Depression and Anxiety Symptoms in Headache Disorders: An Observational, Cross-Sectional Study.

BACKGROUND: Headache disorders have been associated with anxiety and depressive disorders. The aim of this study was to assess symptoms of anxiety and depression in a large sample of individuals with different headache disorders (HDs) in order to determine whether their frequency differs by headache type. METHODS: Consecutive individuals with headache attending a headache outpatient clinic were interviewed with the HAM-D and HAM-A, along with age, sex, and education matched non-headache individuals. RESULTS: Individuals numbering 2673 with headache (females 71.2%) and 464 non-headache individuals (females 70.9%) were interviewed (with participation rates of 98.3% and 91.0%, respectively). Migraine was diagnosed in 49.7%, tension-type headache in 38%, cluster headache 5.2%, and medication overuse (MO) in 21.8%. Participants with HD scored more in HAM-A (OR = 4.741, CI95%: 3.855-5.831, p < 0.001) and HAM-D scales (OR = 2.319, CI95%: 1.892-2.842, p < 0.001) than non-headache individuals. Participants with chronic HDs (≥15 days with headache for ≥3 consecutive months; 52.5%) scored higher for both HAM-A (OR = 1.944, CI95%: 1.640-2.303, p < 0.001) and HAM-D (OR = 1.625, CI95%: 1.359-1.944, p < 0.001) than those with episodic HDs (33.1%), as did participants with MO vs. participants without MO (OR = 3.418, CI95%: 2.655-4.399, p < 0.001 for HAM-A, OR = 3.043, CI95%: 2.322-3.986, p < 0.001 for HAM-D). Female and low-educated participants scored higher on both scales. CONCLUSION: Because symptoms of anxiety and depression are substantial in people with HD, the treating physicians should look out for such symptoms and manage them appropriately.

Headaches and facial pain attributed to SARS-CoV-2 infection and vaccination: a systematic review.

BACKGROUND AND PURPOSE: The aim was to provide insights to the characteristics of headache in the context of COVID-19 on behalf of the Headache Scientific Panel and the Neuro-COVID-19 Task Force of the European Academy of Neurology (EAN) and the European Headache Federation (EHF). METHODS: Following the Delphi method the Task Force identified six relevant questions and then conducted a systematic literature review to provide evidence-based answers and suggest specific diagnostic criteria. RESULTS: No data for facial pain were identified in the literature search. (1) Headache incidence during acute COVID-19 varies considerably, with higher prevalence rates in prospective compared to retrospective studies (28.9%-74.6% vs. 6.5%-34.0%). (2) Acute COVID-19 headache is usually bilateral or holocranial and often moderate to severe with throbbing pain quality lasting 2-14 days after first signs of COVID-19; photo-phonophobia, nausea, anosmia and ageusia are common associated features; persistent headache shares similar clinical characteristics. (3) Acute COVID-19 headache is presumably caused by immune-mediated mechanisms that activate the trigeminovascular system. (4) Headache occurs in 13.3%-76.9% following SARS-CoV-2 vaccination and occurs more often amongst women with a pre-existing primary headache; the risk of developing headache is higher with the adenoviral-vector-type vaccines than with other preparations. (5) Headache related to SARS-CoV-2 vaccination is mostly bilateral, and throbbing, pressing, jolting or stabbing. (6) No studies have been conducted investigating the underlying mechanism of headache attributed to SARS-CoV-2 vaccines. CONCLUSION: The results of this joint EAN/EHF initiative provide a framework for a better understanding of headache in the context of SARS-CoV-2 infection and vaccination.

Induction of cluster headache after opening of adenosine triphosphate-sensitive potassium channels: a randomized clinical trial.

ABSTRACT: Activation of adenosine triphosphate-sensitive potassium (K ATP ) channels has been implicated in triggering migraine attacks. However, whether the opening of these channels provoke cluster headache attacks remains undetermined. The hallmark of cluster headache is a distinct cyclical pattern of recurrent, severe headache episodes, succeeded by intervals of remission where no symptoms are present. In our study, we enrolled 41 participants: 10 with episodic cluster headaches during a bout, 15 in the attack-free remission period, and 17 diagnosed with chronic cluster headaches. Over 2 distinct experimental days, participants underwent a continuous 20-minute infusion of levcromakalim, a K ATP channel opener, or a placebo (isotonic saline), followed by a 90-minute observational period. The primary outcome was comparing the incidence of cluster headache attacks within the postinfusion observation period between the levcromakalim and placebo groups. Six of 10 participants (60%) with episodic cluster headaches in bout experienced attacks after levcromakalim infusion, vs just 1 of 10 (10%) with placebo ( P = 0.037). Among those in the remission phase, 1 of 15 participants (7%) reported attacks after levcromakalim, whereas none did postplacebo ( P = 0.50). In addition, 5 of 17 participants (29%) with chronic cluster headache had attacks after levcromakalim, in contrast to none after placebo ( P = 0.037). These findings demonstrate that K ATP channel activation can induce cluster headache attacks in participants with episodic cluster headaches in bout and chronic cluster headache, but not in those in the remission period. Our results underscore the potential utility of K ATP channel inhibitors as therapeutic agents for cluster headaches.

European Headache Federation (EHF) critical reappraisal and meta-analysis of oral drugs in migraine prevention - part 3: topiramate.

OBJECTIVE: Topiramate is a repurposed first-line treatment for migraine prophylaxis. The aim of this systematic review and meta-analysis is to critically re-appraise the existing evidence supporting the efficacy and tolerability of topiramate. METHODS: A systematic search in MEDLINE, EMBASE, Cochrane CENTRAL, and ClinicalTrials.gov was performed for trials of pharmacological treatment in migraine prophylaxis as of August 13, 2022, following the Preferred Reporting Items for Systematic Reviews (PRISMA). Randomized controlled trials in adult patients that used topiramate for the prophylactic treatment of migraine, with placebo as active comparator, were included. Two reviewers independently screened the retrieved studies and extracted all data. Outcomes of interest were the 50% responder rates, the reduction in monthly migraine days, and adverse events leading to treatment discontinuation. Results were pooled and meta-analyzed, with sensitivity analysis based on the risk of bias of the studies, the monthly migraine days at baseline, and the previous use of other prophylactic treatments. Certainty evidence was judged according to the GRADE framework. RESULTS: Eight out of 10,826 studies fulfilled the inclusion/exclusion criteria, accounting for 2,610 randomized patients. Six studies included patients with episodic migraine and two with chronic migraine. Topiramate dose ranged from 50 to 200 mg/day, and all studies included a placebo arm. There was a high certainty that topiramate: 1) increased the proportion of patients who achieved a 50% responder rate in monthly migraine days, compared to placebo [relative risk: 1.61 (95% confidence interval (CI): 1.29-2.01); absolute risk difference: 168 more per 1,000 (95% CI: 80 to 278 more)]; 2) was associated with 0.99 (95% CI: 1.41-0.58) fewer migraine days than placebo; 3) and had a higher proportion of patients with adverse events leading to treatment discontinuation [absolute risk difference 80 patients more per 1,000 (95% CI: 20 to 140 more patients)]. CONCLUSIONS: There is high-quality evidence of the efficacy of topiramate in the prophylaxis of migraine, albeit its use poses a risk of adverse events that may lead to treatment discontinuation, with a negative effect on patient satisfaction and adherence to care.

European Headache Federation (EHF) critical re-appraisal and meta-analysis of oral drugs in migraine prevention-part 2: flunarizine.

OBJECTIVE: Novel disease-specific and mechanism-based treatments sharing good evidence of efficacy for migraine have been recently marketed. However, reimbursement by insurers depends on treatment failure with classic anti-migraine drugs. In this systematic review and meta-analysis, we aimed to identify and rate the evidence for efficacy of flunarizine, a repurposed, first- or second-line treatment for migraine prophylaxis. METHODS: A systematic search in MEDLINE, Cochrane CENTRAL, and ClinicalTrials.gov was performed for trials of pharmacological treatment in migraine prophylaxis, following the Preferred Reporting Items for Systematic Reviews (PRISMA). Eligible trials for meta-analysis were randomized, placebo-controlled studies comparing flunarizine with placebo. Outcomes of interest according to the Outcome Set for preventive intervention trials in chronic and episodic migraine (COSMIG) were the proportion of patients reaching a 50% or more reduction in monthly migraine days, the change in monthly migraine days (MMDs), and Adverse Events (AEs) leading to discontinuation. RESULTS: Five trials were eligible for narrative description and three for data synthesis and analysis. No studies reported the predefined outcomes, but one study assessed the 50% reduction in monthly migraine attacks with flunarizine as compared to placebo showing a benefit from flunarizine with a low or probably low risk of bias. We found that flunarizine may increase the proportion of patients who discontinue due to adverse events compared to placebo (risk difference: 0.02; 95% CI -0.03 to 0.06). CONCLUSIONS: Published flunarizine trials predate the recommended endpoints for evaluating migraine prophylaxis drugs, hence the lack of an adequate assessment for these endpoints. Further, modern-day, large-scale studies would be valuable in re-evaluating the efficacy of flunarizine for the treatment of migraines, offering additional insights into its potential benefits.

Second messenger signalling bypasses CGRP receptor blockade to provoke migraine attacks in humans.

There are several endogenous molecules that can trigger migraine attacks when administered to humans. Notably, calcitonin gene-related peptide (CGRP) has been identified as a key player in a signalling cascade involved in migraine attacks, acting through the second messenger cyclic adenosine monophosphate (cAMP) in various cells, including intracranial vascular smooth muscle cells. However, it remains unclear whether intracellular cAMP signalling requires CGRP receptor activation during a migraine attack in humans. To address this question, we conducted a randomized, double-blind, placebo-controlled, parallel trial using a human provocation model involving the administration of CGRP and cilostazol in individuals with migraine pretreated with erenumab or placebo. Our study revealed that migraine attacks can be provoked in patients by cAMP-mediated mechanisms using cilostazol, even when the CGRP receptor is blocked by erenumab. Furthermore, the dilation of cranial arteries induced by cilostazol was not influenced by the CGRP receptor blockade. These findings provide clinical evidence that cAMP-evoked migraine attacks do not require CGRP receptor activation. This discovery opens up new possibilities for the development of mechanism-based drugs for the treatment of migraine.

The comparative effectiveness of migraine preventive drugs: a systematic review and network meta-analysis.

OBJECTIVE: While there are several trials that support the efficacy of various drugs for migraine prophylaxis against placebo, there is limited evidence addressing the comparative safety and efficacy of these drugs. We conducted a systematic review and network meta-analysis to facilitate comparison between drugs for migraine prophylaxis. METHODS: We searched MEDLINE, EMBASE, CENTRAL, and clinicaltrials.gov from inception to August 13, 2022, for randomized trials of pharmacological treatments for migraine prophylaxis in adults. Reviewers worked independently and in duplicate to screen references, extract data, and assess risk of bias. We performed a frequentist random-effects network meta-analysis and rated the certainty (quality) of evidence as either high, moderate, low, or very low using the GRADE approach. RESULTS: We identified 74 eligible trials, reporting on 32,990 patients. We found high certainty evidence that monoclonal antibodies acting on the calcitonin gene related peptide or its receptor (CGRP(r)mAbs), gepants, and topiramate increase the proportion of patients who experience a 50% or more reduction in monthly migraine days, compared to placebo. We found moderate certainty evidence that beta-blockers, valproate, and amitriptyline increase the proportion of patients who experience a 50% or more reduction in monthly migraine days, and low certainty evidence that gabapentin may not be different from placebo. We found high certainty evidence that, compared to placebo, valproate and amitriptyline lead to substantial adverse events leading to discontinuation, moderate certainty evidence that topiramate, beta-blockers, and gabapentin increase adverse events leading to discontinuation, and moderate to high certainty evidence that (CGRP(r)mAbs) and gepants do not increase adverse events. CONCLUSIONS: (CGRP(r)mAbs) have the best safety and efficacy profile of all drugs for migraine prophylaxis, followed closely by gepants.

The effect of Lu AG09222 on PACAP38- and VIP-induced vasodilation, heart rate increase, and headache in healthy subjects: an interventional, randomized, double-blind, parallel-group, placebo-controlled study.

BACKGROUND: Pituitary adenylate cyclase-activating polypeptide (PACAP), structurally related to vasoactive intestinal peptide (VIP), is one of the important mediators in the pathogenesis of migraine and is known to dilate cranial arteries and induce headache and migraine. Our objective was to determine whether Lu AG09222-an investigational humanized monoclonal antibody directed against PACAP ligand-would inhibit the PACAP-signaling cascade by abolishing its vasodilatory and headache-inducing abilities. METHODS: In a randomized, double-blind, parallel-group, single-dose, placebo-controlled study of Lu AG09222, healthy volunteers aged 18-45 years without history of headache disorders were randomly allocated to three treatment sequences (1:2:2) on two experimental infusion visits with 9 ± 3 days' interval: placebo + saline + saline (n = 5), placebo + PACAP38 + VIP (n = 10), and Lu AG09222 + PACAP38 + VIP (n = 10). The primary outcome measure was area under the curve (AUC) of the change in superficial temporal artery (STA) diameter from 0 to 120 min after start of infusion of PACAP38. The study was conducted at the Danish Headache Center in Copenhagen, Denmark. RESULTS: In participants who received Lu AG09222 + PACAP38 infusion, there was a significantly lower STA diameter (mean (SE) [95% CI] AUC ‒35.4 (4.32) [‒44.6, ‒26.3] mm × min; P < 0.0001) compared to participants who received placebo + PACAP38 infusion. Secondary and explorative analysis revealed that PACAP38 infusion induced an increase in facial blood flow, heart rate and mild headache, and indicated that these PACAP38-induced responses were inhibited by Lu AG09222. CONCLUSIONS: This proof-of-mechanism study demonstrated that Lu AG09222 inhibited PACAP38-induced cephalic vasodilation and increases in heart rate, and reduced concomitant headache. Lu AG09222 may be a potential therapy against migraine and other PACAP-mediated diseases. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04976309. Registration date: July 19, 2021.

Plasma levels of VIP are not elevated during PACAP- and VIP-induced cluster headache attacks: an exploratory study.

Background: Pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP) provoked cluster headache attacks in individuals with episodic cluster headache during their active phase and individuals with chronic cluster headache. In this study, we investigated whether infusions of PACAP and VIP caused alterations in plasma levels of VIP and their potential contribution to induced cluster headache attacks. Methods: Participants received either PACAP or VIP infusion for 20 min on 2 separate days with an interval of at least 7 days in between. Blood collection was performed at T0, T20, T30, and T90. Plasma levels of VIP were measured using a validated radioimmunoassay method. Results: Blood samples were collected from participants with episodic cluster headache in the active phase (eCHA, n = 14), remission (eCHR, n = 15), and from participants with chronic cluster headache (cCH, n = 15). Baseline levels of VIP did not differ among the three groups (p = 0.1161). During PACAP infusion, mixed-effects analysis revealed a significant increase in plasma levels of VIP in eCHA (p = 0.0300) and eCHR (p = 0.0058) but not in cCH (p = 0.2930). We found no difference in the increase of plasma VIP levels between patients who developed PACAP38- or VIP-induced attacks. Conclusion: Cluster headache attacks induced by PACAP38 or VIP infusion are not associated with changes in plasma levels of VIP. Further studies are needed to investigate the role of VIP and the parasympathetic system in cluster headache. Clinical trial registration: The parent study is registered at ClinicalTrials.gov (NCT03814226).

European Headache Federation (EHF) critical re-appraisal and meta-analysis of oral drugs in migraine prevention-part 1: amitriptyline.

OBJECTIVE: The aim of this paper is to critically re-appraise the published trials assessing amitriptyline for migraine prophylaxis. METHODS: We report our methods and results following the Preferred Reporting Items for Systematic Reviews (PRISMA), by searching MEDLINE, EMBASE, Cochrane CENTRAL, and ClinicalTrials.gov for randomized trials of pharmacologic treatments for migraine prophylaxis. We included randomized trials that compared amitriptyline with placebo for migraine prophylaxis in adults. Our outcomes of interest were informed by the Outcome Set for preventive intervention trials in chronic and episodic migraine (COSMIG) and include the proportion of patients who experience a 50% or more reduction in migraine days per month, migraine days per month, and adverse events leading to discontinuation. We assessed risk of bias by using a modified Cochrane RoB 2.0 tool and the certainty of evidence by using the GRADE approach. RESULTS: Our search yielded 10.826 unique records, of which three trials (n = 622) were eligible for data synthesis and analysis. We found moderate certainty evidence that amitriptyline increases the proportion of patients who experience a 50% or more reduction in monthly migraine days, compared to placebo (relative risk: 1.60 (95% CI 1.17 to 2.19); absolute risk difference: 165 more per 1,000 (95% CI 47 more to 327 more). We found moderate certainty evidence that amitriptyline increases the proportion of patients who discontinue due to adverse events compared to placebo (risk difference: 0.05 (95% CI 0.01 to 0.10); absolute risk difference: 50 more per 1,000 (95% CI 10 more to 100 more). CONCLUSIONS: Our meta-analysis showed that amitriptyline may have a prophylactic role in migraine patients, however these results are far from robust. This warrants further large-scale research to evaluate the role of amitriptyline in migraine prevention.

European Headache Federation (EHF) consensus on the definition of effective treatment of a migraine attack and of triptan failure.

BACKGROUND: Triptans are migraine-specific acute treatments. A well-accepted definition of triptan failure is needed in clinical practice and for research. The primary aim of the present Consensus was to provide a definition of triptan failure. To develop this definition, we deemed necessary to develop as first a consensus definition of effective treatment of an acute migraine attack and of triptan-responder. MAIN BODY: The Consensus process included a preliminary literature review, a Delphi round and a subsequent open discussion. According to the Consensus Panel, effective treatment of a migraine attack is to be defined on patient well-being featured by a) improvement of headache, b) relief of non-pain symptoms and c) absence of adverse events. An attack is considered effectively treated if patient's well-being, as defined above, is restored within 2 hours and for at least 24 hours. An individual with migraine is considered as triptan-responder when the given triptan leads to effective acute attack treatment in at least three out of four migraine attacks. On the other hand, an individual with migraine is considered triptan non-responder in the presence of failure of a single triptan (not matching the definition of triptan-responder). The Consensus Panel defined an individual with migraine as triptan-resistant in the presence of failure of at least 2 triptans; triptan refractory, in the presence of failure to at least 3 triptans, including subcutaneous formulation; triptan ineligibile in the presence of an acknowledged contraindication to triptan use, as specified in the summary of product characteristics. CONCLUSIONS: The novel definitions can be useful in clinical practice for the assessment of acute attack treatments patients with migraine. They may be helpful in identifying people not responding to triptans and in need for novel acute migraine treatments. The definitions will also be of help in standardizing research on migraine acute care.

Visual snow: A systematic review and a case series.

BACKGROUND: Visual Snow Syndrome is a recently recognized neurological condition presenting, continuous, tiny dots across the entire visual field, accompanied by nyctalopia, photophobia and palinopsia that persist for months. It may be part of migraine aura spectrum, yet its definition is still questionable. Diagnostic criteria for Visual Snow Syndrome are included in the supplemental material of ICHD-3. We aimed to summarize recent data to improve the understanding of Visual Snow Syndrome. METHODS: After presenting four new cases, we conducted a PRISMA systematic search in PubMed/MEDLINE and Embase databases using the keyword "visual snow" with specific inclusion and exclusion criteria. RESULTS: From the 855 articles identified 30 were included for the qualitative analysis. These reports covered five aspects related to Visual Snow Syndrome: epidemiology, clinical features, comorbidities, pathophysiology, and treatment. We found limited data concerning Visual Snow Syndrome's epidemiology (one study). Clinical presentation (22 articles) and the comorbidities (migraine with aura and tinnitus most often, five reports) are described in detail. The pathophysiology of Visual Snow Syndrome is only approached with hypotheses, but several neuroimaging studies have been identified (seven articles). Treatment is based on single case reports only. CONCLUSION: Data for Visual Snow Syndrome are few and not strong enough to support Visual Snow Syndrome as a medical identity. Further investigation is needed.

European Headache Federation guideline on the use of monoclonal antibodies targeting the calcitonin gene related peptide pathway for migraine prevention - 2022 update.

BACKGROUND: A previous European Headache Federation (EHF) guideline addressed the use of monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway to prevent migraine. Since then, randomized controlled trials (RCTs) and real-world evidence have expanded the evidence and knowledge for those treatments. Therefore, the EHF panel decided to provide an updated guideline on the use of those treatments. METHODS: The guideline was developed following the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. The working group identified relevant questions, performed a systematic review and an analysis of the literature, assessed the quality of the available evidence, and wrote recommendations. Where the GRADE approach was not applicable, expert opinion was provided. RESULTS: We found moderate to high quality of evidence to recommend eptinezumab, erenumab, fremanezumab, and galcanezumab in individuals with episodic and chronic migraine. For several important clinical questions, we found not enough evidence to provide evidence-based recommendations and guidance relied on experts' opinion. Nevertheless, we provided updated suggestions regarding the long-term management of those treatments and their place with respect to the other migraine preventatives. CONCLUSION: Monoclonal antibodies targeting the CGRP pathway are recommended for migraine prevention as they are effective and safe also in the long-term.

Nocebo-Prone Behavior Associated with SARS-CoV-2 Vaccine Hesitancy in Healthcare Workers.

Among healthcare workers (HCWs), SARS-CoV-2 vaccine hesitancy may be linked to a higher susceptibility to nocebo effects, i.e., adverse events (AEs) experienced after medical treatments due to negative expectations. To investigate this hypothesis a cross-sectional survey was performed with a self-completed questionnaire that included a tool (Q-No) for the identification of nocebo-prone individuals. A total of 1309 HCWs (67.2% women; 43.4% physicians; 28.4% nurses; 11.5% administrative staff; 16.6% other personnel) completed the questionnaires, among whom 237 (18.1%) had declined vaccination. Q-No scores were ≥15 in 325 participants (24.8%) suggesting nocebo-prone behavior. In a multivariate logistic regression model with Q-No score, age, gender, and occupation as independent variables, estimated odds ratios (ORs) of vaccination were 0.43 (i.e., less likely, p < 0.001) in participants with Q-No score ≥ 15 vs. Q-No score < 15, 0.58 in females vs. males (p = 0.013), and 4.7 (i.e., more likely) in physicians vs. other HCWs (p < 0.001), independent of age, which was not significantly associated with OR of vaccination. At least one adverse effect (AE) was reported by 67.5% of vaccinees, mostly local pain and flu-like symptoms. In a multivariate logistic regression model, with Q-No score, age, gender, and occupation as independent variables, estimated ORs of AE reporting were 2.0 in females vs. males (p < 0.001) and 1.47 in physicians vs. other HCWs (p = 0.017) independently of age and Q-No score, which were not significantly associated with OR of AE. These findings suggest that nocebo-prone behavior in HCWs is associated with SARS-CoV-2 vaccination hesitancy indicating a potential benefit of a campaign focused on nocebo-prone people.

Monoclonal Antibodies Targeting CGRP: From Clinical Studies to Real-World Evidence-What Do We Know So Far?

Now more than ever is the time of monoclonal antibody use in neurology. In headaches, disease-specific and mechanism-based treatments existed only for symptomatic management of migraines (i.e., triptans), while the standard prophylactic anti-migraine treatments consist of non-specific and repurposed drugs that share limited safety profiles and high risk for interactions with other medications, resulting in rundown adherence rates. Recent advances in headache science have increased our understanding of the role of calcitonin gene relate peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) pathways in cephalic pain neurotransmission and peripheral or central sensitization, leading to the development of monoclonal antibodies (mAbs) or small molecules targeting these neuropeptides or their receptors. Large scale randomized clinical trials confirmed that inhibition of the CGRP system attenuates migraine, while the PACAP mediated nociception is still under scientific and clinical investigation. In this review, we provide the latest clinical evidence for the use of anti-CGRP in migraine prevention with emphasis on efficacy and safety outcomes from Phase III and real-world studies.

Safety and tolerability evaluation of erenumab for the preventive treatment of migraine.

Introduction: Erenumab, a monoclonal antibody targeting the receptor of calcitonin gene related peptide (CGRP), is the first disease-specific and mechanism-based treatment approved for the prevention of migraine. Although the safety and tolerability data from randomized trials are clear, the physiological effects of CGRP rise reasonable concerns. We aimed to evaluate the current evidence for safety and tolerability related to erenumab use in migraine. Areas covered: This review outlines the severe adverse events (AEs), common AEs, AEs leading to treatment discontinuation and AEs of special interest, reported in all phase 2, phase 3, open label, and observational studies with erenumab in migraine. Individual safety reports were also included in the systematic review of evidence. Expert opinion: No safety and tolerability flags were detected in this review. The most common AE are local skin reactions and constipation. No severe AEs, or frequent AEs leading to treatment discontinuation were detected. Treatment is well tolerated. The only AE of interest that may play a role in decision making and treatment monitoring is constipation. These findings are in line with previous safety reports, further highlighting the substantial tolerability and safety profile of the modern anti-CGRP monoclonal antibodies for the prevention of migraine.