Gabapentin in the prophylaxis of chronic daily headache: a randomized, placebo-controlled study

Headache Management in Individuals with Brain Tumor

Headache occurs commonly in individuals diagnosed with cerebral neoplasm. Though the features of a brain tumor-associated headache may vary, a progressive nature of headache and a change in headache phenotype from a prior primary headache disorder often are identified. Pathophysiologic mechanisms proposed for headache associated with brain tumor include headache related to traction on pain-sensitive structures, activation of central and peripheral pain processes, and complications from surgical, chemotherapeutic and/or radiotherapy treatment(s). Optimization of headache management is important for an individual's quality of life. Treatments are based upon patient-specific goals of care and may include tumor-targeted medical and surgical interventions, as well as a multimodal headache treatment approach incorporating acute and preventive medications, nutraceuticals, neuromodulation devices, behavioral interventions, anesthetic nerve blocks, and lifestyles changes.

Antiseizure Medications for the Prophylaxis of Migraine during the Anti- CGRP Drugs Era

Migraine and epilepsy are fundamentally distinct disorders that can frequently coexist in the same patient. These two conditions significantly differ in diagnosis and therapy but share some widely- used preventive treatments. Antiseizure medications (ASMs) are the mainstay of therapy for epilepsy, and about thirty different ASMs are available to date. ASMs are widely prescribed for other neurological and non-neurological conditions, including migraine. However, only topiramate and valproic acid/valproate currently have an indication for migraine prophylaxis supported by high-quality evidence. Although without specifically approved indications and with a low level of evidence or recommendation, several other ASMs are used for migraine prophylaxis. Understanding ASM antimigraine mechanisms, including their ability to affect the pro-migraine calcitonin gene-related peptide (CGRP) signaling pathway and other pathways, may be instrumental in identifying the specific targets of their antimigraine efficacy and may increase awareness of the neurobiological differences between epilepsy and migraine. Several new ASMs are under clinical testing or have been approved for epilepsy in recent years, providing novel potential drugs for migraine prevention to enrich the treatment armamentarium and drugs that inhibit the CGRP pathway.

Migraine cure: a patients' perspective

Objective To conduct a web-based survey concerning patient’s perspective in the migraine cure. Material and Methods A total of 1,102 patients fitting the International Classification of Headache Disorders (ICHD-3) migraine criteria, seeking medical care at the Brain Research Institute at Albert Einstein Hospital in Sao Paulo, Brazil, from January to December 2015, participated in the survey. The online-based survey was accessed via the institute’s website and consisted of demographic data, a description of migraine symptoms, diagnosis and treatment, and the patient’s opinion of migraine cure and which treatment they would consider taking. Results Migraine intensity was significantly higher in female participants than male participants. Chronic migraine tended to affect female participants more than male participants. There was a significant difference in the rate of migraine cure belief between patients with episodic and chronic migraine. Conclusion Some points that were important to migraineurs have been identified in this study. Ultimately, the findings of this study may facilitate the migraine treatment decision process, by providing a better understanding of patients’ perspectives and beliefs, thus creating a more friendly communication between migraineurs and care providers and hopefully, improving the quality of life of patients.

Chronic Migraine Pathophysiology and Treatment: A Review of Current Perspectives

Chronic migraine is a disabling neurological disorder that imposes a considerable burden on individual and socioeconomic outcomes. Chronic migraine is defined as headaches occurring on at least 15 days per month with at least eight of these fulfilling the criteria for migraine. Chronic migraine typically evolves from episodic migraine as a result of increasing attack frequency and/or several other risk factors that have been implicated with migraine chronification. Despite this evolution, chronic migraine likely develops into its own distinct clinical entity, with unique features and pathophysiology separating it from episodic migraine. Furthermore, chronic migraine is characterized with higher disability and incidence of comorbidities in comparison to episodic migraine. While existing migraine studies primarily focus on episodic migraine, less is known about chronic migraine pathophysiology. Mounting evidence on aberrant alterations suggest that pronounced functional and structural brain changes, central sensitization and neuroinflammation may underlie chronic migraine mechanisms. Current treatment options for chronic migraine include risk factor modification, acute and prophylactic therapies, evidence-based treatments such as onabotulinumtoxinA, topiramate and newly approved calcitonin gene-related peptide or receptor targeted monoclonal antibodies. Unfortunately, treatments are still predominantly ineffective in aborting migraine attacks and decreasing intensity and frequency, and poor adherence and compliance with preventative medications remains a significant challenge. Novel emerging chronic migraine treatments such as neuromodulation offer promising therapeutic approaches that warrant further investigation. The aim of this narrative review is to provide an update of current knowledge and perspectives regarding chronic migraine background, pathophysiology, current and emerging treatment options with the intention of facilitating future research into this debilitating and largely indeterminant disorder.

Clinician-Patient Dialogue About Preventive Chronic Migraine Treatment

Many new medications for the treatment of migraine are now available on the market. In the current evolving migraine treatment landscape, an individualized treatment approach is needed. This review provides practical recommendations on how to obtain a correct diagnosis and then engage in a long-term partnership with patients with the most severe form of migraine: chronic migraine (CM). Given the need to effectively treat this complex neurological disease, clinicians in primary care, general neurologists, and headache specialists are at the forefront to ease the burden of this disease for their patients. This manuscript will review how to discuss the currently available treatment options to help control migraine attacks, manage expectations, and, together with the patient, determine the most effective and appropriate treatment. The goal is to create an environment where the clinician partners with the patient in shared decision-making to choose the most effective appropriate treatment for the individual patient.

Consensus of the Brazilian Headache Society on the treatment of chronic migraine

Chronic migraine poses a significant personal, social and economic burden and is characterized by headache present on 15 or more days per month for at least three months, with at least eight days of migrainous headache per month. It is frequently associated with analgesic or acute migraine medication overuse and this should not be overlooked. The present consensus was elaborated upon by a group of members of the Brazilian Headache Society in order to describe current evidence and to provide recommendations related to chronic migraine pharmacological and nonpharmacological treatment. Withdrawal strategies in medication overuse headache are also described, as well as treatment risks during pregnancy and breastfeeding. Oral topiramate and onabotulinum toxin A injections are the only treatments granted Class A recommendation, while valproate, gabapentin, and tizanidine received Class B recommendation, along with acupuncture, biofeedback, and mindfulness. The anti-CGRP or anti-CGRPr monoclonal antibodies, still unavailable in Brazil, are promising new drugs already approved elsewhere for migraine prophylactic treatment, the efficacy of which in chronic migraine is still to be definitively proven.

Treating Chronic Migraine With Neuromodulation: The Role of Neurophysiological Abnormalities and Maladaptive Plasticity

Chronic migraine (CM) is the most disabling form of migraine, because pharmacological treatments have low efficacy and cumbersome side effects. New evidence has shown that migraine is primarily a disorder of brain plasticity and migraine chronification depends on a maladaptive process favoring the development of a brain state of hyperexcitability. Due to the ability to induce plastic changes in the brain, researchers started to look at Non-Invasive Brain Stimulation (NIBS) as a possible therapeutic option in migraine field. On one side, NIBS techniques induce changes of neural plasticity that outlast the period of the stimulation (a fundamental prerequisite of a prophylactic migraine treatment, concurrently they allow targeting neurophysiological abnormalities that contribute to the transition from episodic to CM. The action may thus influence not only the cortex but also brainstem and diencephalic structures. Plus, NIBS is not burdened by serious medication side effects and drug–drug interactions. Although the majority of the studies reported somewhat beneficial effects in migraine patients, no standard intervention has been defined. This may be due to methodological differences regarding the used techniques (e.g., transcranial magnetic stimulation, transcranial direct current stimulation), the brain regions chosen as targets, and the stimulation types (e.g., the use of inhibitory and excitatory stimulations on the basis of opposite rationales), and an intrinsic variability of stimulation effect. Hence, it is difficult to draw a conclusion on the real effect of neuromodulation in migraine. In this article, we first will review the definition and mechanisms of brain plasticity, some neurophysiological hallmarks of migraine, and migraine chronification-related (dys)plasticity. Secondly, we will review available results from therapeutic and physiological studies using neuromodulation in CM. Lastly we will discuss the results obtained in these preventive trials in the light of a possible effect on brain plasticity.

Botulinum toxin in the management of chronic migraine: clinical evidence and experience

Chronic migraine (CM) is a severely disabling neurological condition characterized by episodes of pulsating unilateral or bilateral headache. The United States Food and Drug Administration (FDA) approved onabotulinumtoxinA (Botox®) for the prophylactic treatment of CM in 2010. It has been shown that onabotulinumtoxinA is effective in the reduction of headache frequency and severity in patients with CM. Treatment is well tolerated by the patients. This review reports on the history of botulinum neurotoxin (BoNT) in CM and presents the current clinical evidence for the use of onabotulinumtoxinA in the treatment of CM.

Chronic Daily Headache: Mechanisms and Principles of Management

Primary headache is a common malady that is often under-recognized and frequently inadequately managed in spite of the fact that it affects up to 95 % of the population in a lifetime. Many forms of headache, including episodic tension and migraine headaches, if properly diagnosed, are reasonably amenable to treatment, but a smaller, though not insignificant, percent of the population suffer daily from a chronic, intractable form of headache that destroys one's productivity and quality of life. These patients are frequently seen in neurological practices at a point when treatment options are limited and largely ineffective. In the following review, we will discuss mechanisms drawn from recent studies that address the transition from acute to chronic pain that may apply to the transformation from episodic to chronic daily headaches which may offer opportunities for preempting headache transformation.

Outcome of Chronic Daily Headache or Chronic Migraine

Chronic daily headache (CDH) is a common neurological condition that affects 1-4% of the general population. Recent epidemiological studies have shown that CDH is mainly represented by chronic migraine (CM). Owing to the frequent headaches, associated symptoms, and comorbid conditions associated with CDH/CM, disability, quality of life (QoL), economic burden, and treatment outcome have become important personal and social issues. There have been several studies assessing the disability, QoL, and economic burden associated with CDH/CM. These studies, conducted in different settings, consistently reported significantly higher disability and economic burden and lower QoL among CDH/CM patients compared to patients with episodic headache (EH) or episodic migraine (EM). Treatment outcome of CDH/CM is often poor. In this review, we describe and summarize the results of relevant studies performed to date.

Chronic migraine: risk factors, mechanisms and treatment

Chronic migraine has a great detrimental influence on a patient's life, with a severe impact on socioeconomic functioning and quality of life. Chronic migraine affects 1-2% of the general population, and about 8% of patients with migraine; it usually develops from episodic migraine at an annual conversion rate of about 3%. The chronification is reversible: about 26% of patients with chronic migraine go into remission within 2 years of chronification. The most important modifiable risk factors for chronic migraine include overuse of acute migraine medication, ineffective acute treatment, obesity, depression and stressful life events. Moreover, age, female sex and low educational status increase the risk of chronic migraine. The pathophysiology of migraine chronification can be understood as a threshold problem: certain predisposing factors, combined with frequent headache pain, lower the threshold of migraine attacks, thereby increasing the risk of chronic migraine. Treatment options include oral medications, nerve blockade with local anaesthetics or corticoids, and neuromodulation. Well-defined diagnostic criteria are crucial for the identification of chronic migraine. The International Headache Society classification of chronic migraine was recently updated, and now allows co-diagnosis of chronic migraine and medication overuse headache. This Review provides an up-to-date overview of the classification of chronic migraine, basic mechanisms and risk factors of migraine chronification, and the currently established treatment options.

WITHDRAWN: Anticonvulsant drugs for migraine prophylaxis

July 2015: This review has been split and updated in a series of four new reviews (Linde 2013a; Linde 2013b; Linde 2013c; Linde 2013d). Readers are referred to those reviews for updated results. This review will not be updated.

May 2016: This review has now been withdrawn as it has been replaced by the four new titles listed above.

The editorial group responsible for this previously published document have withdrawn it from publication.

A Narrative Review of Evidence-Based Preventive Options for Chronic Migraine

Chronic migraine is a debilitating disorder that affects 2 % of the global population and imparts a significant societal and economic impact. The cornerstones of chronic migraine management include making an accurate diagnosis, patient education, treatment of comorbid conditions, and selection of an appropriate, evidence-based acute and preventive treatment regimen. Although it is common to treat chronic migraine with preventive medications effective for episodic migraine, a number of treatment options exist with specific evidence for effectiveness in chronic migraine. Currently, onabotulinumtoxinA injections are the only FDA-approved preventive treatment for chronic migraine. A number of non-medication treatment options including occipital nerve and supraorbital nerve stimulation have shown promise as effective prevention for patients either unable to tolerate or unable to obtain relief from oral medications, but more research is necessary.

Justification for conducting neurological clinical trials as part of patient care within private practice

The aim of this review was to assess the benefits and drawbacks of conducting neurological clinical trials and research in private practice for the patients, clinician, Practice Manager, sponsors/Clinical Research Organisations (CROs) and Clinical Trial Coordinator (CTC) to determine if this is justified for all involved. A combination of literature reviews, original research articles and books were selected from 2005 to 2015. Provided that the practice has sufficient number of active trials to prevent financial loss, support staff, adequate facilities and equipment and time, the benefits outweigh the drawbacks. Clinical trials provide patients with more thorough monitoring, re-imbursement of trial-related expenses and the opportunity to try an innovative treatment at no charge when other options have failed. For the clinician, clinical trials provide more information to ensure better care for their patients and improved treatment methods, technical experience and global recognition. Trials collect detailed and up-to-date information on the benefits and risks of drugs, improving society's confidence in clinical research and pharmaceuticals, allow trial sponsors to explore new scientific questions and accelerate innovation. For the CTC, industry-sponsored clinical trials allow potential entry for a career in clinical research giving CTCs the opportunity to become Clinical Research Associates (CRAs), Study Start-Up Managers or Drug Safety Associates.

Gabapentin in Headache Disorders: What Is the Evidence?

OBJECTIVE

Gabapentin (GBP), originally an antiepileptic drug, is more commonly used in the treatment of pain, including headache disorders. Off-label GBP is used in headache disorders with some success, some failure, and much debate. Due to this ambiguity, a clinical evidence literature review was performed investigating GBP's efficacy in headache disorders.

METHODS

Bibliographic reference searches for GBP use in headache disorders were performed in PUBMED and OVID Medline search engines from January 1, 1983 to August 31, 2014. Based on abstracts read by two reviewers, references were excluded if: GBP was not a study compound or headache symptoms were not studied. The resulting references were then read, reviewed, and analyzed.

RESULTS

Fifty-six articles pertinent to GBP use in headache disorders were retained. Eight headache clinical trials were quality of evidence Class 2 or higher based on American Academy of Neurology criteria. Seven of the eight clinical trials showed statistically significant clinical benefit from GBP in various headache syndromes (though modest affects at times). One study, Mathew et al., had concerns about intention-treat analysis breaches and primary outcomes.

CONCLUSION

Despite the conflicting evidence surrounding select studies, a significant amount of evidence shows that GBP has benefit for a majority of primary headache syndromes, including chronic daily headaches. GBP has some efficacy in migraine headache, but not sufficient evidence to suggest primary therapy. When primary headache treatments fail, a GBP trial may be considered in the individual patient.

Episodic and chronic migraine headache: breaking down barriers to optimal treatment and prevention

Migraine is a common disabling primary headache disorder that affects an estimated 36 million Americans. Migraine headaches often occur over many years or over an individual's lifetime. By definition, episodic migraine is characterized by headaches that occur on fewer than 15 days per month. According to the recent International Classification of Headache Disorders (third revision) beta diagnostic criteria, chronic migraine is defined as "headaches on at least 15 days per month for at least 3 months, with the features of migraine on at least 8 days per month." However, diagnostic criteria distinguishing episodic from chronic migraine continue to evolve. Persons with episodic migraine can remit, not change, or progress to high-frequency episodic or chronic migraine over time. Chronic migraine is associated with a substantially greater personal and societal burden, more frequent comorbidities, and possibly with persistent and progressive brain abnormalities. Many patients are poorly responsive to, or noncompliant with, conventional preventive therapies. The primary goals of migraine treatment include relieving pain, restoring function, and reducing headache frequency; an additional goal may be preventing progression to chronic migraine. Although all migraineurs require abortive treatment, and all patients with chronic migraine require preventive treatment, there are no definitive guidelines delineating which persons with episodic migraine would benefit from preventive therapy. Five US Food and Drug Association strategies are approved for preventing episodic migraine, but only injections with onabotulinumtoxinA are approved for preventing chronic migraine. Identifying persons who require migraine prophylaxis and selecting and initiating the most appropriate treatment strategy may prevent progression from episodic to chronic migraine and alleviate the pain and suffering associated with frequent migraine.

Integrated care for chronic migraine patients: epidemiology, burden, diagnosis and treatment options

Migraine is a common neurological disorder, characterised by severe headaches. Epidemiological studies in the USA and Europe have identified a subgroup of migraine patients with chronic migraine. Chronic migraine is defined as ≥15 headache days per month for ≥3 months, in which ≥8 days of the month meet criteria for migraine with or without aura, or respond to treatment specifically for migraine. Chronic migraine is associated with a higher burden of disease, more severe psychiatric comorbidity, greater use of healthcare resources, and higher overall costs than episodic migraine (<15 headache days per month). There is a strong need to improve diagnosis and therapeutic treatment of chronic migraine. Primary care physicians, as well as hospital-based physicians, are integral to the identification and treatment of these patients. The latest epidemiological data, as well as treatment options for chronic migraine patients, are reviewed here.

A Comparative Effectiveness Meta-Analysis of Drugs for the Prophylaxis of Migraine Headache

OBJECTIVE

To compare the effectiveness and side effects of migraine prophylactic medications.

DESIGN

We performed a network meta-analysis. Data were extracted independently in duplicate and quality was assessed using both the JADAD and Cochrane Risk of Bias instruments. Data were pooled and network meta-analysis performed using random effects models.

DATA SOURCES

PUBMED, EMBASE, Cochrane Trial Registry, bibliography of retrieved articles through 18 May 2014.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included randomized controlled trials of adults with migraine headaches of at least 4 weeks in duration.

RESULTS

Placebo controlled trials included alpha blockers (n = 9), angiotensin converting enzyme inhibitors (n = 3), angiotensin receptor blockers (n = 3), anticonvulsants (n = 32), beta-blockers (n = 39), calcium channel blockers (n = 12), flunarizine (n = 7), serotonin reuptake inhibitors (n = 6), serotonin norepinephrine reuptake inhibitors (n = 1) serotonin agonists (n = 9) and tricyclic antidepressants (n = 11). In addition there were 53 trials comparing different drugs. Drugs with at least 3 trials that were more effective than placebo for episodic migraines included amitriptyline (SMD: -1.2, 95% CI: -1.7 to -0.82), -flunarizine (-1.1 headaches/month (ha/month), 95% CI: -1.6 to -0.67), fluoxetine (SMD: -0.57, 95% CI: -0.97 to -0.17), metoprolol (-0.94 ha/month, 95% CI: -1.4 to -0.46), pizotifen (-0.43 ha/month, 95% CI: -0.6 to -0.21), propranolol (-1.3 ha/month, 95% CI: -2.0 to -0.62), topiramate (-1.1 ha/month, 95% CI: -1.9 to -0.73) and valproate (-1.5 ha/month, 95% CI: -2.1 to -0.8). Several effective drugs with less than 3 trials included: 3 ace inhibitors (enalapril, lisinopril, captopril), two angiotensin receptor blockers (candesartan, telmisartan), two anticonvulsants (lamotrigine, levetiracetam), and several beta-blockers (atenolol, bisoprolol, timolol). Network meta-analysis found amitriptyline to be better than several other medications including candesartan, fluoxetine, propranolol, topiramate and valproate and no different than atenolol, flunarizine, clomipramine or metoprolol.

CONCLUSION

Several drugs good evidence supporting efficacy. There is weak evidence supporting amitriptyline's superiority over some drugs. Selection of prophylactic medication should be tailored according to patient preferences, characteristics and side effect profiles.

Unmet clinical needs in chronic migraine: Rationale for study and design of COMPEL, an open-label, multicenter study of the long-term efficacy, safety, and tolerability of onabotulinumtoxinA for headache prophylaxis in adults with chronic migraine

BACKGROUND

Chronic migraine is a neurological condition with a large individual and socioeconomic burden of disease. The recently completed Phase III REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical development program established the efficacy and safety of onabotulinumtoxinA as a prophylactic treatment for chronic migraine patients. However, clinical questions remain. A long-term evaluation study of onabotulinumtoxinA aims to address some of the remaining questions in the treatment of chronic migraine. The clinical rationale, study design, and treatment plan of this ongoing study are reviewed in this paper.

METHODS/DESIGN

The Chronic migraine OnabotulinuMtoxinA Prolonged Efficacy open Label (COMPEL) study will enroll approximately 500 adult patients with chronic migraine at international sites. Patients will be evaluated over 108 weeks, following a 4-week baseline period. Qualified subjects will receive 155 U of onabotulinumtoxinA every 12 weeks for 9 open-label cycles. The primary endpoint will be mean change from baseline in frequency of headache days at 108 weeks. Other endpoints will include additional assessments of the efficacy and safety of onabotulinumtoxinA and the effect of onabotulinumtoxinA on quality-of-life measures, disability, and health economic outcomes. The impact of onabotulinumtoxinA on common comorbidities (eg, sleep, anxiety, and fatigue) will also be assessed.

DISCUSSION

Recruitment and enrollment are ongoing. Post-approval, open-label studies are often designed to more closely resemble clinical practice and provide an opportunity to continue the evaluation of the efficacy and safety of approved treatments. By creating a large database and analyzing a variety of outcome measures over an extended time frame, the COMPEL study will seek to contribute substantially to the existing knowledge of the chronic migraine population and the long-term management of this debilitating disorder.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01516892.

A Multicenter, Double-Blind, Randomized, Placebo-Controlled Trial to Evaluate the Efficacy and Safety of Duliang Soft Capsule in Patients with Chronic Daily Headache

Objective. To investigate the efficacy and safety of traditional Chinese medicine Duliang soft capsule (DSC) in prophylactic treatment for patients with chronic daily headache (CDH). Methods. A multicenter, double-blind, randomized, placebo-controlled clinical study was conducted at 18 Chinese clinical centers. The participants received either DSC or placebo for 4 weeks. The primary efficacy measure was headache-free rate (HFR) in a 4-week period between the pretreatment and posttreatment stages. The secondary efficacy measures were the decrease of headache days, the duration of headache attacks, the frequency of analgesic usage, quality of life, disability, and the headache severity (VAS scores). The accompanying symptoms and adverse events were also assessed. Results. Of 584 CDH patients assessed, 468 eligible patients were randomized. 338 patients received DSC, while 111 patients were assigned in the placebo group. Following treatment, there was a 16.56% difference in HFR favoring DSC over placebo (P < 0.01). Significant differences were also observed between DSC and placebo groups in the secondary measures. However, no statistical difference was found between the two groups in the associated symptoms. No severe adverse effects were observed in the study. Conclusions. DSC might be an effective and well-tolerated option for the prophylactic treatment of patients with CDH.

Chronic daily headache

Chronic daily headache (CDH) is a challenging condition to treat. CDH is often accompanied by significant comorbidities, such as chronic fatigue, depression, anxiety, and insomnia, which further complicate treatment. Unrealistic expectations of treatment goals can lead to patient frustration, and, as a result, decrease treatment adherence. Patients often desire headache-free status, but this outcome is not realistic for many patients with CDH. By contrast, an effective treatment goal starts with establishing the correct diagnosis and creating a multimodal treatment plan to improve function and well-being. With proper comprehensive treatment, the condition improves in most patients.

Best practices for patients with chronic migraine: burden, diagnosis, and management in primary care

Headache and migraine are common medical complaints among patients visiting primary care physicians (PCPs). A number of these patients may have chronic migraine, which is more difficult to diagnose and manage than many other headache disorders. Identification of those at risk, correct diagnosis, and establishment of a comprehensive management plan for patients with chronic migraine will require a joint effort between the PCP and the headache specialist. Together, the PCP and headache specialist will need to assess the patient for modifiable exacerbating factors and comorbidities while managing prophylactic and as-needed therapies. Herein, we provide a review of chronic migraine for the PCP and describe tools for improving patient care.

Drug-induced cerebellar ataxia: a systematic review

BACKGROUND AND OBJECTIVES

Cerebellar ataxia can be induced by a large number of drugs. We here conducted a systemic review of the drugs that can lead to cerebellar ataxia as an adverse drug reaction (ADR).

METHODS

We performed a systematic literature search in Pubmed (1966 to January 2014) and EMBASE (1988 to January 2014) to identify all of the drugs that can have ataxia as an ADR and to assess the frequency of drug-induced ataxia for individual drugs. Furthermore, we collected reports of drug-induced ataxia over the past 20 years in the Netherlands by querying a national register of ADRs.

RESULTS

Drug-induced ataxia was reported in association with 93 individual drugs (57 from the literature, 36 from the Dutch registry). The most common groups were antiepileptic drugs, benzodiazepines, and antineoplastics. For some, the number needed to harm was below 10. Ataxia was commonly reversible, but persistent symptoms were described with lithium and certain antineoplastics.

CONCLUSIONS

It is important to be aware of the possibility that ataxia might be drug-induced, and for some drugs the relative frequency of this particular ADR is high. In most patients, symptoms occur within days or weeks after the introduction of a new drug or an increase in dose. In general, ataxia tends to disappear after discontinuation of the drug, but chronic ataxia has been described for some drugs.

Providing Care for Patients with Chronic Migraine: Diagnosis, Treatment, and Management

Chronic migraine, a subtype of migraine defined as ≥ 15 headache days per month for ≥ 3 months, in which ≥ 8 days per month meet criteria for migraine with or without aura or respond to migraine-specific treatment, is a disabling, underdiagnosed, and undertreated disorder associated with significant disability, poor health-related quality of life, and high economic burden. The keys to caring for chronic migraine patients include: (1) making a proper diagnosis; (2) identifying and eliminating exacerbating factors; (3) assessing for medication overuse (patients with chronic headache often overuse acute medications); and (4) continued management. Communication between patient and physician about treatment goals is important. The patient management guidelines presented in this article should help physicians improve treatment success and proactively address common comorbidities among their patients with chronic migraine.

Tackling chronic migraine: current perspectives

In the last decade, several diagnostic criteria and definitions have been proposed for chronic migraine (CM). The third edition of the International Classification of Headache Disorders–3 beta, published in 2013, has revised CM diagnostic criteria. CM is defined as “headache occurring on 15 or more days per month for more than 3 months, which has the features of migraine headache on at least 8 days per month.” Patients who meet the criteria for CM and for medication-overuse headache should be given both diagnoses. Worldwide, CM prevalence ranges 1%–3%, and its incidence has been estimated to be 2.5% per year. CM is associated with disability and poor quality of life. Modifiable risk factors include (among others): migraine progression (defined as an increase in frequency and severity of migraine attacks); medication and caffeine overuse; obesity; stressful life events; and snoring. CM patients have a significantly higher frequency of some comorbid conditions, including chronic pain, psychiatric disorders, respiratory illness, and some vascular risk factors. Management includes identification and control of comorbidities and risk factors that predispose to CM; treatment and prevention for medication overuse; early treatment for migraine attacks; and an adequate preventive therapy for CM. Several randomized controlled clinical trials have shown the efficacy of topiramate, amitriptyline, onabotulinumtoxinA, and cognitive-behavioral therapy in CM.

Gabapentin's anti-nausea and anti-emetic effects: a review

Gabapentin's main clinical use is in the treatment of neuropathic pain where its binding to neuronal alpha-2/delta subunits of voltage-gated calcium channels (VGCCs) is critical to its mechanism of action. Over the past 10 years, there have been several reports of gabapentin also having anti-nausea and anti-emetic effects in conditions including postoperative nausea and vomiting (PONV), chemotherapy-induced nausea and vomiting (CINV), and hyperemesis gravidarum (HG). In this report, a MEDLINE electronic search was performed, and relevant citations were reviewed and classified by level of evidence; a grade of recommendation was then assigned for gabapentin's use for each studied indication. Out of 33 clinical trials reviewed, 12 assessed nausea and/or vomiting (N/V) associated with gabapentin therapy as primary outcome measures. These 12 studies provided a Grade A recommendation for gabapentin use in treating PONV, a Grade B recommendation for use in treating CINV, and a Grade C recommendation for use in treating HG. Further research is needed to confirm these initial promising results, which implicate the alpha-2/delta VGCC subunit as a novel therapeutic target in the treatment of several N/V-associated clinical conditions.

A rational approach to the management of chronic migraine

About 2% of the adult population has chronic migraine with only 20% diagnosed with this disorder. Those with medication overuse may improve with withdrawal of overuse medications. The intravenous dihydroergotamine regimen usually produces short-term benefit for those with medically refractory chronic migraine. OnabotulinumtoxinA and topiramate have shown efficacy in large placebo-controlled randomized trials. Sodium valproate, gabapentin, tizanidine, amitriptyline, fluoxetine, zonisamide, and possibly memantine may be alternative or possibly combined treatment options but with lesser levels of evidence supporting their use. Preliminary evidence suggests that nerve blocks might be beneficial. Acupuncture, biofeedback, relaxation therapy, and cognitive behavioral therapy might be of benefit. Surgical treatments including bariatric and deactivation of trigger points are of growing interest but not appropriate for most sufferers. Occipital nerve stimulation is a promising treatment with ongoing studies defining its use.

Gabapentin or pregabalin for the prophylaxis of episodic migraine in adults

BACKGROUND

Some antiepileptic drugs but not others are useful in clinical practice for the prophylaxis of migraine. This might be explained by the variety of actions of these drugs in the central nervous system. The present review is part of an update of a Cochrane review first published in 2004, and previously updated (conclusions not changed) in 2007.

OBJECTIVES

To describe and assess the evidence from controlled trials on the efficacy and tolerability of gabapentin/gabapentin enacarbil or pregabalin for preventing migraine attacks in adult patients with episodic migraine.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2012, Issue 12), PubMed/MEDLINE (1966 to 15 January 2013), MEDLINE In-Process (current week, 15 January 2013), and EMBASE (1974 to 15 January 2013) and handsearched Headache and Cephalalgia through January 2013.

SELECTION CRITERIA

Studies were required to be prospective, controlled trials of gabapentin/gabapentin enacarbil or pregabalin taken regularly to prevent the occurrence of migraine attacks, to improve migraine-related quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data. For headache frequency data, we calculated mean differences (MDs) between gabapentin and comparator (placebo, active control, or gabapentin in a different dose) for individual studies and pooled these across studies. For dichotomous data on responders (patients with ≥ 50% reduction in headache frequency), we calculated odds ratios (ORs) and numbers needed to treat (NNTs). We also summarised data on adverse events from all single dosage studies and calculated risk differences (RDs) and numbers needed to harm (NNHs).

MAIN RESULTS

Five trials on gabapentin and one trial on its prodrug gabapentin enacarbil met the inclusion criteria; no reports on pregabalin were identified. In total, data from 1009 patients were considered. One trial each of gabapentin 900 mg (53 patients), and gabapentin titrated to 1200 mg (63 patients) and 1800 mg (122 patients) failed to show a statistically significant reduction in headache frequency in the active treatment group as compared to the placebo group, whereas one trial of gabapentin titrated to 1800 to 2400 mg (113 patients) demonstrated a small but statistically significant superiority of active treatment for this outcome (MD -0.80; 95% confidence interval (CI) -1.55 to -0.05). The pooled results of these four studies (MD -0.44; 95% CI -1.43 to 0.56; 351 patients) do not demonstrate a significant difference between gabapentin and placebo. One trial of gabapentin titrated to 1800 mg (122 patients) failed to demonstrate a significant difference between active treatment and placebo in the proportion of responders (OR 0.97; 95% CI 0.45 to 2.11), whereas one trial of gabapentin titrated to 1800 to 2400 mg (113 patients) demonstrated a small but statistically significant superiority of active treatment for this outcome (OR 2.79; 95% CI 1.09 to 7.17). The pooled results of these two studies (OR 1.59; 95% CI 0.57 to 4.46; 235 patients) do not demonstrate a significant difference between gabapentin and placebo. Comparisons from one study (135 patients) suggest that gabapentin 2000 mg is no more effective than gabapentin 1200 mg. One trial of gabapentin enacarbil (523 participants) failed to demonstrate a significant difference versus placebo or between doses for gabapentin enacarbil titrated to between 1200 mg and 3000 mg with regard to proportion of responders; there was also no evidence of a dose-response trend. Adverse events, most notably dizziness and somnolence, were common with gabapentin.

AUTHORS' CONCLUSIONS

The pooled evidence derived from trials of gabapentin suggests that it is not efficacious for the prophylaxis of episodic migraine in adults. Since adverse events were common among the gabapentin-treated patients, it is advocated that gabapentin should not be used in routine clinical practice. Gabapentin enacarbil is not efficacious for the prophylaxis of episodic migraine in adults. There is no published evidence from controlled trials of pregabalin for the prophylaxis of episodic migraine in adults.

Chronic migraine and chronic daily headache in the Asia-Pacific region: a systematic review

BACKGROUND

Data on the prevalence and characteristics of chronic migraine (CM) and chronic daily headache (CDH) in the Asia-Pacific region are limited.

METHODS

We performed a systematic review on this topic, searching for studies published from 1996 to 2012 that reported the prevalence (population-based studies) or frequency (clinic studies) of CM or CDH. We calculated 95% confidence intervals for the prevalence in population studies. Results were qualitatively described.

RESULTS

Seven population studies and 19 hospital clinic studies from Asia were included. The CDH prevalence in population studies was 1.0-3.9% (median 2.9%). Only two studies from Taiwan reported the population prevalence of CM (1.0% and 1.7%). In addition, we derived a prevalence of 0.6% from a Malaysian study. Eleven clinic studies reported a CM frequency of 4.7-82% (median 52%) as a subset of CDH; classification of medication overuse varied. CM was associated with substantial disability.

CONCLUSIONS

The prevalence of CM and CDH in Asia appears lower than the global average, but applying the above prevalence estimates to the Asia-Pacific population would suggest that CM alone affects between 23 and 65 million individuals in the region.

Chronic daily headaches

Chronic Daily Headache is a descriptive term that includes disorders with headaches on more days than not and affects 4% of the general population. The condition has a debilitating effect on individuals and society through direct cost to healthcare and indirectly to the economy in general. To successfully manage chronic daily headache syndromes it is important to exclude secondary causes with comprehensive history and relevant investigations; identify risk factors that predict its development and recognise its sub-types to appropriately manage the condition. Chronic migraine, chronic tension-type headache, new daily persistent headache and medication overuse headache accounts for the vast majority of chronic daily headaches. The scope of this article is to review the primary headache disorders. Secondary headaches are not discussed except medication overuse headache that often accompanies primary headache disorders. The article critically reviews the literature on the current understanding of daily headache disorders focusing in particular on recent developments in the treatment of frequent headaches.

Detoxification for medication overuse headache is not necessary

BACKGROUND

Current textbook knowledge states that patients with chronic migraine and medication overuse should be withdrawn from acute medication before initiating preventive drug therapy.

OVERVIEW

This recommendation is based on the clinical impression that patients with chronic migraine and medication overuse are refractory to preventive therapy. Recently, however, four randomised trials, two with topiramate and two with onabotulinum toxin A, showed that about half of patients with chronic migraine and medication overuse will respond to these treatments and show both a reduction in migraine days and intake of acute medication.

CONCLUSIONS

Therefore, we propose to educate patients on the mechanisms of medication overuse and motivate them to reduce intake frequency. Patients who fail should be offered either topiramate or onabotulinum toxin A in combination with behavioural therapy and regular exercise. If this approach fails, patients should be offered withdrawal therapy.

[Diagnosis and therapies of refractory migraine]

It is well known that some migraine patients recognize the change of their migraine characteristics over time. These patients often complain chronic daily headaches instead of episodic attacks of migraine. Such chronic headaches are resistant to medication, and called refractory or intractable migraine. Refractory migraine is a term, which has been used for many years, but until recently, there has been little attention paid to its definition. The criteria used for diagnosis of refractory migraine have varied considerably. In most circumstances, however, the definition has included a poor response to "standard" preventive medications. This review article introduces the proposed criteria for definition of refractory migraine and the therapeutic strategies against refractory migraine.

OnabotulinumtoxinA for treatment of chronic migraine: pooled analyses of the 56-week PREEMPT clinical program

OBJECTIVE

To evaluate safety and efficacy of onabotulinumtoxinA (BOTOX(®) ) as headache prophylaxis in adults with chronic migraine.

BACKGROUND

Chronic migraine is a prevalent, disabling, and undertreated neurological disorder. OnabotulinumtoxinA is the only approved prophylactic therapy in this highly disabled patient population.

DESIGN AND METHODS

Two phase III, 24-week, double-blind, parallel-group, placebo-controlled studies, followed by a 32-week, open-label, single-treatment, onabotulinumtoxinA phase, were conducted (January 23, 2006 to August 11, 2008). Qualified subjects were randomized (1:1) to injections of onabotulinumtoxinA (155-195 U) or placebo every 12 weeks for 5 cycles (double-blind: 2, open-label: 3). The pooled primary variable was mean change from baseline in frequency of headache days. Secondary variables included proportion of patients with severe Headache Impact Test-6 score (≥ 60) and mean changes from baseline in frequencies of migraine days, moderate/severe headache days, and migraine episodes; cumulative hours of headache on headache days; and acute headache medication intakes. The primary time point was week 24. Assessments for the open-label phase (all patients treated with onabotulinumtoxinA) compared double-blind treatment groups (onabotulinumtoxinA/onabotulinumtoxinA vs placebo/onabotulinumtoxinA) and are summarized to give a descriptive view of consistent study results, with inferences regarding statistical significance only examined for week 56.

RESULTS

A total of 1384 patients were randomized to onabotulinumtoxinA (n = 688) or placebo (n = 696) in the double-blind phase; 607 (88.2%) onabotulinumtoxinA/onabotulinumtoxinA and 629 (90.4%) placebo/onabotulinumtoxinA patients continued into the open-label phase. OnabotulinumtoxinA/onabotulinumtoxinA treatment statistically significantly reduced headache-day frequency vs placebo/onabotulinumtoxinA in patients with chronic migraine at week 56 (-11.7 onabotulinumtoxinA/onabotulinumtoxinA, -10.8 placebo/onabotulinumtoxinA; P = .019). Statistically significant reductions also favored onabotulinumtoxinA/onabotulinumtoxinA for several secondary efficacy variables at week 56, including frequencies of migraine days (-11.2 onabotulinumtoxinA/onabotulinumtoxinA, -10.3 placebo/onabotulinumtoxinA; P = .018) and moderate/severe headache days (-10.7 onabotulinumtoxinA/onabotulinumtoxinA, -9.9 placebo/onabotulinumtoxinA; P = .027) and cumulative headache hours on headache days (-169.1 onabotulinumtoxinA/onabotulinumtoxinA, -145.7 placebo/onabotulinumtoxinA; P = .018). After the open-label phase (all treated with onabotulinumtoxinA), statistically significant within-group changes from baseline were observed for all efficacy variables. Most patients (72.6%) completed the open-label phase; few discontinued because of adverse events. No new safety or tolerability issues emerged.

CONCLUSIONS

Repeated treatment with ≤ 5 cycles of onabotulinumtoxinA was effective, safe, and well tolerated in adults with chronic migraine.