Frovatriptan as preemptive treatment for fasting-induced migraine

Intervening in the Premonitory Phase to Prevent Migraine: Prospects for Pharmacotherapy

Migraine is a common brain condition characterised by disabling attacks of headache with sensory sensitivities. Despite increasing understanding of migraine neurobiology and the impacts of this on therapeutic developments, there remains a need for treatment options for patients underserved by currently available therapies. The first specific drugs developed to treat migraine acutely, the serotonin-5-hydroxytryptamine [5-HT1B/1D] receptor agonists (triptans), seem to require headache onset in order to have an effect, while early treatment during mild pain before headache escalation improves short-term and long-term outcomes. Some patients find treating in the early window once headache has started but not escalated difficult, and migraine can arise from sleep or in the early hours of the morning, making prompt treatment after pain onset challenging. Triptans may be deemed unsuitable for use in patients with vascular disease and in those of older age and may not be effective in a proportion of patients. Headache is also increasingly recognised as being just one of the many facets of the migraine attack, and for some patients it is not the most disabling symptom. In many patients, painless symptoms can start prior to headache onset and can reliably warn of impending headache. There is, therefore, a need to identify therapeutic targets and agents that may be used as early as possible in the course of the attack, to prevent headache onset before it starts, and to reduce both headache and non-headache related attack burden. Early small studies using domperidone, naratriptan and dihydroergotamine have suggested that this approach could be useful; these studies were methodologically less rigorous than modern day treatment studies, of small sample size, and have not since been replicated. The emergence of novel targeted migraine treatments more recently, specifically calcitonin gene-related peptide (CGRP) receptor antagonists (gepants), has reignited interest in this strategy, with encouraging results. This review summarises historical and emerging data in this area, supporting use of the premonitory phase as an opportunity to intervene as early as possible in migraine to prevent attack-related morbidity.

What is Needed for Evidence-Based Dietary Recommendations for Migraine: A Call to Action for Nutrition and Microbiome Research

BACKGROUND

The gastrointestinal symptoms of migraine attacks have invited numerous dietary hypotheses for migraine etiology through the centuries. Substantial efforts have been dedicated to identifying dietary interventions for migraine attack prevention, with limited success. Meanwhile, mounting evidence suggests that the reverse relationship may also exist - that the biological mechanisms of migraine may influence dietary intake. More likely, the truth involves some combination of both, where the disease influences food intake, and the foods eaten impact the manifestations of the disease. In addition, the gut's microbiota is increasingly suspected to influence the migraine brain via the gut-brain axis, though these hypotheses remain largely unsubstantiated.

OBJECTIVE

This paper presents an overview of the strength of existing evidence for food-based dietary interventions for migraine, noting that there is frequently evidence to suggest that a dietary risk factor for migraine exists but no evidence for how to best intervene; in fact, our intuitive assumptions on interventions are being challenged with new evidence. We then look to the future for promising avenues of research, notably the gut microbiome.

CONCLUSION

The evidence supports a call to action for high-quality dietary and microbiome research in migraine, both to substantiate hypothesized relationships and build the evidence base regarding nutrition's potential impact on migraine attack prevention and treatment.

Minority Representation in Migraine Treatment Trials

BACKGROUND

Minorities have historically been underrepresented in clinical research trials despite having comparatively poor health indicators. Recognizing the dual inequalities of increased disease burden and decreased research participation, the National Institute of Health (NIH) Revitalization Act of 1993 mandated the inclusion and reporting of women and minorities in NIH-funded research. While progress has been made in the subsequent decades, this underrepresentation of minorities in research trials persists and has been documented in multiple disciplines. However, the extent of adequate representation and reporting of minority inclusion in clinical trials for migraine remains unknown.

OBJECTIVES

In this systematic review and study, we review the literature examining the representation of women and minorities in migraine clinical research trials METHODS: First we searched PubMed for pertinent articles examining the inclusion of women and minorities in migraine clinical research trials. Second, we identified controlled-trials for migraine published since 2011 in major neurology, headache, and general medicine journals using the terms "migraine randomized controlled trial." We then reviewed the results manually and excluded pilot studies and those with fewer than 50 participants. We next determined (a) how frequently representation of minorities and women were reported in these major trials; (b) what factors correlated with reporting; and (c) whether women and minority inclusion comprised their ratios in the general population.

RESULTS

We identified 128 relevant clinical trials, of which 36 met our inclusion criteria. All 36 trials (100%) reported gender frequency, and 25 of 36 (69.4%) reported ethnicity or race. Among all studies, women and Whites represented 84.2 and 82.9% of participants (mean), respectively. Studies conducted in the United States and funded by a private company were more likely to report race than studies conducted exclusively outside of the U.S. or with a public sponsor. No studies stratified efficacy or safety by ethnicity or gender. Men and non-Whites in the U.S. were statistically underrepresented.

CONCLUSIONS

Most recent headache studies comply with the NIH mandate to include women and minorities in research trials, particularly U.S.-based and industry-funded studies. Whites are overrepresented compared to both the general population and the population of migraineurs. Future studies should strive to increase minority participation and investigate race-based differences in migraine expression, treatment response, and medication toxicity.

Glucose modulation of spreading depression susceptibility

Spreading depression of Leão is an intense spreading depolarization (SD) wave associated with massive transmembrane ionic, water, and neurotransmitter shifts. Spreading depolarization underlies migraine aura, and occurs in brain injury, making it a potential therapeutic target. While susceptibility to SD can be modulated pharmacologically, much less is known about modulation by systemic physiological factors, such as the glycemic state. In this study, we systematically examined modulation of SD susceptibility by blood glucose in anesthetized rats under full physiological monitoring. Hyperglycemia and hypoglycemia were induced by insulin or dextrose infusion (blood glucose ∼40 and 400 mg/dL, respectively). Spreading depolarizations were evoked by direct cortical electrical stimulation to determine the intensity threshold, or by continuous topical KCl application to determine SD frequency. Hyperglycemia elevated the electrical SD threshold and reduced the frequency of KCl-induced SDs, without significantly affecting other SD properties. In contrast, hypoglycemia significantly prolonged individual and cumulative SD durations, but did not alter the electrical SD threshold, or SD frequency, amplitude or propagation speed. These data show that increased cerebral glucose availability makes the tissue resistant to SD.

Pharmacokinetic evaluation of frovatriptan

INTRODUCTION

Migraine is the most common painful neurological disorder, affecting 13% of the general population. Triptans represent a powerful pharmacological tool in acute migraine treatment, however, a significant portion of treated patients cannot have access to this class due to possible adverse affects. Today, a total of seven triptan molecules are available, representing a commonly prescribed migraine treatment. Although there is a need of extensive use of triptans, only 25% of migraine patients are using triptans.

AREAS COVERED

This review includes triptans and evidence for the use of frovatriptan. A systematic approach is used to discuss the pharmacodynamic and pharmacokinetic aspects of frovatriptan, considering the emerging data on the clinical efficacy of frovatriptan in the treatment of migraine and cluster headaches. The data were obtained by searching the following key words in MEDLINE: pharmacokinetic, pharmacodynamic, triptans, frovatriptan, migraine, menstrual migraine, relatively to the period 1988 - 2011.

EXPERT OPINION

Frovatriptan has been developed in order to improve safety and efficacy of triptans. It shows a favorable tolerability and efficacy profile, limited to 24/48-h headache recurrence, when compared with other triptans. Preclinical data suggest that the pharmacokinetic profile of frovatriptan may differ from other available triptans. In fact, among triptans, frovatriptan showed the highest potency at the 5-HT1B receptor (8.2) and the longer half-life (26 h). These parameters determine the clinical properties of frovatriptan; in particular the lowest rate of headache recurrence in comparison with other triptans.