexpression was found both in animal models of seizures and in brain samples from epileptic patients. Moreover, modulation of TRPV1 on non-neuronal cells (microglia, astrocytes, and/or peripheral immune cells) may have an impact on the neuroinflammatory processes that play a role in epilepsy and epileptogenesis. In this paper, we provide a comprehensive and critical overview of currently available data on TRPV1 as a possible molecular target for epilepsy management, trying to identify research gaps and future directions. Overall, several converging lines of evidence implicate TRPV1 channel as a potentially attractive target in epilepsy research but more studies are needed to exploit the possible role of TRPV1 in seizures/epilepsy and to evaluate the value of TRPV1 ligands as candidates for new antiseizure drugs.

Blood-Derived Eye Drops for the Treatment of Corneal Neuropathic Pain

Blood-derived preparations, including autologous or allogenic serum, umbilical cord serum/plasma, and platelet-rich plasma eye drops, contain various growth factors, cytokines, and immunoglobulins that resemble natural tears. These components play important roles in corneal cell migration, proliferation, and wound healing. Blood-derived eye drops have demonstrated clinical effectiveness across a spectrum of ocular surface conditions, encompassing dry eye disease, Sjögren's syndrome, graft-versus-host disease, and neuropathic corneal pain (NCP). Currently, management of NCP remains challenging. The emergence of blood-derived eye drops represents a promising therapeutic approach. In this review, we discuss the benefits and limitations of different blood-derived eye drops, their mechanisms of action, and treatment efficacy in patients with NCP. Several studies have demonstrated the clinical efficacy of autologous serum eye drops in relieving pain and pain-like symptoms, such as allodynia and photoallodynia. Corneal nerve parameters were also significantly improved, as evidenced by increased nerve fiber density, length, nerve reflectivity, and tortuosity, as well as a decreased occurrence of beading and neuromas after the treatment. The extent of nerve regeneration correlated with improvement in patient-reported photoallodynia. Cord plasma eye drops also show potential for symptom alleviation and corneal nerve regeneration. Future directions for clinical practice and research involve standardizing preparation protocols, establishing treatment guidelines, elucidating underlying mechanisms, conducting long-term clinical trials, and implementing cost-effective measures such as scaling up manufacturing. With ongoing advancements, blood-derived eye drops hold promise as a valuable therapeutic option for patients suffering from NCP.

Identification of (4-chlorophenyl)(5-hydroxynaphtho[1,2-b]furan-3-yl)methanone as novel COX-2 inhibitor with analgesic profile

Chronic pain is a serious problem that affects billions of people worldwide, but current analgesic drugs limit their use in chronic pain management due to their respective side effects. As a first-line clinical drug for chronic pain, COX-2 selective inhibitors can relieve mild to moderate pain, but they also have some problems. The most prominent one is that their analgesic intensity is not enough, and they cannot well meet the treatment needs of chronic pain. Therefore, there is an urgent need to develop COX-2 inhibitors with stronger analgesic intensity. In this article, we used virtual screening method to screen out the structurally novel COX-2 inhibitor for chronic pain management, and conducted a preliminary study on its mechanism of action using molecular dynamics simulation.

Neuropathic Corneal Pain after Coronavirus Disease 2019 (COVID-19) Infection

INTRODUCTION

This is a case report of a patient with neuropathic corneal pain after coronavirus disease 2019 (COVID-19) infection.

METHODS

A previously healthy 27-year-old female presented with bilateral eye pain accompanied by increased light sensitivity 5 months after COVID-19 infection. She was diagnosed with neuropathic corneal pain based on clear corneas without fluorescein staining, alongside the presence of microneuromas, dendritic cells, and activated stromal keratocytes identified bilaterally on in vivo confocal microscopy.

RESULTS

The patient's tear nerve growth factor, substance P, and calcitonin gene-related peptide levels were 5.9 pg/mL, 2978.7 pg/mL, and 1.1 ng/mL, respectively, for the right eye and 23.1 pg/mL, 4798.7 pg/mL, and 1.2 ng/mL, respectively, for the left eye, suggesting corneal neuroinflammatory status. After 6 weeks of topical 0.1% flurometholone treatment, decreased microneuroma size, less extensive dendritic cells, and reduced tear nerve growth factor and substance P levels were observed. The scores on the Ocular Pain Assessment Survey showed an improvement in burning sensation and light sensitivity, decreasing from 80% and 70% to 50% for both.

CONCLUSIONS

Neuropathic corneal pain is a potential post-COVID-19 complication that warrants ophthalmologists' and neurologists' attention.

Neurophysiology of corneal neuropathic pain and emerging pharmacotherapeutics

The altered activity generated by corneal neuronal injury can result in morphological and physiological changes in the architecture of synaptic connections in the nervous system. These changes can alter the sensitivity of neurons (both second-order and higher-order projection) projecting pain signals. A complex process involving different cell types, molecules, nerves, dendritic cells, neurokines, neuropeptides, and axon guidance molecules causes a high level of sensory rearrangement, which is germane to all the phases in the pathomechanism of corneal neuropathic pain. Immune cells migrating to the region of nerve injury assist in pain generation by secreting neurokines that ensure nerve depolarization. Furthermore, excitability in the central pain pathway is perpetuated by local activation of microglia in the trigeminal ganglion and alterations of the descending inhibitory modulation for corneal pain arriving from central nervous system. Corneal neuropathic pain may be facilitated by dysfunctional structures in the central somatosensory nervous system due to a lesion, altered synaptogenesis, or genetic abnormality. Understanding these important pathways will provide novel therapeutic insight.

PLGA-Based Nanomedicine: History of Advancement and Development in Clinical Applications of Multiple Diseases

Research on the use of biodegradable polymers for drug delivery has been ongoing since they were first used as bioresorbable surgical devices in the 1980s. For tissue engineering and drug delivery, biodegradable polymer poly-lactic-co-glycolic acid (PLGA) has shown enormous promise among all biomaterials. PLGA are a family of FDA-approved biodegradable polymers that are physically strong and highly biocompatible and have been extensively studied as delivery vehicles of drugs, proteins, and macromolecules such as DNA and RNA. PLGA has a wide range of erosion times and mechanical properties that can be modified. Many innovative platforms have been widely studied and created for the development of methods for the controlled delivery of PLGA. In this paper, the various manufacturing processes and characteristics that impact their breakdown and drug release are explored in depth. Besides different PLGA-based nanoparticles, preclinical and clinical applications for different diseases and the PLGA platform types and their scale-up issues will be discussed.

Transcriptional and cellular signatures of cortical morphometric remodelling in chronic pain

ABSTRACT

Chronic pain is a highly debilitating and difficult to treat condition, which affects the structure of the brain. Although the development of chronic pain is moderately heritable, how disease-related alterations at the microscopic genetic architecture drive macroscopic brain abnormalities is currently largely unknown. Here, we examined alterations in morphometric similarity (MS) and applied an integrative imaging transcriptomics approach to identify transcriptional and cellular correlates of these MS changes, in 3 independent small cohorts of patients with distinct chronic pain syndromes (knee osteoarthritis, low back pain, and fibromyalgia) and age-matched and sex-matched pain-free controls. We uncover a novel pattern of cortical MS remodelling involving mostly small-to-medium MS increases in the insula and limbic cortex (none of these changes survived stringent false discovery rate correction for the number of regions tested). This pattern of changes is different from that observed in patients with major depression and cuts across the boundaries of specific pain syndromes. By leveraging transcriptomic data from Allen Human Brain Atlas, we show that cortical MS remodelling in chronic pain spatially correlates with the brain-wide expression of genes related to pain and broadly involved in the glial immune response and neuronal plasticity. Our findings bridge levels to connect genes, cell classes, and biological pathways to in vivo imaging correlates of chronic pain. Although correlational, our data suggest that cortical remodelling in chronic pain might be shaped by multiple elements of the cellular architecture of the brain and identifies several pathways that could be prioritized in future genetic association or drug development studies.

Antinociceptive and Antiallodynic Activity of Some 3-(3-Methylthiophen-2-yl)pyrrolidine-2,5-dione Derivatives in Mouse Models of Tonic and Neuropathic Pain

Antiseizure drugs (ASDs) are commonly used to treat a wide range of nonepileptic conditions, including pain. In this context, the analgesic effect of four pyrrolidine-2,5-dione derivatives (compounds 3, 4, 6, and 9), with previously confirmed anticonvulsant and preliminary antinociceptive activity, was assessed in established pain models. Consequently, antinociceptive activity was examined in a mouse model of tonic pain (the formalin test). In turn, antiallodynic and antihyperalgesic activity were examined in the oxaliplatin-induced model of peripheral neuropathy as well as in the streptozotocin-induced model of painful diabetic neuropathy in mice. In order to assess potential sedative properties (drug safety evaluation), the influence on locomotor activity was also investigated. As a result, three compounds, namely 3, 6, and 9, demonstrated a significant antinociceptive effect in the formalin-induced model of tonic pain. Furthermore, these substances also revealed antiallodynic properties in the model of oxaliplatin-induced peripheral neuropathy, while compound 3 attenuated tactile allodynia in the model of diabetic streptozotocin-induced peripheral neuropathy. Apart from favorable analgesic properties, the most active compound 3 did not induce any sedative effects at the active dose of 30 mg/kg after intraperitoneal (i.p.) injection.

Modulation of nociception and pain-evoked neurobehavioral responses by levetiracetam in a craniotomy pain model

Traditional and novel analgesic modalities have been extensively tested for post-craniotomy pain management, yet the role of newer antiepileptic drugs in this area remains obscure. This study investigates the impact of levetiracetam (LEV) on pain modulation and neurobehavioral performance in a craniotomy model. Fifty-six Wistar rats were randomly assigned into seven groups: no intervention (CTRL), administration of placebo or LEV with no further intervention (PBO and LEV, respectively), and sham-operation or craniotomy in placebo (PBO-SHAM and PBO-CR, respectively) or LEV-treated rats (LEV-SHAM and LEV-CR, respectively). Pain was assessed by the rat grimace scale before, and at 8 and 24 h after craniotomy, following intraperitoneal injections of LEV (100 mg/kg twice daily) or normal saline two consecutive days before and on the craniotomy day. Elevated plus-maze and olfactory social memory tests were performed at 24- and 48 h post-craniotomy, respectively. Upon testing conclusion blood samples were collected for cytokines estimation. Levetiracetam administration enhanced antinociception in sham and craniotomy groups. In the elevated plus-maze test, LEV-CR rats spent more time in investigating open arms and performed more open arm entries than PBO-SHAM and PBO-CR animals. The olfactory test revealed no between-groups difference in acquisition time during first contact with a juvenile rat, while LEV-CR rats spent less time to recognize the same juvenile rat compared to PBO-SHAM and PBO-CR groups. Furthermore, LEV-treatment attenuated cortisol, interleukin-6 and TNF-a release, in sham and craniotomy animals. In conclusion, preemptive use of LEV decreases nociception, improves pain-evoked behavior and attenuates stress response in rats subjected to craniotomy.

Valproate-Induced Epigenetic Upregulation of Hypothalamic Fto Expression Potentially Linked with Weight Gain

Valproate (VPA), a widely-used antiepileptic drug, is a selective inhibitor of histone deacetylase (HDAC) that play important roles in epigenetic regulation. The patient with different diseases receiving this drug tend to exhibit weight gain and abnormal metabolic phenotypes, but the underlying mechanisms remain largely unknown. Here we show that VPA increases the Fto mRNA and protein expression in mouse hypothalamic GT1-7 cells. Interestingly, VPA promotes histone H3/H4 acetylation and the FTO expression which could be reversed by C646, an inhibitor for histone acetyltransferase. Furthermore, VPA weakens the FTO's binding and enhances the binding of transcription factor TAF1 to the Fto promoter, and C646 leads to reverse effect of the VPA, suggesting an involvement of the dynamic of histone H3/H4 acetylation in the regulation of FTO expression. In addition, the mice exhibit an increase in the food intake and body weight at the beginning of 2-week treatment with VPA. Simultaneously, in the hypothalamus of the VPA-treated mice, the FTO expression is upregulated and the H3/H4 acetylation is increased; further the FTO's binding to the Fto promoter is decreased and the TAF1's binding to the promoter is enhanced, suggesting that VPA promotes the assembly of the basal transcriptional machinery of the Fto gene. Finally, the inhibitor C646 could restore the effects of VPA on FTO expression, H3/H4 acetylation, body weight, and food intake; and loss of FTO could reverse the VPA-induced increase of body weight and food intake. Taken together, this study suggests an involvement of VPA in the epigenetic upregulation of hypothalamic FTO expression that is potentially associated with the VPA-induced weight gain.

Novel treatments for chronic pain: moving beyond opioids

It is essential that safe and effective treatment options be available to patients suffering from chronic pain. The emergence of an opioid epidemic has shaped public opinions and created stigmas surrounding the use of opioids for the management of pain. This reality, coupled with high risk of adverse effects from chronic opioid use, has led chronic pain patients and their healthcare providers to utilize nonopioid treatment approaches. In this review, we will explore a number of cellular reorganizations that are associated with the development and progression of chronic pain. We will also discuss the safety and efficacy of opioid and nonopioid treatment options for chronic pain. Finally, we will review the evidence for adenylyl cyclase type 1 (AC1) as a novel target for the treatment of chronic pain.

Effects of antiepileptic drugs on ovaries of female Wistar rats

Valproate (VPA) induced changes in ovarian morphology are observed in humans with epilepsy and in non-epileptic animals. The effects of lamotrigine (LTG) on female reproduction is not well known. We investigated whether LTG might be a safer drug for use with patients of reproductive age. Forty Wistar albino female rats were divided into five groups. The control group was injected with saline-vehicle solution. The low dose (LD)-VPA group was injected with 100 mg/kg VPA. The high dose (HD)-VPA group was injected with 500 mg/kg VPA. The LD-LTG group was injected with 10 mg/kg LTG. The HD-LTG group was injected with 50 mg/kg LTG. We evaluated histological and biochemical changes in the ovaries. The number of atretic and cystic follicles was increased in the HD-VPA and HD-LTG groups compared to the control group. A significant increase in malondialdehyde level was found in the VPA groups compared to the control and LTG groups. No significant differences in total glutathione levels or superoxide dismutase activity were found among study groups. Catalase activity was significantly higher in HD-VPA and HD-LTG groups compared to the control, LD-VPA and LD-LTG groups. Prevalence and intensity of caspase-3 immunoreactivity in the luteal cells were significantly greater in the HD-LTG group compared to the control group. VPA administration caused polycystic ovarian syndrome-like changes in the ovary. We found that LD-LTG, which reflects the dose for humans, might be a safer option for use during the reproductive age.

Development and Validation of a Free Carbamazepine Assay on an Automated Chemistry Analyzer

BACKGROUND

Carbamazepine is an effective drug for treating seizures and trigeminal neuralgia. Therapeutic drug monitoring of free carbamazepine in serum can be useful in situations that drug--protein binding is altered to guide regimen adjustment and to aid in the diagnosis of clinical toxicity.

METHODS

Separation of the nonprotein bound carbamazepine was achieved via ultrafiltration through a molecular weight cut-off filter. A method for free carbamazepine measurement was developed on the automated cobas chemistry analyzers (Roche Diagnostics) by modifying the Carbamazepine Gen 4 assay (Roche Diagnostics). Assay performance characteristics were established including precision, accuracy, reportable range, analytical specificity, and stability.

RESULTS

The intra- and inter-assay imprecision was 0%-1.4% and 2.4%-5.1%, respectively. The lower limit of quantitation was 0.3 µg/mL, and the assay was linear up to 10.0 µg/mL. A spike recovery study, using reference standard material, showed recovery was 93.5%--101.3% across the analytical measurement range. Method comparison with a reference laboratory method demonstrated equivalent performance with a slope of 1.01, intercept of 0.09, and correlation coefficient of 0.9948.

CONCLUSION

This assay provides a simple and accurate method for monitoring free carbamazepine with a fast turnaround time.

Analgesic and Anti-Inflammatory Effects of Perampanel in Acute and Chronic Pain Models in Mice: Interaction With the Cannabinergic System

Pain conditions, such as neuropathic pain (NP) and persistent inflammatory pain are therapeutically difficult to manage. Previous studies have shown the involvement of glutamate receptor in pain modulation and in particular same of these showed the key role of the AMPA ionotropic glutamate receptor subtype. Antiseizure medications (ASMs) are often used to treat this symptom, however the effect of perampanel (PER), an ASM acting as selective, non-competitive inhibitor of the AMPA receptor on the management of pain has not well been investigated yet. Here we tested the potential analgesic and anti-inflammatory effects of PER, in acute and chronic pain models. PER was given orally either in acute (5 mg/kg) or repeated administration (3 mg/kg/d for 4 days). Pain response was assessed using models of nociceptive sensitivity, visceral and inflammatory pain, and mechanical allodynia and hyperalgesia induced by chronic constriction injury to the sciatic nerve. PER significantly reduced pain perception in all behavioral tests as well as CCI-induced mechanical allodynia and hyperalgesia in acute regimen (5 mg/kg). This effect was also observed after repeated treatment using the dose of 3 mg/kg/d. The antinociceptive, antiallodynic and antihyperalgesic effects of PER were attenuated when the CB₁ antagonist AM251 (1 mg/kg/i.p.) was administered before PER treatment, suggesting the involvement of the cannabinergic system. Moreover, Ex vivo analyses showed that PER significantly increased CB₁ receptor expression and reduced inflammatory cytokines (i.e. TNFα, IL-1β, and IL-6) in the spinal cord. In conclusion, these results extend our knowledge on PER antinociceptive and antiallodynic effects and support the involvement of cannabinergic system on its mode of action.

Analgesic opioid use disorders in patients with chronic non-cancer pain: A holistic approach for tailored management

Chronic pain is a major public health issue that frequently leads to analgesic opioid prescriptions. These prescriptions could cause addiction issues in high-risk patients with associated comorbidities, especially those of a psychiatric, addictive, and social nature. Pain management in dependent patients is complex and is yet to be established. By combining the views of professionals from various specialties, we conducted an integrative review on this scope. This methodology synthesizes knowledge and results of significant practical studies to provide a narrative overview of the literature. The main results consisted in first proposing definitions that could allow shared vocabulary among health professionals regardless of their specialties. Next, a discussion was conducted around the main strategies for managing prescription opioid dependence, as well as pain in the context of opioid dependence and associated comorbidities. As a conclusion, we proposed to define the contours of holistic management by outlining the main guidelines for creating a multidisciplinary care framework for multi-comorbid patients with chronic pathologies.

Synthesis, anticonvulsant, and antinociceptive activity of new 3-(3-methyl-2,5-dioxo-3-phenylpyrrolidin-1-yl)propanamides and 3-phenyl-butanamides

A focused library of new 3-(3-methyl-2,5-dioxo-3-phenylpyrrolidin-1-yl)propanamides and their nonimide analogs were synthesized and tested for anticonvulsant activity. These compounds were obtained through the coupling reaction of the starting carboxylic acids with appropriate amines. The initial anticonvulsant screening was performed in mice (intraperitoneal administration) using the maximal electroshock seizure (MES) and the subcutaneous pentylenetetrazole (scPTZ) seizure models. The most promising compound 6 showed more potent protection in the MES and scPTZ tests than valproic acid, which is still recognized as one of the most relevant first-line anticonvulsants. The structure-activity relationship analysis revealed that the presence of the pyrrolidine-2,5-dione ring is important but not indispensable to retain anticonvulsant activity. Additionally, compound 6 showed potent antinociceptive properties in the oxaliplatin-induced neuropathic pain model in mice. The most plausible mechanism of action for compound 6 may result from its influence on the neuronal sodium channel (Site 2) and the high-voltage-activated L-type calcium channel.

Potential Pharmacokinetic Drug-Drug Interactions between Cannabinoids and Drugs Used for Chronic Pain

Choosing an appropriate treatment for chronic pain remains problematic, and despite the available medication for its treatment, still, many patients complain about pain and appeal to the use of cannabis derivatives for pain control. However, few data have been provided to clinicians about the pharmacokinetic drug-drug interactions of cannabinoids with other concomitant administered medications. Therefore, the aim of this brief review is to assess the interactions between cannabinoids and pain medication through drug transporters (ATP-binding cassette superfamily members) and/or metabolizing enzymes (cytochromes P450 and glucuronyl transferases).

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.

Structure-activity relationship and cardiac safety of 2-aryl-2-(pyridin-2-yl)acetamides as a new class of broad-spectrum anticonvulsants derived from Disopyramide

A series of 2-aryl-2-(pyridin-2-yl)acetamides were synthesized and screened for their anticonvulsant activity in animal models of epilepsy. The compounds were broadly active in the 'classical' maximal electroshock seizure (MES) and subcutaneous Metrazol (scMET) tests as well as in the 6 Hz and kindling models of pharmacoresistant seizures. Furthermore, the compounds showed good therapeutic indices between anticonvulsant activity and motor impairment. Structure-activity relationship (SAR) trends clearly showed the highest activity resides in unsubstituted phenyl derivatives or compounds having ortho- and meta- substituents on the phenyl ring. The 2-aryl-2-(pyridin-2-yl)acetamides were derived by redesign of the cardiotoxic sodium channel blocker Disopyramide (DISO). Our results show that the compounds preserve the capability of the parent compound to inhibit voltage gated sodium currents in patch-clamp experiments; however, in contrast to DISO, a representative compound from the series 1 displays high levels of cardiac safety in a panel of in vitro and in vivo experiments.

Antiepileptic Drug Use and the Risk of Stroke Among Community-Dwelling People With Alzheimer Disease: A Matched Cohort Study

Background People with Alzheimer disease ( AD ) are more predisposed to seizures than older people in general, and use of antiepileptic drugs ( AED s) is more frequent. AED use has been linked to a higher risk of vascular events in the general population; however, it is not evident whether the same risk exists in people with AD . We assessed the risk of stroke associated with incident AED use among people with AD . Methods and Results The MEDALZ (Medication Use and Alzheimer's Disease) cohort includes all Finnish people who received a clinically verified AD diagnosis (N=70718) from 2005 to 2011. People with previous strokes were excluded. For each incident AED user (n=5617) one nonuser was matched according to sex, age, and time since AD diagnosis. Analyses were conducted with Cox proportional hazards models and inverse probability of treatment weighting. Compared with nonuse, AED use was associated with an increased risk of stroke (inverse probability of treatment weighting hazard ratio ( HR ), 1.37; 95% confidence interval [CI], 1.07-1.74). The risk was strongest during the first 90 days (adjusted HR , 2.36; 95% CI , 1.25-4.47) of AED use. According to stroke type, the association was with ischemic strokes (inverse probability of treatment weighting HR , 1.34; 95% CI , 1.00-1.79) and hemorrhagic ones (inverse probability of treatment weighting HR , 1.44; 95% CI , 0.86-2.43). The stroke risk of users of older AED s did not differ from that of the users of newer AED s (adjusted HR , 1.04; 95% CI , 0.71-1.53). Conclusions AED use was related to an increased risk of stroke, regardless of AED type. Our results highlight caution in AED use in this vulnerable population.

Medication Use and Pain Management in Pregnancy: A Critical Review

BACKGROUND

Pain during pregnancy is common, and its management is complex. Certain analgesics may increase the risk for adverse fetal and pregnancy outcomes, while poorly managed pain can result in adverse maternal outcomes such as depression and hypertension. Guidelines to assist clinicians in assessing risks and benefits of exposure to analgesics for the mother and unborn infant are lacking, necessitating evidence-based recommendations for managing pain in pregnancy.

METHODS

A comprehensive literature search was conducted to assess pregnancy safety data for pharmacological and nonpharmacological pain management methods. Relevant clinical trials and observational studies were identified using multiple medical databases, and included studies were evaluated for quality and possible biases.

RESULTS

Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are appropriate for mild to moderate pain, but NSAIDs should be avoided in the third trimester due to established risks. Short courses of weaker opioids are generally safe in pregnancy, although neonatal abstinence syndrome must be monitored following third trimester exposure. Limited safety data for pregabalin and gabapentin indicate that these are unlikely to be major teratogens, and tricyclic antidepressants and serotonin-norepinephrine reuptake inhibitors have limited but overall reassuring safety data. Many of the included studies were limited by methodological issues.

CONCLUSIONS

Findings from this review can guide clinicians in their decision to prescribe analgesics for pregnant women. Treatment should be tailored to the lowest therapeutic dose and shortest possible duration, and management should involve a discussion of risks and benefits and monitoring for response. Further research is required to better understand the safety profile of various analgesics in pregnancy.

Benzensulfonamides bearing spyrohydantoin moieties act as potent inhibitors of human carbonic anhydrases II and VII and show neuropathic pain attenuating effects

Carbonic Anhydrases have been recently validated as novel therapeutic targets in neuropathic pain. In this study, we combine the anticonvulsant propriety of spyrohydantoin and the CA inhibitor moiety of benzenesulfonamide to synthesize a novel series of spyrohydantoin bearing sulfonamides with strong activity against hCA II and VII. These isoforms are present in the nervous system and largely expressed both at the central as well as at peripheral level and can be modulated for pain relief. The crystal structures of hCA II in complex with selected compounds 5a-c demonstrate the importance of the tail in the binding modes within the isoform. Finally, in vivo, in an animal model of oxaliplatin induced neuropathy, compounds with organoselenium tails (8b-c) showed potent neuropathic pain attenuating effects. Taken together, these data strongly suggest the translational utility of these inhibitors as novel pain relievers.

Effect of carbamazepine on tetrodotoxin-resistant Na+ channels in trigeminal ganglion neurons innervating to the dura

Migraine is a neurological disorder characterized by recurrent and disabling severe headaches. Although several anticonvulsant drugs that block voltage-dependent Na⁺ channels are widely used for migraine, far less is known about the therapeutic actions of carbamazepine on migraine. In the present study, therefore, we characterized the effects of carbamazepine on tetrodotoxin-resistant (TTX-R) Na⁺ channels in acutely isolated rat dural afferent neurons, which were identified by the fluorescent dye DiI. The TTX-R Na⁺ currents were measured in medium-sized DiIpositive neurons using the whole-cell patch clamp technique in the voltage-clamp mode. While carbamazepine had little effect on the peak amplitude of transient Na⁺ currents, it strongly inhibited steady-state currents of transient as well as persistent Na⁺ currents in a concentration-dependent manner. Carbamazepine had only minor effects on the voltage-activation relationship, the voltage-inactivation relationship, and the use-dependent inhibition of TTX-R Na⁺ channels. However, carbamazepine changed the inactivation kinetics of TTX-R Na⁺ channels, significantly accelerating the development of inactivation and delaying the recovery from inactivation. In the current-clamp mode, carbamazepine decreased the number of action potentials without changing the action potential threshold. Given that the sensitization of dural afferent neurons by inflammatory mediators triggers acute migraine headaches and that inflammatory mediators potentiate TTX-R Na⁺ currents, the present results suggest that carbamazepine may be useful for the treatment of migraine headaches.

Neuropathic pain in leprosy: symptom profile characterization and comparison with neuropathic pain of other etiologies

Supplemental Digital Content is Available in the Text.

Neuropathic pain in leprosy may respond to drugs usually used to control pain of neuropathic profile and amitriptiline may constitute a candidate drug for future formal clinical trials.

Introduction:

Previous studies reported a high prevalence of neuropathic pain in leprosy, being especially present in “pharmacologically cured” patients. The presence of neuropathic pain in leprosy poses a supplementary burden in patient's quality of life, daily activities, and mood.

Objectives:

The aim of this study was to assess whether neuropathic pain in leprosy has similar symptom profile as neuropathic pain of other etiologies and to retrospectively assess the efficacy of neuropathic pain medications regularly prescribed to leprosy.

Methods:

Leprosy and nonleprosy patients had their neuropathic pain characterized by the neuropathic pain symptom inventory (NPSI, ranges from 0 to 100, with 100 being the maximal neuropathic pain intensity) in a first visit. In a second visit, leprosy patients who had significant pain and received pharmacological treatment in the first evaluation were reassessed (NPSI) and had their pain profile and treatment response further characterized, including information on drugs prescribed for neuropathic pain and their respective pain relief.

Results:

The pain characteristics based on NPSI did not significantly differ between leprosy and nonleprosy neuropathic pain patients in visit 1 after correction for multiple analyses, and cluster analyses confirmed these findings (ie, no discrimination between leprosy and nonleprosy groups; Pearson χ2 = 0.072, P = 0.788). The assessment of pain relief response and the drugs taken by each patient, linear regression analysis showed that amitriptyline, when effective, had the highest percentage of analgesic relief.

Conclusions:

Neuropathic pain in leprosy is as heterogeneous as neuropathic pain of other etiologies, further supporting the concept that neuropathic pain is a transetiological entity. Neuropathic pain in leprosy may respond to drugs usually used to control pain of neuropathic profile in general, and amitriptiline may constitute a potential candidate drug for future formal clinical trials aimed at controlling neuropathic pain in leprosy.

Cognitive Behavioral Therapy for Chronic Pain-One Therapeutic Approach for the Opioid Epidemic

Opioids are frequently prescribed for chronic pain. For the past 2 decades, long-term opioid analgesic therapy was considered the cornerstone of effective pain management for chronic nonmalignant conditions, despite a lack of documented effectiveness and safety, with the attendant risk of addiction, overdose, and death. Cognitive behavioral therapy (CBT) may be used effectively to treat chronic pain, either as a stand-alone treatment or with other nonopioid pharmacological treatments. CBT improves pain-related outcomes along with mobility, quality of life, and disability and mood outcomes. Compared with long-term use of opioids, CBT has dramatically lower risks and may therefore be worth pursuing.

Neuropathic Corneal Pain: Approaches for Management

Neuropathic pain is caused by a primary lesion or dysfunction of the nervous system and can occur in the cornea. However, neuropathic corneal pain (NCP) is currently an ill-defined disease. Patients with NCP are extremely challenging to manage, and evidence-based clinical recommendations for the management of patients with NCP are scarce. The objectives of this review are to provide guidelines for diagnosis and treatment of patients with NCP and to summarize current evidence-based literature in this area. We performed a systematic literature search of all relevant publications between 1966 and 2017. Treatment recommendations are, in part, based on methodologically sound randomized controlled trials (RCTs), demonstrating superiority to placebo or relevant control treatments, and on the consistency of evidence, degree of efficacy, and safety. In addition, the recommendations include our own extensive experience in the management of these patients over the past decade. A comprehensive algorithm, based on clinical evaluation and complementary tests, is presented for diagnosis and subcategorization of patients with NCP. Recommended first-line topical treatments include neuroregenerative and anti-inflammatory agents, and first-line systemic pharmacotherapy includes tricyclic antidepressants and an anticonvulsant. Second-line oral treatments recommended include an opioid-antagonist and opiate analgesics. Complementary and alternative treatments, such as cardiovascular exercise, acupuncture, omega-3 fatty acid supplementation, and gluten-free diet, may have additional benefits, as do potential noninvasive and invasive procedures in recalcitrant cases. Medication selection should be tailored on an individual basis, considering side effects, comorbidities, and levels of peripheral and centralized pain. Nevertheless, there is an urgent need for long-term studies and RCTs assessing the efficacy of treatments for NCP.

Analgesic, antiallodynic, and anticonvulsant activity of novel hybrid molecules derived from N-benzyl-2-(2,5-dioxopyrrolidin-1-yl)propanamide and 2-(2,5-dioxopyrrolidin-1-yl)butanamide in animal models of pain and epilepsy

The purpose of the present study was to examine the analgesic activity of six novel hybrid molecules, which demonstrated in the previous research anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole seizure (scPTZ) tests in mice. The antinociceptive properties were estimated in three models of pain in mice—the hot plate test, the formalin test, and in the oxaliplatin-induced neuropathy. Moreover, extended anticonvulsant studies were carried out and the antiseizure activity was investigated in the 6-Hz test. Considering drug safety evaluation, the influence of compounds on locomotor activity and contextual memory were checked. Furthermore, chosen molecules were tested in vitro for potential hepatotoxicity. To explain the probable mechanism of action, the radioligand binding assays were performed. In both phases of formalin test, analgesic activity demonstrated compounds 4, 8, and 9. These agents relieved also mechanical allodynia in oxaliplatin-induced model of neuropathic pain. At active doses, they did not influence locomotor activity of mice. Moreover, for compounds 8 and 9, no deleterious effect on memory was observed, but compound 4 might induce memory deficits. All tested compounds (4, 5, 8, 9, 15, and 16) inhibited psychomotor seizures with the ED₅₀ values = 24.66–47.21 mg/kg. The binding studies showed that compound 4 only at the high concentrations revealed the effective binding to the neuronal sodium channels and moderately binding to the L-type calcium (verapamil site) channels and NMDA receptors. The present preclinical results proved that novel hybrid molecules demonstrate very promising anticonvulsant and analgesic activity.