Coronary side-effect potential of current and prospective antimigraine drugs

Causality between migraine and cardiovascular disease: a bidirectional Mendelian randomization study

BACKGROUND

While growing evidence suggests a relationship between migraine and cardiovascular disease, the genetic evidence for a causal relationship between migraine and cardiovascular disease is still scarce. Investigating the causal association between migraine and cardiovascular disease is vital.

METHODS

We carried out a bidirectional Mendelian randomization (MR) study including discovery samples and replication samples using publicly available genome-wide association study (GWAS) summary datasets and stringent screening instrumental variables. Four different MR techniques-Inverse variance weighted (IVW), MR ‒Egger, weighted median, and weighted mode-as well as various sensitivity analyses-Cochran's Q, IVW radial, leave-one-out (LOO), and MR-PRESSO-were utilized to investigate the causal relationship between cardiovascular disease and migraine.

RESULTS

The protective causal effects of genetically predicted migraine on coronary artery disease (OR, 0.881; 95% CI 0.790-0.982; p = 0.023) and ischemic stroke (OR, 0.912; 95% CI 0.854-0.974; p = 0.006) were detected in forward MR analysis but not in any other cardiovascular disease. Consistently, we also discovered protective causal effects of coronary atherosclerosis (OR, 0.865; 95% CI 0.797-0.940; p = 0.001) and myocardial infarction (OR, 0.798; 95% CI 0.668-0.952; p = 0.012) on migraine in reverse MR analysis.

CONCLUSION

We found a potential protective effect of migraine on coronary artery disease and ischemic stroke and a potential protective effect of coronary atherosclerosis and myocardial infarction on migraine. We emphasised epidemiological and genetic differences and the need for long-term safety monitoring of migraine medications and future research to improve cardiovascular outcomes in migraine patients.

Pharmacology of erenumab in human isolated coronary and meningeal arteries: Additional effect of gepants on top of a maximum effect of erenumab

BACKGROUND AND PURPOSE

Multiple drugs targeting the calcitonin gene-related peptide (CGRP) receptor have been developed for migraine treatment. Here, the effect of the monoclonal antibody erenumab on CGRP-induced vasorelaxation was investigated in human isolated blood vessels, as well as the effect of combining erenumab with the small molecule drugs, namely rimegepant, olcegepant, or sumatriptan.

EXPERIMENTAL APPROACH

Concentration-response curves to CGRP, adrenomedullin or pramlintide were constructed in human coronary artery (HCA) and human middle meningeal artery (HMMA) segments, incubated with or without erenumab and/or olcegepant. pA2 or pKb values were calculated to determine the potency of erenumab in both tissues. To study whether acutely acting antimigraine drugs exerted additional CGRP-blocking effects on top of erenumab, HCA segments were incubated with a maximally effective concentration of erenumab (3 μM), precontracted with KCl and exposed to CGRP, followed by rimegepant, olcegepant, or sumatriptan in increasing concentrations.

KEY RESULTS

Erenumab shifted the concentration-response curve to CGRP in both vascular tissues. However, in HCA, the Schild plot slope was significantly smaller than unity, whereas this was not the case in HMMA, indicating different CGRP receptor mechanisms in these tissues. In HCA, rimegepant, olcegepant and sumatriptan exerted additional effects on CGRP on top of a maximal effect of erenumab.

CONCLUSIONS AND IMPLICATIONS

Gepants have additional effects on top of erenumab for CGRP-induced relaxation and could be effective in treating migraine attacks in patients already using erenumab as prophylaxis.

Update of Gepants in the Treatment of Chronic Migraine

PURPOSE OF REVIEW

Despite the unmet therapeutic needs of patients with chronic migraine (CM) and/or medication overuse, available treatment options are limited. Recently, four calcitonin gene-related peptide receptor antagonists, known as gepants, have been approved for the treatment of migraine. This review focuses on the preventive treatment of CM with gepants and highlights recent findings.

RECENT FINDINGS

Two randomized controlled trials (RCTs) have shown promising results for rimegepant and atogepant as preventive treatments for CM. In an RCT targeting patients with CM, atogepant demonstrated a significant reduction in the mean monthly migraine days, irrespective of acute medication overuse. Moreover, the patients reported no significant safety concerns and exhibited good tolerance to treatment. These findings highlight the potential of gepants as a new and effective therapeutic option for patients with CM and/or medication overuse. Gepant use will help improve the management and quality of life of individuals with this debilitating condition.

Towards precision medicine in migraine: Recent therapeutic advances and potential biomarkers to understand heterogeneity and treatment response

After 35 years since the introduction of the International Classification of Headache Disorders (ICHD), we are living in the era of the second great revolution in migraine therapies. First, discoveries of triptans provided a breakthrough in acute migraine treatment utilizing bench-to-bedside research results on the role of serotonin in migraine. Next, the discovery of the role of neuropeptides, more specifically calcitonin gene-related peptide (CGRP) in migraine attack led to the development of anti-CGRP therapies that are effective both in acute and preventive treatment, and are also able to reduce migraine-related burden. Here, we reviewed the most recent clinical studies and real-world data on available migraine-specific medications, including triptans, ditants, gepants and anti-CGRP monoclonal antibodies. Novel drug targets, such as PACAP and amylins were also discussed. To address the main challenges of migraine therapy, the high heterogeneity of people with migraine, the prevalent presence of various comorbid disorders, and the insufficient medical care of migraine patients were covered. Promising novel approaches from the fields of omics, blood and saliva biomarker, imaging and provocation studies might bring solutions for these challenges with the potential to identify further drug targets, distinguish more homogeneous patient subgroups, contribute to more optimal drug selection strategies, and detect biomarkers in association with headache features or predicting treatment efficacy. In the future, the combined analysis of data of different biomarker modalities with machine learning algorithms may serve precision medicine in migraine treatment.

Migraine and cardiovascular disease: what cardiologists should know

Migraine is a chronic neurovascular disease with a complex, not fully understood pathophysiology with multiple causes. People with migraine suffer from recurrent moderate to severe headache attacks varying from 4 to 72 h. The prevalence of migraine is two to three times higher in women compared with men. Importantly, it is the most disabling disease in women <50 years of age due to a high number of years lived with disability, resulting in a very high global socioeconomic burden. Robust evidence exists on the association between migraine with aura and increased incidence of cardiovascular disease (CVD), in particular ischaemic stroke. People with migraine with aura have an increased risk of atrial fibrillation, myocardial infarction, and cardiovascular death compared with those without migraine. Ongoing studies investigate the relation between migraine and angina with non-obstructive coronary arteries and migraine patients with patent foramen ovale. Medication for the treatment of migraine can be preventative medication, such as beta-blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, antiepileptics, antidepressants, some of the long-acting calcitonin gene-related peptide receptor antagonists, or monoclonal antibodies against calcitonin gene-related peptide or its receptor, or acute medication, such as triptans and calcitonin gene-related peptide receptor antagonists. However, these medications might raise concerns when migraine patients also have CVD due to possible (coronary) side effects. Specifically, knowledge gaps remain for the contraindication to newer treatments for migraine. All cardiologists will encounter patients with CVD and migraine. This state-of-the-art review will outline the basic pathophysiology of migraine and the associations between migraine and CVD, discuss current therapies, and propose future directions for research.

Calcitonin gene-related peptide and neurologic injury: An emerging target for headache management

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide known to be involved in the trigeminovascular system and to function as a potent vasodilator. Although it has emerged as a viable target for headache management with targeted treatments developed for migraine, a highly disabling neurovascular disorder, less is known about CGRP's role in other neurologic conditions such as traumatic brain injury and subarachnoid hemorrhage. The literature has shown that during these injury cascades, CGRP receptors are modulated in varying ways. Therefore, CGRP or its receptors might be viable targets to manage secondary injuries following acute brain injury. In this review, we highlight the pathophysiology of the CGRP pathway and its relation to migraine pathogenesis. Using these same principles, we assess the existing preclinical data for CGRP and its role in acute brain injury. The findings are promising, and set the basis for further work, with specific focus on the therapeutic benefit of CGRP modulation following neurologic injury.

A rare complication of coronary vasospasm associated with concomitant use of ergotamine, cobicistat, and darunavir

Ergotism is a rare cause of peripheral vasoconstriction with varying presentation depending on the affected vessels. Coronary vasospasm is a rare, potentially fatal manifestation of ergotism. Cytochrome P-450 isoenzyme CYP3A metabolizes ergot alkaloids and their derivatives; thus, concomitant use of ergotamine and CYP3A inhibitors significantly increases ergotism risk. The antiretroviral drug darunavir boosted with cobicistat potently inhibits CYP3A. A few deleterious interactions are described in the literature when combining ergotamine with boosted human immunodeficiency virus protease inhibitors. Herein, we describe a patient who presented to the emergency department with profound coronary vasospasm arising from ergotamine’s interaction with darunavir and cobicistat. Emergency coronary angiography revealed no critical atherosclerotic stenosis, but prolonged coronary artery spasm. After prompt cardiopulmonary resuscitation, intravenous vasodilator treatment, and 14-day extracorporeal membrane oxygenation application, the patient fully recovered and was discharged. Concomitant use of ergot alkaloids and their derivatives could be disastrous for patients treated with cobicistat-boosted darunavir.

Acute Care and Treatment of Migraine

OBJECTIVE

Migraine is a chronic neurological disease involving the brain and its vasculature, typically characterized by recurrent attacks of moderate or severe throbbing headache, accompanied by sensitivity to light and sound, and associated with nausea, vomiting, and inability to move due to worsening of pain. About 30% of migraineurs have some type of aura, most often visual. Migraine attacks, if untreated or suboptimally treated, usually result in significant disability, requiring bed rest and resulting in poor quality of life. Increased frequency of attacks and overuse of acute care medication are significant risks for chronification, resulting in the transformation of episodic migraine into chronic migraine. We aim to review most acute care treatments for migraine.

METHODS

Current treatment options for migraine attacks were reviewed from the selected literature and combined with our clinical experience.

RESULTS

Current acute treatment options for migraine attacks include over-the-counter analgesics, at times combined with caffeine, nonsteroidal anti-inflammatory medications, opioids, and migraine-specific medications such as triptans and ergots. In the near future, we will probably have 3 gepants (small-molecule calcitonin gene-related peptide [CGRP] receptor antagonists). The first one was just approved in the United States. A ditan acting as a stimulator of 5-HT1F receptors, was also just approved by the FDA. Stimulation of the trigeminal, vagal, occipital, and even upper arm peripheral nerves through electrical nerve stimulation devices and magnetic stimulation devices are available as alternative, nondrug treatment options. Several devices have already been FDA-allowed for treatment in the United States and/or approved elsewhere, and others will follow soon. Behavioral medicine techniques such as biofeedback training and mindfulness have been available for some time and are often helpful.

CONCLUSION

A wide variety of acute care options to treat migraine are available, and others will soon be and will herein be described in further detail. Some medications have been approved by regulatory authorities in countries other than the United States, and some devices have been given a CE Mark in Europe.

Naratriptan is as effective as sumatriptan for the treatment of migraine attacks when used properly. A mini-review

BACKGROUND

Naratriptan, marketed in a low oral dose of 2.5 mg, is generally regarded as a less-effective triptan with a slower onset of action than most other triptans in the treatment of migraine attacks. In this review, naratriptan will be compared with sumatriptan, the standard triptan.

METHODS

Papers on pharmacodynamics and pharmacokinetics and results from comparative clinical trials with oral and subcutaneous naratriptan versus other triptans were retrieved from PubMed.

RESULTS

Naratriptan and sumatriptan have similar effects in relevant animal models. In a randomized controlled trial, oral naratriptan 2.5 mg is less effective than oral sumatriptan 100 mg after both 2 h and 4 h. In contrast, oral naratriptan 10 mg has a similar time-effect curve as oral sumatriptan 100 mg, in both its steepness and the efficacy at 2 h and 4 h. Subcutaneous naratriptan 10 mg (88% pain free at 2 h) was in one trial superior to subcutaneous sumatriptan 6 mg (55% pain free at 2 h).

CONCLUSION

Naratriptan was marketed for the treatment of migraine attacks as the "gentle triptan" in a low oral dose of 2.5 mg, a dose with no more adverse events than placebo. This low dose results in the slow onset of action and low efficacy of oral naratriptan, but in high doses oral naratriptan is similar to oral sumatriptan. Based on one randomized controlled trial, subcutaneous naratriptan has probably the greatest effect of any triptan.

Acute Treatment of Migraine: What has Changed in Pharmacotherapies?

Background

Migraine is the most prevalent neurological disorder and the leading cause of disability in individuals under 50 years of age. Two types of migraine therapies have been defined: acute therapy (abortive or symptomatic treatment), the purpose of which is to interrupt migraine attacks, and preventive treatment (prophylactic treatment), the purpose of which is to reduce the frequency and severity of migraine attacks.

Objective

This paper reviews research advances in new agents for acute therapy of migraine.

Material and Methods

This review provides an overview of emerging new drugs for acute treatment of migraine based on clinical evidence and summarizes the milestones of different stages of clinical development.

Results

Two new formulations of sumatriptan, DFN-11 (3 mg doses of subcutaneous sumatriptan) and DFN-02 (a nasal spray of sumatriptan 10 mg and a permeation-enhancing excipient), have been developed, and both of them showed a fast-onset action with efficacy for acute treatment of migraine with fewer adverse events. New drug discovery programs shifted the focus to the development of ditans, a group of antimigraine drugs targeting 5-HT_1F receptors. Only lasmiditan has progressed to phase III clinical trials and was finally approved by the Food and Drug Administration (FDA) for acute migraine treatment. The other target for acute therapy is CGRP receptor antagonists, namely, gepants. Ubrogepant and rimegepant demonstrated statistically significant efficacy, and both were recently approved by the FDA. These 5-HT_1F receptor agonists and CGRP receptor antagonists did not cause vasoconstriction, offering advantages over the current mainstay of specific acute migraine treatment.

Conclusions

Overall, these new agents have expanded the available acute therapies for migraine treatment and will likely change the strategy with which we treat patients with migraine in the future.

Current advances in the management of cluster headaches

Introduction: Cluster headache (CH) is probably the most severe idiopathic pain condition, yet its current medical management remains poor.Areas covered: Only repurpose medicines are currently in use for the prevention of CH, partially because the pathophysiology of the condition is still elusive. In this article we performed a systematic review to evaluate the evidence for efficacy of the currently available or emerging treatments for CH.Expert opinion: We found several ongoing randomized clinical trials testing prophylactic treatments for CH and only few for the standard ones. Recent data from randomized trials with monoclonal antibodies targeting the calcitonin gene related peptide pathway (anti-CGRP mAbs) are controversial, although its role in the pathogenesis of the condition is well documented. This inconsistency may depict inadequacies in clinical trial designing. Anti-CGRP mAbs and antagonists of pituitary adenylate cyclase-activating polypeptide (PACAP) along with neuromodulation techniques, are curing the necessary valuable evidence that could illuminate the therapeutical future for cluster headache. Orexin pathway is another attractive target for CH treatment. To improve the evidence for efficacy, we further propose that the design of the clinical trials for CH needs to be radically reviewed to allow more patients to participate.

Lasmiditan inhibits calcitonin gene-related peptide release in the rodent trigeminovascular system

Lasmiditan, an antimigraine drug with selective 5-HT_1F receptor affinity, prejunctionally inhibits calcitonin gene-related peptide release in peripheral and central trigeminal nerve terminals of rodents.

Migraine headache pathophysiology involves trigeminovascular system activation, calcitonin gene-related peptide (CGRP) release, and dysfunctional nociceptive transmission. Triptans are 5-HT_1B/1D/(1F) receptor agonists that prejunctionally inhibit trigeminal CGRP release, but their vasoconstrictor properties limit their use in migraine patients with cardiovascular disease. By contrast, lasmiditan is a novel antimigraine and selective 5-HT_1F receptor agonist devoid of vasoconstrictor properties. On this basis, this study has investigated the modulation of trigeminal CGRP release by lasmiditan. For this purpose, we have comparatively analysed the inhibition of several components of the trigeminovascular system induced by lasmiditan and sumatriptan through: ex vivo KCl-induced CGRP release from isolated dura mater, trigeminal ganglion, and trigeminal nucleus caudalis of mice; and in vivo dural vasodilation in the rat closed-cranial window model induced by endogenous (electrical stimulation and capsaicin) and exogenous CGRP. The ex vivo release of CGRP was similarly inhibited by sumatriptan and lasmiditan in all trigeminovascular system components. In vivo, intravenous (i.v.) lasmiditan or higher doses of sumatriptan significantly attenuated the vasodilatory responses to endogenous CGRP release, but not exogenous CGRP effects. These data suggest that lasmiditan prejunctionally inhibits CGRP release in peripheral and central trigeminal nerve terminals. Because lasmiditan is a lipophilic drug that crosses the blood–brain barrier, additional central sites of action remain to be determined.

Drug interactions and risks associated with the use of triptans, ditans and monoclonal antibodies in migraine

PURPOSE OF REVIEW

The aim of this study was to review current evidence concerning potential risks and interactions associated with concomitant use of drugs indicated for the abortive treatment of migraine, namely triptans and ditans, and more recently developed drugs used for the preventive treatment. The latter drug class encompasses monoclonal antibodies (mAbs), which target either calcitonin gene-related peptide (CGRP) or its receptor.

RECENT FINDINGS

To date, no pharmacokinetic interactions between these drug classes have been reported. However, patients who suffer from triptan- (or ditan-) induced medication overuse headache or those who are nonresponders to triptans might respond less effectively to mAbs. Caution is warranted when coadministrating these drugs in migraine patients with comorbid cardiovascular disease or with an increased cardiovascular risk profile.

SUMMARY

In this review, the main mechanisms of action of triptans, ditans and mAbs targeting CGRP or its receptor are summarized as well as the current evidence on their individual risks. Studies on risks and interactions in case of concomitant use of triptans, ditans and mAbs in migraine patients are relatively scarce. Therefore, these aspects have been considered from a theoretical and hypothetical point of view by taking both their overlapping target, CGRP, and contraindications into account.

Subcutaneous sumatriptan: association with decreases in postoperative pain and opioid use after elective cranial surgery

OBJECTIVE

Sumatriptan, a serotonin receptor agonist, has been used in the management of primary headache disorders and has been shown to affect trigeminal dural afferents. There is limited literature on the safety and efficacy of sumatriptan for postcraniotomy pain management. This study aimed to identify whether subcutaneous sumatriptan is a safe and efficacious pain management strategy after elective craniotomy.

METHODS

The authors retrospectively reviewed patients who underwent supratentorial or suboccipital craniotomy between 2016 and 2019 that was performed by a single provider at a single institution to identify patients given subcutaneous sumatriptan in the postoperative period. Pain scores and intravenous and oral opioid use were compared in patients with (n = 15) and without (n = 45) sumatriptan administration.

RESULTS

Patients with and without sumatriptan administration had no significant differences in baseline characteristics or surgery type. There were no sumatriptan-related complications. The average pain score decreased from 3.9 to 1.3 within 1 hour after sumatriptan administration (p = 0.014). In both adult and pediatric patients there was decreased postoperative pain (adults: pain score of 1.1 vs 7.1, p < 0.001; pediatric: 1.1 vs 3.9, p = 0.007) within the first 48 hours. There were decreases in intravenous opioid use, length of intravenous opioid use, maximum dose of intravenous opioid used, oral opioid use, length of oral opioid use, and maximum dose of oral opioid used in both adult and pediatric patients.

CONCLUSIONS

The authors identified subcutaneous sumatriptan as a safe and efficacious tool for postoperative pain management after craniotomy. Large multicenter randomized controlled studies are needed to further evaluate the specific role of sumatriptan in postoperative pain management after craniotomy.

Lasmiditan in patients with common migraine comorbidities: a post hoc efficacy and safety analysis of two phase 3 randomized clinical trials

OBJECTIVE

Determine whether common migraine comorbidities affect the efficacy and safety of lasmiditan, a 5-HT_1F receptor agonist approved in the United States for the acute treatment of migraine.

METHODS

In SPARTAN and SAMURAI (double-blind Phase 3 clinical trials), patients with migraine were randomized to oral lasmiditan 50 mg (SPARTAN only), 100mg, 200 mg, or placebo. Lasmiditan increased the proportion of pain-free and most bothersome symptom (MBS)-free patients at 2 h after dose compared with placebo. Most common treatment-emergent adverse events (TEAEs) were dizziness, paraesthesia, somnolence, fatigue, nausea, muscular weakness, and hypoesthesia. Based upon literature review of common migraine comorbidities, Anxiety, Allergy, Bronchial, Cardiac, Depression, Fatigue, Gastrointestinal, Hormonal, Musculoskeletal/Pain, Neurological, Obesity, Sleep, and Vascular Comorbidity Groups were created. Using pooled results, efficacy and TEAEs were assessed to compare patients with or without a given common migraine comorbidity. To compare treatment groups, p-values were calculated for treatment-by-subgroup interaction, based on logistic regression with treatment-by-comorbidity condition status (Yes/No) as the interaction term; study, treatment group, and comorbidity condition status (Yes/No) were covariates. Differential treatment effect based upon comorbidity status was also examined. Trial registration at clinicaltrials.gov: SAMURAI (NCT02439320) and SPARTAN (NCT02605174).

RESULTS

Across all the Comorbidity Groups, with the potential exception of fatigue, treatment-by-subgroup interaction analyses did not provide evidence of a lasmiditan-driven lasmiditan versus placebo differential treatment effect dependent on Yes versus No comorbidity subgroup for either efficacy or TEAE assessments.

CONCLUSIONS

The efficacy and safety of lasmiditan for treatment of individual migraine attacks appear to be independent of comorbid conditions.

Pharmacological strategies to treat attacks of episodic migraine in adults

INTRODUCTION

Migraine patients prioritize early complete relief of headache and associated symptoms, sustained freedom of pain, and good tolerability. One major obstacle for the successful use of drug treatment of migraine attack is that the speed of action of triptans, 5-HT_1B/1D receptor agonists, is delayed.

AREAS COVERED

In this review, the author discusses the following features of acute migraine drugs: pharmacology; pharmacokinetics, and absorption of drugs during migraine attacks. Next, dose-response curves for effect; and the delayed onset of action is reviewed. In the more clinical part of the review, the following items are discussed: overall clinical judgments; comparison of triptans; comparison of triptans with NSAIDs; early intervention with triptans; medication-overuse headache; comments on the effect of gepants; and the general principle of acute migraine therapy.

EXPERT OPINION

The delay in the onset of effect of acute migraine drugs is likely due to a complex antimigraine system involving more than one site of action. Investigations into the mechanisms of the delay should have a high priority, both in studies with animals, migraine models, and in migraine patients during attacks. Non-oral administration of antimigraine drugs resulting in early absorption of drugs should be developed as they possibly also can increase E_max.

Pharmacological treatment of migraine: CGRP and 5-HT beyond the triptans

Migraine is a highly disabling neurovascular disorder characterized by a severe headache (associated with nausea, photophobia and/or phonophobia), and trigeminovascular system activation involving the release of calcitonin-gene related peptide (CGRP). Novel anti-migraine drugs target CGRP signaling through either stimulation of 5-HT1F receptors on trigeminovascular nerves (resulting in inhibition of CGRP release) or direct blockade of CGRP or its receptor. Lasmiditan is a highly selective 5-HT1F receptor agonist and, unlike the triptans, is devoid of vasoconstrictive properties, allowing its use in patients with cardiovascular risk. Since lasmiditan can actively penetrate the blood-brain barrier, central therapeutic as well as side effects mediated by 5-HT1F receptor activation should be further investigated. Other novel anti-migraine drugs target CGRP signaling directly. This neuropeptide can be targeted by the monoclonal antibodies eptinezumab, fremanezumab and galcanezumab, or by CGRP-neutralizing L-aptamers called Spiegelmers. The CGRP receptor can be targeted by the monoclonal antibody erenumab, or by small-molecule antagonists called gepants. Currently, rimegepant and ubrogepant have been developed for acute migraine treatment, while atogepant is studied for migraine prophylaxis. Of these drugs targeting CGRP signaling directly, eptinezumab, erenumab, fremanezumab, galcanezumab, rimegepant and ubrogepant have been approved for clinical use, while atogepant is in the last stage before approval. Although all of these drugs seem highly promising for migraine treatment, their safety should be investigated in the long-term. Moreover, the exact mechanism(s) of action of these drugs need to be elucidated further, to increase both safety and efficacy and to increase the number of responders to the different treatments, so that all migraine patients can satisfactorily be treated.

Recent Advances in the Management of Migraine in Older Patients

Although the prevalence of migraine tends to decrease in the fifth to sixth decades of life, there are still a significant number of patients > 65 years of age who experience migraine or have new-onset migraine. Because these older patients are often excluded from clinical trials, there are fewer evidence-based treatment guidelines for them. Migraine treatment in the older population requires careful consideration of changes in medication metabolism and increased medical comorbidities. Furthermore, older patients can present with an atypical migraine phenotype and have a higher rate of secondary headache, which may lead to a delay in diagnosis and subsequent treatment. Classic preventive treatments for migraine, including tricyclic antidepressants, antiepileptic drugs, and beta blockers, often have intolerable side effects. In addition, the presence of coronary artery disease, stroke, and peripheral arterial disease precludes the use of typical rescue medications such as triptans. As such, there has been a dire need for novel acute and preventive treatments for older adults. The purpose of this review is to provide an update on novel acute and preventive treatments for migraine in the older population. The advantages of these therapies include their efficacy, favorable side-effect profile, particularly in patients with atherosclerotic disease, as well as their tolerability.

Targeting the 5-HT1B/1D and 5-HT1F receptors for acute migraine treatment

Migraine is a common and highly disabling headache disorder associated with a substantial socioeconomic burden. Migraine treatments can be categorized as preventive treatment, aimed at reducing the frequency and severity of migraine attacks, and acute therapy, intended to abort attacks. Traditionally, acute treatment can be classified as specific (ergot derivatives and triptans) or nonspecific (analgesics and nonsteroidal anti-inflammatory drugs). Triptans, a class of 5-HT1B/1D receptor agonists with some affinity for the 5-HT1F receptor subtype, have been proven to be efficacious for acute treatment of moderate to severe migraine and have been deemed the gold standard. The availability of triptans in non-oral formulations, such as subcutaneous (SC) and intranasal forms, can be beneficial for patients who suffer from prominent nausea or vomiting, have a suboptimal response to oral agents, and/or seek a more rapid onset of treatment effects. However, triptans are contraindicated in patients with preexisting cardiovascular and/or cerebrovascular diseases due to their 5-HT1B-mediated vasoconstrictive action. For this reason, studies have focused on the development of ditans, a group of antimigraine drugs targeting 5-HT1D and 5-HT1F receptors. Unfortunately, 5-HT1D receptor agonists have been shown to be ineffective in the acute treatment of migraine. Several ditans targeting the 5-HT1F receptor have been developed and have shown no vasoconstrictive effect in preclinical studies, but only two of them, lasmiditan and LY334370, have been tested in clinical trials for migraine, and only lasmiditan has reached to Phase III clinical trials. These Phase III trials have demonstrated the efficacy and safety of lasmiditan, a selective 5-HT1F receptor agonist, in acute migraine treatment. Lasmiditan might offer an alternative migraine therapy without cardiovascular risks. This review will summarize the development of agents targeting the 5-HT1B/1D and 5-HT1F receptors and the clinical evidence supporting the use of these agents for acute migraine treatment.

Emerging Treatment Options for Migraine

Migraine is one of top 5 medical conditions that contribute to Years Lived with Disability and affects approximately 1 billion people from around the world. To date, preventive treatment and acute therapies for migraine are limited, have undesirable side effects and are poorly tolerated in patients. In the last few decades, considerable advances in our understanding of migraine and its pathophysiology have paved the way for the development of targeted treatment options. Calcitonin gene-related peptide (CGRP) plays an integral role in the neurobiology of migraine, and new classes of drugs that target the CGRP pathway have included gepants and CGRP pathway monoclonal antibodies. Serotonin 5-HT1F receptor agonists—namely ditans—have also been developed to treat acute migraine. Lastly, non-invasive neuromodulation offers another treatment option for migraine patients who prefer treatments that have fewer side effects and are well tolerated. In this review, we discussed emerging treatment options for migraine that were made available in recent years. Ann Acad Med Singapore 2020;49:226–35 Key words: Calcitonin gene-related peptide monoclonal antibody, Gepants, Headache, Lasmiditan, Neuromodulation

Characterization of binding, functional activity, and contractile responses of the selective 5-HT1F receptor agonist lasmiditan

BACKGROUND AND PURPOSE

Triptans are 5-HT1B/1D receptor agonists (that also display 5-HT1F receptor affinity) with antimigraine action, contraindicated in patients with coronary artery disease due to their vasoconstrictor properties. Conversely, lasmiditan was developed as an antimigraine 5-HT1F receptor agonist. To assess the selectivity and cardiovascular effects of lasmiditan, we investigated the binding, functional activity, and in vitro/in vivo vascular effects of lasmiditan and compared it to sumatriptan.

EXPERIMENTAL APPROACH

Binding and second messenger activity assays of lasmiditan and other serotoninergic agonists were performed for human 5-HT1A , 5-HT1B , 5-HT1D , 5-ht1E , 5-HT1F , 5-HT2A , 5-HT2B , and 5-HT7 receptors, and the results were correlated with their potency to constrict isolated human coronary arteries (HCAs). Furthermore, concentration-response curves to lasmiditan and sumatriptan were performed in proximal and distal HCA, internal mammary, and middle meningeal arteries. Finally, anaesthetized female beagle dogs received i.v. infusions of lasmiditan or sumatriptan in escalating cumulative doses, and carotid and coronary artery diameters were measured.

KEY RESULTS

Lasmiditan showed high selectivity for 5-HT1F receptors. Moreover, the functional potency of the analysed compounds to inhibit cAMP increase through 5-HT1B receptor activation positively correlated with their potency to contract HCA. In isolated human arteries, sumatriptan, but not lasmiditan, induced contractions. Likewise, in vivo, sumatriptan decreased coronary and carotid artery diameters at clinically relevant doses, while lasmiditan was devoid of vasoconstrictor activity at all doses tested.

CONCLUSIONS AND IMPLICATIONS

Lasmiditan is a selective 5-HT1F receptor agonist devoid of vasoconstrictor activity. This may represent a cardiovascular safety advantage when compared to the triptans.

Why is the therapeutic effect of acute antimigraine drugs delayed? A review of controlled trials and hypotheses about the delay of effect

In randomised controlled trials (RCTs) of oral drug treatment of migraine attacks, efficacy is evaluated after 2 hours. The effect of oral naratriptan 2.5 mg with a maximum blood concentration (Tmax ) at 2 hours increases from 2 to 4 hours in RCTs. To check whether such a delayed effect is also present for other oral antimigraine drugs, we hand-searched the literature for publications on RCTs reporting efficacy. Two triptans, 3 nonsteroidal anti-inflammatory drugs (NSAIDs), a triptan combined with an NSAID and a calcitonin gene-related peptide receptor antagonist were evaluated for their therapeutic gain with determination of time to maximum effect (Emax ). Emax was compared with known Tmax from pharmacokinetic studies to estimate the delay to pain-free. The delay in therapeutic gain varied from 1-2 hours for zolmitriptan 5 mg to 7 hours for naproxen 500 mg. An increase in effect from 2 to 4 hours was observed after eletriptan 40 mg, frovatriptan 2.5 mg and lasmiditan 200 mg, and after rizatriptan 10 mg (Tmax  = 1 h) from 1 to 2 hours. This strongly indicates a general delay of effect in oral antimigraine drugs. A review of 5 possible effects of triptans on the trigemino-vascular system did not yield a simple explanation for the delay. In addition, Emax for triptans probably depends partly on the rise in plasma levels and not only on its maximum. The most likely explanation for the delay in effect is that a complex antimigraine system with more than 1 site of action is involved.

Characterisation of the calcitonin gene-related peptide receptor antagonists ubrogepant and atogepant in human isolated coronary, cerebral and middle meningeal arteries

BACKGROUND

Migraine has been associated with a dysfunctional activation of the trigeminovascular system. Calcitonin gene-related peptide, a neuropeptide released from the trigeminal nerve fibres, has an important role in the pathophysiology of migraine and is a current therapeutic target for migraine treatment.

METHODS

We examined the effects of two novel calcitonin gene-related peptide receptor antagonists, ubrogepant and atogepant, on the relaxations induced by α calcitonin gene-related peptide in human isolated middle meningeal, cerebral and coronary arteries. Furthermore, the contractile responses to atogepant and ubrogepant per se were studied and compared to the responses elicited by zolmitriptan in proximal and distal human coronary arteries.

RESULTS

In intracranial arteries, both blockers antagonized the calcitonin gene-related peptide-induced relaxations more potently when compared to the inhibition observed in distal human coronary arteries, with atogepant showing a higher potency. When analysing their antagonistic profile in HCA, ubrogepant showed a competitive antagonist profile, while atogepant showed a non-competitive one. Neither of the gepants had vasoconstrictor effect at any of the concentrations studied in human coronary arteries, whereas zolmitriptan elicited concentration-dependent contractions.

CONCLUSION

ubrogepant and atogepant differentially inhibit the calcitonin gene-related peptide-dependent vasodilatory responses in intracranial arteries when compared to distal human coronary arteries. Also, both gepants are devoid of vasoconstrictive properties in human coronary arteries.

The need for new acutely acting antimigraine drugs: moving safely outside acute medication overuse

Background

The treatment of migraine is impeded by several difficulties, among which insufficient headache relief, side effects, and risk for developing medication overuse headache (MOH). Thus, new acutely acting antimigraine drugs are currently being developed, among which the small molecule CGRP receptor antagonists, gepants, and the 5-HT_1F receptor agonist lasmiditan. Whether treatment with these drugs carries the same risk for developing MOH is currently unknown.

Main body

Pathophysiological studies on MOH in animal models have suggested that decreased 5-hydroxytryptamine (5-HT, serotonin) levels, increased calcitonin-gene related peptide (CGRP) expression and changes in 5-HT receptor expression (lower 5-HT_1B/D and higher 5-HT_2A expression) may be involved in MOH. The decreased 5-HT may increase cortical spreading depression frequency and induce central sensitization in the cerebral cortex and caudal nucleus of the trigeminal tract. Additionally, low concentrations of 5-HT, a feature often observed in MOH patients, could increase CGRP expression. This provides a possible link between the pathways of 5-HT and CGRP, targets of lasmiditan and gepants, respectively. Since lasmiditan is a 5-HT_1F receptor agonist and gepants are CGRP receptor antagonists, they could have different risks for developing MOH because of the different (over) compensation mechanisms following prolonged agonist versus antagonist treatment.

Conclusion

The acute treatment of migraine will certainly improve with the advent of two novel classes of drugs, i.e., the 5-HT_1F receptor agonists (lasmiditan) and the small molecule CGRP receptor antagonists (gepants). Data on the effects of 5-HT_1F receptor agonism in relation to MOH, as well as the effects of chronic CGRP receptor blockade, are awaited with interest.

Nonclinical safety evaluation of erenumab, a CGRP receptor inhibitor for the prevention of migraine

Calcitonin gene-related peptide (CGRP) and its receptor have been implicated as a key mediator in the pathophysiology of migraine. Thus, erenumab, a monoclonal antibody antagonist of the CGRP receptor, administered as a once monthly dose of 70 or 140 mg has been approved for the preventive treatment of migraine in adults. Due to the species specificity of erenumab, the cynomolgus monkey was used in the pharmacology, pharmacokinetics, and toxicology studies to support the clinical program. There were no effects of erenumab on platelets in vitro (by binding, activation or phagocytosis assays). Specific staining of human tissues with erenumab did not indicated any off-target binding. There were no erenumab-related findings in a cardiovascular safety pharmacology study in cynomolgus monkeys or in vitro in human isolated coronary arteries. Repeat-dose toxicology studies conducted in cynomolgus monkeys at dose levels up to 225 mg/kg (1 month) or up to 150 mg/kg (up to 6 months) with twice weekly subcutaneous (SC) doses showed no evidence of erenumab-mediated adverse toxicity. There were no effects on pregnancy, embryo-fetal or postnatal growth and development in an enhanced pre-postnatal development study in the cynomolgus monkey. There was evidence of placental transfer of erenumab based on measurable serum concentrations in the infants up to 3 months post birth. The maternal and developmental no-observed-effect level (NOEL) was the highest dose tested (50 mg/kg SC Q2W). These nonclinical data in total indicate no safety signal of concern to date and provide adequate margins of exposure between the observed safe doses in animals and clinical dose levels.

Effects of two isometheptene enantiomers in isolated human blood vessels and rat middle meningeal artery - potential antimigraine efficacy

Background

Racemic isometheptene [(RS)-isometheptene] is an antimigraine drug that due to its cardiovascular side-effects was separated into its enantiomers, (R)- and (S)-isometheptene. This study set out to characterize the contribution of each enantiomer to its vasoactive profile. Moreover, rat neurogenic dural vasodilatation was used to explore their antimigraine mechanism of action.

Methods

Human blood vessel segments (middle meningeal artery, proximal and distal coronary arteries, and saphenous vein) were mounted in organ baths and concentration response curves to isometheptene were constructed. Calcitonin gene-related peptide (CGRP)-induced neurogenic dural vasodilation was elicited in the presence of the enantiomers using a rat closed cranial window model.

Results

The isometheptene enantiomers did not induce any significant contraction in human blood vessels, except in the middle meningeal artery, when they were administered at the highest concentration (100 μM). Interestingly in rats, (S)-isometheptene induced more pronounced vasopressor responses than (R)-isometheptene. However, none of these compounds affected the CGRP-induced vasodilator responses.

Conclusion

The isometheptene enantiomers displayed a relatively safe peripheral vascular profile, as they failed to constrict the human coronary artery. These compounds do not appear to modulate neurogenic dural CGRP release, therefore, their antimigraine site of action remains to be determined.

Therapeutic novelties in migraine: new drugs, new hope?

Background

In the past decade, migraine research has identified novel drug targets. In this review, we discuss recent data on emerging anti-migraine therapies.

Main body

The development of ditans, gepants and anti-calcitonin gene-related peptide monoclonal antibodies for the treatment of migraine is one of the greatest advances in the migraine field. Lasmiditan, rimegepant and ubrogepant will extend our therapeutic armamentarium for managing acute migraine attacks when triptans are not effective or contraindicated due to cardiovascular disorders. The monoclonal antibodies are migraine specific prophylactic drugs with high responder rates and favorable adverse event profiles. Furthermore, they offer convenient treatment regimens of 4- or 12-week intervals.

Conclusion

Collectively, novel migraine therapies represent a major progress in migraine treatment and will undoubtedly transform headache medicine.

Trigeminovascular calcitonin gene-related peptide function in Cacna1a R192Q-mutated knock-in mice

Familial hemiplegic migraine type 1 (FHM1) is a rare migraine subtype. Whereas transgenic knock-in mice with the human pathogenic FHM1 R192Q missense mutation in the Cacna1a gene reveal overall neuronal hyperexcitability, the effects on the trigeminovascular system and calcitonin gene-related peptide (CGRP) receptor are largely unknown. This gains relevance as blockade of CGRP and its receptor are therapeutic targets under development. Hence, we set out to test these effects in FHM1 mice. We characterized the trigeminovascular system of wild-type and FHM1 mice through: (i) in vivo capsaicin- and CGRP-induced dural vasodilation in a closed-cranial window; (ii) ex vivo KCl-induced CGRP release from isolated dura mater, trigeminal ganglion and trigeminal nucleus caudalis; and (iii) peripheral vascular function in vitro . In mutant mice, dural vasodilatory responses were significantly decreased compared to controls. The ex vivo release of CGRP was not different in the components of the trigeminovascular system between genotypes; however, sumatriptan diminished the release in the trigeminal ganglion, trigeminal nucleus caudalis and dura mater but only in wild-type mice. Peripheral vascular function was similar between genotypes. These data suggest that the R192Q mutation might be associated with trigeminovascular CGRP receptor desensitization. Novel antimigraine drugs should be able to revert this complex phenomenon.

Pharmacokinetics and pharmacodynamics of new acute treatments for migraine

INTRODUCTION

Recommended medications for the acute treatment of migraine encompass triptans, nonsteroidal anti-inflammatory drugs (NSAIDs), and analgesics. While it is true that triptans have been the first successful mechanism-driven treatment in the field, recently, new targets involved in migraine pathogenesis have emerged and new drug classes have been studied for migraine attack therapy. Areas covered: Pharmacodynamics and pharmacokinetics of the new acute treatments of migraine (i.e. ditans, gepants, and glutamate receptor antagonists), considering also marketed drugs in new formulations and administration routes. Expert opinion: Research on the administration routes of marketed drugs was performed in order to improve, in accordance with basic pharmacokinetics parameters, the speed of action of these medications. Similar to the triptans, the new acute treatments are migraine-specific medications, acting on the trigeminovascular system, albeit with different mechanisms. Although available data do not conclusively indicate the superiority of a class over the others, the pharmacodynamics explains the peculiar tolerability and safety profile of different drug classes emerging from clinical trials. Further studies are needed to investigate the possibility of combining different drug classes to optimize the clinical response and the potential role of the novel drugs in medication-overuse headache.

Lasmiditan for the treatment of acute migraine: a review and potential role in clinical practice

Now that the vascular hypothesis of migraine is no longer the prevailing theory of migraine pathogenesis, there is interest in developing acute migraine treatments that act exclusively on non-vascular targets. There is a large percentage of non-responders to current acute migraine treatments and the vasoconstriction associated with triptans limit their use in patients with pre-existing cardiovascular risk factors. Preferential 5-HT_1F agonists have shown promising results in in vitro and early proof-of-concept trials. Lasmiditan, a highly selective 5-HT_1F agonist, has completed two Phase III randomized, double blind, placebo-controlled clinical trials, with a third - a long-term, open-label safety study - still underway. Research to date suggests lasmiditan lacks vasoconstrictive properties and may be a safe and effective treatment option in patients refractory to current acute migraine medications or who have cardiovascular risk factors.

Is selective 5-HT1F receptor agonism an entity apart from that of the triptans in antimigraine therapy?

Migraine is a neurovascular disorder that involves activation of the trigeminovascular system and cranial vasodilation mediated by release of calcitonin gene-related peptide (CGRP). The gold standard for acute migraine treatment are the triptans, 5-HT1B/1D/(1F) receptor agonists. Their actions are thought to be mediated through activation of: (i) 5-HT1B receptors in cranial blood vessels with subsequent cranial vasoconstriction; (ii) prejunctional 5-HT1D receptors on trigeminal fibers that inhibit trigeminal CGRP release; and (iii) 5-HT1B/1D/1F receptors in central nervous system involved in (anti)nociceptive modulation. Unfortunately, coronary arteries also express 5-HT1B receptors whose activation would produce coronary vasoconstriction; hence, triptans are contraindicated in patients with cardiovascular disease. In addition, since migraineurs have an increased cardiovascular risk, it is important to develop antimigraine drugs devoid of vascular (side) effects. Ditans, here defined as selective 5-HT1F receptor agonists, were developed on the basis that most of the triptans activate trigeminal 5-HT1F receptors, which may explain part of the triptans' antimigraine action. Amongst the ditans, lasmiditan: (i) fails to constrict human coronary arteries; and (ii) is effective for the acute treatment of migraine in preliminary Phase III clinical trials. Admittedly, the exact site of action is still unknown, but lasmiditan possess a high lipophilicity, which suggests a direct action on the central descending antinociceptive pathways. Furthermore, since 5-HT1F receptors are located on trigeminal fibers, they could modulate CGRP release. This review will be particularly focussed on the similarities and differences between the triptans and the ditans, their proposed sites of action, side effects and their cardiovascular risk profile.

Targeted 5-HT1F Therapies for Migraine

Migraine is a common neurological disease characterised by the presence of attacks of unilateral, severe head pain accompanied by other symptoms. Although it has been classified as the sixth most disabling disorder, the available therapeutic options to treat this condition have not progressed accordingly. The advance in the development of 5-HT1 receptor agonists for migraine, including 5-HT1B/D and 5-HT1F receptor agonists, has meant a major step forward towards the progression of a better treatment for migraine. Triptans have a limited efficacy, and their effect on vasoconstriction makes them unsafe for patients with cardiovascular and/or cerebrovascular diseases. Therefore, novel effective antimigraine treatments without cardiovascular effects are required, such as selective 5-HT1F receptor agonists (ditans). Lasmiditan has much higher affinity for the 5-HT1F receptor than for the vasoconstrictor 5-HT1B receptor. This has been confirmed in preclinical studies performed to date, where lasmiditan showed no effect on vasoconstriction, and in clinical trials, where healthy individuals and patients did not report cardiac events due to treatment with lasmiditan, although it should be confirmed in larger cohorts. Lasmiditan crosses the blood-brain barrier and may act both centrally and peripherally on 5-HT1F receptors expressed on trigeminal neurons. It is a well-tolerated compound that does not induce major adverse events. Although ongoing phase III clinical trials are needed to confirm its efficacy and safety, lasmiditan might offer an alternative to treat acute migraine with no associated cardiovascular risk. This review will focus on the characterisation of 5-HT1 receptor agonists and their effects as migraine therapies.

Migraine Treatment: Current Acute Medications and Their Potential Mechanisms of Action

Migraine is a common and disabling primary headache disorder with a significant socioeconomic burden. The management of migraine is multifaceted and is generally dichotomized into acute and preventive strategies, with several treatment modalities. The aims of acute pharmacological treatment are to rapidly restore function with minimal recurrence, with the avoidance of side effects. The choice of pharmacological treatment is individualized, and is based on the consideration of the characteristics of the migraine attack, the patient's concomitant medical problems, and treatment preferences. Notwithstanding, a good understanding of the pharmacodynamic and pharmacokinetic properties of the various drug options is essential to guide therapy. The current approach and concepts relevant to the acute pharmacological treatment of migraine will be explored in this review.

Serotonin receptor agonists in the acute treatment of migraine: a review on their therapeutic potential

Migraine is an important socioeconomic burden and is ranked the sixth cause of years of life lost because of disability in the general population and the third cause of years of life lost in people younger than 50 years. The cornerstone of pharmacological treatment is represented by the acute therapy. The serotonin (5-hydroxytryptamine [5-HT]) receptor subtype 1_B/1_D agonists, called triptans, are nowadays the first-line acute therapy for patients who experience moderate-to-severe migraine attacks. Unfortunately, a high percentage of patients are not satisfied with this acute treatment, either for lack of response or side effects. Moreover, their mechanism of action based on vasoconstriction makes them unsuitable for patients with previous cardio- and cerebrovascular diseases and for those with uncontrolled hypertension. Since the introduction of triptans, no other acute drug class has passed all developmental stages. The research for a new drug lacking vasoconstrictive effects led to the development of lasmiditan, a highly selective 5-HT1_F receptor agonist with minimized interactions with other 5-HT receptor subtypes. Lasmiditan is considered to be the first member of a new drug category, the neurally acting anti-migraine agent (NAAMA). Phase II and III trials had shown superiority compared to placebo and absence of typical triptan-associated adverse events (AEs). Most of the AEs were related to the central nervous system, depending on the high permeability through the blood–brain barrier and mild to moderate severity. The results of ongoing long-term Phase III trials will determine whether lasmiditan will become available in the market, and then active triptan comparator studies will assess patients’ preference. Future studies could then explore the safety during pregnancy and breastfeeding or the risk that overuse of lasmiditan leads to medication overuse headache.

Side effects associated with current and prospective antimigraine pharmacotherapies

INTRODUCTION

Migraine is a neurovascular disorder. Current acute specific antimigraine pharmacotherapies target trigeminovascular 5-HT1B/1D, 5-HT1F and CGRP receptors but, unfortunately, they induce some cardiovascular and central side effects that lead to poor treatment adherence/compliance. Therefore, new antimigraine drugs are being explored. Areas covered: This review considers the adverse (or potential) side effects produced by current and prospective antimigraine drugs, including medication overuse headache (MOH) produced by ergots and triptans, the side effects observed in clinical trials for the new gepants and CGRP antibodies, and a section discussing the potential effects resulting from disruption of the cardiovascular CGRPergic neurotransmission. Expert opinion: The last decades have witnessed remarkable developments in antimigraine therapy, which includes acute (e.g. triptans) and prophylactic (e.g. β-adrenoceptor blockers) antimigraine drugs. Indeed, the triptans represent a considerable advance, but their side effects (including nausea, dizziness and coronary vasoconstriction) preclude some patients from using triptans. This has led to the development of the ditans (5-HT1F receptor agonists), the gepants (CGRP receptor antagonists) and the monoclonal antibodies against CGRP or its receptor. The latter drugs represent a new hope in the antimigraine armamentarium, but as CGRP plays a role in cardiovascular homeostasis, the potential for adverse cardiovascular side effects remains latent.

The role of α1- and α2-adrenoceptor subtypes in the vasopressor responses induced by dihydroergotamine in ritanserin-pretreated pithed rats

Background

Dihydroergotamine (DHE) is an acute antimigraine agent that displays affinity for dopamine D₂-like receptors, serotonin 5-HT_1/2 receptors and α₁/α₂-adrenoceptors. Since activation of vascular α₁/α₂-adrenoceptors results in systemic vasopressor responses, the purpose of this study was to investigate the specific role of α₁- and α₂-adrenoceptors mediating DHE-induced vasopressor responses using several antagonists for these receptors.

Methods

For this purpose, 135 male Wistar rats were pithed and divided into 35 control and 100 pretreated i.v. with ritanserin (100 μg/kg; to exclude the 5-HT₂ receptor-mediated systemic vasoconstriction). Then, the vasopressor responses to i.v. DHE (1–3100 μg/kg, given cumulatively) were determined after i.v. administration of some α₁/α₂-adrenoceptor antagonists.

Results

In control animals (without ritanserin pretreatment), the vasopressor responses to DHE were: (i) unaffected after prazosin (α₁; 30 μg/kg); (ii) slightly, but significantly, blocked after rauwolscine (α₂; 300 μg/kg); and (iii) markedly blocked after prazosin (30 μg/kg) plus rauwolscine (300 μg/kg). In contrast, after pretreatment with ritanserin, the vasopressor responses to DHE were: (i) attenuated after prazosin (α₁; 10 and 30 μg/kg) or rauwolscine (α₂; 100 and 300 μg/kg); (ii) markedly blocked after prazosin (30 μg/kg) plus rauwolscine (300 μg/kg); (iii) attenuated after 5-methylurapidil (α_1A; 30–100 μg/kg), L-765,314 (α_1B; 100 μg/kg), BMY 7378 (α_1D; 30–100 μg/kg), BRL44408 (α_2A; 100–300 μg/kg), imiloxan (α_2B; 1000–3000 μg/kg) or JP-1302 (α_2C; 1000 μg/kg); and (iv) unaffected after the corresponding vehicles (1 ml/kg).

Conclusion

These results suggest that the DHE-induced vasopressor responses in ritanserin-pretreated pithed rats are mediated by α₁- (probably α_1A, α_1B and α_1D) and α₂- (probably α_2A, α_2B and α_2C) adrenoceptors. These findings could shed light on the pharmacological profile of the vascular side effects (i.e. systemic vasoconstriction) produced by DHE and may lead to the development of more selective antimigraine drugs devoid vascular side effects.

Increased rate of venous thrombosis may be associated with inpatient dihydroergotamine treatment

OBJECTIVE

To review whether the incidence of catheter-associated venous thromboses was higher in patients receiving IV dihydroergotamine compared to lidocaine.

METHODS

We retrospectively reviewed all admissions at the University of California, San Francisco Headache Center from February 25, 2008, through October 31, 2014, for age, sex, diagnosis, aura, treatment dose, type of IV line used, days with line, superficial (SVT) or deep venous thrombosis (DVT), and pulmonary embolism (PE).

RESULTS

A peripherally inserted central catheter (PICC) or midline catheter was placed in 315 of 589 (53%) admissions. Mean age was 38 years with a range of 6 to 79 years; 121 patients (21%) were ≤18 years old. Seventy-four percent (433 of 589) of patients were female. Of 263 dihydroergotamine admissions using a PICC or midline catheter, 19 (7.2%) had either an SVT or DVT or a PE; 2 patients were diagnosed with both DVT and PE. Of 52 lidocaine admissions using a PICC or midline catheter, none had a thrombotic event (p = 0.05, Fisher exact test). Age, sex, aura, total dihydroergotamine dose, and number of days with line were not significant predictors of venous thrombosis.

CONCLUSIONS

IV dihydroergotamine treatment may be associated with an increased risk of catheter-associated venous thrombosis. A low threshold for diagnostic ultrasound investigation is appropriate because anticoagulation therapy was frequently required.

Lasmiditan for the treatment of migraine

INTRODUCTION

Migraine is one of the most common diseases in the world, with high economical and subjective burden. Migraine acute therapy is nowadays based on specific and non-specific drugs but up to 40% of episodic migraineurs still have unmet treatment needs and over 35% do not benefit from triptans administration. Serotonin-1F receptors have been identified in trigeminal system and became an ideal target for anti-migraine drug development as potential trigeminal neural inhibitors. Lasmiditan, a novel serotonin1F receptor agonist, showed specific affinity in vitro for the receptor without any vasoconstrictive action and inhibited markers associated with electrical stimulation of trigeminal ganglion in migraine animal models. Areas covered: This article reviews both preclinical and clinical studies on lasmiditan as a potential acute therapy for migraine, as well as pharmacokinetic and pharmacodynamic features. It also summarizes safety and tolerability data gathered in the various human studies. Expert opinion: The absence of vasoconstrictive effects makes lasmiditan a promising novel migraine acute therapy. Although preclinical and Phase I and II studies established a significant efficacy, the limited knowledge about pharmacokinetics and metabolism, the high rate of non-serious central nervous system side effects and the lack of larger studies remain still a matter of concern that should be addressed in future studies.

A human trigeminovascular biomarker for antimigraine drugs: A randomised, double-blind, placebo-controlled, crossover trial with sumatriptan

Objective

The objective of this report is to establish a biomarker for the CGRP-interfering effect of antimigraine drugs.

Methods

We quantified the effect of sumatriptan on the trigeminal nerve-mediated rise in forehead dermal blood flow (DBF), induced by capsaicin application (0.6 mg/ml) and electrical stimulation (0.2–1.0 mA), in a randomised, double-blind, placebo-controlled, crossover study in healthy male ( n = 11, age ± SD: 29 ± 8 years) and female ( n = 11, 32 ± 7 years) individuals.

Results

DBF responses to capsaicin were attenuated by sumatriptan (ΔDBF, mean ± SEM: 82 ± 18 AU, p = 0.0002), but not by placebo (ΔDBF: 21 ± 12 AU, p = 0.1026).

Conclusion

We demonstrated that sumatriptan inhibits increases in DBF, induced by the release of, most likely, CGRP. Thus, our model may be used as a biomarker to establish the trigeminovascular effects of (potential) antimigraine drugs, such as CGRP receptor antagonists or antibodies directed against CGRP or its receptor.

Effect of High-Dose Intravenous Eletriptan on Coronary Artery Diameter

The goal of this study was to evaluate the coronary vasoconstrictive effects of high doses of eletriptan compared with a standard dose of sumatriptan. Patients with no clinically significant coronary artery disease were randomized to receive high-dose intravenous eletriptan ( n = 24) vs a standard dose of sumatriptan ( n = 18; 6 mg subcutaneously) vs placebo ( n = 18). Serial angiograms were obtained. The primary non-inferiority analysis found equivalence between the mean maximum change in left anterior descending coronary artery diameter for eletriptan, -22% [95% confidence interval (CI) -26, -19], and sumatriptan, -19% (95% CI -22, -16). The change due to placebo was -16% (95% CI -20, -12). No individual cases of clinically significant vasoconstriction were observed. The results confirm that eletriptan has a broad cardiovascular safety margin, with plasma concentrations comparable to three to five times the Cmax of an oral 80-mg dose associated with modest vasoconstriction equivalent to standard therapeutic doses of sumatriptan.

Effects of Chronic Sumatriptan and Zolmitriptan Treatment on 5-HT1 Receptor Expression and Function in Rats

Triptans are commonly used anti-migraine drugs and show agonist action mainly at serotonin 5-HT1B/1D/1F receptors. It is not known whether frequent or long-term treatment with these drugs would alter 5-HT receptor function. We investigated the effects of protracted (14-18 days) sumatriptan and zolmitriptan treatment in rats on 5-HT1 receptor mRNA expression and function in tissues related to migraine pathophysiology. RT-PCR analysis revealed that 5-HT1B/1D/1F receptor mRNA was reduced in the trigeminal ganglion after treatment with either triptan (reduction by: sumatriptan 39% and zolmitriptan 61% for 5-HT1B; 60% vs 41% for 5-HT1D; 32% vs 68% for 5-HT1F). Sumatriptan attenuated 5-HT1D receptor mRNA by 49% in the basilar artery, whereas zolmitriptan reduced 5-HT1B mRNA in this tissue by 70%. No change in 5-HT1 receptor mRNA expression was observed in coronary artery and dura mater. Chronic triptan treatment had no effect in two functional assays [sumatriptan mediated inhibition (50 mg/kg, i.p.) of electrically induced plasma protein extravasation in dura mater and 5-nonyloxytryptaminestimulated [35S]guanosine-5′-O-(3-thio)triphosphate binding in substantia nigra]. Furthermore, vasoconstriction to 5-HT in isolated basilar artery was not affected by chronic triptan treatment, while it was slightly reduced in coronary artery. We conclude that, although our treatment protocol altered mRNA receptor expression in several tissues relevant to migraine pathophysiology, it did not attenuate 5-HT1 receptor-dependent functions in rats.

Triptans and Chest Symptoms: The Role of Pulmonary Vasoconstriction

Triptans are effective and well tolerated in the treatment of acute migraine. Chest symptoms are a common adverse effect unrelated to coronary vasoconstriction in most patients. Although the aetiology of chest symptoms remains to be fully defined, pulmonary vasoconstriction is a possible underlying mechanism. Preclinical studies of isolated human blood vessels were used to identify the cerebral selectivity of triptans and ascertain if selectivity vs the pulmonary vasculature predicts a lower rate of chest symptoms. Controlled clinical trials and post-marketing surveillance studies were reviewed to document the incidence of chest symptoms after triptan therapy. In clinical trials, the incidence of chest symptoms at usual therapeutic doses ranged from 1 to 4% depending on the triptan and study design, whereas in post-marketing surveillance studies, up to 41% of patients specifically asked about chest symptoms reported them. A comparative clinical trial showed that almotriptan was associated with lower incidence of chest symptoms than sumatriptan (0.3 vs 2.2%). The intrinsic activity of almotriptan, a second-generation triptan, on human pulmonary arteries and veins was lower than that of sumatriptan. Pre-clinical studies of isolated pulmonary blood vessels may predict the clinical likelihood of chest symptoms; however, additional comparisons are needed.

Migraine in the era of precision medicine

Migraine is a common neurovascular disorder in the neurologic clinics whose mechanisms have been explored for several years. The aura has been considered to be attributed to cortical spreading depression (CSD) and dysfunction of the trigeminovascular system is the key factor that has been considered in the pathogenesis of migraine pain. Moreover, three genes (CACNA1A, ATP1A2, and SCN1A) have come from studies performed in individuals with familial hemiplegic migraine (FHM), a monogenic form of migraine with aura. Therapies targeting on the neuropeptids and genes may be helpful in the precision medicine of migraineurs. 5-hydroxytryptamine (5-HT) receptor agonists and calcitonin gene-related peptide (CGRP) receptor antagonists have demonstrated efficacy in the acute specific treatment of migraine attacks. Therefore, ongoing and future efforts to find new vulnerabilities of migraine, unravel the complexity of drug therapy, and perform biomarker-driven clinical trials are necessary to improve outcomes for patients with migraine.

Interaction of Isoflavones and Endophyte-Infected Tall Fescue Seed Extract on Vasoactivity of Bovine Mesenteric Vasculature

It was hypothesized that isoflavones may attenuate ergot alkaloid-induced vasoconstriction and possibly alleviate diminished contractility of vasculature after exposure to ergot alkaloids. The objective of this study was to determine if prior incubation of bovine mesenteric vasculature with the isoflavones formononetin (F), biochanin A (B), or an ergovaline-containing tall fescue seed extract (EXT) and their combinations affect ergotamine (ERT)-induced contractility. Multiple segments of mesenteric artery and vein supporting the ileal flange of the small intestine were collected from Angus heifers at slaughter (n = 5, bodyweight = 639 ± 39 kg). Duplicates of each vessel type were incubated in tissue culture flasks at 37°C with a 50-mL volume of Krebs–Henseleit buffer containing: only buffer (control); or 1 × 10⁻⁶ M EXT; F; or B; and combinations of 1 × 10⁻⁶ M EXT + F; 1 × 10⁻⁶ M EXT + B; 1 × 10⁻⁶ M F + B; or 1 × 10⁻⁶ M EXT + F + B. After incubation for 2 h, sections were mounted in a multimyograph chamber. The ERT dose responses were normalized to 0.12 M KCl. Pretreatment with F, B, and F + B without EXT resulted in similar contractile responses to ERT in mesenteric artery and all incubations containing EXT resulted in a complete loss of vasoactivity to ERT. In mesenteric artery pretreated with EXT, treatments that contained B had higher contractile responses (P < 0.05) at ERT concentrations of 1 × 10⁻⁷ and 5 × 10⁻⁷ M. Also, treatments containing B tended (P < 0.1) to have greater responses than treatments without B at ERT concentrations of 1 × 10⁻⁶, 5 × 10⁻⁶, and 5 × 10⁻⁵ M. In mesenteric vein pretreated with EXT, treatments containing F had greater contractile responses to ERT at 1 × 10⁻⁵, 5 × 10⁻⁵, and 1 × 10⁻⁴ M (P < 0.05). These data indicated that F and B at 1 × 10⁻⁶ M and their combination did not impact the overall contractile response to ERT in mesenteric vasculature. However, F and B may offset some of the vasoconstriction caused by prior exposure to ergot alkaloids.

ST-Elevation Myocardial Infarction After Sumitriptan Ingestion in Patient with Normal Coronary Arteries

Sumitriptan has been used by millions as a migraine abortant; however, there have been studies showing angina pectoris, coronary vasospasm, and even myocardial infarction in patients with predisposing cardiac risk factors. The majority are patients using the injectable form subcutaneously. We present the case of a patient who presents with ST-elevation myocardial infarction, with no cardiovascular risk factors, after ingesting oral sumitriptan for her typical migraine.

Pharmacological Acute Migraine Treatment Strategies: Choosing the Right Drug for a Specific Patient

Background:

In our targeted review (Section 2), 12 acute medications received a strong recommendation for use in acute migraine therapy while four received a weak recommendation for use. Strong recommendations were made to avoid use of two other medications, except for exceptional circumstances. Two anti-emetics received strong recommendations for use as needed.

Objective:

To organize the available acute migraine medications into acute migraine treatment strategies in order to assist the practitioner in choosing a specific medication(s) for an individual patient.

Methods:

Acute migraine treatment strategies were developed based on the targeted literature review used for the development of this guideline (Section 2), and a general literature review. Expert consensus groups were used to refine and validate these strategies.

Results:

Based on evidence for drug efficacy, drug side effects, migraine severity, and coexistent medical disorders, our analysis resulted in the formulation of eight general acute migraine treatment strategies. These could be grouped into four categories: 1) two mild-moderate attack strategies, 2) two moderate-severe attack or NSAID failure strategies, 3) three refractory migraine strategies, and 4) a vasoconstrictor unresponsive-contraindicated strategy. In addition, strategies were developed for menstrual migraine, migraine during pregnancy, and migraine during lactation. The eight general treatment strategies were coordinated with a “combined acute medication approach” to therapy which used features of both the “stratified” and the “step care across attacks” approaches to acute migraine management.

Conclusions:

The available medications for acute migraine treatment can be organized into a series of strategies based on patient clinical features. These strategies may help practitioners make appropriate acute medication choices for patients with migraine.