Lamotrigine in the Prevention of Migraine With Aura: A Narrative Review

Phytol from Faeces Bombycis alleviated migraine pain by inhibiting Nav1.7 sodium channels

ETHNOPHARMACOLOGICAL RELEVANCE

Faeces Bombycis (silkworm excrement, called Cansha in Chinese), is the dried faeces of the larvae of silkworm. According to the theories of traditional Chinese medicine recorded in "Compendium of Materia Medica", Faeces Bombycis has often been prescribed in traditional Chinese medicine for the treatment of recurrent headache, rheumatalgia, rubella and itching et al. However, the bioactive components and their exact mechanisms underlying the pain-relieving effects remain to be revealed.

AIM OF THE STUDY

The present study aimed to evaluate the analgesic effect of Faeces Bombycis extract (FBE) on migraine, explore the main active constituents and investigate the pharmacological mechanisms for its pain relief.

MATERIALS AND METHODS

The bioactivity of different extracts from Faeces Bombycis was tracked by the nitroglycerin (NTG)-induced migraine model on rats and identified by NMR spectroscopic data. Whole-cell patch clamp technique, an electrophysiological method, was used to screen the potential targets and study the mechanism of action for the bioactive compound. The following targets have been screened and studied, including Nav1.7 sodium channels, Nav1.8 sodium channels, TRPV1 channels and TRPA1 channels. The trigeminal ganglion neurons were further used to study the effects of the identified compound on neuronal excitability.

RESULTS

By testing the bioactivity of the different extracts proceedingly, fraction petroleum ether showed higher anti-migraine activity. Through further step-by-step isolations, 7 compounds were isolated. Among them, phytol was identified with the highest yield and displayed a potent anti-migraine effect. By screening the potential ion channel targets for migraine, phytol was found to preferentially block the inactivated state of Nav1.7 sodium channels with half-inhibition concentration 0.32 ± 0.05 μM. Thus, the effects of phytol on the biophysical properties of Nav1.7 sodium channels were further characterized. Phytol induced a hyperpolarizing shift of voltage-dependent inactivation and slowed the recovery from inactivation. The affinity of phytol became weaker in the inactivation-deficient Nav1.7 channels (Nav1.7-WCW). And such an effect was independent on the local anesthetic site (Nav1.7 F1737A). Consistent with the data from recombinant channels, the compound also displayed state-dependent inhibition on neuronal sodium channels and further decreased the neuronal excitability in trigeminal ganglion neurons. Moreover, besides Nav1.7 channel, phytol also antagonized the activation of TRPV1 and TRPA1 channels at micromolar concentrations with a weaker affinity.

CONCLUSION

Our results demonstrated that phytol is the major anti-migraine ingredient of Faeces Bombycis and alleviates migraine behaviors by acting on Nav1.7 sodium channels in the trigeminal ganglion neurons. This study provided evidences for the therapeutic application of Faeces Bombycis and phytol on migraine disease.

Differential Diagnosis of Visual Phenomena Associated with Migraine: Spotlight on Aura and Visual Snow Syndrome

Migraine is a severe and common primary headache disorder, characterized by pain as well as a plethora of non-painful symptoms. Among these, visual phenomena have long been known to be associated with migraine, to the point where they can constitute a hallmark of the disease itself. In this review we focus on two key visual disorders that are directly or indirectly connected to migraine: visual aura and visual snow syndrome (VSS). Visual aura is characterized by the transient presence of positive and negative visual symptoms, before, during or outside of a migraine attack. VSS is a novel stand-alone phenomenon which has been shown to be comorbid with migraine. We discuss key clinical features of the two disorders, including pathophysiological mechanisms, their differential diagnoses and best treatment practices. Our aim is to provide an aid for clinicians and researchers in recognizing these common visual phenomena, which can even appear simultaneously in patients with an underlying migraine biology.

Visual Snow Syndrome as a Network Disorder: A Systematic Review

Aim: By reviewing the existing clinical studies about visual snow (VS) as a symptom or as part of visual snow syndrome (VSS), we aim at improving our understanding of VSS being a network disorder. Background: Patients with VSS suffer from a continuous visual disturbance resembling the view of a badly tuned analog television (i.e., VS) and other visual, as well as non-visual symptoms. These symptoms can persist over years and often strongly impact the quality of life. The exact prevalence is still unknown, but up to 2.2% of the population could be affected. Presently, there is no established treatment, and the underlying pathophysiology is unknown. In recent years, there have been several approaches to identify the brain areas involved and their interplay to explain the complex presentation. Methods: We collected the clinical and paraclinical evidence from the currently published original studies on VS and its syndrome by searching PubMed and Google Scholar for the term visual snow. We included original studies in English or German and excluded all reviews, case reports that did not add new information to the topic of this review, and articles that were not retrievable in PubMed or Google Scholar. We grouped the studies according to the methods that were used. Results: Fifty-three studies were found for this review. In VSS, the clinical spectrum includes additional visual disturbances such as excessive floaters, palinopsia, nyctalopia, photophobia, and entoptic phenomena. There is also an association with other perceptual and affective disorders as well as cognitive symptoms. The studies that have been included in this review demonstrate structural, functional, and metabolic alterations in the primary and/or secondary visual areas of the brain. Beyond that, results indicate a disruption in the pre-cortical visual pathways and large-scale networks including the default mode network and the salience network. Discussion: The combination of the clinical picture and widespread functional and structural alterations in visual and extra-visual areas indicates that the VSS is a network disorder. The involvement of pre-cortical visual structures and attentional networks might result in an impairment of "filtering" and prioritizing stimuli as top-down process with subsequent excessive activation of the visual cortices when exposed to irrelevant external and internal stimuli. Limitations of the existing literature are that not all authors used the ICHD-3 definition of the VSS. Some were referring to the symptom VS, and in many cases, the control groups were not matched for migraine or migraine aura.

Headache in multiple sclerosis - pharmacological aspects

For decades, headache was not considered a typical symptom of multiple sclerosis (MS) and was construed as a "red flag" for important differential diagnoses such as cerebral vasculitis. Meanwhile, several studies have demonstrated an increased prevalence of headache in MS compared to the general population. This is due to the heterogeneity of headache genesis with frequent occurrence of both primary and secondary headaches in MS. On the one hand, MS and migraine are often comorbid. On the other hand, secondary headaches occur frequently, especially in the course of MS relapses. These are often migraine-like headaches caused by inflammation, which can improve as a result of MS-specific therapy. Headaches are particularly common in the early stages of chronic inflammatory CNS disease, where inflammatory activity is greatest. In addition, headache can also occur as a side effect of disease-modifying drugs (DMDs). Headache can occur with most DMDs and is most frequently described with interferon-beta therapy. The aim of this work is to present the prevalence of headache and describe the heterogeneity of possible causes of headache in MS. In addition, important therapeutic aspects in the treatment of MS patients in general will be presented as well as different approaches to the treatment of headache in MS depending on the etiological classification.

Headache in people with epilepsy

Epidemiological estimates indicate that individuals with epilepsy are more likely to experience headaches, including migraine, than individuals without epilepsy. Headaches can be temporally unrelated to seizures, or can occur before, during or after an episode; seizures and migraine attacks are mostly not temporally linked. The pathophysiological links between headaches (including migraine) and epilepsy are complex and have not yet been fully elucidated. Correct diagnoses and appropriate treatment of headaches in individuals with epilepsy is essential, as headaches can contribute substantially to disease burden. Here, we review the insights that have been made into the associations between headache and epilepsy over the past 5 years, including information on the pathophysiological mechanisms and genetic variants that link the two disorders. We also discuss the current best practice for the management of headaches co-occurring with epilepsy and highlight future challenges for this area of research.

Relationships between migraine and epilepsy: Pathophysiological mechanisms and clinical implications

Migraine and epilepsy are distinct neurological diseases with specific clinical features and underlying pathophysiological mechanisms. However, numerous studies have highlighted the complex and multifaceted relationships between the two conditions. The relationships between headache and epilepsy manifest themselves in different ways. Firstly, the clinical diagnosis of these disorders may be challenging in view of possible overlapping. While post-ictal headache is a frequent condition, ictal epileptic headache is a rare but challenging diagnosis. Both situations raise the question of the pathophysiological mechanism of headache triggered by seizures. Migraine aura and epilepsy can also exhibit overlapping symptoms leading to their misdiagnosis, in particular in the case of visual aura. Secondly, migraine with aura and epilepsy can occur as a co-morbid condition, particularly in familial hemiplegic migraine (FHM). From a pathophysiological perspective, the identification of genetic mutations in FHM has brought significant advances in the understanding of dysfunctions of neuronal networks leading to hyperexcitability. The purpose of this review is to present clinical situations encompassing headache and epilepsy that can be challenging in neurological practice and to discuss the underlying pathophysiological mechanism of such interactions.

Revised guidelines of the French headache society for the diagnosis and management of migraine in adults. Part 2: Pharmacological treatment

The French Headache Society proposes updated French guidelines for the management of migraine. This article presents the second part of the guidelines, which is focused on the pharmacological treatment of migraine, including both the acute treatment of attacks and the prophylaxis of episodic migraine as well as chronic migraine with and without medication overuse. The specific situations that can be encountered in women with migraine are also discussed, including pregnancy, menstrual migraine, contraception and hormonal replacement therapy.

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.

Headaches during pregnancy

Headache during pregnancy is frequent and challenging. A secondary headache is diagnosed in one third of women, and most causes are vascular and infectious disorders. Anamnestic and clinical features must be investigated, and brain imaging is often required. Primary headaches are commonly modified during pregnancy. Migraine is mainly improved in this context, especially migraine without aura. Particular cautions about treatment must be applied, and non-pharmacological measures must be preferred. Tension-type headache and cluster headache seem to be less hormone-dependent.

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).

Monoclonal antibodies blocking CGRP transmission: An update on their added value in migraine prevention

The avenue of effective migraine therapies blocking calcitonin gene-related peptide (CGRP) transmission is the successful outcome of 35 years of translational research. Developed after short-acting, the small antagonists of the CGRP receptor (the "gepants"), the monoclonal antibodies blocking CGRP or its receptor (CGRP/rec mAbs) have changed the paradigm in migraine treatment. Contrary to the classical acute medications like triptans or nonsteroidal anti-inflammatory drugs (NSAIDs) with a transient effect, they act for long durations exclusively in the peripheral portion of the trigeminovascular system and can thus be assimilated to a durable attack treatment, unlike the classical preventives that chiefly act upstream on the central facets of migraine pathophysiology. Randomized controlled trials (RCT) of eptinezumab, erenumab, fremanezumab and galcanezumab have included collectively several thousands of patients, making them the most extensively studied class of preventive migraine treatments. Their results clearly indicate that CGRP/rec mAbs are significantly superior to placebo and have been comprehensively reviewed by Dodick [Cephalalgia 2019;39(3):445-458]. In this review we will briefly summarize the placebo-subtracted outcomes and number-needed-to-treat (NNT) of these pivotal RCTs and analyze new and post-hoc studies published afterwards focusing on effect size, effect onset and sustainability, response in subgroups of patients, safety and tolerability, and cost-effectiveness. We will also summarize our limited real-world experience with one of the CGRP/rec mAbs. Although methodological differences and lack of direct comparative trials preclude any reliable comparison, the overall impression is that there are only minor differences in efficacy and tolerability profiles between the four monoclonals: the average placebo-subtracted 50% responder rates for reduction in migraine headaches are 21.4% in episodic migraine (NNTs: 4-5), 17.4% in chronic migraine (NNTs: 4-8). Patients with an improvement exceeding 50% are rare, chronic migraineurs with continuous headache are unlikely to be responders and migraine auras are not improved. The effect starts within the first week after administration and is quasi maximal at one month. It is sustained for long time periods and may last for several months after treatment termination. CGRP/rec mAbs are effective even after prior preventive treatment failures and in patients with medication overuse, but the effect size might be smaller. They significantly reduce disability and health care resource utilization. The adverse effect profile of CGRP/rec mAbs is close to that of placebo with few minor exceptions and despite concerns related to the safeguarding role of CGRP in ischemia, no treatment-related vascular adverse events have been reported to date. Putting the CGRP/rec mAbs in perspective with available preventive migraine drug treatments, their major advantage seems not to be chiefly their superior efficacy but their unprecedented efficacy over adverse event ratio. Regarding cost-effectiveness, preliminary pharmaco-economic analyses of erenumab suggest that it is cost-effective for chronic migraine compared to no treatment or to onabotulinumtoxinA, but likely not for episodic migraine unless attack frequency is high, indirect costs are considered and its price is lowered.

Therapeutic implications of cortical spreading depression models in migraine

Migraine is among the most common and disabling neurological diseases in the world. Cortical spreading depression (CSD) is a wave of near-complete depolarization of neurons and glial cells that slowly propagates along the cortex creating the perception of aura. Evidence suggests that CSD can trigger migraine headache. Experimental models of CSD have been considered highly translational as they recapitulate migraine-related phenomena and have been validated for screening migraine therapeutics. Here we outline the essential components of validated experimental models of CSD and provide a comprehensive review of potential modulators and targets against CSD. We further focus on novel interventions that have been recently shown to suppress CSD susceptibility that may lead to therapeutic targets in migraine.

Emergency Department and Inpatient Management of Headache in Adults

PURPOSE OF REVIEW

This article reviews treatment options for patients presenting with headache in the emergency department (ED) and for inpatients, including red flags and status migrainosus (SM).

RECENT FINDINGS

Most patients presenting with headache in the ED will have migraine, but red flags must be reviewed to rule out secondary headaches. SM refractory to home treatment is a common reason for ED presentation or inpatient admission, but high-quality treatment evidence is lacking. Common treatments include intravenous fluids, anti-dopaminergic agents with diphenhydramine, steroids, divalproex, nonsteroidal anti-inflammatory drugs, intravenous dihydroergotamine, and nerve blocks. Other therapies (e.g., ketamine and lidocaine) are used with limited or inconsistent evidence. There is evidence for inpatient behavioral management therapy. This article details red flags to review in the workup of headache presentation in the ED and provides a step-wise approach to ED and inpatient management. However, more studies are needed to better optimize care.