Why pharmacokinetic differences among oral triptans have little clinical importance: a comment

Regional distribution of unbound eletriptan and sumatriptan in the CNS and PNS in rats: implications for a potential central action

BACKGROUND

Triptans are potent 5-HT1B/1D/1F receptor agonists used in migraine therapy, thought to act through peripheral mechanisms. It remains unclear whether triptans cross the blood-brain barrier (BBB) sufficiently to stimulate central 5-HT1B/1D/1F receptors. This study investigates the disposition of eletriptan and sumatriptan in central nervous system (CNS) and peripheral nervous system (PNS) regions and predicts regional 5-HT1B/1D/1F receptor occupancies at clinically relevant concentrations.

METHODS

Using the Combinatory Mapping Approach (CMA) for regions of interest (ROI), we assessed the unbound tissue-to-plasma concentration ratio (Kp, uu, ROI) in rats at steady state across CNS (hypothalamus, brain stem, cerebellum, frontal cortex, parietal cortex, striatum, hippocampus, whole brain, and spinal cord) and PNS (trigeminal ganglion and sciatic nerve) regions. We used Kp, uu, ROI values to estimate unbound target-site concentrations and 5-HT1B/1D/1F receptor occupancies in humans.

RESULTS

We observed heterogenous triptan transport across CNS and PNS regions with the highest extent of unbound drug transport across the blood-nerve barrier in the trigeminal ganglion (Kp, uu, TG: eletriptan: 0.519, and sumatriptan: 0.923). Both drugs displayed restricted entry across the BBB (Kp, uu, whole brain: eletriptan: 0.058, and sumatriptan: 0.045) combined with high inter-regional variability. We estimated near-complete receptor occupancy in the trigeminal ganglion, while lower occupancies were observed in the whole brain, irrespective of the drug or receptor subtype. For instance, eletriptan was predicted to achieve 84% 5-HT1B receptor occupancy in the trigeminal ganglion and 37% in the whole brain at clinically relevant concentrations.

CONCLUSIONS

This study suggests that despite low BBB transport, both eletriptan and sumatriptan achieve unbound concentrations sufficient to stimulate 5-HT1B, 5-HT1D, and 5-HT1F receptors not only in the trigeminal ganglion, but also in the CNS. Further research is needed to determine whether central mechanisms contribute to triptan's antimigraine effect and/or side effects.

Gender bias in clinical trials of biological agents for migraine: A systematic review

Migraine is considered one of the most disabling diseases. Currently, there are few studies on clinical migraine treatment based on sex-related differences, despite the important role of sex in migraine. Our aim was to evaluate gender bias in published clinical trials on monoclonal antibodies (erenumab, galcanezumab, fremanezumab and eptinezumab). We performed a systematic review of controlled clinical trials of erenumab, galcanezumab, fremanezumab and eptinezumab, searching the PubMed/MEDLINE database for articles published before December 2021. The search identified 760 articles, 25 of which met the inclusion criteria. Of all the patients included in these trials, 85.1% were women. Only one study had female lead authors. Two of the 25 studies included a sex-based analysis of the primary endpoint. None of the articles discussed the results separately for men and for women. The proportion of men recruited in trials is scarce and more studies are needed to guarantee the safety and tolerability of monoclonal antibodies used in male migraine. As observed in our study, despite the high number of women recruited, only 2 studies analysed the results separately by sex. Thus, a potential risk of gender bias was found in these clinical trials.

Delivery of Dihydroergotamine Mesylate to the Upper Nasal Space for the Acute Treatment of Migraine: Technology in Action

Oral tablets account for the majority of medications used to acutely treat migraine, but relief can be limited by their rates of dissolution and absorption. The nose is an attractive alternative route of drug delivery since it provides patient convenience of at-home use, gastrointestinal (GI) avoidance, and rapid absorption of drugs into systemic circulation because of its large surface area. However, the site of drug deposition within the nasal cavity should be considered since it can influence drug absorption. Traditional nasal devices have been shown to target drug delivery to the lower nasal space where epithelium is not best-suited for drug absorption and where there is an increased likelihood of drug clearance due to nasal drip, swallowing, or mucociliary clearance, potentially resulting in variable absorption and suboptimal efficacy. Alternatively, the upper nasal space (UNS) offers a permeable, richly vascularized epithelium with a decreased likelihood of drug loss or clearance due to the anatomy of this area. Traditional nasal pumps deposit <5% of active drug into the UNS because of the nasal cavity's complex architecture. A new technology, Precision Olfactory Delivery (POD^®), is a handheld, manually actuated, propellant-powered, administration device that delivers drug specifically to the UNS. A dihydroergotamine (DHE) mesylate product, INP104, utilizes POD technology to deliver drug to the UNS for the acute treatment of migraine. Results from clinical studies of INP104 demonstrate a favorable pharmacokinetic profile, consistent and predictable dosing, rapid systemic levels known to be effective (similar to other DHE mesylate clinical programs), safety and tolerability on the upper nasal mucosa, and high patient acceptance. POD technology may have the potential to overcome the limitations of traditional nasal delivery systems, while utilizing the nasal delivery benefits of GI tract avoidance, rapid onset, patient convenience, and ease of use.

Migraine and Gastroparesis

PURPOSEOF REVIEW

Migraine is a chronic and disabling disease affecting a significant proportion of the world's population. There is evidence that gastroparesis, a gastrointestinal (GI) dysmotility disorder in which transit of gastric contents is delayed, can occur in the setting of migraine. This article aims to review recent literature on overlap in the pathophysiology and clinical manifestations of migraine and gastroparesis and highlight management considerations when these disorders coexist.

RECENT FINDINGS

There has been increasing recognition of the importance of the connection between the GI tract and the brain, and mounting evidence for the overlap in the pathophysiology of migraine and gastroparesis specifically. There exists a complex interplay between the central, autonomic, and enteric nervous systems. Studies show that gastroparesis may be present during and between acute migraine attacks necessitating modification of management to optimize outcomes. Gastric dysmotility in the setting of migraine can impact absorption of oral migraine medications and alternate formulations should be considered for some patients. Noninvasive vagus nerve stimulation has been FDA cleared for migraine treatment and is also being studied in gastroparesis. Dysfunction of the autonomic nervous system is a significant feature in the pathophysiology of gut motility and migraine, making treatments that modulate the vagus nerve attractive for future research.

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.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01502-z.

Early alterations of cortical thickness and gyrification in migraine without aura: a retrospective MRI study in pediatric patients

Background

Migraine is the most common neurological disease, with high social-economical burden. Although there is growing evidence of brain structural and functional abnormalities in patients with migraine, few studies have been conducted on children and no studies investigating cortical gyrification have been conducted on pediatric patients affected by migraine without aura.

Methods

Seventy-two pediatric patients affected by migraine without aura and eighty-two controls aged between 6 and 18 were retrospectively recruited with the following inclusion criteria: MRI exam showing no morphological or signal abnormalities, no systemic comorbidities, no abnormal neurological examination. Cortical thickness (CT) and local gyrification index (LGI) were obtained through a dedicated algorithm, consisting of a combination of voxel-based and surface-based morphometric techniques. The statistical analysis was performed separately on CT and LGI between: patients and controls; subgroups of controls and subgroups of patients.

Results

Patients showed a decreased LGI in the left superior parietal lobule and in the supramarginal gyrus, compared to controls. Female patients presented a decreased LGI in the right superior, middle and transverse temporal gyri, right postcentral gyrus and supramarginal gyrus compared to male patients. Compared to migraine patients younger than 12 years, the ≥ 12-year-old subjects showed a decreased CT in the superior and middle frontal gyri, pre- and post-central cortex, paracentral lobule, superior and transverse temporal gyri, supramarginal gyrus and posterior insula. Migraine patients experiencing nausea and/or vomiting during headache attacks presented an increased CT in the pars opercularis of the left inferior frontal gyrus.

Conclusions

Differences in CT and LGI in patients affected by migraine without aura may suggest the presence of congenital and acquired abnormalities in migraine and that migraine might represent a vast spectrum of different entities. In particular, ≥ 12-year-old pediatric patients showed a decreased CT in areas related to the executive function and nociceptive networks compared to younger patients, while female patients compared to males showed a decreased CT of the auditory cortex compared to males. Therefore, early and tailored therapies are paramount to obtain migraine control, prevent cerebral reduction of cortical thickness and preserve executive function and nociception networks to ensure a high quality of life.

Gender-related differences in migraine

Migraine is considered mostly a woman’s complaint, even if it affects also men. Epidemiological data show a higher incidence of the disease in women, starting from puberty throughout life. The sex-related differences of migraine hold clinical relevance too. The frequency, duration, and disability of attacks tend to be higher in women. Because of this, probably, they also consult specialists more frequently and take more prescription drugs than men. Different mechanisms have been evaluated to explain these differences. Hormonal milieu and its modulation of neuronal and vascular reactivity is probably one of the most important aspects. Estrogens and progesterone regulate a host of biological functions through two mechanisms: nongenomic and genomic. They influence several neuromediators and neurotransmitters, and they may cause functional and structural differences in several brain regions, involved in migraine pathogenesis. In addition to their central action, sex hormones exert rapid modulation of vascular tone. The resulting specific sex phenotype should be considered during clinical management and experimental studies.

Evaluation of Patients with Insufficient Efficacy and/or Tolerability to Triptans for the Acute Treatment of Migraine: A Systematic Literature Review

INTRODUCTION

Use of triptans for acute treatment of migraine is associated with insufficient efficacy and/or tolerability in approximately 30-40% of people. We conducted a systematic literature review (SLR) to synthesize definitions, terminology, subsequent treatment outcomes, and characteristics associated with this subpopulation.

METHODS

A comprehensive SLR was conducted to identify studies, published from Jan 1995 to May 2019, which focused on insufficient efficacy and/or tolerability to triptans.

RESULTS

Thirty-five publications were identified, of which 22 described randomized controlled trials and open-label studies, and 13 described observational studies. Across studies, multiple objectives and a high amount of variability in methodologies and outcomes were noted. The most commonly applied measures of efficacy were headache pain freedom and pain relief at 2 h. Ten studies assessed efficacy of switching or optimizing treatment in patients with historical insufficient efficacy or tolerability to previous triptan treatment and demonstrated varying levels of success. Factors associated with increased risk of triptan insufficient efficacy included severe baseline headache severity, photophobia, phonophobia, nausea, and depression.

CONCLUSIONS

Irrespective of the methodology or definition used to identify people with insufficient efficacy and/or tolerability to triptans, study results support the assertion that a high unmet need remains for effective acute treatment of migraine.

Targeting the 5-HT1B/1D and 5-HT1F receptors for acute migraine treatment

Migraine is a common and highly disabling headache disorder associated with a substantial socioeconomic burden. Migraine treatments can be categorized as preventive treatment, aimed at reducing the frequency and severity of migraine attacks, and acute therapy, intended to abort attacks. Traditionally, acute treatment can be classified as specific (ergot derivatives and triptans) or nonspecific (analgesics and nonsteroidal anti-inflammatory drugs). Triptans, a class of 5-HT1B/1D receptor agonists with some affinity for the 5-HT1F receptor subtype, have been proven to be efficacious for acute treatment of moderate to severe migraine and have been deemed the gold standard. The availability of triptans in non-oral formulations, such as subcutaneous (SC) and intranasal forms, can be beneficial for patients who suffer from prominent nausea or vomiting, have a suboptimal response to oral agents, and/or seek a more rapid onset of treatment effects. However, triptans are contraindicated in patients with preexisting cardiovascular and/or cerebrovascular diseases due to their 5-HT1B-mediated vasoconstrictive action. For this reason, studies have focused on the development of ditans, a group of antimigraine drugs targeting 5-HT1D and 5-HT1F receptors. Unfortunately, 5-HT1D receptor agonists have been shown to be ineffective in the acute treatment of migraine. Several ditans targeting the 5-HT1F receptor have been developed and have shown no vasoconstrictive effect in preclinical studies, but only two of them, lasmiditan and LY334370, have been tested in clinical trials for migraine, and only lasmiditan has reached to Phase III clinical trials. These Phase III trials have demonstrated the efficacy and safety of lasmiditan, a selective 5-HT1F receptor agonist, in acute migraine treatment. Lasmiditan might offer an alternative migraine therapy without cardiovascular risks. This review will summarize the development of agents targeting the 5-HT1B/1D and 5-HT1F receptors and the clinical evidence supporting the use of these agents for acute migraine treatment.

Sex-Specific Pharmacotherapy for Migraine: A Narrative Review

Migraine is a common neurological disorder characterized by recurrent headache episodes that accompany sensory-motor disturbances, such as higher sensitivity to touch and light, extremity heaviness or weakness, and speech or language disabilities. Worldwide, migraine is one of the top 10 causes of disability and hence poses a huge economic burden to society. On average, migraine occurs in 12% of population but its occurrence is sexually dimorphic, as it is two to three times more prevalent in women than in men. This female to male ratio of migraine prevalence is age- and sex hormone-dependent. Advancements in understanding migraine pathogenesis have also revealed an association with both genetics and epigenetics. The severity of migraine, in terms of its attack duration, headache intensity, frequency, and occurrence of migraine-associated symptoms, has generally been reported to be greater in women. Sex differences in migraine disability and comorbidities, such as psychiatric disorders, have also been noted in some population-based studies. However, research on sex-related differences in response to migraine treatments is relatively scarce. Although a general observation is that women consume more medication than men for migraine treatment, strategies for the use of abortive and preventive medications for migraine are generally similar in both sexes. This narrative review summarizes available findings on sexually distinct responses to abortive and prophylactic pharmacotherapy of migraine. Basic experimental data and clinical findings will be presented, and potential mechanisms underlying sex-based responses will be discussed to highlight the importance and value of sex-based treatment in migraine research and practice.

The Upper Nasal Space—A Novel Delivery Route Ideal for Central Nervous System Drugs

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A Phase I, Randomized, Single‑Blind, Placebo‑Controlled, Single Ascending Dose Study of the Safety, Tolerability, and Pharmacokinetics of Subcutaneous and Oral TRV250, a G Protein-Selective Delta Receptor Agonist, in Healthy Subjects

BACKGROUND

The delta opioid receptor (DOR) has been identified as a therapeutic target for migraine, with DOR agonists exhibiting low abuse potential compared with conventional µ-opioid agonists. TRV250 is a novel small molecule agonist of the DOR that is preferentially selective for G-protein signaling, with relatively little activation of the β-arrestin2 post-receptor signaling pathway. This selectivity provides reduced susceptibility to proconvulsant activity seen with non-selective DOR agonists. TRV250 significantly reduced nitroglycerin-evoked hyperalgesia in rodents, indicating a potential utility in acute migraine without the risk of seizure activity or abuse potential.

OBJECTIVE

This trial evaluated the safety, tolerability, and pharmacokinetics of ascending dose levels of TRV250 administered subcutaneously (SC) and the relative bioavailability of TRV250 administered orally compared with SC administration.

METHODS

This was a two-part, single ascending dose study. Part A included four cohorts of healthy adults (N = 38). Each cohort was dosed on three occasions (placebo and two different dose levels of TRV250, allocated in randomized order and administered by SC route). In Part B, a single cohort of nine subjects received an oral dose of either TRV250 (n = 7) or placebo (n = 2) in a fed or fasted state. Serial blood samples were obtained for pharmacokinetic determination across a 24-h post-dose period. Safety assessments included clinical laboratory measures, vital signs, 12-lead electrocardiogram (ECG), and electroencephalogram (EEG) pre- and post-dosing.

RESULTS

TRV250 was well tolerated. There were no serious adverse events (SAEs), and all AEs were mild in severity. Injection-site reactions and headache were the most common AEs. One subject was withdrawn from the study due to a TRV250-related AE of postural orthostatic tachycardia. There were no clinically relevant changes in physical examination, hematology, clinical chemistry, urinalysis, suicidal ideation, or vital signs, with the exception of orthostatic changes in some subjects. No subject experienced abnormalities in EEGs or experienced a change from baseline in heart-rate-corrected QT interval (QTcF) > 60 ms, or an absolute QTcF interval > 480 ms at any post-dosing observation. Peak and total plasma exposure to TRV250 increased in a dose-proportional manner following 0.1-30 mg SC doses, with the mean half-life ranging from 2.39 to 3.76 h. Oral bioavailability of TRV250 ranged from 14% (fasting) to 19% (fed) relative to SC dosing, while administration with food increased the AUC but decreased the rate of absorption as reflected by a modest delay in median time to maximum concentration and a slight reduction in maximum concentration.

CONCLUSION

The findings from the first-in-human study support further evaluation of TRV250, a G-protein selective DOR agonist, in the treatment of acute migraine.

Efficacy, safety, and tolerability of rimegepant orally disintegrating tablet for the acute treatment of migraine: a randomised, phase 3, double-blind, placebo-controlled trial

BACKGROUND

Rimegepant, a small molecule calcitonin gene-related peptide receptor antagonist, has shown efficacy in the acute treatment of migraine using a standard tablet formulation. The objective of this trial was to compare the efficacy, safety, and tolerability of a novel orally disintegrating tablet formulation of rimegepant at 75 mg with placebo in the acute treatment of migraine.

METHODS

In this double-blind, randomised, placebo-controlled, multicentre phase 3 trial, adults aged 18 years or older with history of migraine of at least 1 year were recruited to 69 study centres in the USA. Participants were randomly assigned to receive rimegepant (75 mg orally disintegrating tablet) or placebo and instructed to treat a single migraine attack of moderate or severe pain intensity. The randomisation was stratified by the use of prophylactic medication (yes or no), and was carried out using an interactive web response system that was accessed by each clinical site. All participants, investigators, and the sponsor were masked to treatment group assignment. The coprimary endpoints were freedom from pain and freedom from the most bothersome symptom at 2 h postdose. The efficacy analyses used the modified intention-to-treat population, which included all patients who were randomly assigned, had a migraine attack with pain of moderate or severe intensity, took a dose of rimegepant or placebo, and had at least one efficacy assessment after administration of the dose. The safety analyses included all randomly assigned participants who received at least one dose of study medication. This study is registered with ClinicalTrials.gov, number NCT03461757, and is closed to accrual.

FINDINGS

Between Feb 27 and Aug 28, 2018, 1811 participants were recruited and assessed for eligibility. 1466 participants were randomly assigned to the rimegepant (n=732) or placebo (n=734) groups, of whom 1375 received treatment with rimegepant (n=682) or placebo (n=693), and 1351 were evaluated for efficacy (rimegepant n=669, placebo n=682). At 2 h postdose, rimegepant orally disintegrating tablet was superior to placebo for freedom from pain (21% vs 11%, p<0·0001; risk difference 10, 95% CI 6-14) and freedom from the most bothersome symptom (35% vs 27%, p=0·0009; risk difference 8, 95% CI 3-13). The most common adverse events were nausea (rimegepant n=11 [2%]; placebo n=3 [<1%]) and urinary tract infection (rimegepant n=10 [1%]; placebo n=4 [1%]). One participant in each treatment group had a transaminase concentration of more than 3 × the upper limit of normal; neither was related to study medication, and no elevations in bilirubin greater than 2 × the upper limit of normal were reported. Treated participants reported no serious adverse events.

INTERPRETATION

In the acute treatment of migraine, a single 75 mg dose of rimegepant in an orally disintegrating tablet formulation was more effective than placebo. Tolerability was similar to placebo, with no safety concerns.

FUNDING

Biohaven Pharmaceuticals.

Emerging Novel Pharmacological Non-opioid Therapies in Headache Management: a Comprehensive Review

PURPOSE OF REVIEW

Chronic headache is a significant worldwide problem despite advances in treatment options. Chronic headaches can have significant a detrimental impact on the activities of daily living.

RECENT FINDINGS

Patients who do not obtain relief from chronic head and neck pain from conservative treatments are commonly being managed with interventional treatments. These interventional treatment options include botulinum toxin A, injections, local occipital nerve anesthetic and corticosteroid infiltration, occipital nerve subcutaneous stimulation and occipital nerve pulsed radiofrequency (PRF), sphenopalatine ganglion block, and radiofrequency techniques. Recently, evidence has emerged to support non-opioid-based drug and interventional approaches. Overall, more research is necessary to clarify the safety and efficacy of interventional treatments and to better understand the pathogenesis of chronic headache pain.

Female versus male migraine: an event-related potential study of visual neurocognitive processing

Background

Several studies have suggested cognitive deficits in migraineurs, and sex differences have also been observed in migraine, such as a higher prevalence in females. Nevertheless, little is known about gender-related differences in cognitive processing. In this study, we aimed to investigate the effect of gender on neurocognitive processing in migraineurs.

Methods

Altogether, 46 migraine patients without aura (23 females; mean age 32.848 years) during the interictal period and 46 age-matched healthy controls (23 females; mean age 32.652 years) were recruited. The emotional characteristics of participants were evaluated, and attentive processing was analyzed via event-related potential examinations using a three-stimulus visual oddball paradigm.

Results

We found that migraineurs suffered from emotional and visual cognitive processing abnormalities compared with healthy controls, including higher levels of anxiety and reduced P3 amplitude. These parameters were modulated by gender in migraine patients, but not in healthy participants. Our findings indicated that female patients seemed to be more anxious and have more severe impairment in attentive processing of visual stimuli than their male counterparts. The gender-related differences in migraineurs were further validated using event-related potential difference waveforms.

Conclusions

These results suggested that migraine might have an additional influence on females and lead to more dysfunction in their interictal neurocognitive processing. Our findings provide evidence that a gender effect exists in migraineurs, which should be considered when designing experiments and exploring treatment approaches. The gender-related differences and underlying mechanisms deserve further investigation for patients with migraine.

Electronic supplementary material

The online version of this article (10.1186/s10194-019-0995-y) contains supplementary material, which is available to authorized users.

Sex, Gender, and Orofacial Pain

This review examines gender prevalence in orofacial pain to elucidate underlying factors that can explain such differences. This review highlights how gender affects (1) the association of hormonal factors and pain modulation; (2) the genetic aspects influencing pain sensitivity and pain perception; (3) the role of resting blood pressure and pain threshold; and (4) the impact of sociocultural, environmental, and psychological factors on pain.

Preparation and Optimization of Fast-Disintegrating Tablet Containing Naratriptan Hydrochloride Using D-Optimal Mixture Design

Optimization of a lyophilized fast-disintegrating tablet (LFDT) formulation containing naratriptan hydrochloride, an antimigraine drug, was the foremost objective of the study, aiming in achieving fast headache pain relief. The Design-Expert® v10 software was used to generate formulations using D-optimal mixture design with four components: gelatin (X₁), hydrolyzed gelatin (X₂), glycine (X₃), and mannitol (X₄) of total solid material (TSM) w/w. The effect of the relative proportion of each component was determined on friability (Y₁), hardness (Y₂), and in vitro disintegration time (Y₃), which was then applied for formulation optimization. In addition, their effect on tablet porosity was determined via scanning electron microscopy (SEM). Drug-excipient interaction was evaluated using differential scanning calorimetry (DSC). A comparative dissolution study against the conventional tablets was studied. Accelerated stability study was carried out in (Al/Al) and (Al/PVC) blister packs. An in vivo pharmacokinetic study was carried out to compare the optimized formulation and the conventional tablets. The optimized formulation's responses were 0.30%, 3.4 kg, and 6.12 s for Y₁, Y₂, and Y₃, respectively. No drug-excipient interaction was specified via DSC. The optimized formulation exhibited porous structure as determined via SEM. Dissolution study demonstrated complete dissolution within 1.5 min. Study indicated stability for 78 months in (Al/Al) blister packs. In vivo pharmacokinetic study demonstrated that C_max, AUC_last, and AUC_inf were significantly higher for the developed formulation. As well, the T_max was 1 h earlier than that of convenient tablet. An LFDT would achieve a faster onset of action for naratriptan compared to other formulations.

Glutamate receptor antagonists with the potential for migraine treatment

INTRODUCTION

Preclinical, clinical, and other (e.g., genetic) evidence support the concept that migraine susceptibility may at least partially result from a glutamatergic system disorder. Therefore, the receptors of the glutamatergic system are considered relatively new targets for investigational drugs to treat migraine. Investigational and established glutamate receptor antagonists (GluRAs) have been shown to possess antinociceptive properties in preclinical models of trigeminovascular nociception and have been evaluated in clinical trials. This review focuses on preclinical and clinical studies of GluRAs for the treatment of migraine. Areas covered: A PubMed database search (from 1987 to December 2016) and a review of published studies on GluRAs in migraine were conducted. Expert opinion: All published clinical trials of investigational GluRAs have been unsuccessful in establishing benefit for acute migraine treatment. Clinical trial results contrast with the preclinical data, suggesting that glutamate (Glu) does not play a decisive role after the attack has already been triggered. These antagonists may instead be useful for migraine prophylaxis. Improving patient care requires further investigating and critically analyzing the role of Glu in migraine, designing experimental models to study more receptors and their corresponding antagonists, and identifying biomarkers to facilitate trials designed to target specific subgroups of migraine patients.

Sex differences in the epidemiology, clinical features, and pathophysiology of migraine

Migraine is two to three times more prevalent in women than men, and women report a longer attack duration, increased risk of headache recurrence, greater disability, and a longer period of time required to recover. Conditions recognised to be comorbid with migraine include asthma, anxiety, depression, and other chronic pain conditions, and these comorbidities add to the amount of disability in both sexes. Migraine-specifically migraine with aura-has been identified as a risk factor for vascular disorders, particularly in women, but because of the scarcity of data, the comparative risk in men has yet to be established. There is evidence implicating the role of female sex hormones as a major factor in determining migraine risk and characteristics, which accounts for sex differences, but there is also evidence to support underlying genetic variance. Although migraine is often recognised in women, it is underdiagnosed in men, resulting in suboptimal management and less participation of men in clinical trials.

Hair analysis for detection of triptans occasionally used or overused by migraine patients-a pilot study

Purpose

The aim of this study is to evaluate the detection rate of almotriptan, eletriptan, frovatriptan, sumatriptan, rizatriptan, and zolmitriptan in the hair of migraineurs taking these drugs; the degree of agreement between type of self-reported triptan and triptan found in hair; if the concentrations in hair were related to the reported cumulative doses of triptans; and whether hair analysis was able to distinguish occasional use from the overuse of these drugs.

Methods

Out of 300 headache patients consecutively enrolled, we included 147 migraine patients who reported to have taken at least one dose of one triptan in the previous 3 months; 51 % of the patients overused triptans. A detailed pharmacological history and a sample of hair were collected for each patient. Hair samples were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) by a method that we developed.

Results

All the triptans could be detected in the hair of the patients. The agreement between type of self-reported triptan and type of triptan found in hair was from fair to good for frovatriptan and zolmitriptan and excellent for almotriptan, eletriptan, sumatriptan, and rizatriptan (P < 0.01, Cohen’s kappa). The correlation between the reported quantities of triptan and hair concentrations was statistically significant for almotriptan, eletriptan, rizatriptan, and sumatriptan (P < 0.01, Spearman’s rank correlation coefficient). The accuracy of hair analysis in distinguishing occasionally users from overusers was high for almotriptan (ROC AUC = 0.9092), eletriptan (ROC AUC = 0.8721), rizatriptan (ROC AUC = 0.9724), and sumatriptan (ROC AUC = 0.9583).

Conclusions

Hair analysis can be a valuable system to discriminate occasional use from triptan overuse.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-016-2074-5) contains supplementary material, which is available to authorized users.

Roads Less Traveled: Sexual Dimorphism and Mast Cell Contributions to Migraine Pathology

Migraine is a common, little understood, and debilitating disease. It is much more prominent in women than in men (~2/3 are women) but the reasons for female preponderance are not clear. Migraineurs frequently experience severe comorbidities, such as allergies, depression, irritable bowel syndrome, and others; many of the comorbidities are more common in females. Current treatments for migraine are not gender specific, and rarely are migraine and its comorbidities considered and treated by the same specialist. Thus, migraine treatments represent a huge unmet medical need, which will only be addressed with greater understanding of its underlying pathophysiology. We discuss the current knowledge about sex differences in migraine and its comorbidities, and focus on the potential role of mast cells (MCs) in both. Sex-based differences in pain recognition and drug responses, fluid balance, and the blood–brain barrier are recognized but their impact on migraine is not well studied. Furthermore, MCs are well recognized for their prominent role in allergies but much less is known about their contributions to pain pathways in general and migraine specifically. MC-neuron bidirectional communication uniquely positions these cells as potential initiators and/or perpetuators of pain. MCs can secrete nociceptor sensitizing and activating agents, such as serotonin, prostaglandins, histamine, and proteolytic enzymes that can also activate the pain-mediating transient receptor potential vanilloid channels. MCs express receptors for both estrogen and progesterone that induce degranulation upon binding. Furthermore, environmental estrogens, such as Bisphenol A, activate MCs in preclinical models but their impact on pain pathways or migraine is understudied. We hope that this discussion will encourage scientists and physicians alike to bridge the knowledge gaps linking sex, MCs, and migraine to develop better, more comprehensive treatments for migraine patients.

Development and validation of a liquid chromatography-tandem mass spectrometric assay for quantitative analyses of triptans in hair

Triptans are specific drugs widely used for acute treatment of migraine, being selective 5HT1B/1D receptor agonists. A proper assumption of triptans is very important for an effective treatment; nevertheless patients often underuse, misuse, overuse or use triptans inconsistently, i.e., not following the prescribed therapy. Drug analysis in hair can represent a powerful tool for monitoring the compliance of the patient to the therapy, since it can greatly increase the time-window of detection compared to analyses in biological fluids, such as plasma or urine. In the present study, a liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the quantitative analysis in human hair of five triptans commonly prescribed in Italy: almotriptan (AL), eletriptan (EP), rizatriptan (RIZ), sumatriptan (SUM) and zolmitriptan (ZP). Hair samples were decontaminated and incubated overnight in diluted hydrochloric acid; the extracts were purified by mixed-mode SPE cartridges and analyzed by LC-MS/MS under gradient elution in positive multiple reaction monitoring (MRM) mode. The procedure was fully validated in terms of selectivity, linearity, limit of detection (LOD) and lower limit of quantitation (LLOQ), accuracy, precision, carry-over, recovery, matrix effect and dilution integrity. The method was linear in the range 10-1000pg/mg hair, with R(2) values of at least 0.990; the validated LLOQ values were in the range 5-7pg/mg hair. The method offered satisfactory precision (RSD <10%), accuracy (90-110%) and recovery (>85%) values. The validated procedure was applied on 147 authentic hair samples from subjects being treated in the Headache Centre of Modena University Hospital in order to verify the possibility of monitoring the corresponding hair levels for the taken triptans.

Efficacy and pharmacokinetic activity of frovatriptan compared to rizatriptan in patients with moderate-to-severe migraine

BACKGROUND

Migraine is a painful neurological disorder that affects over 10% of the general population. Frovatriptan and rizatriptan are antimigraine agents belonging to the triptan class. Although previous studies have independently compared the efficacy of these agents, contemporaneous data examining both pharmacokinetic (PK) properties and efficacy in parallel have not previously been available.

MATERIALS AND METHODS

In this single-center double-blind study, 18 subjects (ten female) were treated for a single migraine attack with frovatriptan 2.5 mg or rizatriptan 10 mg. Plasma concentrations were measured predose and at 2, 4, 6, 12, 24, 48, and 72 hours after drug administration. The primary end point of this study was to evaluate the association between PK parameters and efficacy measures and recurrence rate. Secondary end points were pain-free and pain-relief episodes at 2 and 4 hours, recurrent episodes within 48 hours, and cumulative hazard of recurrence within 72 hours.

RESULTS

At baseline, approximately 17% of patients had mild migraine, while 83% had moderate-severe migraine. Although the time to maximum concentration was similar for both drugs (2.7 versus 2.3 hours), the terminal half-life for frovatriptan was longer than rizatriptan (29.3 versus 3.2 hours, P<0.0001). The proportion of patients who were pain-free at 4 hours without rescue medication was higher in the frovatriptan-treated group, (38.9 versus 5.6%, P=0.045). The cumulative hazard of recurrence over 72 h was reduced by frovatriptan compared to rizatriptan-treated patients (log-rank test, P=0.04). Pain-free and pain-relief episodes for the study period were positively correlated with the concentration:maximum concentration (Cmax) ratio for frovatriptan (r=0.52, P=0.028), but not rizatriptan. Recurrence rate was negatively correlated with the concentration:Cmax ratio for both frovatriptan (r=-0.96, P=0.0024) and rizatriptan (r=-0.98, P=0.0004). Fewer adverse events were observed for frovatriptan compared to rizatriptan (one versus eight, P=0.021).

CONCLUSION

This pilot study indicates that a similar extent of initial pain relief is afforded by both triptans in migraine treatment. The longer duration of action of frovatriptan parallels and correlates with its PK profile.

Pain and temporomandibular disorders: a pharmaco-gender dilemma

Gender is the biggest risk factor in the development of temporomandibular disorders (TMD) and orofacial pain. Gender differences in pain thresholds, temporal summation, pain expectations, and somatic awareness exist in patients with chronic TMD or orofacial pain. There are gender differences in pharmacokenetics and pharmacodynamics of medications used to treat pain. A better understanding of the mechanisms that contribute to the increased incidence and persistence of chronic pain in females is needed. Future research will elucidate the sex effects on factors that protect against developing pain or prevent debilitating pain. Gender-based treatments for TMD and orofacial pain treatment will evolve from the translational research stimulated by this knowledge.

Activation of 5-hydroxytryptamine1B/1D/1F receptors as a mechanism of action of antimigraine drugs

INTRODUCTION

The introduction of the triptans (5-hydroxytryptamine (5-HT)1B/1D receptor agonists) was a great improvement in the acute treatment of migraine. However, shortcomings of the triptans have prompted research on novel serotonergic targets for the treatment of migraine.

AREAS COVERED

In this review the different types of antimigraine drugs acting at 5-HT receptors, their discovery and development are discussed. The first specific antimigraine drugs were the ergot alkaloids, consisting of ergotamine, dihydroergotamine and methysergide, which are agonists at 5-HT receptors, but can also bind α-adrenoceptors and dopamine receptors. In the 1990s, the triptans became available on the market. They are 5-HT1B/1D receptor agonists, showing fewer side effects due to their receptor specificity. In the last years, compounds that bind specifically to 5-HT1D, 5-HT1F and 5-HT7 receptors have been explored for their antimigraine potential. Furthermore, the serotonergic system seems to act in tight connection with the glutamatergic as well as the CGRP-ergic systems, which may open novel therapeutic avenues.

EXPERT OPINION

Although the triptans are very effective in treating migraine attacks, their shortcomings have stimulated the search for novel drugs. Currently, the focus is on 5-HT1F receptor agonists, which seem devoid of vascular side effects. Moreover, novel compounds that affect multiple transmitter and/or neuropeptide systems that are involved in migraine could be of therapeutic relevance.

Gastric stasis in migraineurs: etiology, characteristics, and clinical and therapeutic implications

BACKGROUND

Migraine is a disabling neurological disorder often complicated by gastrointestinal conditions such as gastric stasis. The association between migraine and gastric stasis has received very little attention in the literature, but the existing evidence suggests that they may share a common etiology.

RESULTS

Patients with migraine and those with gastric stasis exhibit abnormal autonomic nervous system function. Furthermore, empirical studies demonstrate that migraineurs experience significant delays in gastric emptying, both during and outside of attacks, when compared to non-migrainous controls.

CONCLUSION

More research is needed to establish the relationship between gastric stasis and migraine burden and to determine the impact of gastric stasis on migraine treatment.

An open-label trial of a sumatriptan auto-injector for migraine in patients currently treated with subcutaneous sumatriptan

OBJECTIVE

To assess the ability of patients, during an acute migraine attack, to successfully self-inject a single dose of sumatriptan using a novel sumatriptan auto-injector (Alsuma(®)), and to evaluate the safety, tolerability, and effectiveness of this sumatriptan auto-injector during an acute migraine attack.

BACKGROUND

This sumatriptan auto-injector is a single-use system for the rapid subcutaneous delivery of 6 mg of sumatriptan succinate in the acute management of migraine pain. This auto-injector was developed to address the clinical need for an easy-to-use and rapid-to-administer system that did not require any assembly during the time of an ongoing attack.

METHODS

This was an open-label, phase 3 trial conducted at 10 sites in the USA. Male or female adults, ages 18-60 years old, were eligible for study entry if they met International Headache Society criteria for migraine with or without aura, with at least 2 attacks per month, and if they reported use of subcutaneous injectable sumatriptan on at least 2 occasions within the previous 2 months. During the onset of a migraine attack of moderate-to-severe intensity, patients were asked to administer a 6-mg subcutaneous dose of sumatriptan using the auto-injector. Patients returned to the study site within 72 hours of the migraine for the post-treatment assessment visit.

RESULTS

A total of 63 patients met entry criteria and received a dose of study medication (the intent-to-treat sample). Sixty-one patients (96.8%) reported injection in the thigh, and 2 patients (3.2%) reported injection in the arm. On the patient questionnaire, 100% of patients (95% confidence interval [CI] 94.3-100%) "agreed" or "agreed strongly" that the written instructions for the auto-injector were clear and easy to follow (30.2% "agreed"; 69.8% "agreed strongly"); 95.2% of patients (95% CI 86.7-99.0%) found that the auto-injector was easy to use (36.5% "agreed"; 58.7% "agreed strongly"), and 65.1% of patients (95% CI 52.0-76.7%) stated that they preferred the new auto-injector to the traditional auto-injector that they were using prior to study entry (42.9% "agreed"; 22.2% "agreed strongly"). Headache response rate at 2 hours was 93.7% (95% CI 84.5-98.2%), and pain-free rate at 2 hours was 60.3% (95% CI 47.2-72.4%). Pain-free rates at 2 hours were similarly high (58.3%; 95% CI 36.6-77.9%) in the subgroup of patients reporting severe baseline headache pain. Only 1 patient reported use of rescue medication after use of the auto-injector, a single oral dose of sumatriptan 100 mg on the same day. The most frequent adverse event was injection site bruising, reported by 15.9% of patients, and rated in all instance as mild in intensity. The second most frequent adverse event was injection site pain, reported by 6.3% of patients, and rated as mild by all patients except 1, who rated it as moderate in intensity.

CONCLUSION

The majority of injection-experienced patients reported the pre-assembled, single-use sumatriptan auto-injector to be an easy-to-use, preferred treatment for an acute migraine attack. The study found the auto-injector to be safe and well tolerated, with levels of injection site reactions that were mild and infrequent.

Her versus his migraine: multiple sex differences in brain function and structure

Migraine is twice as common in females as in males, but the mechanisms behind this difference are still poorly understood. We used high-field magnetic resonance imaging in male and female age-matched interictal (migraine free) migraineurs and matched healthy controls to determine alterations in brain structure. Female migraineurs had thicker posterior insula and precuneus cortices compared with male migraineurs and healthy controls of both sexes. Furthermore, evaluation of functional responses to heat within the migraine groups indicated concurrent functional differences in male and female migraineurs and a sex-specific pattern of functional connectivity of these two regions with the rest of the brain. The results support the notion of a 'sex phenotype' in migraine and indicate that brains are differentially affected by migraine in females compared with males. Furthermore, the results also support the notion that sex differences involve both brain structure as well as functional circuits, in that emotional circuitry compared with sensory processing appears involved to a greater degree in female than male migraineurs.

Pharmacokinetic evaluation of zolmitriptan for the treatment of migraines

INTRODUCTION

Migraine is a multifactorial neurovascular disorder characterized by recurrent episodes of disabling pain attacks, accompanied with gastrointestinal, neurological systems dysfunction. The pharmacologic treatment of migraine is classically divided in the management of the acute attack and preventive strategies. Acute treatments consist of triptan, ergot, opioid, antiemetic and NSAIDs.

AREAS COVERED

This article discusses pharmacodynamics and pharmacokinetics of zolmitriptan . The data were obtained by searching the following keywords in MEDLINE: zolmitriptan, pharmacokinetics, pharmacodynamics, triptans, migraine, menstrual-related migraine, cluster headache, relatively to the period 1989 - 2012.

EXPERT OPINION

Zolmitriptan has been considered effective treatment in the acute phase of migraine, menstrual-related migraine and cluster headache attacks. Pharmacokinetic parameters may vary as a consequence of gender differences, inter- and intra-subjects variability and delivery system. Zolmitriptan was developed with the aim of obtaining a lipophilic compound in order to be more rapidly absorbed and centrally active. Pharmacologically, pharmacokinetic parameters are responsible for its wide efficacy and the limited adverse effect profile.