A correlation between severity of migraine and delayed gastric emptying measured by an epigastric impedance method

The Gut-brain Connection and Episodic Migraine: an Update

PURPOSE OF REVIEW

Historical evidence suggests a shared underlying etiology for migraine and gastrointestinal (GI) disorders that involves the gut-brain axis. Here we provide narrative review of recent literature on the gut-brain connection and migraine to emphasize the importance of tailoring treatment plans for patients with episodic migraine who experience GI comorbidities and symptoms.

RECENT FINDINGS

Recent population-based studies report the prevalence of migraine and GI disorders as comorbidities as well as overlapping symptomology. American Headache Society (AHS) guidelines have integrated GI symptoms as part of migraine diagnostic criteria and recommend nonoral therapies for patients with GI symptoms or conditions. Nasal delivery is a recommended nonoral alternative; however, it is important to understand potential adverse events that may cause or worsen GI symptoms in some patients due to the site of drug deposition within the nasal cavity with some nasal therapies. Lastly, clinical perspectives emphasize the importance of identifying GI symptoms and comorbidities in patients with episodic migraine to best individualize migraine management. Support for an association between the gut-brain axis and migraine continues to prevail in recent literature; however, the relationship remains complex and not well elucidated. The presence of GI comorbidities and symptoms must be carefully considered when making treatment decisions for patients with episodic migraine.

All Roads Lead to the Gut: The Importance of the Microbiota and Diet in Migraine

Migraine, a prevalent neurological condition and the third most common disease globally, places a significant economic burden on society. Despite extensive research efforts, the precise underlying mechanism of the disease remains incompletely comprehended. Nevertheless, it is established that the activation and sensitization of the trigeminal system are crucial during migraine attacks, and specific substances have been recognized for their distinct involvement in the pathomechanism of migraine. Recently, an expanding body of data indicates that migraine attacks can be prevented and treated through dietary means. It is important to highlight that the various diets available pose risks for patients without professional guidance. This comprehensive overview explores the connection between migraine, the gut microbiome, and gastrointestinal disorders. It provides insight into migraine-triggering foods, and discusses potential diets to help reduce the frequency and severity of migraine attacks. Additionally, it delves into the benefits of using pre- and probiotics as adjunctive therapy in migraine treatment.

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.

Gut microbiota and migraine

Migraine is a leading cause of disability among the adult population and is a significant burden on the economies of the world. Studies into the underlying causes of migraine have spanned centuries but its underlying mechanisms are still not fully understood. In recent years, accumulating evidence implicates that microbiota-mediated gut-brain crosstalk may contribute to the pathogenesis of migraine. This review provides a brief account of the history of migraine theories and summarizes the recent studies showing how gut microbiota is involved in the pathophysiology of migraine. Future research perspectives for better understanding the role of the gut microbiota in migraine are also discussed.

Pathophysiological Bases of Comorbidity in Migraine

Despite that it is commonly accepted that migraine is a disorder of the nervous system with a prominent genetic basis, it is comorbid with a plethora of medical conditions. Several studies have found bidirectional comorbidity between migraine and different disorders including neurological, psychiatric, cardio- and cerebrovascular, gastrointestinal, metaboloendocrine, and immunological conditions. Each of these has its own genetic load and shares some common characteristics with migraine. The bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other diseases are manifold. Comorbid pathologies can induce and promote thalamocortical network dysexcitability, multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs in a variable combination, which in turn may be causative mechanisms of the activation of an ample defensive system with includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. This strategy is designed to maintain brain homeostasis by regulating homeostatic needs, such as normal subcortico-cortical excitability, energy balance, osmoregulation, and emotional response. In this light, the treatment of migraine should always involves a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors.

A link between gastrointestinal disorders and migraine: Insights into the gut-brain connection

Background

Migraine is a complex, multifaceted, and disabling headache disease that is often complicated by gastrointestinal (GI) conditions, such as gastroparesis, functional dyspepsia, and cyclic vomiting syndrome (CVS). Functional dyspepsia and CVS are part of a spectrum of disorders newly classified as disorders of gut–brain interaction (DGBI). Gastroparesis and functional dyspepsia are both associated with delayed gastric emptying, while nausea and vomiting are prominent in CVS, which are also symptoms that commonly occur with migraine attacks. Furthermore, these gastric disorders are comorbidities frequently reported by patients with migraine. While very few studies assessing GI disorders in patients with migraine have been performed, they do demonstrate a physiological link between these conditions.

Objective

To summarize the available studies supporting a link between GI comorbidities and migraine, including historical and current scientific evidence, as well as provide evidence that symptoms of GI disorders are also observed outside of migraine attacks during the interictal period. Additionally, the importance of route of administration and formulation of migraine therapies for patients with GI symptoms will be discussed.

Methods

A literature search of PubMed for articles relating to the relationship between the gut and the brain with no restriction on the publication year was performed. Studies providing scientific support for associations of gastroparesis, functional dyspepsia, and CVS with migraine and the impact these associations may have on migraine treatment were the primary focus. This is a narrative review of identified studies.

Results

Although the association between migraine and GI disorders has received very little attention in the literature, the existing evidence suggests that they may share a common etiology. In particular, the relationship between migraine, gastric motility, and vomiting has important clinical implications in the treatment of migraine, as delayed gastric emptying and vomiting may affect oral dosing compliance, and thus, the absorption and efficacy of oral migraine treatments.

Conclusions

There is evidence of a link between migraine and GI comorbidities, including those under the DGBI classification. Many patients do not find adequate relief with oral migraine therapies, which further necessitates increased recognition of GI disorders in patients with migraine by the headache community.

Efficacy, safety, and tolerability of sublingual fentanyl orally disintegrating tablet in the treatment of breakthrough cancer pain: a randomized, double-blind, placebo-controlled study

BACKGROUND

Breakthrough pain (BTP) is an important challenge in treatment and requires a rapid onset of action for pain control. BTP should be adequately controlled with a stable dose of a short-acting oral opioid. So far, no drug is available for the treatment of BTP in cancer patients in Iran, so we designed the first study in Iran to investigate the effect of sublingual fentanyl in relief of pain episodes in these patients.

OBJECTIVE

The purpose of this study was to evaluate the efficacy and safety of sublingual fentanyl in the treatment of breakthrough pain in cancer patients.

METHOD

This study was a randomized double-blind placebo-controlled clinical trial in cancer patients with breakthrough pain (at least 1-4 episodes of acute pain with moderate to severe pain daily) referred to the pain clinic of Akhtar and Masih Daneshvari hospitals in 2019. The study consisted of two stages: 100 patients were selected by simple, non-random sampling and entered the open-label titration phase. The primary efficacy endpoint was the sum of pain intensity difference over 30 min post-administration. Secondary efficacy endpoints included pain intensity difference (PID) and pain relief (PR) throughout the 60-min post-dose assessment period. In the double-blind study, patients were randomly divided into two groups of placebo (n=50) and intervention (sublingual fentanyl tablet) (n=50). For evaluation of efficacy, 10 episodes were treated in each group and the results were recorded by the patient. (Clinical trial registration: IRCT20131124015515N8).

RESULTS

A total of 100 patients entered the titration phase, primary efficacy of sublingual fentanyl was 3.5±0.6 and secondary efficacy of sublingual fentanyl (60 min, after treatment) was 0.3±0.6 which was statistically significant. In the titration phase, the treatment success rate was 100%. In the double-blind phase of the study, the pain intensity in multiple episodes showed a significant improvement at 15, 30, 45, and 60 min after drug administration (P=0.0001). The intensity of pain in each episode was significantly decreased compared to the next episode (P=0.0001). The mean frequency of pain episodes in the sublingual fentanyl group showed a significant decrease (P=0.0001). The most common adverse drug events in the titration phase were drowsiness (20%), dizziness (7%), and nausea 4%, and in the double-blind phase only drowsiness (12%). (Cancer Research Center, Shahid Beheshti University of Medical Sciences, Survey).

CONCLUSION

Sublingual fentanyl appears to be effective for patients with rapid-onset analgesia, has short-acting duration, is effective medication, safe, and well tolerated. It is a suitable choice in Iranian patients with chronic cancer-related pain controlled suffering from acute pain episodes related to cancer.

Self-Emulsifying Drug Delivery System of Celecoxib for Avoiding Delayed Oral Absorption in Rats with Impaired Gastric Motility

This study aimed to develop a self-emulsifying drug delivery system (SEDDS) of celecoxib (CEL) for suppressed delay in oral absorption under impaired gastric motility. A pseudo-ternary phase diagram was constructed for the determination of the optimal component ratio in SEDDS of CEL (SEDDS/CEL), and the SEDDS/CEL was physicochemically characterized. A pharmacokinetic study on orally dosed CEL samples (5-mg CEL/kg) was carried out in normal and propantheline (PPT)-treated rats to mimic impaired gastric motility. SEDDS/CEL rapidly formed a fine emulsion with a mean size of 147 nm in distilled water and significantly improved the dissolution behavior of CEL under pH 1.2 condition with a 20-fold higher dissolved amount than crystalline CEL. In normal rats, orally dosed SEDDS/CEL provided a 4.6-fold higher systemic exposure than that of crystalline CEL, due to the improved dissolution properties of CEL. Crystalline CEL showed delayed and decreased oral absorption of CEL in PPT-treated rats as evidenced by a 6.9-h-delayed mean absorption time and only 12% of the systemic exposure of CEL compared with those in normal rats. In contrast, SEDDS/CEL enhanced the oral absorption of CEL with a 14.6-fold higher systemic exposure with significant suppression of delay in absorption than crystalline CEL even in PPT-treated rats. SEDDS/CEL could be an efficacious option for suppressing delay in CEL absorption even under impairment of gastric motility, possibly leading to rapid and reproducible management of severe acute pain.

No Gastrointestinal Dysmotility in Transgenic Mouse Models of Migraine

OBJECTIVE

To determine whether transgenic mouse models of migraine exhibit upper gastrointestinal dysmotility comparable to those observed in migraine patients.

BACKGROUND

There is considerable evidence supporting the comorbidity of gastrointestinal dysmotility and migraine. Gastrointestinal motility, however, has never been investigated in transgenic mouse models of migraine.

METHODS

Three transgenic mouse strains that express pathogenic gene mutations linked to monogenic migraine-relevant phenotypes were studied: CADASIL (Notch3-Tg88), FASP (CSNK1D-T44A), and FHM1 (CACNA1A-S218L). Upper gastrointestinal motility was quantified by measuring gastric emptying and small intestinal transit in mutant and control animals. Gastrointestinal motility was measured at baseline and after pretreatment with 10 mg/kg nitroglycerin (NTG).

RESULTS

No significant differences were observed for gastric emptying or small intestinal transit at baseline for any of the 3 transgenic strains when compared to appropriate controls or after pretreatment with NTG when compared to vehicle.

CONCLUSIONS

We detected no evidence of upper gastrointestinal dysmotility in mice that express mutations in genes linked to monogenic migraine-relevant phenotypes. Future studies seeking to understand why humans with migraine experience delayed gastric emptying may benefit from pursuing other modifiers of gastrointestinal motility, such as epigenetic or microbiome-related factors.

Physicochemical and biopharmaceutical characterization of celecoxib nanoparticle: Avoidance of delayed oral absorption caused by impaired gastric motility

The present study aimed to develop a celecoxib (CEL) nanoparticle with improved dissolution/dispersion and consistent absorption even in the presence of impaired gastric motility. CEL was pulverized by a wet-milling with hydroxypropyl cellulose (HPC), and the prepared nanoparticles were physicochemically characterized after freeze-drying. CEL nanoparticle with HPC-SSL (NP/CEL) exhibited better dissolution/dispersion behavior in pH1.2 solution compared with CEL nanoparticles with other polymers, as evidenced by a 21.8-fold higher initial dissolution/dispersion rate than crystalline CEL. The mean particle diameter of water suspended-NP/CEL was 250 nm, and the CEL nanoparticle existed in an amorphous state. Even after storage at 40 °C for 4 weeks, there were no significant changes in the dissolution/dispersion behavior. Oral absorption of CEL samples (5 mg-CEL/kg) was evaluated in normal and propantheline (PPT)-treated rats with simulated gastric motility impairment. In PPT-treated rats, oral crystalline CEL led to a decrease in oral absorption by 12% of the AUC_0-4 compared with that in normal rats, whereas NP/CEL suppressed the pharmacokinetic transition of CEL by 43% of the AUC_0-4 due to the improved dissolution/dispersion behavior of CEL. The NP/CEL system might be promising to avoid decreased absorption of CEL caused by impaired gastric motility.

A multicenter, open-label, long-term safety and tolerability study of DFN-02, an intranasal spray of sumatriptan 10 mg plus permeation enhancer DDM, for the acute treatment of episodic migraine

BACKGROUND

DFN-02 is a novel intranasal spray formulation composed of sumatriptan 10 mg and a permeation-enhancing excipient comprised of 0.2% 1-O-n-Dodecyl-β-D-Maltopyranoside (DDM). This composition of DFN-02 allows sumatriptan to be rapidly absorbed into the systemic circulation and exhibit pharmacokinetics comparable to subcutaneously administered sumatriptan. Rapid rate of absorption is suggested to be important for optimal efficacy. The objective of this study was to evaluate the safety and tolerability of DFN-02 (10 mg) in the acute treatment of episodic migraine with and without aura over a 6-month period based on the incidence of treatment-emergent adverse events and the evaluation of results of clinical laboratory tests, vital signs, physical examination, and electrocardiograms.

METHODS

This was a multi-center, open-label, repeat-dose safety study in adults with episodic migraine with and without aura. Subjects diagnosed with migraine with or without aura according to the criteria set forth in the International Classification of Headache Disorders, 2nd edition, who experienced 2 to 6 attacks per month with fewer than 15 headache days per month and at least 48 headache-free hours between attacks, used DFN-02 to treat their migraine attacks acutely over the course of 6 months.

RESULTS

A total of 173 subjects was enrolled, 167 (96.5%) subjects used at least 1 dose of study medication and were evaluable for safety, and 134 (77.5%) subjects completed the 6-month study. A total of 2211 migraine attacks was reported, and 3292 doses of DFN-02 were administered; mean per subject monthly use of DFN-02 was 3.6 doses. Adverse events were those expected for triptans, as well as for nasally administered compounds. No new safety signals emerged. Dysgeusia and application site pain were the most commonly reported treatment-emergent adverse events over 6 months (21% and 30.5%, respectively). Most of the treatment-emergent adverse events were mild. There were 5 serious adverse events, all considered unrelated to the study medication; the early discontinuation rate was 22.5% over the 6-month treatment period.

CONCLUSION

DFN-02 was shown to be well tolerated when used over 6 months to treat episodic migraine acutely.

Post Hoc Subanalysis of Two Randomized, Controlled Phase 3 Trials Evaluating Diclofenac Potassium for Oral Solution: Impact of Migraine-Associated Nausea and Prior Triptan Use on Efficacy

Objective

To determine whether baseline nausea or prior triptan treatment for migraine impact the effectiveness of diclofenac potassium for oral solution in treating acute migraine.

Background

A great deal of variability exists in patients' response to migraine medications. Migraine‐associated nausea is common and debilitating and can reduce the effectiveness of oral medications. It may cause patients to delay taking oral medications, which is known to diminish therapeutic outcomes, or to avoid taking them altogether. Gastroparesis, which may be associated with nausea, also inhibits drug absorption, resulting in lower bioavailability. Studies have shown that having nausea at the time of drug administration predicts a poorer response to triptan treatment. It is of interest to understand how effective other migraine medications are in patients with a poor response to triptans.

Methods

Data from two randomized, double‐blind, placebo controlled trials were pooled and post hoc subgroup analyses were performed in patients with and without nausea at baseline, and in patients with and without prior triptan treatment. Efficacy assessments included the percentage of patients who, at 2 hours postdosing, were headache pain‐free (2hPF, primary endpoint), without photophobia, without phonophobia, without nausea, or without a severe degree of disability. A Cochran–Mantel–Haenszel test, stratified by analysis center was used to evaluate treatment effect. Effects of nausea or prior triptan use were determined using logistic regression with factors of treatment group, analysis center, nausea or prior triptan use at time of dosing, and interaction of treatment group by nausea or prior triptan use at time of dosing.

Results

The modified intent to treat population consisted of 1272 patients, 644 on active drug and 628 on placebo. The majority of patients (85%) were female. At the time of dosing, 783 (62%) patients reported nausea with the treated attack. Prior triptan use was recorded in 570 (45%). For headache pain, nausea, photophobia, and phonophobia, patients in the active treatment group had a statistically significantly better response than those receiving placebo, regardless of whether they had nausea at baseline. In logistic regression analysis only treatment group predicted a response for these parameters with no detectable group interaction. Baseline nausea, as well as treatment group, predicted whether patients recorded severe disability at 2 hours. While patients in the active treatment group were significantly more likely to be headache pain‐free at 2 hours after dosing, whether or not they had previously been treated with triptan, more triptan‐naïve patients (30%) than triptan‐experienced patients (20%) were headache pain‐free. Interestingly, in the placebo groups, triptan‐naïve patients were also more likely to be PF (14% vs 7%). In the logistic regression analysis, treatment group predicted a headache pain response, triptan use predicted a lack of response, and there was no interaction between the two. Prior triptan use did not predict any of the other outcome measures.

Conclusions

Nausea at the time of dosing does not diminish the effectiveness of diclofenac potassium for oral solution. The rapid absorption profile may enhance the effectiveness in patients with nausea. Prior triptan use predicted poorer headache response at 2 hours postdose, suggesting the possibility of a subset of patients who are more likely to be refractory to both triptans and diclofenac. Diclofenac potassium for oral solution is effective in triptan‐naïve patients but no reliable inference can be made from this study as to about how to order treatment.

Gastrointestinal disorders associated with migraine: A comprehensive review

Migraine is a recurrent and commonly disabling primary headache disorder that affects over 17% of women and 5%-8% of men. Migraine susceptibility is multifactorial with genetic, hormonal and environmental factors all playing an important role. The physiopathology of migraine is complex and still not fully understood. Many different neuropeptides, neurotransmitters and brain pathways have been implicated. In connection with the myriad mechanisms and pathways implicated in migraine, a variety of multisystemic comorbidities (e.g., cardiovascular, psychiatric and other neurological conditions) have been found to be closely associated with migraine. Recent reports demonstrate an increased frequency of gastrointestinal (GI) disorders in patients with migraine compared with the general population. Helicobacter pylori infection, irritable bowel syndrome, gastroparesis, hepatobiliary disorders, celiac disease and alterations in the microbiota have been linked to the occurrence of migraine. Several mechanisms involving the gut-brain axis, such as a chronic inflammatory response with inflammatory and vasoactive mediators passing to the circulatory system, intestinal microbiota modulation of the enteric immunological milieu and dysfunction of the autonomic and enteric nervous system, have been postulated to explain these associations. However, the precise mechanisms and pathways related to the gut-brain axis in migraine need to be fully elucidated. In this review, we survey the available literature linking migraine with GI disorders. We discuss the possible physiopathological mechanisms, and clinical implications as well as several future areas of interest for research.

A Randomized Trial Comparing the Pharmacokinetics, Safety, and Tolerability of DFN-02, an Intranasal Sumatriptan Spray Containing a Permeation Enhancer, With Intranasal and Subcutaneous Sumatriptan in Healthy Adults

OBJECTIVE/BACKGROUND

Intranasal sumatriptan (Imitrex^® ) may be an alternative for patients who refuse injections and cannot tolerate oral agents, but due to low bioavailability and slow absorption, the clinical utility of the currently marketed formulation is limited, highlighting an unmet need for an effective non-oral migraine medication with a rapid onset of action. To overcome the slow absorption profile associated with intranasal administration, we evaluated the impact of 1-O-n-Dodecyl-β-D-Maltopyranoside (DDM, Intravail A-3™), a permeation enhancer, on sumatriptan's pharmacokinetic profile by comparing the pharmacokinetic characteristics of two commercial sumatriptan products, 4 mg subcutaneous and 6 mg subcutaneous in healthy adults, with DFN-02 - a novel intranasal agent comprised of sumatriptan 10 mg plus 0.20% DDM. We also determined the pharmacokinetic characteristics of DDM and evaluated its safety and tolerability.

METHODS

We conducted two studies: a randomized, three-way crossover study comparing monodose and multidose devices for delivery of single doses of DFN-02 with commercially available intranasal sumatriptan 20 mg in 18 healthy, fasted adults, and an open-label, randomized, single-dose, three-way crossover bioavailability study comparing DFN-02 with 4 mg and 6 mg subcutaneous sumatriptan in 78 healthy, fasted adults. In the study comparing DFN-02 with IN sumatriptan, subjects received a single dose of DFN-02 (sumatriptan 10 mg plus DDM 0.20%) via monodose and multidose delivery systems with at least 5 days between treatments. In the comparison with SC sumatriptan, subjects received a single dose of each treatment with at least 3 days between treatments. In both studies, blood was sampled for pharmacokinetic evaluation of sumatriptan and DDM through 24 hours post-dose; safety and tolerability were monitored throughout.

RESULTS

In the comparison with commercially available intranasal sumatriptan 20 mg, DFN-02 had a more rapid absorption profile; t_max was 15 minutes for DFN-02 monodose, 10.2 minutes for DFN-02 multidose, and 2.0 hours for commercially available intranasal sumatriptan 20 mg. Compared with 4 and 6 mg subcutaneous sumatriptan, DFN-02's median t_max (10 minutes) was significantly earlier (15 minutes; P < .0001). Mean sumatriptan exposure metrics were similar for DFN-02 and 4 mg sumatriptan: AUC_0-2 : 35.12 and 44.82 ng*hour/mL, respectively; AUC_0-∞ : 60.70 and 69.21 ng*hour/mL, respectively; C_max : 51.79 and 49.07 ng/mL, respectively. With 6 mg subcutaneous sumatriptan, these exposure metrics were about 50% larger (AUC_0-2 : 67.17 ng*hour/mL; AUC_0-∞ : 103.78 ng*hour/mL; C_max : 72.75 ng/mL). Inter-subject variability of AUC_0-2 , AUC_0-∞ , and C_max was 42-58% for DFN-02, 15-22% for 4 mg subcutaneous sumatriptan, and 15-25% for 6 mg subcutaneous sumatriptan. DDM exposure was low (mean C_max : 1.63 ng/mL), t_max was 30 minutes, and it was undetectable by 4 hours. There were no serious adverse events, discontinuations due to adverse events, or remarkable findings for vital signs, physical examinations (including nasal and injection site examinations), or clinical laboratory assessments. The overall incidence of adverse events was comparable across treatments, and all treatment-related events were mild in severity. Adverse events occurring in ≥10% of subjects were dysgeusia (19%), headache (18%), nausea (15%), paresthesia (15%), and dizziness (12%).

CONCLUSIONS

In healthy subjects, DFN-02, an intranasal spray containing 10 mg sumatriptan plus DDM, had a more rapid absorption profile than commercially available intranasal sumatriptan 20 mg, and systemic exposure from a single-dose administration of DFN-02 was similar to 4 mg SC sumatriptan and two-thirds that of 6 mg SC sumatriptan. With DFN-02, plasma sumatriptan peaked 5 minutes earlier than with both subcutaneous formulations. Systemic exposure to sumatriptan was similar with DFN-02 and 4 mg subcutaneous sumatriptan; both yielded lower systemic exposure than 6 mg subcutaneous sumatriptan. Systemic exposure to DFN-02's excipient DDM was short-lived. DFN-02's safety and tolerability appear to be comparable to subcutaneous sumatriptan. Addition of a permeation enhancer improved the absorption profile compared with commercially available intranasal sumatriptan 20 mg.

Delayed absorption of many (paracetamol, aspirin, other NSAIDs and zolmitriptan) but not all (sumatriptan, rizatriptan) drugs during migraine attacks and most likely normal gastric emptying outside attacks. A review

Background In most pharmacokinetic studies, the oral absorption of drugs is impaired during migraine attacks but exceptions occur. A study on gastric emptying using gastric scintigraphy indicated that gastric stasis also occurs interictally in migraine. These studies were reviewed critically. Results In seven studies, mainly investigating NSAIDs and analgesics, the early absorption of the drugs during 112 migraine attacks was delayed. The absorption of sumatriptan is usual in therapeutic doses, and rizatriptan was normal during 131 migraine attacks. The interictal gastric stasis observed using gastric emptying scintigraphy (GES) with solids ( n = 13) could not be confirmed in a larger study ( n = 27) using the same method. Also gastric emptying measured with GES with liquids ( n = 7) and epigastric impedance ( n = 64) was normal outside migraine attacks. Conclusions and possible clinical implications Drug absorption is not generally impaired during migraine attacks. Gastric emptying is most likely normal in the majority of migraine patients outside attacks. Prokinetic and antiemetic drugs such as metoclopramide and domperidone should not be routinely combined with oral analgesics or oral triptans. If, however, nausea is severe or vomiting occurs, treatment with an antiemetic with proven efficacy on the nausea of migraine can be indicated.

Migraineurs Initially Visiting the Gastroenterology Department

BACKGROUND AND OBJECTIVES

Migraine-related nausea and vomiting are usually associated with severe and debilitating headache. However, there are unique headache patients with a chief complaint of prominent gastrointestinal (GI) discomfort, instead of headache. We sought to investigate distinctive characteristics and clinical outcomes of such patients, compared to migraine patients initially visiting headache clinic.

METHODS

This was a retrospective case-control study using a headache registry from April 2012 to December 2013. Case subjects were defined as patients who had first visited the gastroenterology clinic with chief complaint of nausea and/or vomiting, but then referred to the headache clinic for evaluation and management of concurrent headache. They were 1:2 matched to control subjects who met the migraine criteria based on propensity scores adjusted for age, sex, aura, headache frequency, and headache intensity.

RESULTS

We identified 51 case subjects, of which 80.4% were compatible with the migraine criteria. In multivariate testing, the case subjects were inversely associated with family history of headache (odds ratios [OR]: 0.36, 95% confidence interval [CI]: 0.13-0.99), alcohol drinking (OR: 0.18, 95% CI: 0.05-0.69), and aggravation by physical activity (OR: 0.19, 95% CI: 0.08-0.43). The proportions of subjects with a favorable clinical outcome in migraine management did not differ between the case and control groups (82.2% vs 79.1%, P = .670).

CONCLUSIONS

Primary symptoms of the case subjects had been GI; however, migraine management was most effective in relieving both prominent GI discomfort and headache. Our findings suggest that physicians should consider and investigate for the presence of migraine in patients with prominent GI symptoms and concurrent headache.

Why triptan treatment can fail: focus on gastrointestinal manifestations of migraine

BACKGROUND

Results of randomized, double-blind, controlled studies establish the efficacy of triptans in the acute treatment of migraine, but triptan benefits demonstrated in clinical trials have not consistently been realized in clinical practice. This paper explores the contribution of gastrointestinal manifestations of migraine--namely nausea (with or without vomiting) and gastroparesis--to triptan treatment failure.

SYNTHESIS

Migraine-related nausea and vomiting and migraine-associated gastroparesis appear to be prevalent and highly impactful and have been characterized as being among the greatest challenges affecting migraine care today. These gastrointestinal signs and symptoms have not been satisfactorily taken into account in the management of migraine, which is dominated by the use of oral therapies. Oral triptans are not the optimal therapy in the presence of migraine-related nausea because nausea predicts poor response to oral triptans and because nausea can cause patients to delay oral treatment, which can further compromise therapeutic efficacy. Oral triptans are not the optimal therapy in the presence of migraine-associated gastroparesis because these agents rely on gastric motility and gastrointestinal absorption and may be ineffective or slowly or inconsistently effective in the presence of gastroparesis. Health care providers need to work with their patients to address the still-all-too-frequent problem of treatment failure in migraine. First, health care providers need to have greater appreciation of the importance of nausea, vomiting, and gastroparesis as factors affecting migraine prognosis and treatment success. Second, health care providers need to systematically assess migraine patients for gastrointestinal signs and symptoms. Finally, patients and health care providers need to be willing to practice customized migraine care, in which patients tailor the treatment and formulation to the characteristics and context of the individual migraine episode.

Gastrointestinal manifestations of migraine: meeting the treatment challenges

Nausea is a defining feature of episodic migraine. Migraine-associated nausea can cause patients to delay or avoid taking oral medication. In April 2011, a round table of headache specialists and a gastroenterologist was convened to explore unmet needs in the treatment of migraine vis-à-vis gastrointestinal signs and symptoms. This supplement summarizes the proceedings of that roundtable meeting.

Migraine and gastroparesis from a gastroenterologist's perspective

Gastroparesis is a chronic stomach disorder manifested by delayed emptying of solids and liquids without evidence of mechanical obstruction. Evidence from pharmacokinetic and gastric motor studies conducted over the past 40 years shows that delayed gastric emptying often occurs in migraine. This paper provides a general overview of gastroparesis for the headache specialist, discusses the research on the association of gastroparesis and migraine, and considers the clinical implications of that association. The nature, causes, correlates, and consequences of gastric stasis in migraine are just beginning to be elucidated; much further study is warranted. The data available to date show that gastric stasis in migraine appears to be clinically important. Evidence from both pharmacokinetic studies and studies measuring gastric motor function suggests that gastric stasis may delay absorption of an orally administered drug, delay its peak serum concentrations, and delay its effectiveness. These results suggest that oral migraine medications, which rely on absorption from the gastrointestinal tract, may be affected in the presence of migraine-associated gastric stasis. Several non-oral formulations that do not rely on gastrointestinal absorption are available or in development for the treatment of migraine and symptoms of gastroparesis.

Changes in liquid emptying in migraine patients: diagnosed with liquid phase gastric emptying scintigraphy

Gastric stasis is suspected mostly to be encountered during acute migraine attack. The aim of this study is to evaluate the liquid phase gastric emptying and motility in migraine patients in ictal and interictal periods in comparison to normal subjects with gastric emptying scintigraphy. Seven women with migraine and age, sex matched controls who applied to the Neurology Department from May 2009 to May 2010 were compared. Gastric emptying study with a standard liquid was performed one time in the non-migraineur group and two times in the migraineur group. Non-migraineur controls and migraineurs were compared. The mean T1/2 was longer in ictal period in migraineurs. The T1/2 of migraineurs interictally and the control groups were similar. The T1/2 of migraineurs ictally and migraineurs interictally were also compared. We also considered the percentage of the radioactive material remaining in the stomach. There were no significant differences between non-migraineurs and migraineurs interictally. However, increased amount of radioactive material remaining in the stomach was observed in migraineurs ictally. We concluded that the liquid emptying was delayed in spontaneous migraine attacks in migraine without aura, however in the interictal period the emptying of liquids did not differ between migraineurs and non-migraineurs.

Improved pharmacokinetics of sumatriptan with Breath Powered™ nasal delivery of sumatriptan powder

Objectives.—

The purpose of this study was to directly compare the pharmacokinetic (PK) profile of 22-mg sumatriptan powder delivered intranasally with a novel Breath Powered™ device (11 mg in each nostril) vs a 20-mg sumatriptan liquid nasal spray, a 100-mg oral tablet, and a 6-mg subcutaneous injection.

Background.—

A prior PK study found that low doses of sumatriptan powder delivered intranasally with a Breath Powered device were efficiently and rapidly absorbed. An early phase clinical trial with the same device and doses found excellent tolerability with high response rates and rapid onset of pain relief, approaching the benefits of injection despite significantly lower predicted drug levels.

Methods.—

An open-label, cross-over, comparative bioavailability study was conducted in 20 healthy subjects at a single center in the USA. Following randomization, fasted subjects received a single dose of each of the 4 treatments separated by a 7-day washout. Blood samples were taken pre-dose and serially over 14 hours post-dose for PK analysis.

Results.—

Quantitative measurement of residuals in used Breath Powered devices demonstrated that the devices delivered 8 ± 0.9 mg (mean ± standard deviation) of sumatriptan powder in each nostril (total dose 16 mg). Although the extent of systemic exposure over 14 hours was similar following Breath Powered delivery of 16-mg sumatriptan powder and 20-mg liquid nasal spray (area under the curve [AUC]0-∞ 64.9 ng*hour/mL vs 61.1 ng*hour/mL), sumatriptan powder, despite a 20% lower dose, produced 27% higher peak exposure (Cmax 20.8 ng/mL vs 16.4 ng/mL) and 61% higher exposure in the first 30 minutes compared with the nasal spray (AUC0-30 minutes 5.8 ng*hour/mL vs 3.6 ng*hour/mL). The magnitude of difference is larger on a per-milligram basis. The absorption profile following standard nasal spray demonstrated bimodal peaks, consistent with lower early followed by higher later absorptions. In contrast, the profile following Breath Powered delivery showed higher early and lower late absorptions. Relative to the 100-mg oral tablet (Cmax 70.2 ng/mL, AUC0-∞, 308.8 ng*hour/mL) and 6-mg injection (Cmax 111.6 ng/mL, AUC0-∞ 128.2 ng*hour/mL), the peak and overall exposure following Breath Powered intranasal delivery of sumatriptan powder was substantially lower.

Conclusions.—

Breath Powered intranasal delivery of sumatriptan powder is a more efficient form of drug delivery, producing a higher peak and earlier exposure with a lower delivered dose than nasal spray and faster absorption than either nasal spray or oral administration. It also produces a significantly lower peak and total systemic exposure than oral tablet or subcutaneous injection.

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.

Painful heat reveals hyperexcitability of the temporal pole in interictal and ictal migraine States

During migraine attacks, alterations in sensation accompanying headache may manifest as allodynia and enhanced sensitivity to light, sound, and odors. Our objective was to identify physiological changes in cortical regions in migraine patients using painful heat and functional magnetic resonance imaging (fMRI) and the structural basis for such changes using diffusion tensor imaging (DTI). In 11 interictal patients, painful heat threshold + 1°C was applied unilaterally to the forehead during fMRI scanning. Significantly greater activation was identified in the medial temporal lobe in patients relative to healthy subjects, specifically in the anterior temporal pole (TP). In patients, TP showed significantly increased functional connectivity in several brain regions relative to controls, suggesting that TP hyperexcitability may contribute to functional abnormalities in migraine. In 9 healthy subjects, DTI identified white matter connectivity between TP and pulvinar nucleus, which has been related to migraine. In 8 patients, fMRI activation in TP with painful heat was exacerbated during migraine, suggesting that repeated migraines may sensitize TP. This article investigates a nonclassical role of TP in migraineurs. Observed temporal lobe abnormalities may provide a basis for many of the perceptual changes in migraineurs and may serve as a potential interictal biomarker for drug efficacy.

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

Triptans, selective 5-HT1B/1D receptor agonists, are specific drugs for the acute treatment of migraine that have the same mechanism of action. Here, it is discussed why the differences among kinetic parameters of oral triptans have proved not to be very important in clinical practice. There are three main reasons: (1) the differences among the kinetic parameters of oral triptans are smaller than what appears from their average values; (2) there is a large inter-subject, gender-dependent, and intra-subject (outside/during the attack) variability of kinetic parameters related to the rate and extent of absorption, i.e., those which are considered as critical for the response; (3) no dose-concentration–response curves have been defined and it is, therefore, impossible both to compare the kinetics of triptans, and to verify the objective importance of kinetic differences; (4) the importance of kinetic differences is outweighed by non-kinetic factors of variability of response to triptans. If no oral formulations are found that can allow more predictable pharmacokinetics, the same problems will probably also arise with new classes of drugs for the acute treatment of migraine.

A randomized, double blind, placebo-controlled study of MAP0004 in adult patients with migraine

BACKGROUND

Dihydroergotamine mesylate (DHE) is an effective treatment for acute migraine, but its effective use is often limited by the inconvenience and inconsistency of intranasal, intramuscular, or subcutaneous routes of administration. A new formulation of DHE delivered through the lungs by the novel Tempo inhaler is being developed and is designed to offer fast onset, consistent dosing, and sustained response.

OBJECTIVE

This proof of principle and dose setting study evaluated the efficacy and tolerability of inhaled DHE delivered by a breath-synchronized, plume-controlled inhaler (Tempo) in adult migraineurs.

METHODS

This was a randomized, double blind, placebo-controlled, 2-period study conducted at 9 headache centers in the United States. Adult men and women with a documented history of acute migraine for at least 12 months, with an average of 2 to 8 attacks per month in the preceding 6 months were treated with MAP0004 0.5 or 1.0 mg systemic equivalent dose (1.0 or 2.0 mg nominal dose) or matching placebo during Treatment Period 1 (TP1). Patients who responded to treatment during TP1 were re-randomized in Treatment Period 2 (TP2) to receive MAP0004 0.25 mg systemic equivalent dose or placebo.

RESULTS

Of 86 patients randomized to treatment, 69 were included in the As-Treated population in TP1. Pain relief at 2 hours was greater for MAP0004 0.5 mg (72%, P = .019) and 1.0 mg (65%, P = .071) than for placebo (33%). Pain relief at 10 (32%), 15 (46%), and 30 (55%) minutes was significantly (P < .05) greater with MAP0004 0.5 mg than with placebo (0%, 7% and 14%, respectively). Pain-free at 2 hours was significantly greater with MAP0004 0.5 mg (44%, P = .015) and 1.0 mg (35%, P = .050) than with placebo (7%). Total migraine relief at 2 hours was significantly (P = .019) greater with MAP0004 0.5 mg (72%) than with placebo (33%). Sustained pain relief and pain-free rates exhibited a therapeutic gain of 30% (P = .066) and 31% (P = .037) at 24 hours and 28% (P = .096) and 30% (P = .057) at 48 hours with MAP0004 0.5 mg vs placebo. MAP0004 was well tolerated with no serious or severe adverse events. Dysgeusia was reported as treatment-related in 2 patients on placebo, 0 patients on MAP0004 0.5 mg, and 6 patients on MAP0004 1.0 mg. No clinically relevant changes were noted in spirometry, vital signs, electrocardiogram, or clinical laboratory values. No significant differences between treatments were observed in TP2.

CONCLUSIONS

In this study MAP0004 0.5 mg and 1.0 mg were well tolerated and effective at delivering clinically significant, rapid, and sustained pain relief in adult migraine patients. No additional benefit was observed with the higher dose, thus the MAP0004 0.5 mg systemic equivalent dose has been selected as the dose for further clinical study.

Relevance of absorption rate and lag time to the onset of action in migraine

OBJECTIVE

The objective of this analysis was to simulate the performance of oral triptan formulations with varying absorption characteristics and their impact on the onset and magnitude of the antimigraine effect using a Markov model for migraine attacks.

ANALYSIS

Sumatriptan pharmacokinetic data were obtained from clinical pharmacology studies in which marketed solid formulations were administered. Based on a population pharmacokinetic model, mean concentration-time profiles were generated by varying the absorption rate constant and lag time. Subsequently, the simulated profiles were evaluated in a disease model of migraine to predict the onset and duration of the effect (the pain-free, pain-relief response).

RESULTS

Based on a therapeutic dose of 50 mg of sumatriptan, a maximum gain in the pain-free response of 12% was achieved with an increased absorption rate. This gain in the response was reached approximately 0.5 hours after administration. A decrease only in the lag time with respect to the currently available formulations (i.e. 0.24 hours) resulted in a maximum gain of 5% in the pain-free response, which in contrast may not be interpreted as clinically relevant.

CONCLUSION

Model-based predictions suggest that increases in the absorption rate of the currently marketed oral formulation of sumatriptan result in a gain in the pain-free response that is both clinically and statistically relevant.

Cyclic vomiting syndrome: what a gastroenterologist needs to know

BACKGROUND

CVS (cyclic vomiting syndrome) is a functional disorder that may occur in any age group of patients. In the past the disorder was considered to be fairly uncommon of unknown etiology. Treatment has generally been based on anecdotal reports.

METHODS

Literature review was performed based on internet/Medline search as of April 2006.

RESULTS

CVS is much more common than previously thought, especially in adults and is commonly associated with migraine headaches and sharing many of its characteristic features. Genetic association with mitochondrial DNA has been recognized with CVS. Prompt diagnosis is essential in order to prevent the significant morbidity associated with CVS. It is mandatory to rule out certain life-threatening disorders that can mimic CVS. Treatment options are based on the particular phase of the syndrome in which a patient is in and carried out in a systematic manner.

CONCLUSION

Expert consensus is that CVS is a distinct disorder and is a part of the migraine spectrum (migraine headaches, CVS, and abdominal migraines). Once patients are properly diagnosed, treatment is highly effective. Because of renewed interest in CVS since the 1990's, many more patients in all age groups are being recognized who suffer from this disabling disorder. An increase in basic science and clinical research in CVS will hopefully lead to better patient outcomes.

Gastric stasis occurs in spontaneous, visually induced, and interictal migraine

OBJECTIVE

To evaluate and compare gastric motility and emptying during spontaneous migraine to previous observations from induced migraine.

BACKGROUND

We have previously demonstrated a delay in gastric emptying both during the interictal period and during an induced migraine. A limitation noted in these studies was whether there are differences gastrointestinally during a visually induced migraine compared to spontaneous migraines. To address this, 9 additional studies have been performed to ascertain if there is a similar delay during spontaneous migraine

METHODS

Gastric scintigraphy using a standard meal was performed in 3 subjects during 3 periods: spontaneous migraine, induced migraine, and interictal period.

RESULTS

On average, the time to half emptying was delayed during spontaneous migraine (124 minutes), during induced migraine (182 minutes), and during the interictal period migraine (243 minutes) compared to normative values established at our center (112 minutes). On average, similar gastric slowing was seen in all 3 groups when the percentage of nuclear material remaining in the stomach at 2 hours was measured.

CONCLUSIONS

This study provides additional evidence of gastric stasis in migraineurs interictally during induced and spontaneous migraine.

Gastric stasis in migraine: more than just a paroxysmal abnormality during a migraine attack

OBJECTIVE

The aim of this article is to evaluate gastric motility and emptying in the ictal and interictal period in migraine.

BACKGROUND

Nausea is a predominant symptom of migraine and the basis of it is thought to be gastric stasis. Objective methods to establish this are however lacking. We utilized gastric scintigraphy studies to determine gastric motility in the ictal and interictal period of migraine.

METHODS

Ten migraine subjects were compared to equal number of age and sex matched controls. Gastric scintigraphy using a standard meal was performed in all control subjects once and in all 10 migraine subjects in the interictal period and nine studies were performed in the ictal period migraine.

RESULTS

The time to half emptying was delayed in migraine ictally (78%) and interictal period (80%) using normative data at this institution. Gastric stasis was less pronounced ictally (149.9 minutes) compared to interictal period (188.8 minutes). There was a significant delay compared to nonmigrainous controls (migraine 188.8 minutes vs normal controls 111.8 minutes; P < .05). These data were replicated in percentage of radioactive material remaining in the stomach at 2 hours.

CONCLUSIONS

Contrary to previous belief, this study has demonstrated that migraineurs suffer from gastric stasis both during and outside an acute migraine attack. This may suggest that migraineurs may have an abnormal autonomic function compared to nonmigrainous controls. The potential role of this in pathophysiology of migraine is discussed and avenues for further investigations are explored.

Zolmitriptan Intranasal: A Review of the Pharmacokinetics and Clinical Efficacy

Migraine is a common disabling neurological disorder, associated with headache, nausea, and on occasions vomiting. Zolmitriptan is a widely available serotonin 5HT(1B/1D) receptor agonist with a long track record in clinical studies and in the treatment of acute migraine. A nasal formulation has been developed that has clear evidence for local absorption, resulting in plasma drug concentrations within 2 minutes of dosing, central nervous system penetration 3 minutes later, and a significant efficacy benefit versus placebo 10 to 15 minutes after dosing. Intranasal zolmitriptan offers advantages to migraineurs, particularly those seeking a more rapid onset of effect without wishing to self-inject, or those with gastrointestinal upset. The comparison of pharmacokinetic and clinical data available from different formulations of zolmitriptan contributes both to the understanding of its mode of action and the characteristics required of an acute migraine treatment if it is to meet patient needs.

Uncertainty Analysis in Pharmacokinetics and Pharmacodynamics: Application to Naratriptan

PURPOSE

The aim of the study was to predict pain relief of migraine in patients following naratriptan oral (tablet) administration by using uncertainty analysis. The analysis was based on phase I pharmacokinetic naratriptan data, sumatriptan pharmacodynamic data, and naratriptan preclinical (animal) potency information, together with general knowledge as to how migraine affects oral absorption.

METHODS

A previously developed pharmacokinetic (PK)/pharmacodynamic (PD) model for naratriptan disposition and effect was used. The uncertain parameters in the model, which were associated with absorption and scaling between first-in-class compound sumatriptan and naratriptan, were modeled using fuzzy sets theory. Global sensitivity analysis was then used to investigate the impact of each PK/PD parameter on the responses.

RESULTS

Acknowledging parametric uncertainty did not improve prediction of the probability of pain relief. Global sensitivity analysis demonstrated that predictions were heavily influenced by interindividual variability in pharmacodynamics, as the dose response relationship was relatively insensitive to the pharmacokinetics.

CONCLUSIONS

To predict the probability of pain relief following oral (tablet) administration of naratriptan, a simple dose response, instead of the PK/PD model, would have yielded very similar predictions. The naratriptan PK/PD model may be improved by either refining the PD model or better still by specifying the interindividual error by additional data collecting with an improved design.

Pharmacokinetics and tolerability of different doses of fentanyl following sublingual administration of a rapidly dissolving tablet to cancer patients: a new approach to treatment of incident pain

AIMS

It is estimated that two-thirds of cancer patients will at some point during their illness experience breakthrough pain. In this study, the pharmacokinetics of a novel sublingual dosage form of fentanyl developed for breakthrough pain was evaluated.

METHODS

Eleven Caucasian patients (seven male and 4 female, aged 34-75 years, median 60 years) with metastatic malignant disease were recruited initially, but three patients withdrew. Prior to the study all patients were on continuous nonfentanyl opiate medication. The study was a double-blind, cross-over trial, consisting of three 1-day treatment periods. A new rapidly dissolving preparation of fentanyl, was administered sublingually in single doses of 100, 200 and 400 microg, respectively, on three separate occasions. Plasma fentanyl concentrations were determined using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Pharmacokinetic parameters were calculated by noncompartment analysis. Tolerability and the occurrence of adverse events were monitored throughout the study by patient questionnaire.

RESULTS

The data from nine subjects who completed at least two periods were used in the analysis of variance. There were no significant differences between doses (100, 200 and 400 microg) for dose adjusted AUC (F = 0.42, P = 0.6660), dose adjusted C(max) (F = 0.08, P = 0.9206) and Tmax (F = 0.94, P = 0.4107). Thus, these parameters showed dose proportionality. The differences (400-100microg) in dose adjusted AUC from the three-period crossover analysis was -0.016 min.ng/ml (t = 0.71, P = 0.8718). Interindividual variability in systemic exposure to fentanyl was fairly small (25-40%), which may be related to a good in vivo biopharmaceutical performance of the sublingual tablet, and a relatively small fraction of the dose being swallowed. The first detectable plasma concentration of fentanyl was observed between 8 and 11 min after administration. t(max) increased from 39.7 +/- 17.4 to 48.7 +/- 26.3 and 56.7 +/- 24.6 min for the 100, 200 and 400 microg doses, respectively. Adverse events were few and did not increase with increasing dose.

CONCLUSION

With this rapidly dissolving fentanyl formulation, the first detectable plasma concentration of fentanyl was observed at 8-11 min after administration. The pharmacokinetics of the drug showed dose proportionately. This formulation of fentanyl seemed to be well tolerated by the patients.

Migraine mechanism and management

Migraine affects an estimated 10% to 15% of the population with greater or lesser regularity and throughout much of their lifetime. It causes disability, be it often temporary, and strains personal relationships and professional development. Little is known about it scientifically, and its treatment remains mostly empirical. This article describes the pathogenesis of migraine, as well as its management in terms of abortive and preventive treatment.

The changing face of migraine

Migraine is a major source of pain-related disability. Despite the personal and societal impact of this disorder, migraine continues to be misdiagnosed and undertreated even though well-established diagnostic criteria and safe and effective treatments are available. The recent revision of diagnostic criteria for headache diagnosis and consensus guidelines for migraine treatment hopefully will promote better medical care for headache sufferers. Advancements in understanding the neurobiology of migraine will guide the development of new treatments.

Newer formulations of the triptans: advances in migraine management

Migraine is a common, frequently incapacitating, headache disorder that imposes a substantial burden on both the individual patient and society. The last two decades have witnessed an explosion in our understanding of the pathophysiology of migraine, and in our development of an efficacious and diverse therapeutic armamentarium. There are several routes of drug administration available to patients with migraine. All the serotonin 5-HT(1B/1D) receptor agonists (triptans) are available as oral tablets (sumatriptan, rizatriptan, zolmitriptan, naratriptan, almotriptan, frovatriptan and eletriptan). Only sumatriptan is available as a subcutaneous injection. Some triptans are also available via newer routes of administration, including orally disintegrating tablets (rizatriptan and zolmitriptan), rectal suppositories (sumatriptan) and intranasal sprays (sumatriptan and zolmitriptan). Oral disintegrating tablets and other non-oral triptan routes (subcutaneous, intranasal, rectal) are a useful alternative to conventional oral tablets for patients who have difficulty swallowing pills or prefer not to do so, and for patients whose nausea and/or vomiting precludes swallowing tablets and/or makes the likelihood of complete absorption unpredictable. This is important because epidemiological studies in migraine reveal that the vast majority of patients (>90%) have experienced nausea during a migraine attack and more than 50% have nausea with the majority of attacks. Similarly, most (almost 70%) have vomited at some time during an attack and of these patients, almost one-third vomit in the majority of attacks. The newer formulations, rapidly dissolving tablets and intranasal sprays, afford patients the opportunity to use abortive therapy without the need for liquids, at anytime and anywhere, at the onset of a migraine attack. Furthermore, the intranasal sprays are absorbed rapidly and have a prompt onset of action allowing for significant pain free rates versus placebo as early as 15 minutes post administration. The ability to administer treatment early in a migraine attack and have a rapid onset of action is particularly important in acute migraine treatment in order to prevent the development of central sensitisation. While many patients and physicians choose conventional oral tablets because of familiarity and ease of administration, the newer formulations, oral disintegrating tablets and intranasal sprays, should be given consideration as first-line agents in selected patients.

Mechanism and management of migraine

Migraine is a condition that affects 10%-15% of the population. Abortive treatment is always indicated because the intense headaches interfere with normal functioning. Preventive treatment is indicated when the headaches exceed 3-4 per month.

Introduction: a welcome to the First Special Animal Health Issue of AAPS PharmSci

The goal of this special volume is to provide veterinary scientists with state-of-the art reviews in animal health and to inform human health scientists of the various challenges and collaborative opportunities associated with their animal health counterparts. The contributors are highly respected experts, providing invaluable insights into current issues and state-of-the-art advances within veterinary medicine.

Gastric motor effects of triptans: open questions and future perspectives

Sumatriptan is a 5-HT1B/D receptor agonist of documented efficacy in relieving migraine and associated symptoms such as nausea and vomiting. In the past decade, several studies reported an important delay of gastric emptying induced by sumatriptan in healthy humans. The impact of this gastric motor effect of sumatriptan in migraineurs is difficult to predict: a further delay in gastric emptying could be detrimental (i.e. increased nausea and epigastric symptoms) in patients already having delayed gastric emptying. However, in patients with functional dyspepsia, sumatriptan is also reported to improve gastric accommodation to a meal and reduce perception of gastric distention, hence relieving epigastric symptoms. Thus, reduced visceral perception could be a mechanism involved in reducing nausea during a migraine attack. Paradoxically, sumatriptan is reported both to relieve the nausea of a migraine attack and to have nausea as a side effect. Although careful analysis of the time of onset of nausea may offer a clue as to the origin of this symptom, available data do not support definite conclusions, all the more so because the gastric motor effect of second-generation triptans are still unexplored. Taken together, the available evidence warrants further studies to clarify the following issues: first, the mechanism responsible for the gastric motor effect of sumatriptan [receptor subtype(s) involved; central vs peripheral mechanism]; secondly, the effects on gastric motility/visceral sensitivity of second-generation triptans (which are 5-HT1B/D receptor agonists) and more recent selective 5-HT1D receptor agonists (proposed as investigational antimigraine agents with less potential to induce coronary vasoconstriction through 5-HT1B receptors); finally, the possible use of drugs improving gastric accommodation to a meal in the management of those dyspeptic patients with impaired fundic relaxation/altered visceral sensitivity.

Symptomatic pharmacotherapy of migraine

This review summarizes data on the effectiveness of various symptomatic migraine pharmacotherapies and makes recommendations for treatment. A wide variety of agents are available for the symptomatic treatment of migraine headache, including over-the-counter analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), combination products, opiates, ergot alkaloids, corticosteroids, dopamine antagonists, and triptans. In the stepped-care approach, simple analgesics and NSAIDs are the recommended first step for the treatment of mild-to-moderate migraine headaches. Patients who do not respond to first-step treatments may be given ergots, combination products, dopamine antagonists, or triptans as the second step. Corticosteroids or opiates may be used as rescue treatment in patients who do not respond to second-step treatment. A stratified approach to care individualizes treatment based on the severity of the headache and other patient-specific factors. In a stratified approach, dihydroergotamine or triptans may be the first-step treatment for patients who present with a history of severe migraines that have responded poorly to previous treatments. Sumatriptan was the first triptan approved for the symptomatic treatment of migraine headache; newer triptans include zolmitriptan, naratriptan, and rizatriptan. Since sumatriptan is rapidly absorbed by the subcutaneous route, its time to onset of effect is shortest. Among triptan drugs that are administered orally, the relative time to onset may be shorter with rizatriptan than sumatriptan. Naratriptan has a longer time to onset but is associated with a lower rate of migraine recurrence than other triptans. graine headache, ergot alkaloids, triptans,

Mixed effect modeling of sumatriptan pharmacokinetics during drug development: II. From healthy subjects to phase 2 dose ranging in patients

Sumatriptan is indicated for the treatment of migraine attack and cluster headache; it is currently marketed as a subcutaneous injection, nasal spray, and oral tablet. New formulations are under consideration. The knowledge of sumatriptan absorption, combined with PK/PD information would help the design of more efficient formulations. In this perspective, we attempted to model the absorption of sumatriptan by population PK analysis. Data following administration by the intravenous (i.v.), the subcutaneous (s.c.), and the oral (po) route in healthy subjects were analyzed. A large database with full kinetic profiles was constituted. Sumatriptan was administered to 215 healthy subjects (i.v., s.c., and po) and to 143 migraine sufferers (po). The mean age was 31 years (18-86 years) in healthy subject population and was 38 years (18-65 years) in migraine patients. The mean weights were 74 kg (54-104 kg) and 66 kg (38-136 kg) in healthy subjects and migraine patients, respectively, and the mean heights were 176 cm (157-193 cm) and 164 cm (152-183 cm) in healthy subjects and migraine patients, respectively. A NONMEN analysis was performed using a two-compartment disposition model. Oral absorption was modeled with a first-order input followed by a zero-order input. Less biased results were obtained using the FOCE method. The total clearance and the distribution volume at steady state were 71.2 L/hr and 94.5 L after i.v. dosing and 68.7 L/hr and 109 L after inclusion of the s.c. and po data. The absorption phase appeared to last for about 5 hr. The interindividual variability of the main PK parameters was low: It was around 20% for the total clearance and around 30% for the distribution volume at steady state. Although significant, the combination of age and height on clearance did not decrease considerably the interindividual variability of this parameter (decrease of 2.2%); nor was it possible to establish clearly if a migraine attack has an effect on drug absorption because of the sampling scheme during absorption. Simulations have shown that it would have been possible to estimate all the PK parameters with a data set reduced to one quarter of its actual number of samples.

Pharmacokinetic profile of alniditan nasal spray during and outside migraine attacks

AIMS

To compare the pharmacokinetic profile of intranasal alniditan during and outside migraine attacks, and to investigate the relationship between initial rise of alniditan plasma concentration, and headache improvement.

METHODS

Twenty-seven migraine patients (age: 18-65 years) were randomized to receive alniditan 2 mg or 4 mg, and investigated both during and outside a migraine attack. Maximal plasma concentrations (Cmax), time to Cmax (tmax), and the area under the curve over 2 h (AUC(0,2 h)), were calculated from the individual plasma concentration-time profile, obtained from 10 blood samples in each patient, during each of the two administrations.

RESULTS

Alniditan was rapidly absorbed into the systemic circulation (tmax=11 min). All investigated pharmacokinetic parameters (Cmax, tmax, AUC(0,2 h)) were similar during and outside migraine attacks, both in the 2 mg (n = 13) and the 4 mg group (n = 14). In the 4 mg group, during attacks, mean plasma alniditan concentration at 5 min after administration (Ct=5) in responders (21+/-16 ng ml(-1); n=10) was significantly higher than the Ct=5 in nonresponders (3+/-3 ng ml(-1); P=0.01; n=4). However, the Cmax and AUC(0,2 h) in responders (33+/-18 ng ml(-1) and 12+/-6 ng ml(-1) h) were also significantly higher than the Cmax and AUC(0,2 h) in nonresponders (13+/-9 ng ml(-1); P=0.048 and 5+/-3 ng ml(-1) h; P=0.03).

CONCLUSIONS

Absorption of alniditan nasal spray was not affected by migraine attacks, although 95% confidence intervals were wide. Early rise of plasma concentrations and the amount of drug in the circulation were related to headache improvement in the higher dose group.