Divalproex sodium extended-release for the prophylaxis of migraine headache in adolescents: results of a stand-alone, long-term open-label safety study

Management of Chronic Migraine in Children and Adolescents: A Brief Discussion on Preventive Therapies

Pediatric migraine is a debilitating disease that affects about 10% of school-aged children. Like other pain disorders, migraines can be accompanied with sleep, mood, and cognitive difficulties, leading to interruptions in daily tasks required at both school and home. This paper serves as a review of the most current pharmacological treatments available for managing migraine in the pediatric population. Because the management of migraine is complex, we discuss the importance of multidisciplinary care involving pharmacological and non-pharmacological measures, behavioral modifications, and a shared treatment plan between the clinician, patient, and parent/care giver. A diverse group of medications are used to prevent migraine attacks including antiepileptics, antidepressants, antihistamines, and antihypertensive agents, in addition to newer classes of medications; yet there remains a serious lack of controlled studies in the pediatric population. Further clinical research is necessary to have Food and Drug Administration (FDA)-approved medications readily available for migraine sufferers.

Lessons learned from the discovery of sodium valproate and what has this meant to future drug discovery efforts?

INTRODUCTION

The discovery of the anticonvulsant properties of valproic acid and the development of valproic acid/valproate to market authorization for specific epilepsy types and syndromes, as well as their repurposing for other indications, are illustrative examples of both the strengths and weaknesses of drug development strategies.

AREAS COVERED

This review summarizes and interprets the development and repurposing history of valproic acid/valproate. The article is based on articles, including original studies and systematic reviews obtained from PubMed, Scopus, EBSCO, SCIndeks and Google Scholar databases.

EXPERT OPINION

Random screening and careful observation of the experimental effects of tested substances were crucial for discovering the anticonvulsant effects of valproic acid, while rational drug design and clinical observation strategies led to repurposing valproic acid and valproate for bipolar disorder maintenance treatmentand prevention of migraine attacks. Early planning and feasibility studies of future clinical trials are essential for obtaining marketing authorization of new substances or new indications of old anticonvulsants. Significant progress has been made recently toward understanding, treatment and prevention of hepatotoxicity caused by valproic acid/valproate, making its long-term administration safer. There are ongoing efforts to repurpose valproic acid/valproate for augmentation with antipsychotic drugs for the treatment of schizophrenia.

Treatment of migraine attacks and prevention of migraine: Guidelines by the German Migraine and Headache Society and the German Society of Neurology

In collaboration with some of the leading headache centres in Germany, Switzerland and Austria, we have established new guidelines for the treatment of migraine attacks and the prevention of migraine. A thorough literature research of the last 10 years has been the basis of the current recommendations. At the beginning, we present therapeutic novelties, followed by a summary of all recommendations. After an introduction, we cover topics like drug therapy and practical experience, non-effective medication, migraine prevention, interventional methods, non-medicational and psychological methods for prevention and therapies without proof of efficacy.

The optimal management of headaches in children and adolescents

The recognition of the diagnosis of migraine in children is increasing. Early and aggressive treatment of migraine in this population with the use of over-the-counter medications has proven effective. The off-label use of many migraine-specific medications is often accepted in the absence of sufficient evidenced-based trials. Mild to severe cases of migraine should be treated with nonsteroidal anti-inflammatory drugs, with triptans used in moderate to severe headaches unresponsive to over-the-counter therapy. Rescue medication including dihydroergotamine [DHE] should be used for status migrainosus, preferably in the hospital setting. Antiemetics that have antidopaminergic properties can be helpful in patients with associated symptoms of nausea and vomiting through their action on central migraine generation. Furthermore, patients and families should be educated on nonpharmacologic management such as lifestyle modification and avoidance of triggers that can prevent episodic migraine.

Prophylaxis of migraine in children and adolescents

While it has been established that headaches in the pediatric age group are relatively common, the characterization of headache disorders and their treatment in this group has historically been limited. Due to the paucity of controlled studies on prophylaxis of the primary headache disorders in children, the diagnosis of migraine often rests on criteria similar to those used in adults. Data from adult studies are often extrapolated and applied to the pediatric patient. Although it appears that many prophylactic agents are safe, well tolerated and efficacious in children, currently only topiramate is FDA-approved for use in patients 12 years and over. As a result, despite often experiencing significant disability, many children who present to their physician with migraines do not receive preventive therapy. One-third of adolescents meet the criteria for warranting prophylactic therapy, yet few are offered a preventative medication. Moreover, controlled clinical trials investigating the use of both abortive and prophylactic medications in children have suffered from high placebo response rates. A diverse group of medications are used to prevent migraine attacks, including antidepressants, antiepileptics, antihistamines and antihypertensive agents, yet there still remains a serious lack of controlled studies on the pharmacological treatment of pediatric migraine.

Preventive drugs in childhood and adolescent migraine

While headaches in children are quite common, the study and characterization of headache disorders in the pediatric age group has historically been limited. In the absence of controlled studies on prophylactic treatment of the primary headache disorders in this age group, the diagnosis of childhood migraine rests on criteria similar to those in adults. Data from adult studies are often extrapolated and applied to children as well. Although it appears that many preventive agents are safe in children, none are currently FDA-approved for this age group. As a result, despite experiencing significant disability, the vast majority of children who present to their physician with migraine headache do not receive prophylactic therapy. Furthermore, controlled clinical trials investigating the use of both abortive and preventive medications in children have suffered from high placebo response rates. The shorter duration of headaches and other characteristic features seen in children are such that designing randomized controlled trials in this age group is more problematic and limiting. As such, treatment practices vary widely, even among specialists, due to the absence of evidence-based guidelines from clinical trials.

Pediatric migraine and episodic syndromes that may be associated with migraine

Importance

Migraine is a common disorder and a frequent cause of medical consultation in children. Many childhood episodic syndromes have been described as common precursors of migraine.

Objective

To review current knowledge on migraine and childhood episodic syndromes, and to discuss future directions for research and clinical practice.

Findings

For most children it is difficult to describe a headache and fully verbalize symptoms such as photophobia and phonophobia that must be inferred from behaviour. Classical migraine features are rare before the age of 6 years, but some migraine-related syndromes have been described. Benign paroxysmal torticollis of infancy, benign paroxysmal vertigo of childhood, cyclic vomiting syndrome and abdominal migraine are currently classified as childhood episodic syndromes, and therefore common precursors of migraine. A strong association between infantile colic and migraine has recently been reported. There are similarities between children with episodic syndromes and children with migraine, regarding social and demographic factors, precipitating and relieving factors, and accompanying gastrointestinal, neurologic, and vasomotor features. The real pathophysiological mechanisms of migraine are not fully understood. Current data obtained through molecular and functional studies provide a complex model in which vascular and neurologic events cooperate in the pathogenesis of migraine attacks. Genetic factors causing disturbances in neuronal ion channels, make a migraineur more sensitive to multiple trigger factors that activate the nociception cascade. The expanding knowledge on migraine genetics and pathophysiology may be applicable to childhood episodic syndromes. Migraine preventive strategies are particularly important in children, and could be beneficial in childhood episodic syndromes. Nonspecific analgesics like ibuprofen and acetaminophen are widely used in pediatrics to control pain and have been found to be effective also in the treatment of acute migraine attacks. Triptans are the specific fist-line drugs for acute migraine treatment.

Conclusions and relevance

Migraine phenotype differs somewhat in the developing brain, and childhood episodic syndromes may arise before typical migraine headache. Diagnosing pediatric migraine may be difficult because of children’s language and cognitive abilities. The risk of underestimating migraine in pediatric age is high. An adequate diagnosis is important to maintain a good quality of life and to avoid inappropriate therapy.

The pathophysiological and pharmacological basis of current drug treatment of migraine headache

Migraine is a common neurological syndrome that affects approximately 10-20% of the population. The pathophysiology of migraine is unclear. 5-hydroxytriptamine is a key mediator in the pathogenesis of migraine and thus 5-HT1-receptor agonists are the principal drugs for acute migraine therapy. There are three classes of drugs for migraine: over-the-counter analgesics and nonsteroidal anti-inflammatory drugs for acute mild migraine, specific prescription drugs (triptans and ergot alkaloids) for acute severe migraine and pharmacological agents for prophylaxis of migraine. Sumatriptan, naratriptan and others, referred to as 'triptans', are the mainstay for acute treatment of migraine. Ergot alkaloids (ergotamine, dihydroergotamine) are used in patients with frequent, moderate migraine, but are less effective than triptans. There are several agents for prevention of migraine occurrence in patients with frequent or severe disabling migraine attacks. New drugs with improved efficacy and reduced side effects are needed for effective treatment and prevention of migraine.

Episodic migraines in children: limited evidence on preventive pharmacological treatments

The authors conducted a systematic literature review of preventive pharmacological treatments for episodic childhood migraines searching several databases through May 20, 2012. Episodic migraine prevention was examined in 24 publications of randomized controlled trials that enrolled 1578 children in 16 nonrandomized studies. Single randomized controlled trials provided low-strength evidence that propranolol would result in complete cessation of migraine attacks in 713 per 1000 children treated (95% confidence interval, 452-974); trazodone and nimodipine decreased migraine days, while topiramate, divalproex, and clonidine were no more effective than placebo in preventing migraines. Migraine prevention with multidisciplinary drug management was not sustained at 6 months. Divalproex resulted in treatment discontinuation due to adverse effects, and topiramate increased the risk of paresthesia, upper respiratory tract infection, and weight loss. Long-term preventive benefits and improvement in disability and quality of life are unknown. No studies examined quality of life or provided evidence for individualized treatment decisions.

Management of chronic daily headache in children

Children and adolescents can develop frequent, at times daily, headaches. The more severe forms of headaches that these children experience are often migrainous. This article discusses the typical characteristics of these patients and reviews treatments considered in this condition. Unfortunately, there are no high-quality studies to definitively guide treatment in children with chronic daily headache. Treatment decisions are often made using data from adult studies, childhood studies on episodic migraine or expert opinion. Current data on which to base treatment decisions are reviewed in this article.

Migraine treatment in developmental age: guidelines update

There is a serious lack of controlled studies on the pharmacological treatment of primary migraine in the developmental age; there is, consequently, an urgent need for new, evidence-based approaches to this long-neglected field of research. Moreover, previous studies have stated that the placebo response is greater in pediatric patients than in adults and that a reduction in the attack frequency in the absence of any pharmacological treatment is observed more frequently in pediatric migraine patients than in adults. Besides these preliminary considerations, the shorter duration of migraine attacks and other characteristic semeiological features of the clinical picture in children are such that the design of randomized controlled trial (RCT) is more problematic in the developmental age than in the adult. Bearing in mind all these weak points, the aim of this review was to summarize and update recent guidelines for the treatment of primary migraine in children and adolescents. The most recent guidelines are those published by the Italian Society for the study of Headache, the French Society for the study of Migraine and Headache, and the American Academy of Neurology. We have incorporated into these guidelines the results from the few, recent RCTs, clinical controlled trials, open-label studies, meta-analyses and reviews that have been published since 2004; owing to the lack of strong evidence in this field of research, we have sometimes even mentioned pilot non-controlled studies, case series and expert opinions. Lastly, evidence was classified and the recommendations were categorized according to different levels.