Pathophysiology of medication overuse headache: insights and hypotheses from preclinical studies

Complicated Form of Medication Overuse Headache Is Severe Version of Chronic Migraine

Background: MOH (medication overuse headache) is regarded as a complication of chronic migraines (CMs), with a general acknowledgment of reciprocal triggering between these two conditions. The present study aims to investigate the clinical parameters of relevance for the development of MOH among patients with CM, as well as for the subtype classification of MOHs. Method: We compared two groups of CM patients, with and without MOH, separated based on their demographic data and migraine characteristics. A subgroup of MOH accompanied by psychiatric co-morbidities (depression, anxiety, sleep disorder) was delineated, and the clinical features of relevance for the progression of MOH into the complicated state were evaluated. Results: The study revealed a higher prevalence of a family history of migraine in both the MOH and potentially complicated MOH subgroups (p < 0.001, p = 0.036), along with a higher prevalence of bilateral pain localization (p = 0.033, 0.021). Symptoms commonly associated with migraines, such as nausea, vomiting, photophobia, phonophobia, and osmophobia, were more common in both the MOH and potentially complicated MOH subgroups (p < 0.05). Furthermore, a positive correlation was found for the frequency (p < 0.001) and severity (p = 0.010) of migraine attacks and the duration of headaches (p = 0.007), atopy (p = 0.017), sleep disturbances (p = 0.011), and emotional stress (p = 0.022) in the MOH group. Conclusion: We found a positive correlation between the prevalence of MOH among patients with CM and a family history of migraines, higher frequency and intensity of headaches, bilateral manifestation, sleep disturbances, and emotional stress. Moreover, symptoms accompanying migraines were found to be more prevalent in individuals with MOH and potentially complicated MOH.

The 'in's and out's' of descending pain modulation from the rostral ventromedial medulla

The descending-pain modulating circuit controls the experience of pain by modulating transmission of sensory signals through the dorsal horn. This circuit's key output node, the rostral ventromedial medulla (RVM), integrates 'top-down' and 'bottom-up' inputs that regulate functionally defined RVM cell types, 'OFF-cells' and 'ON-cells', which respectively suppress or facilitate pain-related sensory processing. While recent advances have sought molecular definition of RVM cell types, conflicting behavioral findings highlight challenges involved in aligning functional and molecularly defined types. This review summarizes current understanding, derived primarily from rodent studies but with corroborating evidence from human imaging, of the role of RVM populations in pain modulation and persistent pain states and explores recent advances outlining inputs to, and outputs from, RVM pain-modulating neurons.

New perspectives on migraine treatment: a review of the mechanisms and effects of complementary and alternative therapies

Migraine is a prevalent and disabling neurovascular disorder, with women being more susceptible, characterized by unilateral throbbing headache, often accompanied by nausea and vomiting, and often associated with various comorbidities such as brain and cardiovascular diseases, which can have a serious impact on quality of life. Although nonsteroidal anti-inflammatory drugs (NSAIDs) are the main first-line medications for the treatment of pain, long-term use often leads to side effects and drug addiction, which emphasizes the need to investigate alternative pain management strategies with fewer adverse effects. Complementary and alternative medicine is a viable pain intervention often used in conjunction with traditional medications, including acupuncture, herbs, moxibustion, transcutaneous electrical stimulation, bio-supplements, and acupressure, which offer non-pharmacological alternatives that are now viable pain management options. This review focuses on the mechanistic doctrine of migraine generation and the role and potential mechanisms of Complementary and Alternative Therapies (CAT) in the treatment of migraine, summarizes the research evidences for CAT as an adjunct or alternative to conventional therapies for migraine, and focuses on the potential of novel migraine therapies (calcitonin gene-related peptide (CGRP) antagonists and pituitary adenylyl cyclase-activating peptide (PACAP) antagonists) with the aim of evaluating CAT therapies as adjunctive or alternative therapies to conventional migraine treatment, thereby providing a broader perspective on migraine management and the design of treatment programs for more effective pain management.

Central sensitization mechanisms in chronic migraine with medication overuse headache: a study of thalamocortical activation and lateral cortical inhibition

BACKGROUND

It is unclear whether cortical hyperexcitability in chronic migraine with medication overuse headache (CM-MOH) is due to increased thalamocortical drive or aberrant cortical inhibitory mechanisms.

METHODS

Somatosensory evoked potentials (SSEP) were performed by electrical stimulation of the median nerve (M), ulnar nerve (U) and simultaneous stimulation of both nerves (MU) in 27 patients with CM-MOH and, for comparison, in 23 healthy volunteers (HVs) of a comparable age distribution. We calculated the degree of cortical lateral inhibition using the formula: 100 - [MU/(M + U) × 100] and the level of thalamocortical activation by analyzing the high frequency oscillations (HFOs) embedded in parietal N20 median SSEPs.

RESULTS

Compared to HV, CM-MOH patients showed higher lateral inhibition (CM-MOH 52.2% ± 15.4 vs. HV 40.4% ± 13.3; p = 0.005), which positively correlated with monthly headache days, and greater amplitude of pre-synaptic HFOs (p = 0.010) but normal post-synaptic HFOs (p = 0.122).

CONCLUSION

Our findings suggest that central neuronal circuits are highly sensitized in CM-MOH patients, at both thalamocortical and cortical levels. The observed changes could be due to the combination of dysfunctional central pain control mechanisms, hypersensitivity and hyperresponsiveness directly linked to the chronic intake of acute migraine drugs.

Targeting Nociceptive Neurons and Transient Receptor Potential Channels for the Treatment of Migraine

Migraine is a neurovascular disorder that affects approximately 12% of the global population. While its exact causes are still being studied, researchers believe that nociceptive neurons in the trigeminal ganglia play a key role in the pain signals of migraine. These nociceptive neurons innervate the intracranial meninges and convey pain signals from the meninges to the thalamus. Targeting nociceptive neurons is considered promising due to their accessibility and distinct molecular profile, which includes the expression of several transient receptor potential (TRP) channels. These channels have been linked to various pain conditions, including migraine. This review discusses the role and mechanisms of nociceptive neurons in migraine, the challenges of current anti-migraine drugs, and the evidence for well-studied and emerging TRP channels, particularly TRPC4, as novel targets for migraine prevention and treatment.

Medication overuse headache

Medication overuse headache (MOH) is a secondary headache disorder attributed to overuse of acute headache medications by a person with an underlying headache disorder, usually migraine or tension-type headache. MOH is common among individuals with 15 or more headache days per month. Although MOH is associated with substantial disability and reductions in quality of life, this condition is often under-recognized. As MOH is both preventable and treatable, it warrants greater attention and awareness. The diagnosis of MOH is based on the history and an unremarkable neurological examination, and is made according to the diagnostic criteria of the International Classification of Headache Disorders third edition (ICHD-3). Pathophysiological mechanisms of MOH include altered descending pain modulation, central sensitization and biobehavioural factors. Treatment of MOH includes the use of headache preventive therapies, but essential to success is eliminating the cause, by reducing the frequency of use of acute headache medication, and perhaps withdrawing the overused medication altogether. Appropriate treatment is usually highly effective, leading to reduced headache burden and acute medication consumption.

Efficacy of Ubrogepant in the Acute Treatment of Migraine With Mild Pain vs Moderate or Severe Pain

BACKGROUND AND OBJECTIVES

To examine the efficacy of ubrogepant in the treatment of migraine with mild vs moderate or severe pain.

METHODS

This was a phase 3, open-label, dose-blinded, 52-week extension trial. Adults with migraine were randomized 1:1:1 (usual care, ubrogepant 50 mg, or ubrogepant 100 mg). Participants treated up to 8 migraine attacks of any pain intensity every 4 weeks. Efficacy outcomes (only collected for ubrogepant) included 2-hour pain freedom (2hPF), freedom from associated symptoms, and from disability. A generalized linear mixed model with binomial distribution and logit link function was used to assess the influence of baseline pain intensity on treatment outcomes in this post hoc analysis.

RESULTS

Data for 19,291 attacks from 808 participants were included. 2hPF rates were higher for attacks treated when pain was mild vs moderate or severe: ubrogepant 50 mg (47.1% vs 23.6%; odds ratio [95% CI] 2.89 [2.57-3.24]) and ubrogepant 100 mg (55.2% vs 26.1%; 3.50 [3.12-3.92]; p < 0.0001 both doses). Rates of freedom from photophobia, phonophobia, and nausea 2 hours after treatment were also significantly higher following the treatment of mild vs moderate or severe pain (p < 0.001 all symptoms, both doses). At 2 hours, the proportion of attacks with normal function was more than double for both doses of ubrogepant (p < 0.001). The most common adverse event was upper respiratory tract infection (∼11% both doses). Serious adverse events were reported by 2% in ubrogepant 50 mg and 3% in ubrogepant 100 mg.

DISCUSSION

Relative to treatment of attacks with moderate or severe pain, treatment with ubrogepant during mild pain resulted in significantly higher rates of freedom from pain, freedom from associated symptoms, and achieving normal function 2 hours after administration.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov, NCT02873221.

CLASSIFICATION OF EVIDENCE

This trial provides Class III evidence that treatment of migraine with ubrogepant when pain is mild vs moderate or severe increases the likelihood of achieving pain freedom, absence of symptoms, and normal function within 2 hours postdose.

Histone Deacetylase Inhibitors Counteract CGRP Signaling and Pronociceptive Sensitization in a Rat Model of Medication Overuse Headache

Chronic triptan exposurein rodents recapitulates medication overuse headache (MOH), causing cephalic pain sensitization and trigeminal ganglion overexpression of pronociceptive proteins including CGRP. Because of these transcriptional derangements, as well as the emerging role of epigenetics in chronic pain, in the present study, we evaluated the effects of the histone deacetylase inhibitors (HDACis) panobinostat and givinostat, in rats chronically exposed to eletriptan for one month. Both panobinostat and givinostat counteracted overexpression of genes coding for CGRP and its receptor subunit RAMP1, having no effects on CLR and RCP receptor subunits in the trigeminal ganglion (TG) of eletriptan-exposed rats. Within the trigeminal nucleus caudalis (TNc), transcripts for these genes were neither upregulated by eletriptan nor altered by concomitant treatment with panobinostat or givinostat. HDACis counteracted hypersensitivity to capsaicin-induced vasodilatation in the trigeminal territory, as well as photophobic behavior and cephalic allodyniain eletriptan-exposed rats. Eletriptan did not affect CGRP, CLR, and RAMP1 expression in cultured trigeminal ganglia, whereas both inhibitors reduced transcripts for CLR and RAMP-1. The drugs, however, increased luciferase expression driven by CGRP promoter in cultured cells. Our findings provide evidence for a key role of HDACs and epigenetics in MOH pathogenesis, highlighting the therapeutic potential of HDAC inhibition in the prevention of migraine chronification.

Therapies targeting CGRP signaling for medication overuse headache

PURPOSE OF REVIEW

Medication overuse headache (MOH) affects more than 60 million individuals worldwide causing enormous personal and social burden. Only repurposed drugs are available for MOH that share limited evidence for efficacy. The preclinical data suggesting that activation of the calcitonin gene-related peptide (CGRP) pathway is involved in headache chronification along with clinical evidence that monoclonal antibodies targeting CGRP (anti-CGRP mAbs) have good efficacy in preventing chronic migraine, triggered this review that aims to summarize the current data on the effectiveness and safety of mAbs against CGRP in MOH.

RECENT FINDINGS

Post hoc analyses of phase-3 trials of erenumab, fremanezumab, galcanezumab, and eptinezumab for the prevention of chronic migraine revealed that patients with MOH benefit from the treatment over placebo. Several real-world studies confirm the efficacy of erenumab and galcanezumab in patients with MO. However, all published trials evaluated treatments in patients with chronic migraine with MO collectively, not in patients with MOH exclusively.

SUMMARY

The available data indicate that anti-CGRP mAbs represent a good mechanism-based and disease-specific therapeutical option with for MOH as long as detoxification and additional nonpharmaceutical interventions are operated. Future research should focus on long-term-controlled trials in MOH populations exclusively.

Post-traumatic Headache: Pharmacologic Management and Targeting CGRP Signaling

PURPOSE OF REVIEW

Post-traumatic headache is a common sequela of injury to the head and/or neck. Here, we review the current approach to pharmacologic management of post-traumatic headache and explore the therapeutic promise of targeting calcitonin gene-related peptide signaling to address unmet treatment needs.

RECENT FINDINGS

The scarcity of data from controlled trials has left clinicians to rely on mainly expert opinion for the pharmacologic management of post-traumatic headache. The current view is that a phenotype-guided approach should be used, in which patients are treated according to the primary headache phenotype that their clinical features resemble the most (e.g. migraine, tension-type headache). Moreover, incremental advances are being made in the field that aim to identify possible cellular and molecular drivers of headache persistence. Calcitonin gene-related peptide has emerged as a key drug target which, in turn, has prompted novel insights on the potential importance of early initiation of pharmacologic treatment following the onset of post-traumatic headache. This, in turn, might prevent subsequent persistence and chronification of headache.

Safety and efficacy of remote electrical neuromodulation for the acute treatment of chronic migraine: an open-label study

Supplemental Digital Content is Available in the Text. The efficacy of REN was evaluated in patients with chronic migraine. Pain relief was achieved in 59.3% of participants and pain disappearance in 20.9% (2 hours posttreatment).

Introduction:

Remote electrical neuromodulation (REN) is an acute treatment of migraine. The results from several studies in patients with episodic migraine suggest that REN is an effective and safe acute treatment of migraine. A recent pilot study provided initial support that REN is effective in patients with chronic migraine as well.

Objectives:

The current study aimed to validate and provide further evidence for the safety and efficacy of REN in a large sample of patients impacted by chronic migraine.

Methods:

In this open-label, single-arm study, patients with chronic migraine treated their headaches with the REN device (Nerivio, Theranica Bio-Electronics Ltd, Israel) for 4 weeks. Participants used an electronic diary to record their symptoms at treatment initiation, 2 hours after treatment, and 24 hours after treatment. The primary end point was the percentage of subjects who achieved pain relief at 2 hours posttreatment. Secondary end points included pain freedom and improvement of associated symptoms and functional disability.

Results:

One hundred twenty-six subjects were enrolled into the study, of which 91 subjects had an evaluable treatment with REN. Pain relief and pain disappearance at 2 hours were achieved by 59.3% (54/91) and 20.9% (19/91) of modified intent-to-treat subjects, respectively (with worst-case sensitivity analysis indicating 54.5% and 19.2%, respectively). Sustained pain relief at 24 hours was observed in 64.4% (29/45) of those who achieved pain relief at 2 hours (with worst-case sensitivity analysis indicating 45.6%). The findings of the study show that REN has a favorable effect on nausea, photophobia, and phonophobia and improves functional ability. One device-related adverse event was reported.

Conclusions:

Remote electrical neuromodulation treatments results in the relief of migraine headaches and associated symptoms, thus offering a drug-free acute treatment option for people with chronic migraine.

Trial registration:

ClinicalTrials.gov NCT04194008.

Nerivio® remote electrical neuromodulation for acute treatment of chronic migraine

Nerivio^® (by Theranica Bio-Electronics Ltd, Tel Aviv, Israel) is a wireless, wearable, noninvasive, battery-operated, remote electrical neuromodulation device controlled by a smartphone application. It is US FDA authorized for the acute treatment of migraine with or without aura in people 12 years and older in the US, and European Conformity (CE) marked for the same indication in the EU. The American Headache Society Consensus Statement recommends Nerivio as a tier 2 treatment for migraines. This review summarizes a series of five independent clinical trials and two real-world evidence studies that established safety, tolerability and efficacy of Nerivio in treating migraine attacks. It further provides up-to-date practical information on device usability. Based on findings of this review, Nerivio offers a safe and effective nonpharmacological alternative for acute treatment in patients with chronic (and nonchronic) migraine.

A critical review of the neurovascular nature of migraine and the main mechanisms of action of prophylactic antimigraine medications

INTRODUCTION

Migraine involves neurovascular, functional, and anatomical alterations. Migraineurs experience an intense unilateral and pulsatile headache frequently accompanied with vomiting, nausea, photophobia, etc. Although there is no ideal preventive medication, frequency in migraine days may be partially decreased by some prophylactics, including antihypertensives, antidepressants, antiepileptics, and CGRPergic inhibitors. However, the mechanisms of action involved in antimigraine prophylaxis remain elusive.

AREAS COVERED

This review recaps some of the main neurovascular phenomena related to migraine and currently available preventive medications. Moreover, it discusses the major mechanisms of action of the recommended prophylactic medications.

EXPERT OPINION

In the last three years, migraine prophylaxis has evolved from nonspecific to specific antimigraine treatments. Overall, nonspecific treatments  mainly involve neural actions, whereas specific pharmacotherapy (represented by CGRP receptor antagonists and CGRPergic monoclonal antibodies) is predominantly mediated by neurovascular mechanisms that may include, among others: (i) reduction in the cortical spreading depression (CSD)-associated events; (ii) inhibition of pain sensitization; (iii) blockade of neurogenic inflammation; and/or (iv) increase in cranial vascular tone. Accordingly, the novel antimigraine prophylaxis promises to be more effective, devoid of significant adverse effects (unlike nonspecific treatments), and more beneficial for the quality of life of migraineurs.

Medication overuse in a subgroup analysis of phase 3 placebo-controlled studies of galcanezumab in the prevention of episodic and chronic migraine

INTRODUCTION

Acute medication overuse is prevalent in patients with migraine.

METHODS

In three phase 3, double-blind, randomized, placebo-controlled studies, patients with episodic migraine (EVOLVE-1 and EVOLVE-2) or chronic migraine (REGAIN) were randomized 2:1:1 to monthly subcutaneous injections of placebo or galcanezumab 120 or 240 mg for 3 or 6 months. This subgroup analysis evaluated mean changes in the number of monthly migraine headache days in each treatment among patients with versus without baseline acute medication overuse via mixing modelling with repeated measures.

RESULTS

The percentages of patients with baseline medication overuse in placebo, galcanezumab 120-mg and 240-mg groups, respectively, were 19.4%, 17.3%, and 19.3% for EVOLVE-1/-2 (pooled; post hoc), and 63.4%, 64.3%, and 64.1% for REGAIN (a priori). Both galcanezumab doses demonstrated significant improvement compared with placebo for overall least squares mean change in monthly migraine headache days in patients with baseline medication overuse in both the episodic and chronic migraine studies (p ≤ 0.001). Furthermore, both galcanezumab doses reduced average monthly medication overuse rates compared to placebo (p < 0.001) in both patient populations with medication overuse at baseline.

CONCLUSIONS

Galcanezumab appears to be effective for the preventive treatment of episodic and chronic migraine in patients who overuse acute medications.Trial registration: ClinicalTrials.gov Identifiers: NCT02614183, NCT02614196, and NCT02614261.

Plasma levels of CGRP and expression of specific microRNAs in blood cells of episodic and chronic migraine subjects: towards the identification of a panel of peripheral biomarkers of migraine?

Background

Migraine can manifest with an episodic or a chronic pattern in a continuum of disease severity. Multiple factors are associated with the progression of the pattern from episodic to chronic. One of the most consistently reported factors is the overuse of medications (MO) for the acute treatment of migraine attacks. The mechanisms through which MO facilitates the transformation of episodic migraine (EM) into chronic migraine (CM) are elusive. In order to provide insights into these mechanisms, the present study aims to identify possible peripheral biomarkers associated with the two forms of migraine, and with the presence of MO.

Methods

We evaluated the plasma levels of calcitonin gene-related peptide (CGRP) and the expression of miR-34a-5p and miR-382-5p in peripheral blood mononuclear cells of subjects with EM (n = 27) or CM-MO (n = 28). Subjects in the CM-MO group were also tested 2 months after an in-hospital detoxification protocol.

Results

CGRP, miR-382-5p, and miR-34a-5p levels were significantly higher in CM-MO subjects when compared to EM patients (p = 0.003 for all comparisons). After correcting for age, sex, and disease duration, miRNAs expression was still significantly associated with migraine phenotype (EM vs. CM-MO: p = 0.014 for miR-382-5p, p = 0.038 for miR-34a-5p), while CGRP levels were not (p = 0.115). CGRP plasma levels significantly and positively correlated with miR-382-5p (Spearman’s rho: 0.491, p = 0.001) and miR-34a-5p (Spearman’s rho: 0.303, p =0.025) in the overall population. In the CM-MO group, detoxification significantly decreased CGRP levels and miRNAs expression (p = 0.001). When comparing responders and non-responders to the detoxification, the former group (n = 23) showed significantly higher levels of CGRP at baseline, and significantly lower expression of miR-382-5p after the detoxification.

Conclusions

Our findings identify a potential panel of peripheral markers associated with migraine subtypes and disease severity. CGRP levels as well as miRNAs expression were influenced by MO, and modulated by detoxification in subjects with CM-MO.

Trial registration

The study protocol was registered at www.clinicaltrials.gov (NCT04473976).

Remote Electrical Neuromodulation for the Acute Treatment of Migraine in Patients with Chronic Migraine: An Open-Label Pilot Study

INTRODUCTION

Remote electrical neuromodulation (REN) is a novel acute treatment of migraine. Upper arm peripheral nerves are stimulated to induce conditioned pain modulation (CPM)-an endogenous analgesic mechanism in which conditioning stimulation inhibits pain in remote body regions. The REN device (Nerivio^®, Theranica Bio-Electronics LTD., Israel) is FDA-authorized for acute treatment of migraine in adults who do not have chronic migraine. The current study assessed the consistency of response over multiple migraine attacks in people with chronic migraine who are typically characterized with severe pain intensity, high disability, and less robust response to triptans.

METHODS

This was an open-label, single-arm, dual-center study conducted on adults with chronic migraine. Participants underwent a 4-week treatment phase in which they treated their migraine headaches with the device for 45 min within 1 h of attack onset. Pain levels were recorded at baseline, 2 h, and 24 h post-treatment. Efficacy outcomes (pain relief and pain-free responses at 2 h, sustained pain relief and sustained pain-free responses at 24 h) focused on intra-individual consistency of response across multiple attacks, which was defined as response in at least 50% of the treatments.

RESULTS

Forty-two participants were enrolled, and 38 participants were evaluable for analyses; 73.7% (28/38) achieved pain relief at 2 h, 26.3% (10/38) were pain-free at 2 h, 84.4% (27/32) had sustained pain relief response at 24 h and 45.0% (9/20) had sustained pain relief response at 24 h in at least 50% of their treated attacks. The effects of REN on associated symptoms and improvement in function were also consistent. The incidence of device-related adverse events was low (1.8%).

CONCLUSIONS

REN used for a series of migraine attacks was effective and well tolerated across attacks. REN may offer a safe and effective non-pharmacological alternative for acute treatment in patients with chronic migraine.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04161807. Retrospectively registered on November 13, 2019.

Identification of candidate proteomic markers in the serum of medication overuse headache patients: An exploratory study

PURPOSE OF THE STUDY

The pathophysiological mechanism of medication overuse headache is uncertain; no distinctive markers have been described right now. The aim of this study was to conduct proteomic analyses on serum samples from patients with medication overuse headache and healthy individuals. Specifically, mono- (SDS-PAGE) and two-dimensional gel electrophoresis (2-DE) followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) were used to evaluate changes in serum proteins.

MAIN FINDINGS

By SDS-PAGE, four over-expressed bands were revealed in patients, compared to controls. 2-DE combined with LC-MS/MS analysis allowed confirmation of some proteins preliminarily detected by SDS-PAGE: Hemopexin, alpha-1-acid glycoprotein 1, apolipoprotein A4 and haptoglobin. Moreover, other differential proteins were isolated, mostly increased in MOH patients: Alpha-1-antitrypsin, immunoglobulin heavy constant alpha 1, retinol binding protein and transthyretin. Only one protein, immunoglobulin kappa constant, was decreased in the patients' group.

CONCLUSIONS

The investigation of the serum proteome can offer a better understanding about biological mechanisms underlying medication overuse headache. Specifically, medication overuse headache shares some serum biochemical markers with chronic pain conditions. Further studies might uncover the relevance of these proteins in medication overuse headache.

Incorporating Remote Electrical Neuromodulation (REN) Into Usual Care Reduces Acute Migraine Medication Use: An Open-Label Extension Study

Background: A recent randomized controlled study showed that 66.7% (66/99) and 37.4% (37/99) of people undergoing remote electrical neuromodulation (REN), a novel non-pharmacological migraine treatment, achieve pain relief and pain freedom, respectively, at 2 h post-treatment. The participants who completed the 6-weeks double-blind phase of this study were offered to participate in an open-label extension (OLE) with an active REN device. Objective: This study investigated the clinical use of REN, focusing on its potential in reducing the use of acute migraine medications. Methods: The parent study for this open-label extension (OLE) was a randomized, double-blind, sham-controlled study of acute treatment conducted on 296 participants enrolled at 12 sites in the USA and Israel. This study included a run-in phase, in which migraine attacks were treated with usual care, and an 8-weeks double-blind treatment phase. One hundred sixty participants continued in an 8-weeks OLE phase in which they could incorporate a REN device into their usual care. Medication use rate (percentage of participants who treated their attacks only with REN and avoided medications in all their attacks) and pain outcomes at 2 h post-treatment were compared between the OLE and the run-in phase in a within-subject design. Results: The analyses were performed on 117 participants with episodic migraine. During the OLE, 89.7% of the participants treated their attacks only with REN and avoided medications in all their attacks compared with 15.4% in the run-in phase (p < 0.0001). The rates of pain relief and pain-free in at least 50% of the treatments at 2 h post-treatment were comparable (pain relief: 58.1% in the run-in phase and 57.3% in the OLE, p = 0.999; pain-free: 23.1% in the run-in vs. 30.8% in the OLE, p = 0.175). Conclusions: REN may reduce the use of acute migraine medications. Thus, incorporating REN into usual care may reduce the risk for medication overuse headache (MOH). Future studies should evaluate whether REN reduces the use of acute migraine medications in a population at risk for MOH.

An unsuspected and unrecognized cause of medication overuse headache in a chronic migraineur—essential oil-related medication overuse headache: A case report

Essential oils are widely used by people for common ailments like headache and backache. We report a case of chronic daily headache in an adolescent migraineur refractory to most antimigraine drugs secondary to topical application of essential oils containing camphor and eucalyptus. A 14-year-old boy presented with chronic daily headache of 1-year duration, refractory to four antimigraine drugs including valproate and topiramate. He was daily applying a balm called Amruthanjan (10% camphor and 14.5% eucalyptus) on his forehead to relieve headache. Patient had complete relief of headache in 2 weeks after stopping the balm application. All his antimigraine drugs were tapered and stopped over a period of 3 months. At 1-year follow-up, he is headache free. Brain-stimulant essential oils of camphor and eucalyptus may be an important unrecognized cause of medication overuse headache.

Comparison of chronic daily headache with and without medication overuse headache using ICHD II R and ICHD 3 beta criteria

OBJECTIVE

To evaluate the frequency of Medication Overuse Headache (MOH) in the patients with Chronic Daily Headache (CDH) using International Classification of Headache Disorder II Revision (ICHD II R) and International Classification of Headache Disorder 3 Beta (ICHD-3 beta) criteria. We also compare the CHD patients with and without MOH using both the criteria.

PATIENTS AND METHODS

Consecutive CDH patients from neurology service between 2014 and 2015 were included. The patients with CDH was categorised to MOH was based on ICHDIIR and ICHD-3 beta criteria. Their demographic and headache characteristics including frequency, duration, severity and disability were noted. Severity of headache was assessed using Visual Analogue Scale (VAS). Predictors of MOH were evaluated by multivariate analysis. Demographic and headache characteristics of CDH patients without MOH were compared with those with MOH.

RESULTS

202 patients were included whose median age was 32 (range 18-65) years, and 151(74.8%) were females. 12.3% patients fulfilled ICHDIIR criteria for MOH and 46.5% fulfilled ICHD-3 beta criteria. The predictors of MOH were female gender (OR = 3.72; 95% CI 1.72-8.02, p = 0.001), low education level (OR = 1.07, 95%CI 1.02-1.13; p = 0.007) and higher VAS score (OR = 0.67, 95%CI 0.51-0.88; p = 0.004). MOH patients as per ICHD-3 beta criteria had higher education (p = 0.02) and consumed lesser abortive drugs (p = 0.03) as compared with ICHDIIR criteria.

CONCLUSION

The frequency of MOH increases by four-fold when using ICHD-3 beta criteria instead of ICHDIIR criteria. Females with lower education level predispose to MOH.

CGRP and the Trigeminal System in Migraine

OBJECTIVE

The goal of this narrative review is to provide an overview of migraine pathophysiology, with an emphasis on the role of calcitonin gene-related peptide (CGRP) within the context of the trigeminovascular system.

BACKGROUND

Migraine is a prevalent and disabling neurological disease that is characterized in part by intense, throbbing, and unilateral headaches. Despite recent advances in understanding its pathophysiology, migraine still represents an unmet medical need, as it is often underrecognized and undertreated. Although CGRP has been known to play a pivotal role in migraine for the last 2 decades, this has now received more interest spurred by the early clinical successes of drugs that block CGRP signaling in the trigeminovascular system.

DESIGN

This narrative review presents an update on the role of CGRP within the trigeminovascular system. PubMed searches were used to find recent (ie, 2016 to November 2018) published articles presenting new study results. Review articles are also included not as primary references but to bring these to the attention of the reader. Original research is referenced in describing the core of the narrative, and review articles are used to support ancillary points.

RESULTS

The trigeminal ganglion neurons provide the connection between the periphery, stemming from the interface between the primary afferent fibers of the trigeminal ganglion and the meningeal vasculature and the central terminals in the trigeminal nucleus caudalis. The neuropeptide CGRP is abundant in trigeminal ganglion neurons, and is released from the peripheral nerve and central nerve terminals as well as being secreted within the trigeminal ganglion. Release of CGRP from the peripheral terminals initiates a cascade of events that include increased synthesis of nitric oxide and sensitization of the trigeminal nerves. Secreted CGRP in the trigeminal ganglion interacts with adjacent neurons and satellite glial cells to perpetuate peripheral sensitization, and can drive central sensitization of the second-order neurons. A shift in central sensitization from activity-dependent to activity-independent central sensitization may indicate a mechanism driving the progression of episodic migraine to chronic migraine. The pathophysiology of cluster headache is much more obscure than that of migraine, but emerging evidence suggests that it may also involve hypersensitivity of the trigeminovascular system. Ongoing clinical studies with therapies targeted at CGRP will provide additional, valuable insights into the pathophysiology of this disorder.

CONCLUSIONS

CGRP plays an essential role in the pathophysiology of migraine. Treatments that interfere with the functioning of CGRP in the peripheral trigeminal system are effective against migraine. Blocking sensitization of the trigeminal nerve by attenuating CGRP activity in the periphery may be sufficient to block a migraine attack. Additionally, the potential exists that this therapeutic strategy may also alleviate cluster headache as well.

CGRP ligand and receptor monoclonal antibodies for migraine prevention: Evidence review and clinical implications

Background: Monoclonal antibodies that target calcitonin gene-related peptide or the canonical calcitonin gene-related peptide receptor have emerged as effective and well tolerated for the preventive treatment of migraine. These large molecules appear ideally suited for migraine prevention. They have an extended biological half-life, are administered either monthly or quarterly either by subcutaneous injection or intravenous infusion, require minimal or no dose-titration and have the potential for a rapid onset of effect compared to conventional oral preventive drugs. There is high selectivity and they target an important mediator in the pathogenesis of migraine. Investigation: Phase II and pivotal phase III studies have all yielded positive results with a favorable adverse event profile. No serious treatment-related adverse outcomes have thus far been reported in controlled or long-term open-label extension studies. This tolerability profile promises to improve adherence and, possibly, long-term outcomes. Conclusions: Calcitonin gene-related peptide monoclonal antibodies are effective and well tolerated for the preventive treatment of migraine. They have distinct advantages over currently available oral preventive drugs. While treatment-related serious adverse events have not been observed in open-label extension studies, long-term outcomes and safety will require broad exposure in heterogeneous patient populations in clinical practice. In addition, their safety in women, especially during pregnancy, will require longitudinal surveillance. Given the overlapping mechanism(s), the effectiveness of existing (triptans) and emerging (calcitonin gene-related peptide receptor antagonists) acute therapies in those using a calcitonin gene-related peptide mAb will require further study.

Sumatriptan improves postoperative quality of recovery and reduces postcraniotomy headache after cranial nerve decompression

BACKGROUND

Microvascular decompression (MVD) is a surgical treatment for cranial nerve disorders via a small craniotomy. The postoperative pain of this procedure can be classified as surgical site somatic pain and postcraniotomy headache similar in nature to a migraine, including its association with photophobia, nausea, and vomiting. This headache can be difficult to treat and can impact on postoperative recovery. Sumatriptan is used to treat migraine-like headaches in various settings. This single-centre randomized controlled trial investigated whether postoperative administration of sumatriptan after MVD surgery impacts the quality of postoperative recovery.

METHODS

Fifty patients who complained of postoperative headache after MVD were randomized to receive an s.c. injection of sumatriptan (6 mg) or saline. The primary outcome was quality of recovery as measured by the Quality of Recovery-40 (QoR-40) score at 24 h.

RESULTS

The QoR-40 scores were significantly higher in the sumatriptan group (median 184; interquartile range 169-196) than in the placebo group (133; 119-155; P<0.01), suggesting higher quality of recovery. The sumatriptan group also had significantly lower headache scores at 4, 12, and 24 h. There were no significant differences in other secondary outcomes.

CONCLUSIONS

Use of sumatriptan improved the quality of recovery as measured by the QoR-40 and reduction of headache at 24 h after surgery. Sumatriptan is a useful alternative treatment for postcraniotomy headache. The mechanism remains unknown but could be related to reduction in headache, mood modulation, or both, mediated by a serotonin effect.

CLINICAL TRIAL REGISTRATION

NCT01632657.

Factors associated to chronic migraine with medication overuse: A cross-sectional study

BACKGROUND AND AIM

Factors implicated in the evolution of episodic migraine into chronic migraine are largely elusive. Medication overuse is considered to be one of the main determinants, but other possible clinical and psychological factors can play a role. The aim of this study is to identify factors that are associated with chronic migraine with medication overuse.

METHOD

We enrolled consecutive migraine patients, subdividing them in two groups: Subjects with a long history of episodic migraine and subjects with chronic migraine and medication overuse. We then compared their clinical and psychological variables in a cross-sectional study.

RESULTS

Three hundred and eighteen patients were enrolled, of which 156 were episodic migraine and 162 were chronic migraine and medication overuse patients. The mean age was 42.1 ± 10.3, 80.8% were female. The duration of migraine was 24.6 years in episodic migraine and 24.0 years in chronic migraine and medication overuse ( p = 0.57). After the multivariate analysis, the factors associated to chronic migraine and medication overuse were: Marital status (married vs. unmarried, OR 3.65, 95% CI 1.63-8.19, p = 0.002; separated/divorced/widowed vs. unmarried, OR 4.19, 95% CI 1.13-15.47, p = 0.031), physical activity (OR 0.42, 95% CI 0.19-0.91, p = 0.029), age at onset of migraine (OR 0.94, 95% CI 0.89-0.98, p = 0.016), use of at least one migraine preventive medication (OR 2.36, 95% CI 1.18-4.71, p = 0.014), history of depression (OR 2.91, 95% CI 1.25-6.73, p = 0.012), insomnia associated with the use of hypnotics (OR 5.59, 95% CI 1.65-18.93, p = 0.006), traumatic head injuries (OR 3.54, 95% CI 1.57-7.99, p = 0.002), snoring (OR 2.24, 95% CI 1.05-4.79, p = 0.036), previous and/or actual use of combined oral contraceptives (OR 3.38, 95% CI 1.10-10.3, p = 0.031) and higher scores in the Childhood Trauma questionnaire (OR 1.48, 95% CI 1.09-2.02, p = 0.012).

CONCLUSION

We considered several aspects that may be involved in the development of chronic migraine and medication overuse. A multivariate analysis identified 10 factors belonging to five different areas, to suggest that chronic migraine and medication overuse onset is likely influenced by a complex mixture of factors. This information is useful when planning strategies to prevent and manage chronic migraine and medication overuse.

Primary Headache Disorders- Part 2: Tension-type headache and medication overuse headache

In Part 2 of Primary Headache disorders, we discuss the fourth Primary Headache Disorder, Tension-Type Headache (TTHA). We are again using the ICHD-III (Beta) definitions of such headaches, taking into consideration episodic and chronic TTHA, as well as the presence or absence of pericranial muscle tenderness. We discuss the pathophysiology and pharmacotherapeutic treatment of TTHA, and the aspects of the Myofascial Pain Syndrome that enhance and help the development of TTHA. We then discuss Medication Overuse Headache (MOH), itself a Secondary headache disorder, but one that is extremely important as it assists with the chronification of both migraine and TTHA. Finally we discuss how to manage and treat those patients with MOH. Chronic migraine, which is TTHA, Migraine as well as, in many patients, MOH, is discussed along with the treatment of this multifaceted disorder.

The role of calcitonin gene-related peptide in peripheral and central pain mechanisms including migraine

Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide found primarily in the C and Aδ sensory fibers arising from the dorsal root and trigeminal ganglia, as well as the central nervous system. Calcitonin gene-related peptide was found to play important roles in cardiovascular, digestive, and sensory functions. Although the vasodilatory properties of CGRP are well documented, its somatosensory function regarding modulation of neuronal sensitization and of enhanced pain has received considerable attention recently. Growing evidence indicates that CGRP plays a key role in the development of peripheral sensitization and the associated enhanced pain. Calcitonin gene-related peptide is implicated in the development of neurogenic inflammation and it is upregulated in conditions of inflammatory and neuropathic pain. It is most likely that CGRP facilitates nociceptive transmission and contributes to the development and maintenance of a sensitized, hyperresponsive state not only of the primary afferent sensory neurons but also of the second-order pain transmission neurons within the central nervous system, thus contributing to central sensitization as well. The maintenance of a sensitized neuronal condition is believed to be an important factor underlying migraine. Recent successful clinical studies have shown that blocking the function of CGRP can alleviate migraine. However, the mechanisms through which CGRP may contribute to migraine are still not fully understood. We reviewed the role of CGRP in primary afferents, the dorsal root ganglion, and in the trigeminal system as well as its role in peripheral and central sensitization and its potential contribution to pain processing and to migraine.

The burden of headache in people with epilepsy

PURPOSE

To investigate and classify headaches in adult people with epilepsy, to evaluate the burden of headaches, and to compare findings with a population-based epidemiological study.

METHODS

Two hundred eighty (61.4% women) people with epilepsy (mean age 37.8±14.5, mean duration of epilepsy 13.2±11.9years) completed a questionnaire collecting socio-demographic and clinical data, questions clarifying their type of a headache, a Qolie-10 questionnaire and a Headache-Attributed Lost Time (HALT) index. An experienced neurologist also interviewed them.

RESULTS

83.2% of respondents reported some type of headache. From those with inter-ictal headaches (77.9%), 39% reported tension-type headache, 31.7% reported migraine, and 7.8% reported medication-overuse headache and 16% reported possible persistent headache attributed to traumatic head injury. The impact of headache assessed through the HALT grading showed that 40.4% were grade 1, 9.6% grade 2, 14.7% grade 3 and 35.3% grade 4. Although, the prevalences of different headache types were similar to those in our population-based study, migraine seemed to be more common in males with epilepsy than in general population, and medication-overuse headache was more common in people with epilepsy than in the general population.

CONCLUSIONS

People with epilepsy experience headaches irrespective of their sex or age. The burden of headaches is very important in patients with epilepsy, since headaches usually cause a moderate or severe burden to their quality of life and suggest a clear clinical need. Clinicians should recognize headache as a common comorbidity of epilepsy, as it may influence antiepileptic drug choice, and may need specific treatment.

Activation of dura-sensitive trigeminal neurons and increased c-Fos protein induced by morphine withdrawal in the rostral ventromedial medulla

Aims

Overuse of medications used to treat migraine headache can increase the frequency of headaches. Sudden abstinence from migraine medication can also lead to a period of withdrawal-induced headaches. The aim of this study was to examine the effect of morphine withdrawal localized to the rostral ventromedial medulla (RVM) on the activity of dura-sensitive spinal trigeminal nucleus caudalis (Vc) neurons.

Methods

Rats were implanted with either morphine or placebo pellets for six to seven days before the microinjection of naloxone methiodide or phosphate-buffered saline into the RVM in urethane-anesthetized animals. Dura-sensitive neurons were recorded in the Vc and the production of c-Fos-like immunoreactivity was quantified.

Results

In chronic morphine-treated animals, naloxone methiodide microinjections produced a significant increase both in ongoing and facial heat-evoked activity and an increase in Fos-positive neurons in the Vc and in the nucleus reticularis dorsalis, a brainstem region involved in diffuse noxious inhibitory controls.

Conclusions

These results indicate that activation of pronociceptive neurons in the RVM under conditions of morphine withdrawal can increase the activity of neurons that transmit headache pain. Modulation of the subnucleus reticularis dorsalis by the RVM may explain the attenuation of conditioned pain modulation in patients with chronic headache.

Medication overuse and chronic migraine: a critical review according to clinical pharmacology

INTRODUCTION

Chronic migraine is often complicated by medication-overuse headache (MOH), a headache due to excessive intake of acute medications. Chronic migraine and MOH are serious and disabling disorders. Since chronic migraine derives from the progression of originally episodic migraine, the fundamental therapeutic strategy is prevention. This narrative review describes how to try to prevent the development of MOH and how to manage it once it has appeared.

AREAS COVERED

A PubMed database search (from 1988 to January 2015) and a review of published studies on chronic migraine and MOH were conducted.

EXPERT OPINION

In spite of progress in migraine treatment, the prevalence of chronic headaches and MOH has not changed in the course of time. Today, a large number of migraine patients have turned to numerous expert physicians and experienced all sorts of prophylactic treatments without decisive benefits. Their condition seems to have crystallized even more as chronic and intractable. This means that to prevent chronification and MOH, we need more effective drugs and better strategies to use them. In particular, we must detect disease biomarkers and predictive factors for drug response that allow for personalized treatment when migraine is still episodic and make analgesic overuse pointless.

Preclinical assessment of pain: improving models in discovery research

To date, animal models have not sufficiently "filtered" targets for new analgesics, increasing the failure rate and cost of drug development. Preclinical assessment of "pain" has historically relied on measures of evoked behavioral responses to sensory stimuli in animals. Such measures can often be observed in decerebrated animals and therefore may not sufficiently capture affective and motivational aspects of pain, potentially diminishing translation from preclinical studies to the clinical setting. Further, evidence indicates that there are important mechanistic differences between evoked behavioral responses of hypersensitivity and ongoing pain, limiting evaluation of mechanisms that could mediate aspects of clinically relevant pain. The mechanisms underlying ongoing pain in preclinical models are currently being explored and may serve to inform decisions towards the transition from drug discovery to drug development for a given target.

Medication-overuse headache: a review

Medication-overuse headache (MOH) is a worldwide health problem with a prevalence of 1%–2%. It is a severe form of headache where the patients often have a long history of headache and of unsuccessful treatments. MOH is characterized by chronic headache and overuse of different headache medications. Through the years, withdrawal of the overused medication has been recognized as the treatment of choice. However, currently, there is no clear consensus regarding the optimal strategy for management of MOH. Treatment approaches are based on expert opinion rather than scientific evidence. This review focuses on aspects of epidemiology, diagnosis, pathogenesis, prevention, and treatment of MOH. We suggest that information and education about the risk of MOH is important since the condition is preventable. Most patients experience reduction of headache days and intensity after successful treatment. The first step in the treatment of MOH should be carried out in primary care and focus primarily on withdrawal, leaving prophylactic medication to those who do not manage primary detoxification. For most patients, a general practitioner can perform the follow-up after detoxification. More complicated cases should be referred to neurologists and headache clinics. Patients suffering with MOH have much to gain by an earlier treatment-focused approach, since the condition is both preventable and treatable.

Medication-overuse headache: epidemiology, diagnosis and treatment

Medication-overuse headache (MOH) is one of the most common chronic headache disorders and a public health problem with a worldwide prevalence of 1-2%. It is a condition characterized by chronic headache and overuse of different headache medications, and withdrawal of the overused medication is recognised as the treatment of choice. However, the strategy for achieving withdrawal is, at present, based on expert opinion rather than scientific evidence, partly due to the lack of randomised controlled studies. This narrative review investigates different aspects of epidemiology, diagnosis, risk factors and pathogenesis as well as management for MOH. We suggest that the first step in the treatment of MOH should be carried out in general practice and should focus primarily on detoxification. For most patients, both prevention and follow up after detoxification can also be performed in general practice, thus freeing resources for referral of more complicated cases to headache clinics and neurologists. These suffering patients have much to gain by an earlier treatment-focused approach lower down on the treatment ladder.

Increased susceptibility to cortical spreading depression in an animal model of medication-overuse headache

OBJECTIVE

The objective of this article is to evaluate electrically evoked thresholds for cortical spreading depression (CSD) and stress-induced activation of trigeminal afferents in a rat model of medication-overuse headache (MOH).

METHODS

Sumatriptan or saline was delivered subcutaneously by osmotic minipump for six days to Sprague-Dawley rats. Two weeks after pump removal, animals were anesthetized and recording/stimulating electrodes implanted. The animals were pretreated with vehicle or topiramate followed by graded electrical stimulation within the visual cortex. CSD events were identified by decreased EEG amplitude and DC potential shift. Additional unanesthetized sumatriptan or saline-pretreated rats were exposed to bright light environmental stress and periorbital and hindpaw withdrawal thresholds were measured. Following CSD stimulation or environmental stress, immunohistochemical staining for Fos in the trigeminal nucleus caudalis (TNC) was performed.

RESULTS

Sumatriptan pre-exposure significantly decreased electrical stimulation threshold to generate a CSD event. Topiramate normalized the decreased CSD threshold as well as stress-induced behavioral withdrawal thresholds in sumatriptan-treated rats compared to saline-treated animals. Moreover, CSD and environmental stress increased Fos expression in the TNC of sumatriptan-treated rats, and these effects were blocked by topiramate. Environmental stress did not elicit cutaneous allodynia or elevate TNC Fos expression in saline-treated rats.

CONCLUSIONS

A previous period of sumatriptan exposure produced long-lasting increased susceptibility to evoked CSD and environmental stress-induced activation of the TNC that was prevented by topiramate. Lowered CSD threshold, and enhanced consequences of CSD events (increased activation of TNC), may represent an underlying biological mechanism of MOH related to triptans.

Pathophysiology of medication overuse headache--an update

The pathogenesis of medication overuse headache is unclear. Clinical and preclinical studies have consistently demonstrated increased excitability of neurons in the cerebral cortex and trigeminal system after medication overuse. Cortical hyperexcitability may facilitate the development of cortical spreading depression, while increased excitability of trigeminal neurons may facilitate the process of peripheral and central sensitization. These changes may be secondary to the derangement of central, probably serotonin (5-HT)-, and perhaps endocannabinoid-dependent or other, modulating systems. Increased expression of excitatory cortical 5-HT2A receptors may increase the susceptibility to developing cortical spreading depression, an analog of migraine aura. A reduction of diffuse noxious inhibitory controls may facilitate the process of central sensitization, activate the nociceptive facilitating system, or promote similar molecular mechanisms to those involved in kindling. Low 5-HT levels also increase the expression and release of calcitonin gene-related peptide from the trigeminal ganglion and sensitize trigeminal nociceptors. Thus, derangement of central modulation of the trigeminal system as a result of chronic medication use may increase sensitivity to pain perception and foster or reinforce medication overuse headache.

Discovery by a proteomic approach of possible early biomarkers of drug-induced nephrotoxicity in medication-overuse headache

Background

Medication-overuse headache (MOH) is a chronic headache condition that results from the overuse of analgesics drugs, triptans, or other antimigraine compounds. The epidemiology of drug-induced disorders suggests that medication overuse could lead to nephrotoxicity, particularly in chronic patients. The aim of this work was to confirm and extend the results obtained from a previous study, in which we analyzed the urinary proteome of 3 MOH patients groups: non-steroidal anti-inflammatory drugs (NSAIDs), triptans and mixtures abusers, in comparison with non-abusers individuals (controls).

Methods

In the present work we employed specialized proteomic techniques, namely two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry (MS), and the innovative Surface-Enhanced Laser Desorption/Ionization Time-of-Flight mass spectrometry (SELDI-TOF-MS), to discover characteristic proteomic profiles associated with MOH condition.

Results

By 2-DE and MS analysis we identified 21 over-excreted proteins in MOH patients, particularly in NSAIDs abusers, and the majority of these proteins were involved in a variety of renal impairments, as resulted from a literature search. Urine protein profiles generated by SELDI-TOF-MS analysis showed different spectra among groups. Moreover, significantly higher number of total protein spots and protein peaks were detected in NSAIDs and mixtures abusers.

Conclusions

These findings confirm the presence of alterations in proteins excretion in MOH patients. Analysis of urinary proteins by powerful proteomic technologies could lead to the discovery of early candidate biomarkers, that might allow to identify MOH patients prone to develop potential drug overuse-induced nephrotoxicity.

Medication-overuse headache and opioid-induced hyperalgesia: A review of mechanisms, a neuroimmune hypothesis and a novel approach to treatment

Introduction

Patients with chronic headache who consume large amounts of analgesics are often encountered in clinical practice. Excessive intake of analgesics is now considered to be a cause, rather than simply a consequence, of frequent headaches, and as such the diagnosis “medication-overuse headache” (MOH) has been formulated. Despite the prevalence and clinical impact of MOH, the pathophysiology behind this disorder remains unclear and specific mechanism-based treatment options are lacking.

Discussion

Although most acute headache treatments have been alleged to cause MOH, here we conclude from the literature that opioids are a particularly problematic drug class consistently associated with worsening headache. MOH may not be a single entity, as each class of drug implicated may cause MOH via a different mechanism. Recent evidence indicates that chronic opioid administration may exacerbate pain in the long term by activating toll-like receptor-4 on glial cells, resulting in a pro-inflammatory state that manifests clinically as increased pain. Thus, from the available evidence it seems opioid-overuse headache is a phenomenon similar to opioid-induced hyperalgesia, which derives from a cumulative interaction between central sensitisation, due to repeated activation of nociceptive pathways by recurrent headaches, and pain facilitation due to glial activation.

Conclusion

Treatment strategies directed at inhibiting glial activation may be of benefit alongside medication withdrawal in the management of MOH.

Nabilone for the treatment of medication overuse headache: results of a preliminary double-blind, active-controlled, randomized trial

Medication overuse headache (MOH) is a severe burden to sufferers and its treatment has few evidence-based indications. The aim of this study is to evaluate efficacy and safety of nabilone in reducing pain and frequency of headache, the number of analgesic intake and in increasing the quality of life on patients with long-standing intractable MOH. Thirty MOH patients were enrolled at the University of Modena’s Interdepartmental Centre for Research on Headache and Drug Abuse (Italy) in a randomized, double-blind, active-controlled, crossover study comparing nabilone 0.5 mg/day and ibuprofen 400 mg. The patients received each treatment orally for 8 weeks (before nabilone and then ibuprofen or vice versa), with 1 week wash-out between them. Randomization and allocation (ratio 1:1) were carried out by an independent pharmacy through a central computer system. Participants, care givers, and those assessing the outcomes were blinded to treatment sequence. Twenty-six subjects completed the study. Improvements from baseline were observed with both treatments. However, nabilone was more effective than ibuprofen in reducing pain intensity and daily analgesic intake (p < 0.05); moreover, nabilone was the only drug able to reduce the level of medication dependence (−41 %, p < 0.01) and to improve the quality of life (p < 0.05). Side effects were uncommon, mild and disappeared when nabilone was discontinued. This is the first randomized controlled trial demonstrating the benefits of nabilone on headache, analgesic consumption and the quality of life in patients with intractable MOH. This drug also appears to be safe and well-tolerated. Larger scale studies are needed to confirm these preliminary findings.

Cortical response to somatosensory stimulation in medication overuse headache patients is influenced by angiotensin converting enzyme (ACE) I/D genetic polymorphism

BACKGROUND

Medication overuse headache (MOH) is a disabling health problem. Convincing evidence attributes a pathophysiologic role to central sensitization. By recording somatosensory evoked potentials (SSEPs) in patients with MOH, we observed increased sensitization and deficient habituation to repetitive sensory stimuli consistent with drug overuse. The renin-angiotensin system in the brain seems to play a relevant role in neural plasticity and dependence behavior. We therefore sought differences in SSEP sensitization and habituation in patients with MOH who underwent angiotensin converting enzyme (ACE) I/D polymorphism analysis.

METHODS

We recorded median-nerve SSEPs (two blocks of 100 sweeps) in 43 patients with MOH. We measured N20-P25 amplitudes, and assessed sensitization using the first block amplitudes, and habituation using amplitude changes between the two sequential blocks. According to their genotype, subjects were divided into three groups: "D/D", "D/I" and "I/I" carriers.

RESULTS

The habituation slope of the two SSEP block amplitudes was significantly increased in the D/D subgroup (n = 16) with respect to that of the I/I subgroup (n = 6), with the D/I subgroup (n = 21) falling in between. In D/D carriers, the habituation slope correlated positively with the duration of the overuse headache, and the first SSEP block amplitudes, a measure of sensitization, increased in strict relationship with the type of overused medication in the MOH patients overall and in the D/D subgroup; this was not so in the D/I and I/I subgroups.

CONCLUSION

In patients with MOH, the homozygote D/D ACE polymorphism influences habituation and sensitization to repeated sensory stimuli in strict relationship with medication overuse. We suggest that angiotensin peptides influence neuronal mechanisms of plasticity by interacting with central monoaminergic synaptic transmission.

Dependent behavior in patients with medication-overuse headache

Two thirds of patients with medication-overuse headache (MOH) fulfilled criteria for dependence on acute symptomatic treatments for pain, not exclusive of psychoactive medications, based on the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders. Several questionnaires have been used to assess dependent behavior in patients with MOH. Findings regarding underlying psychological profiles of dependence and MOH are not consistent. Nevertheless, several neuroimaging, genetic, and neurobiological studies support the existence of the common pathophysiological features of dependence and MOH and suggest a link between them. This review highlights recent studies on the relationship between dependence and MOH. This issue is important because it implies a treatment strategy in managing patients with MOH by providing the treatment of dependence.