Levetiracetam in chronic daily headache: a double-blind, randomised placebo-controlled study. (The Australian KEPPRA Headache Trial [AUS-KHT])

Preventive drug treatments for adults with chronic migraine: a systematic review with economic modelling

Background

Chronic migraine is a disabling condition, affecting 2-4% of adults globally. With the introduction of expensive calcitonin gene-related peptide monoclonal antibodies, it is timely to compare the clinical effectiveness and cost-effectiveness of preventive drugs for chronic migraine.

Objective

To assess the clinical effectiveness and cost-effectiveness of medications used for chronic migraine through systematic reviews and economic modelling.

Eligibility criteria

Randomised controlled trials of drug treatments for efficacy with > 100 participants with chronic migraine per arm; for adverse events > 100 participants with episodic or chronic migraine per arm. Previous economic analyses of preventive drugs for chronic migraine.

Data sources

Eight databases.

Reviews methods

Systematic reviews, network meta-analysis and economic modelling.

Outcomes

Monthly headache days, monthly migraine days, headache-related quality of life, cost-effectiveness.

Results

We found 51 individual articles, reporting 11 randomised controlled trials, testing 6 drugs (topiramate, Botox, eptinezumab, erenumab, fremanezumab, galcanezumab), versus placebo, on 7352 adults with chronic migraine. Calcitonin gene-related peptide monoclonal antibodies, Botox and topiramate reduced headache/migraine days by 2.0-2.5, just under two, or by less than 1.5 days per month, respectively. In the network meta-analysis, eptinezumab 300 mg and fremanezumab monthly ranked in first place in both monthly headache day and monthly migraine day analyses. The calcitonin gene-related peptide monoclonal antibodies were consistently the best choices for headache/migraine days and headache-related quality of life. Topiramate was very unlikely to be the best choice for headache/migraine days and headache-related quality of life when compared to calcitonin gene-related peptide monoclonal antibodies or Botox. We found no trials of the commonly used drugs, such as propranolol or amitriptyline, to include in the analysis. The adverse events review included 40 randomised controlled trials with 25,891 participants; 3 additional drugs, amitriptyline, atogepant and rimegepant, were included. There were very few serious adverse events - none of which were linked to the use of these medications. Adverse events were common. Most people using some calcitonin gene-related peptide monoclonal antibodies reported injection site issues; and people using topiramate or amitriptyline had nervous system or gastrointestinal issues. The cost-effectiveness review identified 16 studies evaluating chronic migraine medications in adults. The newer, injected drugs are more costly than the oral preventatives, but they were cost-effective. Our economic model showed that topiramate was the least costly option and had the fewest quality-adjusted life-year gains, whereas eptinezumab 300 mg was more costly but generated the most quality-adjusted life-year gains. The cost-effectiveness acceptability frontier showed that topiramate was the most cost-effective medication if the decision maker is willing to pay up to £50,000 per quality-adjusted life-year. Our consensus workshop brought together people with chronic migraine and headache experts. Consensus was reached on the top three recommendations for future research on medications to prevent chronic migraine: (1) calcitonin gene-related peptide monoclonal antibodies and Botox versus calcitonin gene-related peptide monoclonal antibodies, (2) candesartan versus placebo and (3) flunarizine versus placebo.

Limitations

Topiramate was the only oral drug for which we were able to include data. We did not find sufficient quality evidence to support the use of other oral drugs.

Conclusions

We did not find evidence that the calcitonin gene-related peptide monoclonal antibodies are more clinically and cost-effective when compared to topiramate or Botox. We identified directions for future research these drugs might take.

Study registration

This study is registered as PROSPERO CRD42021265990, CRD42021265993 and CRD42021265995.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR132803) and is published in full in Health Technology Assessment; Vol. 28, No. 63. See the NIHR Funding and Awards website for further award information.

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.

Pharmacological Profile of MP-101, a Novel Non-racemic Mixture of R- and S-dimiracetam with Increased Potency in Rat Models of Cognition, Depression and Neuropathic Pain

The racemic mixture dimiracetam negatively modulates NMDA-induced glutamate release in rat spinal cord synaptosomal preparations and is orally effective in models of neuropathic pain. In this study, we compared the effects of dimiracetam, its R- or S-enantiomers, and the R:S 3:1 non-racemic mixture (MP-101). In vitro, dimiracetam was more potent than its R- or S-enantiomers in reducing the NMDA-induced [³H]D-aspartate release in rat spinal cord synaptosomes. Similarly, acute oral administration of dimiracetam was more effective than a single enantiomer in the sodium monoiodoacetate (MIA) paradigm of painful osteoarthritis. Then, we compared the in vitro effects of a broad range of non-racemic enantiomeric mixtures on the NMDA-induced [³H]D-aspartate release. Dimiracetam was a more potent blocker than each isolated enantiomer but the R:S 3:1 non-racemic mixture (MP-101) was even more potent than dimiracetam, with an IC₅₀ in the picomolar range. In the chronic oxaliplatin-induced neuropathic pain model, MP-101 showed a significantly improved anti-neuropathic profile, and its effect continued one week after treatment suspension. MP-101 also performed better than dimiracetam in animal models of cognition and depression. Based on the benign safety and tolerability profile previously observed with racemic dimiracetam, MP-101 appears to be a novel, promising clinical candidate for the prevention and treatment of several neuropathic and neurological disorders.

Levetiracetam in the prophylactic treatment of episodic migraine: A prospective open label study

BACKGROUND

The prophylactic treatment of migraine includes anticonvulsant drugs such as valproic acid and topiramate. However, these substances are often poorly tolerated by migraine patients. So far levetiracetam has hardly been studied as an episodic migraine prophylactic agent in adults.

OBJECTIVE

To perform a prospective pilot study for the evaluation of the efficacy and tolerability of levetiracetam in the prophylactic treatment of episodic migraine.

METHODS

Fifty patients with episodic migraine were enrolled in this prospective, open label study. After a baseline period of four weeks, patients received 1,000 mg (starting dose 500 mg) bid levetiracetam for 12 weeks. Migraine frequency and accompanying symptoms were recorded in a headache diary. The primary endpoint was the comparison of attack frequency during the baseline with attack frequency during the last four weeks of treatment (treatment period 3).

RESULTS

In the Intent-To-Treat analysis, 46% of the patients had a migraine reduction of more than 50% in the third period as compared to the baseline period. The mean number of migraine attacks decreased from 5.2 +/- 2.1 (baseline) to 3.4 +/- 2.7 (period 3). The most frequently reported side effects were somnolence, nausea, and weight gain; all were mild and transient. In a post-hoc comparison, responders to levetiracetam had significantly less migraine attacks at baseline and had significantly more often migraine with aura.

CONCLUSION

The data suggest that levetiracetam has some potential in the prophylactic treatment of episodic migraine which seems, however, to be not superior to that of other anticonvulsant drugs. Levetiracetam was well tolerated and showed better efficacy in patients with migraine with aura and in less affected migraine patients. A larger placebo-controlled, double-blind study in adults seems justified on the basis of these data.

Levetiracetam for the Prophylaxis of Migraine in Adults

Migraine is the second most common primary headache disorder after tension-type headache and is the leading cause of disability worldwide. Cortical spreading depression involves neuronal excitation and inhibition and is involved in pathophysiology of migraine. Many anti-epileptic drugs act by inhibiting Cortical Spreading Depression and block desensitization. Anti-convulsants are commonly used in Migraine prophylaxis and the ones being more effective than placebo include Sodium Valproate and Topiramate. Levetiracetam has unique mechanism as it targets hyper-excitable neurons by binding to synaptic vesicle protein. This results in inhibition of neurotransmitter release thus decreases hyper-excitability. Levetiracetam has minimal side effect profile (dizziness, somnolence and mood changes) and it can be well tolerated by patients. In this review, a total of seven studies were included (four open-label trials and three randomized-control trials) which evaluated the role of Levetiracetam in the prophylaxis of migraine in adult patients. On review of this evidence, Levetiracetam appears to be effective in treating migraine with and without aura and is considered safe because of its limited side effects. There was a significant reduction in the frequency, severity, and duration of migraine with a high responder rate. Levetiracetam was well tolerated with minimal side effects and no reported interactions. However, larger randomized controlled trials are needed and these studies should be done on special population to see the outcomes. In addition, studies for extended-release formulations should also be done.

Comprehensive management of adults with chronic migraine: Clinical practice guidelines in Mexico

Introduction:

Migraine is a polygenic multifactorial disorder with a neuronal initiation of a cascade of neurochemical processes leading to incapacitating headaches. Headaches are generally unilateral, throbbing, 4–72 h in duration, and associated with nausea, vomiting, photophobia, and sonophobia. Chronic migraine (CM) is the presence of a headache at least 15 days per month for ≥3 months and has a high global impact on health and economy, and therapeutic guidelines are lacking.

Methods:

Using the Grading of Recommendations, Assessment, Development, and Evaluations system, we conducted a search in MEDLINE and Cochrane to investigate the current evidence and generate recommendations of clinical practice on the identification of risk factors and treatment of CM in adults.

Results:

We recommend avoiding overmedication of non-steroidal anti-inflammatory drugs (NSAIDs); ergotamine; caffeine; opioids; barbiturates; and initiating individualized prophylactic treatment with topiramate eptinezumab, galcanezumab, erenumab, fremanezumab, or botulinum toxin. We highlight the necessity of managing comorbidities initially. In the acute management, we recommend NSAIDs, triptans, lasmiditan, and gepants alone or with metoclopramide if nausea or vomiting. Non-pharmacological measures include neurostimulation.

Conclusions:

We have identified the risk factors and treatments available for the management of CM based on a grading system, which facilitates selection for individualized management.

Levetiracetam for prophylactic treatment of pediatric migraine: A randomized double-blind placebo-controlled trial

INTRODUCTION

Few drugs are available for migraine prophylaxis in children. Levetiracetam is a broad-spectrum anti-seizure drug that has been suggested to be effective in reducing adult migraine episodes. We assessed the safety and efficacy of levetiracetam in the prevention of pediatric migraine.

METHODS

A randomized double-blind placebo-controlled trial was performed. Eligible participants were aged 4-17 years old with at least four migrainous episodes monthly or had severe disabling or intolerable episodes. Primary endpoints were the mean changes in monthly frequency and intensity of headaches from the baseline phase to the last month of the double-blind phase. Safety endpoint was the adverse effects reported.

RESULTS

Sixty-one participants (31 taking levetiracetam and 30 taking placebo) completed the study. All had a significant reduction in frequency and intensity of episodes that was significantly greater in the levetiracetam arm. Sixty eight percent of individuals in the treatment group reported more than 50% reduction of episodes at the end of the trial compared with 30% in the placebo group (p-value: 0.007). Irritability, day-time sedation, and mild tic were reported.

CONCLUSION

Levetiracetam may be useful in migraine prevention and may decrease migraine episodes and severity.

TRIAL REGISTRATION

The study is prospectively registered with Iranian Registry of Clinical Trials; IRCT.ir, number IRCT2017021632603N1.

Current Status of Antiepileptic Drugs as Preventive Migraine Therapy

BACKGROUND

Antiepileptic drugs (AEDs) are an important class of agents used in the treatment of migraine, a neurological disorder that imparts significant socioeconomic burden. It is important for neurologists to understand the rationale for AEDs in migraine-preventive treatment, as well as each agent's efficacy and tolerability profile, in order to best determine clinical care.

PURPOSE OF THIS REVIEW

This article specifically provides the following: (1) a review of the mechanism of action, efficacy, and tolerability of topiramate and divalproex sodium/sodium valproate, the most widely used AEDs for migraine prevention, (2) a discussion on emerging evidence regarding the efficacy of zonisamide and levetiracetam, and (3) comments on gabapentin, pregabalin, carbamazepine, oxcarbazepine, and lamotrigine, AEDs which have insufficient evidence for use in migraine prevention.

RECENT FINDINGS

The potential role for new extended-release formulations of topiramate in migraine prevention is discussed. There is substantial evidence supporting the use of AEDs in migraine prevention. Specific agents should be chosen based on their efficacy and tolerability profiles. Further studies are needed to determine the efficacy of the newer AEDs, zonisamide and levetiracetam, in migraine prevention and to clarify the role of gabapentinoids in headache management.

Comparative effects of traditional Chinese and Western migraine medicines in an animal model of nociceptive trigeminovascular activation

Background

Migraine is a highly prevalent and disabling disorder of the brain with limited therapeutic options, particularly for preventive treatment. There is a need to identify novel targets and test their potential efficacy in relevant preclinical migraine models. Traditional Chinese medicines have been used for millennia and may offer avenues for exploration.

Methods

We evaluated two traditional Chinese medicines, gastrodin and ligustrazine, and compared them to two Western approaches with propranolol and levetiracetam, one effective and one ineffective, in an established in vivo rodent model of nociceptive durovascular trigeminal activation.

Results

Intravenous gastrodin (30 and 100 mg/kg) significantly inhibited nociceptive dural-evoked neuronal firing in the trigeminocervical complex. Ligustrazine (10 mg/kg) and propranolol (3 mg/kg) also significantly inhibited dural-evoked trigeminocervical complex responses, although the timing of responses of ligustrazine does not match its pharmacokinetic profile. Levetiracetam had no effects on trigeminovascular responses.

Conclusion

Our data suggest gastrodin has potential as an anti-migraine treatment, whereas ligustrazine seems less promising. Interestingly, in line with clinical trial data, propranolol was effective and levetiracetam not. Exploration of the mechanisms and modelling effects of Chinese traditional therapies offers novel route for drug discovery in migraine.

Current Status of the New Antiepileptic Drugs in Chronic Pain

Antiepileptic drugs (AEDs) are extensively used worldwide to treat a wide range of disorders other than epilepsy, such as neuropathic pain, migraine, and bipolar disorder. Due to this situation more than 20 new third-generation AEDs have been introduced in the market recently. The future design of new AEDs must also have potential to help in the non-epileptic disorders. The wide acceptance of second generation AEDs for the management of various non-epileptic disorders has caused the emergence of generics in the market. The wide use of approved AEDs outside epilepsy is based on both economic and scientific reasons. Bipolar disorders, migraine prophylaxis, fibromyalgia, and neuropathic pain represent the most attractive indication expansion opportunities for anticonvulsant developers, providing blockbuster revenues. Strong growth in non-epilepsy conditions will see Pfizer's Lyrica become the market leading brand by 2018. In this review, we mainly focus on the current status of new AEDs in the treatment of chronic pain and migraine prophylaxis. AEDs have a strong analgesic potential and this is demonstrated by the wide use of carbamazepine in trigeminal neuralgia and sodium valproate in migraine prophylaxis. At present, data on the new AEDs for non-epileptic conditions are inconclusive. Not all AEDs are effective in the management of neuropathic pain and migraine. Only those AEDs whose mechanisms of action are match with pathophysiology of the disease, have potential to show efficacy in non-epileptic disorder. For this better understanding of the pathophysiology of the disease and mechanisms of action of new AEDs are essential requirement before initiating pre-clinical and clinical trials. Many new AEDs show good results in the animal model and open-label studies but fail to provide strong evidence at randomized, placebo-controlled trials. The final decision regarding the clinical efficacy of the particular AEDs in a specific non-epileptic disorder should be withdrawal from randomized placebo trials rather than open-label studies; otherwise this may lead to off-label uses of drug. The purpose of the present review is to relate the various mechanisms of action of new AEDs to pathophysiological mechanisms and clinical efficacy in neuropathic pain and migraine.

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.

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.

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.

Levetiracetam in migraine prophylaxis: a randomized placebo-controlled study in a rural medical institute in northern India

OBJECTIVE

Migraine is often a chronic and disabling disorder. The objective of our study was to assess the efficacy and tolerability of levetiracetam (LEV) in adult migraine prophylaxis.

METHODS

We conducted a prospective, randomized, placebo-controlled study. A total of 65 patients were randomized in a 1:1 ratio to receive LEV (n = 32) or placebo (n = 33). Twenty-five patients completed the study in the LEV group and 27 patients in the placebo group. Thirteen subjects discontinued early during the trial. After a 1-month run in period, LEV was started at a dose of 250 mg/d (or the matching placebo) and was increased by 250 mg/wk until the final dosage of 1000 mg/d was reached. The titration phase was followed by maintained phase of 3 months.

RESULTS

In LEV group, we found a significant reduction in the frequency (attacks per month) of migraine (from 5.17 [SD, 1.19] at baseline to 2.21 [1.47] in the last 4 weeks) and also in severity of migraine from (2.75 [0.44] to1.29 [0.75]) as compared to the placebo group. Patients treated with LEV also reported a statistically significant reduction in the quantity of symptomatic drugs needed for symptom control as compared to the placebo group (P < 0.0001). The percentage of patients on LEV who experienced greater than or equal to 50% reduction in headache frequency was 64% compared with 22% for placebo.

CONCLUSIONS

Compared with the placebo group, LEV offers improvement in headache frequency and severity as well as it lowers the requirement for other symptomatic drugs in adult migraine patients.

Efficacy and mechanism of anticonvulsant drugs in migraine

Anticonvulsants represent one of the main substance classes used for the preventive treatment of migraine. Efficacy has been demonstrated in randomized placebo-controlled trials for topiramate and valproic acid including divalproex sodium. In the case of topiramate, efficacy has recently been proven for chronic migraine and even medication overuse headache, questioning the established concept of medication withdrawal. However, preventive treatment with anticonvulsants is frequently hampered by side effects that occasionally require treatment discontinuation. In addition, these data indicate that some anticonvulsant drugs are effective in migraine, while a number are clearly not useful. Effective anticonvulsants, such as topiramate and valproate, target nociceptive trigeminovascular and trigeminothalamic dural pathways or mechanisms involved in cortical spreading depression. Dissecting out how the anticonvulsants that do not work differ mechanistically from those that do will almost certainly provide avenues through which one can develop new treatments to bring to patients with migraine.

Broad spectrum and prolonged efficacy of dimiracetam in models of neuropathic pain

Dimiracetam, a bicyclic 2-pyrrolidinone derivative originally developed as cognition enhancer, is a member of the nootropic family for which anecdotal efficacy in models of neuropathic pain has been reported. Its antineuropathic activity was evaluated in established models of neuropathic pain induced by nerve injury, chemotherapy or MIA-induced osteoarthritis. Acutely, dimiracetam was very effective in models of antiretroviral drug induced painful neuropathy, oxaliplatin-induced hyperalgesia and in the MIA-osteoarthritis. Chronic dimiracetam dosing in the MIA and ART- induced models completely reverted hyperalgesia back to the level of healthy controls. Once reached, the maximal effect was maintained despite dose diminution and increased inter-dose interval. The effect of the last dose outlasted dimiracetam half-life longer than 12 times. In synaptosomal preparations, dimiracetam counteracted the NMDA-induced release of glutamate with highest potency in the spinal cord, possibly via NMDA receptor isoforms containing pH-sensitive GluN1 and GluN2A subunits. Dimiracetam appears to be a promising and safe treatment for neuropathic pain conditions for which there are very limited therapeutic options.

Disability and quality of life in headache: where we are now and where we are heading

Headache disorders determine relevant personal and societal burden, and thus the use of patient-reported outcome measures (PROMs) investigating the level of disability and health-related quality of life (HRQoL) have been increasingly used in headache research. The aim of this review was to address the status of research on disability and HRQoL, by addressing results from recently published clinical trials as well as in longitudinal observational studies on headache patients. PubMed has been searched for papers in which measures of HRQoL and/or disability were used as primary or secondary outcome on adult subjects with primary headache, and published in 2010-2012. Among the 70 records retrieved, 12 papers were selected for narrative synthesis. They included data on 2,621 patients with episodic migraine with and without aura, chronic daily headache, and/or chronic migraine with and without medication overuse. The selected trials investigated the efficacy of different pharmacological prophylaxis, of some surgical approaches, of education programmes and osteopathic manipulative treatment; two studies reported longitudinal observations of patients currently under treatment. Overall, the results of our review showed that headache frequency as well as HRQoL and disability were positively impacted by treatment interventions; positive outcomes were less evident in two studies, and similar results were found in the two observational studies. Our findings confirmed that the most commonly used PROMs, including disease-specific tools to assess disability and HRQoL and SF-36, are sensitive to the beneficial effects occurring over time in functioning and quality of life domains in headache patients. They also suggest that the personal and societal costs of headache disorders are likely to be reduced when headache patients receive appropriate treatments and when continuity of care is offered. In terms of future directions, we note that the systematic use of appropriate PROMs should be encouraged both in the clinical practice and in the research field, as they offer a valid option to assess the global effect of treatments on patient-perceived sense of well-being and quality of performance.

Neurovascular unit in chronic pain

Chronic pain is a debilitating condition with major socioeconomic impact, whose neurobiological basis is still not clear. An involvement of the neurovascular unit (NVU) has been recently proposed. In particular, the blood-brain barrier (BBB) and blood-spinal cord barrier (BSCB), two NVU key players, may be affected during the development of chronic pain; in particular, transient permeabilization of the barrier is suggested by several inflammatory- and nerve-injury-based pain models, and we argue that the clarification of molecular BBB/BSCB permeabilization events will shed new light in understanding chronic pain mechanisms. Possible biases in experiments supporting this theory and its translational potentials are discussed. Moving beyond an exclusive focus on the role of the endothelium, we propose that our understanding of the mechanisms subserving chronic pain will benefit from the extension of research efforts to the NVU as a whole. In this view, the available evidence on the interaction between analgesic drugs and the NVU is here reviewed. Chronic pain comorbidities, such as neuroinflammatory and neurodegenerative diseases, are also discussed in view of NVU changes, together with innovative pharmacological solutions targeting NVU components in chronic pain treatment.

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.