Intranasal medications for the treatment of migraine and cluster headache

Reduction of pain and functional disability over time in patients treated with zavegepant: a post-hoc analysis of the BHV3500-301 phase 3 randomized controlled trial

BACKGROUND

Migraine is a disabling disorder that impacts 40 million people in the US. Zavegepant is the first calcitonin gene-related peptide (CGRP) receptor antagonist nasal-spray approved for the acute treatment of migraine with or without aura in adults. This study aimed to evaluate the proportion of patients in various pain and functional disability states over 48-h, for patients treated with zavegepant 10 mg nasal-spray versus placebo.

METHODS

This post-hoc analysis included adult patients with > 1-year history of migraine from BHV3500-301 (NCT04571060): a phase 3 double-blind, randomized, placebo-controlled, single-attack study. Over 48-h, pain severity and functional disability were captured at various timepoints (pre- and post-dosing). The proportion of patients at each pain severity or functional disability state and the time spent in each category was calculated. These were analyzed for patients with complete timepoint data available and using missing not at random (MNAR) imputation for missing timepoints. Predictors of functional disability were assessed using a mixed-effects logistic regression model.

RESULTS

There were 1,269 patients included in the MNAR imputation analysis, and between 630-641 in the complete-case analysis. As early as 15-min post-dose, a larger proportion of zavegepant patients achieved no/mild pain compared to placebo, despite balanced migraine severity pre-dose. Furthermore, zavegepant patients spent significantly more time (over 2.5-h) in pain freedom compared to placebo. Similarly, a higher proportion of patients with normal function was observed with zavegepant vs placebo, as early as 30-min post-dose. Over 48-h, patients treated with zavegepant spent an average of ~ 3-h longer with normal functioning compared to placebo. Results were similar when analyzing both analytic groups. In a regression model, treatment with zavegepant, lower pain severity, fewer baseline monthly migraine days, and absence of photophobia, phonophobia, and nausea were associated with better functioning (p < 0.05) over 48-h.

CONCLUSION

This post-hoc analysis demonstrates the benefit of zavegepant nasal spray over placebo on two patient-centric endpoints: time spent with pain freedom and normal functioning over 48-h post-dose. These data support the use of zavegepant for providing rapid and sustained freedom from migraine pain and freedom from migraine related disability, particularly for those who would benefit from the nasal CGRP formulation.

Novel derivatives of capsaicin as a potent hypolipidemic and anti-obesity agent

Capsaicin is a natural product with multiple biological activities, such as anti-inflammatory, analgesic, weight loss, anti-cancer and cardiovascular disease prevention. However, its further applications have been limited by its strong irritation, poor water solubility, and unsatisfied pharmacological effects. To ameliorate the problem, a series of derivatives of capsaicin and its analogues were designed and synthesized. Three candidate compounds (HJ-1-3, HJ-1-4, HJ-1-6) have shown the potential to reduce body fat accumulation and lose weight on different indicators with biological evaluation in vitro and in vivo.

International Headache Society global practice recommendations for the acute pharmacological treatment of migraine

BACKGROUND

In an effort to improve migraine management around the world, the International Headache Society (IHS) has here developed a list of practical recommendations for the acute pharmacological treatment of migraine. The recommendations are categorized into optimal and essential, in order to provide treatment options for all possible settings, including those with limited access to migraine medications.

METHODS

An IHS steering committee developed a list of clinical questions based on practical issues in the management of migraine. A selected group of international senior and junior headache experts developed the recommendations, following expert consensus and the review of available national and international headache guidelines and guidance documents. Following the initial search, a bibliography of twenty-one national and international guidelines was created and reviewed by the working group.

RESULTS

A total of seventeen questions addressing different aspects of acute migraine treatment have been outlined. For each of them we provide an optimal recommendation, to be used whenever possible, and an essential recommendation to be used when the optimal level cannot be attained.

CONCLUSION

Adoption of these international recommendations will improve the quality of acute migraine treatment around the world, even where pharmacological options remain limited.

Formulation and Characterization of Intranasal Drug Delivery of Frovatriptan-Loaded Binary Ethosomes Gel for Brain Targeting

Background

Frovatriptan succinate (FVT) is an effective medication used to treat migraines; however, available oral formulations suffer from low permeability; accordingly, several formulations of FVT were prepared.

Objective

Prepare, optimize, and evaluate FVT-BE formulation to develop enhanced intranasal binary nano-ethosome gel.‎.

Methods

Binary ethosomes were prepared using different concentrations of phospholipid PLH90, ethanol, propylene glycol, and cholesterol by thin film hydration and characterized by particle size, zeta potential, and entrapment efficiency. Furthermore, in-vitro, in-vivo, ex-vivo, pharmacokinetics, and histopathological studies were done.

Results

Regarding FVT-loaded BE, formula (F9) demonstrated the best parameters from the other formulas; with the lowest particle size (154.1±4.38‎ nm), lowest PDI (‎0.213±0.05), highest zeta potential (‎-46.94±1.05), and highest entrapment efficiency (89.34±2.37%). Regarding gel formulation, G2 showed the best gel formula with drug content (‎99.82±0.02‎%) and spreadability (12.88 g/cm2). In-vitro study results showed that, in the first 30 minutes, around 22.3% of the medication is released, whereas, after 24 hours, about 98.56% is released in G2.

Conclusion

Based on enhancing the bioavailability and sustaining the drug release, it can be concluded that the Frovatriptan-Loaded Binary ethosome Gel as nano-delivery was developed as a promising non-invasive drug delivery system for treating migraine.

Safety and Efficacy of Zavegepant in Treating Migraine: A Systematic Review

Drugs that act on the calcitonin gene-related peptide (CGRP) pathway herald the dawn of a new era in the management of migraine headaches. The blockade of CGRP alleviates neural inflammation and has been associated with reduced pain sensitization. Zavegepant is a third-generation drug and is the first intranasal CGRP antagonist to be developed. This systematic review aims to assess the safety, efficacy, pharmacokinetics, and tolerability of Zavegepant as an abortive treatment for migraine. Studies that assessed the safety, tolerability, and efficacy of Zavegepant for migraine were identified through a systematic literature review of PubMed, Clinicaltrials.gov, and Cochrane databases in April 2023. Our systematic review yielded a total of six studies that fit our inclusion criteria. Of these, data from only two randomized control trials (RCTs) was homogenous; hence, forest plots of results pooled from the included studies were not reported. The included studies showed that Zavegepant is an efficacious and well-tolerated abortive treatment modality for episodic migraine in adult patients. Zavegepant showed safety and efficacy in migraine treatment according to various parameters throughout the six included studies. These parameters include adverse events, pharmacokinetic properties, CGRP inhibition, effect on blood pressure/electrocardiogram, pain freedom, and freedom from most bothersome symptoms.

Access to the CNS: Strategies to overcome the BBB

The blood-brain barrier (BBB) limits the access of substances to the central nervous system (CNS) which hinders the treatment of pathologies affecting the brain and the spinal cord. Nowadays, research is focus on new strategies to overcome the BBB and can treat the pathologies affecting the CNS are needed. In this review, the different strategies that allow and increase the access of substances to the CNS are analysed and extended commented, not only invasive strategies but also non-invasive ones. The invasive techniques include the direct injection into the brain parenchyma or the CSF and the therapeutic opening of the BBB, while the non-invasive techniques include the use of alternative routes of administration (nose-to-brain route), the inhibition of efflux transporters (as it is important to prevent the drug efflux from the brain and enhance the therapeutic efficiency), the chemical modification of the molecules (prodrugs and chemical drug delivery systems (CDDS)) and the use of nanocarriers. In the future, knowledge about nanocarriers to treat CNS diseases will continue to increase, but the use of other strategies such as drug repurposing or drug reprofiling, which are cheaper and less time consuming, may limit its transfer to society. The main conclusion is that the combination of different strategies may be the most interesting approach to increase the access of substances to the CNS.

Development of intranasal implantable devices for schizophrenia treatment

In this work the preparation and characterisation of intranasal implants for the delivery of risperidone (RIS) is described. The aim of this work is to develop better therapies to treat chronic conditions affecting the brain such as schizophrenia. This type of systems combines the advantages of intranasal drug delivery with sustained drug release. The resulting implants were prepared using biodegradable materials, including poly(caprolactone) (PCL) and poly(lactic-co-glycolic acid) (PLGA). These polymers were combined with water-soluble compounds, such as poly(ethylene glycol) (PEG) 600, PEG 3000, and Tween® 80 using a solvent-casting method. The resulting implants contained RIS loadings ranging between 25 and 50%. The obtained implants were characterised using a range of techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). Moreover, in vitro RIS release was evaluated showing that the addition of water-soluble compounds exhibited significant faster release profiles compared to pristine PCL and PLGA-based implants. Interestingly, PCL-based implants containing 25% of RIS and PLGA-based implants loaded with 50% of RIS showed sustained drug release profiles up to 90 days. The former showed faster release rates over the first 28 days but after this period PLGA implants presented higher release rates. The permeability of RIS released from the implants through a model membrane simulating nasal mucosa was subsequently evaluated showing desirable permeation rate of around 2 mg/day. Finally, following in vitro biocompatibility studies, PCL and PLGA-based implants showed acceptable biocompatibility. These results suggested that the resulting implants displayed potential of providing prolonged drug release for brain-targeting drugs.

Topical Capsaicin for the Treatment of Sensory Neuropathic Cough

Objective

To evaluate a novel treatment for sensory neuropathic cough (SNC): topical capsaicin.

Study Design

Retrospective review.

Setting

Tertiary care laryngology clinic.

Methods

A retrospective review was performed on 201 consecutive patients treated for SNC with capsaicin 0.02% to 0.04% applied topically to the upper aerodigestive tract, typically after failure of standard medications. Patients were asked to use the spray 4 times daily for 2 weeks prior to assessment of benefit. Items assessed included the percentage reduction of coughing, type of benefit noted, and side effects.

Results

Of the 201 patients who used the spray, 36.3% noted no benefit, whereas 63.7% (n = 128) had benefit in terms of cough reduction: 30.8% (n = 62) reported ≥75% reduction; 17.4% (n = 35), 50%-74% reduction; 7.0% (n = 14), 25%-49% reduction; and 8.5% (n = 17), 1%-24% reduction. Of all patients, 78.3% reported no side effects or complications. Of the remaining 21.7%, 1 patient noted a nosebleed after a single administration, and 1 patient noted transient wheezing after administration. The others reported unpleasant local effects, including throat/ear discomfort, voice change, sneezing, reflexive vomiting, and headache.

Conclusion

In our group of 201 patients with SNC, most of which had failed to respond to standard treatments, 63.7% had some response to capsaicin spray, with 30.8% reporting ≥75% reduction. Minimal side effects of treatment were reported. Thus, we suggest that this therapy can be another treatment option for patients with SNC.

Efficacy and Safety of Butorphanol Use in Patient-Controlled Analgesia: A Meta-Analysis

Objective

This meta-analysis evaluates the efficacy and safety regarding usage of butorphanol in patient-controlled analgesia (PCA).

Methods

Several databases such as PubMed, Cochrane Library, Embase, CNKI, and VIP were explored with the help of computer search and manual retrieval. Randomized controlled trial (RCT) was selected, and the meta-analysis was conducted using RevMan 5.1. The primary efficacy endpoint was the postoperative visual analog scale score, postoperative Ramsay sedation scale (RSS), and adverse events.

Results

Nine RCTs met the inclusion criteria and were included in this meta-analysis. No significant differences were found between the butorphanol group and nonbutorphanol group at 12 h and 48 h. The postoperative RSS score at 12 h, 24 h, and 48 h was representative of the calming effect of butorphanol. No significant difference was found on the endpoint of the postoperative RSS score at 12 h, 48 h, and 24 h. The RSS score was lower in the butorphanol group in comparison to the nonbutorphanol group. The butorphanol group was also associated with lower rate of nausea, vomiting, itching, and dizziness compared to the nonbutorphanol group.

Conclusion

Butorphanol may be used in PCA as a successful postoperative analgesia and is also associated with lower side effects. Further research is needed to verify the efficacy and safety of butorphanol.

Nasal Delivery of Acute Medications for Migraine: The Upper Versus Lower Nasal Space

The acute treatment of migraine requires effective drugs that are well tolerated and provide rapid and consistent pain relief. Oral tablets are the most commonly used acute treatment for migraine; however, their effectiveness is limited by the rate of gastrointestinal (GI) tract absorption and first-pass hepatic metabolism, and they may not be ideal for patients experiencing GI motility issues. Nasal delivery is an attractive alternative route as it may circumvent GI tract absorption, avoid first-pass metabolism in the liver, and potentially reduce the frequency of GI adverse events. The large surface area and high vascularity within the nose may permit rapid absorption of therapeutics into the systemic circulation, allowing for rapid onset of action. However, the site of drug deposition (upper versus lower nasal cavity) may influence drug pharmacokinetics. Most approved nasal migraine therapies target the lower nasal space where the epithelium is less permeable, and they may be quickly cleared away due to increased ciliary function or dripping from the nose or swallowing, resulting in variable absorption and limited bioavailability. Together with its abundant vascularization, relative mucosal thickness stability, and low clearance rates, the upper nasal space harnesses the benefits of nasal delivery to potentially maximize drug efficacy.

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

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High-dose phenylephrine increases meningeal blood flow through TRPV1 receptor activation and release of calcitonin gene-related peptide

BACKGROUND

The α₁ -adrenoceptor agonist, phenylephrine, is used at high concentrations as a mydriatic agent and for the treatment of nasal congestion. Among its adverse side-effects transient burning sensations are reported indicating activation of the trigeminal nociceptive system.

METHODS

Neuropeptide release, calcium imaging and meningeal blood flow recordings were applied in rodent models of meningeal nociception to clarify possible receptor mechanisms underlying these pain phenomena.

RESULTS

Phenylephrine above 10 mM dose-dependently released calcitonin gene-related peptide (CGRP) from the dura mater and isolated trigeminal ganglia, whereas hyperosmotic mannitol at 90 mM was ineffective. The phenylephrine-evoked release was blocked by the transient receptor potential vanilloid 1 (TRPV1) antagonist BCTC and did not occur in trigeminal ganglia of TRPV1-deficient mice. Phenylephrine at 30 mM caused calcium transients in cultured trigeminal ganglion neurons responding to the TRPV1 agonist capsaicin and in HEK293T cells expressing human TRPV1. Local application of phenylephrine at micromolar concentrations to the exposed rat dura mater reduced meningeal blood flow, whereas concentrations above 10 mM caused increased meningeal blood flow. The flow increase was abolished by pre-application of the CGRP receptor antagonist CGRP_8-37 or the TRPV1 antagonist BCTC.

CONCLUSIONS

Phenylephrine at high millimolar concentrations activates TRPV1 receptor channels of perivascular afferents and, upon calcium inflow, releases CGRP, which increases meningeal blood flow. Activation of TRPV1 receptors may underlie trigeminal nociception leading to cranial pain such as local burning sensations or headaches caused by administration of high doses of phenylephrine.

SIGNIFICANCE

Phenylephrine is used at high concentrations as a mydriaticum and for treating nasal congestion. As adverse side-effects burning sensations and headaches have been described. Phenylephrine at high concentrations causes calcium transients in trigeminal afferents, CGRP release and increased meningeal blood flow upon activation of TRPV1 receptor channels, which is likely underlying the reported pain phenomena.

Intranasal lidocaine for acute migraine: A meta-analysis of randomized controlled trials

Background

Intranasal lidocaine has been shown to be effective in treating patients with acute migraines; however, its efficacy is still controversial. In this study, we intend to assess the efficacy and safety of intranasal lidocaine compared with a placebo or an active comparator for the treatment of migraines.

Method

PubMed, EMBASE, Cochrane library, and Scopus databases were searched from their inceptions to November 2018. Randomized controlled studies investigating the efficacy of intranasal lidocaine compared with a placebo or an active comparator were selected. Two reviewers independently extracted and synthesized data using a random-effects model. The primary outcome was pain intensity. The secondary outcomes were success rate, the need for rescue medicine, and relapse occurrences. We registered the study at PROSPERO with an ID of CRD42018116226.

Results

Six studies (n = 613) were eligible for the meta-analysis. Overall, the results revealed that the study population who was administered intranasal lidocaine had a lower pain intensity at 5 min (standardized mean difference (SMD) = -0.61; 95% CI = -1.04 to -0.19) and 15 min (SMD = -0.72; 95% CI = -1.14 to -0.19), had a higher success rate (RR = 3.55; 95% CI: 1.89 to 6.64) and a less frequent need for rescue medicine (RR = 0.51; 95% CI = 0.36 to 0.72) than the control group. These beneficial effects were not observed when an antiemetic was administered. Furthermore, intranasal lidocaine use had no significant influence on the relapse rate (RR = 0.89; 95% CI = 0.51–1.56), regardless of the use of antiemetics. Using lidocaine caused local irritation in up to 49.4% of the patients in one report but did not cause major adverse events.

Conclusion

Intranasal lidocaine can be considered a useful option for patients with an acute migraine. It yields a high success rate, a low pain intensity, an infrequent need for rescue medicine, and tolerable adverse events. The administration of antiemetics is an important confounding factor.

Comparing the Effect of Intranasal Lidocaine 4% with Peppermint Essential Oil Drop 1.5% on Migraine Attacks: A Double-Blind Clinical Trial

Background:

Prevalence of migraine, as a chronic neurovascular disorder, was approximately 10.3 and 23.1% among men and women, respectively, mostly in people younger than 40 years old. Migraine is prevalent in different geographic areas worldwide. The present study was designed to compare the impact of intranasal lidocaine 4% and peppermint essential oil drop 1.5% on migraine attacks.

Methods:

In this double-blind, parallel, randomized controlled trial, 120 adult patients with a diagnosis of migraine based on the International Headache Society criteria were treated with intranasal lidocaine drop 4% or peppermint essential oil drop 1.5% or placebo. Patients expressed their symptoms 5 and 15 min after dripping, and if they still had a headache after 15 min, they were given the second dose. Patients with a second dose of medication, 15 min later recorded their headache rate. All patients recorded their symptoms after 30 min. Symptoms of the patients were followed by a researcher through the phone and in-person after 2 months. Then, the questionnaires were filled.

Results:

In the present study, there was a significant difference among groups in headache intensity after treatment (P < 0.001). In 40% of the patients in the peppermint oil and lidocaine groups, the intensity of headache decreased. In the placebo group, fewer patients responded highly to the treatment, whereas 41.5% of patients in the lidocaine group and 42.1% of patients in the peppermint oil group responded to the treatment considerably.

Conclusions:

Concerning the findings of the present study, nasal application of peppermint oil caused considerable reduction in the intensity and frequency of headache and relieved majority of patients' pain similar to lidocaine. On the basis of findings of this study, it can be concluded that nasal menthol, such as lidocaine, can be used to relieve migraine headaches.

Intranasal Lidocaine in Acute Treatment of Migraine: A Randomized Controlled Trial

STUDY OBJECTIVE

The study aims to evaluate the efficacy and safety of intranasal lidocaine administration for migraine treatment.

METHODS

This single-center, double-blind, randomized, controlled trial was conducted in a tertiary care emergency department. Included patients met the migraine criteria of the International Headache Society. Patients were randomized to intranasal lidocaine or saline solution; all participants received 10 mg of intravenous metoclopramide. Patient pain intensity was assessed with an 11-point numeric rating scale score. The primary outcome measure was the change in pain scores at 15 minutes; secondary outcomes were changes in pain intensity after pain onset and need for rescue medication.

RESULTS

Patients (n=162) were randomized into 2 groups with similar baseline migraine characteristics and numeric rating scale scores. The median reduction in numeric rating scale score at 15 minutes was 3 (interquartile range [IQR] 2 to 5) for the lidocaine group and 2 (IQR 1 to 4) for the saline solution group (median difference=1.0; 95% confidence interval 0.1 to 2.1). The reduction in pain score at 30 minutes was 4 (IQR 3 to 7) for the lidocaine group and 5 (IQR 2 to 7) for the saline solution group (median difference=1.0; 95% confidence interval 0.1 to 2.1). Need for rescue medication did not differ between the groups, and local irritation was the most common adverse event in the lidocaine group.

CONCLUSION

Although intranasal lidocaine was found no more efficacious than normal saline solution in our study, future studies should focus on patients who present earlier after headache onset.

Understanding migraine: Potential role of neurogenic inflammation

Neurogenic inflammation, a well-defined pathophysiologial process is characterized by the release of potent vasoactive neuropeptides, predominantly calcitonin gene-related peptide (CGRP), substance P (SP), and neurokinin A from activated peripheral nociceptive sensory nerve terminals (usually C and A delta-fibers). These peptides lead to a cascade of inflammatory tissue responses including arteriolar vasodilation, plasma protein extravasation, and degranulation of mast cells in their peripheral target tissue. Neurogenic inflammatory processes have long been implicated as a possible mechanism involved in the pathophysiology of various human diseases of the nervous system, respiratory system, gastrointestinal tract, urogenital tract, and skin. The recent development of several innovative experimental migraine models has provided evidence suggestive of the involvement of neuropeptides (SP, neurokinin A, and CGRP) in migraine headache. Antidromic stimulation of nociceptive fibers of the trigeminal nerve resulted in a neurogenic inflammatory response with marked increase in plasma protein extravasation from dural blood vessels by the release of various sensory neuropeptides. Several clinically effective abortive antimigraine medications, such as ergots and triptans, have been shown to attenuate the release of neuropeptide and neurogenic plasma protein extravasation. These findings provide support for the validity of using animal models to investigate mechanisms of neurogenic inflammation in migraine. These also further strengthen the notion of migraine being a neuroinflammatory disease. In the clinical context, there is a paucity of knowledge and awareness among physicians regarding the role of neurogenic inflammation in migraine. Improved understanding of the molecular biology, pharmacology, and pathophysiology of neurogenic inflammation may provide the practitioner the context-specific feedback to identify the novel and most effective therapeutic approach to treatment. With this objective, the present review summarizes the evidence supporting the involvement of neurogenic inflammation and neuropeptides in the pathophysiology and pharmacology of migraine headache as well as its potential significance in better tailoring therapeutic interventions in migraine or other neurological disorders. In addition, we have briefly highlighted the pathophysiological role of neurogenic inflammation in various other neurological disorders.

The Neuropharmacology of Cluster Headache and other Trigeminal Autonomic Cephalalgias

Trigeminal autonomic cephalalgias (TACs) are a group of primary headaches including cluster headache (CH), paroxysmal hemicrania (PH) and short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT). Another form, hemicrania continua (HC), is also included this group due to its clinical and pathophysiological similarities. CH is the most common of these syndromes, the others being infrequent in the general population. The pathophysiology of the TACs has been partly elucidated by a number of recent neuroimaging studies, which implicate brain regions associated with nociception (pain matrix). In addition, the hypothalamic activation observed in the course of TAC attacks and the observed efficacy of hypothalamic neurostimulation in CH patients suggest that the hypothalamus is another key structure. Hypothalamic activation may indeed be involved in attack initiation, but it may also lead to a condition of central facilitation underlying the recurrence of pain episodes. The TACs share many pathophysiological features, but are characterised by differences in attack duration and frequency, and to some extent treatment response. Although alternative strategies for the TACs, especially CH, are now emerging (such as neurostimulation techniques), this review focuses on the available pharmacological treatments complying with the most recent guidelines. We discuss the clinical efficacy and tolerability of the currently used drugs. Due to the low frequency of most TACs, few randomised controlled trials have been conducted. The therapies of choice in CH continue to be the triptans and oxygen for acute treatment, and verapamil and lithium for prevention, but promising results have recently been obtained with novel modes of administration of the triptans and other agents, and several other treatments are currently under study. Indomethacin is extremely effective in PH and HC, while antiepileptic drugs (especially lamotrigine) appear to be increasingly useful in SUNCT. We highlight the need for appropriate studies investigating treatments for these rare, but lifelong and disabling conditions.

Breath powered nasal delivery: a new route to rapid headache relief

The nose offers an attractive noninvasive alternative for drug delivery. Nasal anatomy, with a large mucosal surface area and high vascularity, allows for rapid systemic absorption and other potential benefits. However, the complex nasal geometry, including the narrow anterior valve, poses a serious challenge to efficient drug delivery. This barrier, plus the inherent limitations of traditional nasal delivery mechanisms, has precluded achievement of the full potential of nasal delivery. Breath Powered bi-directional delivery, a simple but novel nasal delivery mechanism, overcomes these barriers. This innovative mechanism has now been applied to the delivery of sumatriptan. Multiple studies of drug deposition, including comparisons of traditional nasal sprays to Breath Powered delivery, demonstrate significantly improved deposition to superior and posterior intranasal target sites beyond the nasal valve. Pharmacokinetic studies in both healthy subjects and migraineurs suggest that improved deposition of sumatriptan translates into improved absorption and pharmacokinetics. Importantly, the absorption profile is shifted toward a more pronounced early peak, representing nasal absorption, with a reduced late peak, representing predominantly gastrointestinal (GI) absorption. The flattening and “spreading out” of the GI peak appears more pronounced in migraine sufferers than healthy volunteers, likely reflecting impaired GI absorption described in migraineurs. In replicated clinical trials, Breath Powered delivery of low-dose sumatriptan was well accepted and well tolerated by patients, and onset of pain relief was faster than generally reported in previous trials with noninjectable triptans. Interestingly, Breath Powered delivery also allows for the potential of headache-targeted medications to be better delivered to the trigeminal nerve and the sphenopalatine ganglion, potentially improving treatment of various types of headache. In brief, Breath Powered bi-directional intranasal delivery offers a new and more efficient mechanism for nasal drug delivery, providing an attractive option for improved treatment of headaches by enabling or enhancing the benefits of current and future headache therapies.

Preparation of imidazoles as potent calcitonin gene-related peptide (CGRP) antagonists

Several new potent CGRP receptor antagonists have been prepared in which the amide bond of lead compound 1 has been replaced by bioisosteric imidazole moieties. Substitution at N-1 of the imidazole was optimized to afford compounds with comparable potency to that of lead 1. Conformational restraint of the imidazole to form tetrahydroimidazo[1,5-a]pyrazine 43 gave substantially improved permeability.

Influence of polymeric microcarriers on the in vivo intranasal uptake of an anti-migraine drug for brain targeting

The objective of this study was to investigate the effect of polymeric microcarriers on the in vivo intranasal uptake of an anti-migraine drug for brain targeting. Mucoadhesive powder formulations consisted of antimigraine drug, zolmitriptan, and chitosans (various molecular weights and types) or hydroxypropyl methylcellulose (HPMC). Their suitability for nasal administration was evaluated by in vitro and ex vivo mucoadhesion and permeation tests. The formulations based on chitosan glutamate (CG) or HPMC were tested in vivo because they showed good mucoadhesive properties and altered the permeation rate of the drug. The in vivo results from intravenous infusion and nasal aqueous suspension of the drug or nasal particulate powders were compared. The plasmatic AUC values obtained within 8h following intravenous administration appeared about three times higher than those obtained by nasal administration, independent of the formulations. Zolmitriptan concentrations in the cerebrospinal fluid obtained from nasal and intravenous administrations were, respectively, 30 and 90 times lower than the concentrations of the drug in the blood. Thus, nasal administration potentiated the central zolmitriptan activity, allowing a reduction in the drug peripheral levels, with respect to the intravenous administration. Among nasally administered formulations, CG microparticles showed the highest efficacy in promoting the central uptake of zolmitriptan within 1h.

Reactive intermediates produced from the metabolism of the vanilloid ring of capsaicinoids by p450 enzymes

This study characterized electrophilic and radical products derived from the metabolism of capsaicin by cytochrome P450 and peroxidase enzymes. Multiple glutathione and β-mercaptoethanol conjugates (a.k.a., adducts), derived from the trapping of quinone methide and quinone intermediates of capsaicin, its analogue nonivamide, and O-demethylated and aromatic hydroxylated metabolites thereof, were produced by human liver microsomes and individual recombinant human P450 enzymes. Conjugates derived from concomitant dehydrogenation of the alkyl terminus of capsaicin were also characterized. Modifications to the 4-OH substituent of the vanilloid ring of capsaicinoids largely prevented the formation of electrophilic intermediates, consistent with the proposed structures and mechanisms of formation for the various conjugates. 5,5'-Dicapsaicin, presumably arising from the bimolecular coupling of free radical intermediates was also characterized. Finally, the analysis of hepatic glutathione conjugates and urinary N-acetylcysteine conjugates from mice dosed with capsaicin confirmed the formation of glutathione conjugates of O-demethylated quinone methide and 5-OH-capsaicin in vivo. These data demonstrated that capsaicin and structurally similar analogues are converted to reactive intermediates by certain P450 enzymes, which may partially explain conflicting reports related to the cytotoxic, pro-carcinogenic, and chemoprotective effects of capsaicinoids in different cells and/or organ systems.

Intranasal ketorolac tromethamine (SPRIX®) containing 6% of lidocaine (ROX-828) for acute treatment of migraine: Safety and efficacy data from a phase II clinical trial

Objective

Ketorolac is a non-triptan, non-opioid, mixed cyclooxygenase (COX)1/2-inhibitor for short-term management of moderate-to-severe acute pain. This trial evaluated an intranasal formulation of ketorolac tromethamine (SPRIX®) containing 6% lidocaine (ROX-828) for the acute treatment of migraine with and without aura as defined by the International Headache Society.

Methods

Patients were randomly assigned 1:1 to self-treat with intranasal ROX-828 (31.5 mg ketorolac tromethamine/200 µL, containing 6% of lidocaine) or placebo (with 6% lidocaine) within four hours of a new migraine attack rated ≥ moderate in pain intensity. Assessments included headache intensity and associated migraine symptoms (nausea, vomiting, phonophobia, photophobia) measured at baseline and at regular intervals through 48 hours post-dosing, and global impression of efficacy (seven-point scale) measured at two hours.

Results

Randomized patients who had a migraine attack ( N = 140) were evaluable (ROX-828, N = 68; placebo, N = 72). Patients receiving ROX-828 showed a significant ( p < 0.05) improvement in pain relief at all time points except 0.5 and 24 hours compared with those who received placebo. More patients achieved pain-free status with ROX-828 than with placebo at 1.5, 3, 4, 24 and 48 hours ( p < 0.05); significance at the two-hour time point, which was the primary endpoint, was not met. Patients’ global impression of efficacy showed statistically significantly better results for patients receiving ROX-828 than for those receiving placebo. Associated migraine symptoms were significantly improved ( p < 0.05) with ROX-828 relative to placebo at several time points throughout the observation period. The most frequently reported adverse events in both groups were associated with nasal discomfort.

Conclusion

Self-administered intranasal ROX-828 was well tolerated. While the primary endpoint was not met, the results provide preliminary evidence that ROX-828 improves migraine pain.

Italian guidelines for primary headaches: 2012 revised version

The first edition of the Italian diagnostic and therapeutic guidelines for primary headaches in adults was published in J Headache Pain 2(Suppl. 1):105-190 (2001). Ten years later, the guideline committee of the Italian Society for the Study of Headaches (SISC) decided it was time to update therapeutic guidelines. A literature search was carried out on Medline database, and all articles on primary headache treatments in English, German, French and Italian published from February 2001 to December 2011 were taken into account. Only randomized controlled trials (RCT) and meta-analyses were analysed for each drug. If RCT were lacking, open studies and case series were also examined. According to the previous edition, four levels of recommendation were defined on the basis of levels of evidence, scientific strength of evidence and clinical effectiveness. Recommendations for symptomatic and prophylactic treatment of migraine and cluster headache were therefore revised with respect to previous 2001 guidelines and a section was dedicated to non-pharmacological treatment. This article reports a summary of the revised version published in extenso in an Italian version.

Topical capsaicin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patch

Topical capsaicin formulations are used for pain management. Safety and modest efficacy of low-concentration capsaicin formulations, which require repeated daily self-administration, are supported by meta-analyses of numerous studies. A high-concentration capsaicin 8% patch (Qutenza™) was recently approved in the EU and USA. A single 60-min application in patients with neuropathic pain produced effective pain relief for up to 12 weeks. Advantages of the high-concentration capsaicin patch include longer duration of effect, patient compliance, and low risk for systemic effects or drug-drug interactions. The mechanism of action of topical capsaicin has been ascribed to depletion of substance P. However, experimental and clinical studies show that depletion of substance P from nociceptors is only a correlate of capsaicin treatment and has little, if any, causative role in pain relief. Rather, topical capsaicin acts in the skin to attenuate cutaneous hypersensitivity and reduce pain by a process best described as 'defunctionalization' of nociceptor fibres. Defunctionalization is due to a number of effects that include temporary loss of membrane potential, inability to transport neurotrophic factors leading to altered phenotype, and reversible retraction of epidermal and dermal nerve fibre terminals. Peripheral neuropathic hypersensitivity is mediated by diverse mechanisms, including altered expression of the capsaicin receptor TRPV1 or other key ion channels in affected or intact adjacent peripheral nociceptive nerve fibres, aberrant re-innervation, and collateral sprouting, all of which are defunctionalized by topical capsaicin. Evidence suggests that the utility of topical capsaicin may extend beyond painful peripheral neuropathies.

A randomized, double-blind, parallel trial comparing capsaicin nasal spray with placebo in subjects with a significant component of nonallergic rhinitis

OBJECTIVE

To investigate the efficacy and safety of ICX72 or Sinus Buster, a proprietary homeopathic preparation of Capsicum annum and Eucalyptol, versus placebo administered continuously over 2 weeks in subjects with a significant component of nonallergic rhinitis (NAR).

METHODS

Forty-two consented subjects meeting inclusion/exclusion criteria were randomized to ICX72 (n = 20) or control (n = 22) administered twice daily over 2 weeks. The primary endpoint was change in total nasal symptom scores (TNSS) from baseline to end of study. Secondary endpoints included changes in individual symptom scores (ISS) over 2 weeks and average time to first relief. Mean TNSS and ISS were recorded after single dosing at different intervals over 60 minutes. Rhinitis quality-of-life, rescue medication, and safety endpoints were analyzed.

RESULTS

ICX72 versus placebo subjects exhibited significant differences in changes from baseline to end of study for TNSS and each ISS (P < .01), had an average time to first relief of 52.6 seconds (P < .01), and improvement in nasal congestion, sinus pain, sinus pressure, and headache at 5, 10, 15, and 30 minutes, persisting at 60 minutes for nasal congestion and sinus pain (P < .05). No difference between groups in adverse events or rescue medication was observed. ICX72 versus placebo subjects experienced no rebound congestion or impaired olfaction at the end of the study.

CONCLUSION

This is the first controlled trial demonstrating intranasal capsaicin, when used continuously over 2 weeks, rapidly and safely improves symptoms in rhinitis subjects with a significant NAR component.

Innovative delivery systems for migraine: the clinical utility of a transdermal patch for the acute treatment of migraine

Migraine is a disabling, painful primary headache disorder that is associated with various combinations of neurological, gastrointestinal, autonomic and pain symptoms. Gastrointestinal disturbances associated with migraine, including nausea and vomiting, affect a majority of migraineurs and often result in a delay in taking or avoidance of pharmacological intervention. Gastric stasis and vomiting may lead to delayed or inconsistent absorption of orally administered medications. Many migraineurs awake early in the morning with their attack progressing and already associated with nausea and vomiting. As a result, there is a need for a novel, non-invasive, non-oral delivery system for fast and effective acute treatment of migraine. There are two non-oral delivery systems currently available in the US for the acute treatment of migraine: three nasal sprays and two injectable formulations. Although nasal sprays depend partially on nasal mucosal absorption, a significant amount of drug is swallowed, transits the stomach and is absorbed in the small intestine, which is not as rapid or effective a route of delivery for those migraineurs with gastric stasis. Sumatriptan is rapidly absorbed by subcutaneous injection with or without a needle, but the invasiveness and discomfort of the delivery, the high incidence of adverse events and the high recurrence rate all limit its use for many patients. Iontophoretic delivery of medication is a non-invasive transdermal approach that uses small amounts of electrical current to promote rapid movement of the ionized drug through the skin and into the systemic circulation. This delivery bypasses hepatic first-pass metabolism and also avoids gastric transit delay and slowing of small intestinal absorption associated with gastrointestinal stasis in migraineurs. Two pharmacokinetic studies have demonstrated that iontophoretic transdermal delivery of sumatriptan results in rapid and consistent achievement of therapeutic plasma concentrations. These studies also suggest that, by avoiding patient exposure to a rapid rise in and high plasma concentrations of sumatriptan as seen with injectable sumatriptan, transdermal delivery using iontophoresis may significantly reduce typical triptan-related adverse events. A large, randomized, double-blind, placebo-controlled, multicentre clinical trial showed statistically significant efficacy, good tolerability and virtually no triptan-related adverse events. Iontophoretic delivery of sumatriptan, with a novel transdermal patch device, offers patients a migraine-specific medication that is non-invasive and non-oral. Clinically, transdermal delivery provides rapid and effective relief of migraine while bypassing the gastrointestinal tract, with minimal classic triptan-related adverse effects. This unique approach facilitates the rapid absorption of this migraine-specific triptan, which should improve the chances of consistently achieving a therapeutic plasma concentration of sumatriptan, resulting in effective migraine relief.

Trigeminal pathways deliver a low molecular weight drug from the nose to the brain and orofacial structures

Intranasal delivery has been shown to noninvasively deliver drugs from the nose to the brain in minutes along the olfactory and trigeminal nerve pathways, bypassing the blood-brain barrier. However, no one has investigated whether nasally applied drugs target orofacial structures, despite high concentrations observed in the trigeminal nerve innervating these tissues. Following intranasal administration of lidocaine to rats, trigeminally innervated structures (teeth, temporomandibular joint (TMJ), and masseter muscle) were found to have up to 20-fold higher tissue concentrations of lidocaine than the brain and blood as measured by ELISA. This concentration difference could allow intranasally administered therapeutics to treat disorders of orofacial structures (i.e., teeth, TMJ, and masseter muscle) without causing unwanted side effects in the brain and the rest of the body. In this study, an intranasally administered infrared dye reached the brain within 10 minutes. Distribution of dye is consistent with dye entering the trigeminal nerve after intranasal administration through three regions with high drug concentrations in the nasal cavity: the middle concha, the maxillary sinus, and the choana. In humans the trigeminal nerve passes through the maxillary sinus to innervate the maxillary teeth. Delivering lidocaine intranasally may provide an effective anesthetic technique for a noninvasive maxillary nerve block. Intranasal delivery could be used to target vaccinations and treat disorders with fewer side effects such as tooth pain, TMJ disorder, trigeminal neuralgia, headache, and brain diseases.

Brain targeting studies on buspirone hydrochloride after intranasal administration of mucoadhesive formulation in rats

Objectives

The purpose of this study was to find out whether nasal application of buspirone could increase its bioavailability and directly transport the drug from nose to brain.

Methods

A nasal formulation (Bus-chitosan) was prepared by dissolving 15.5 mg buspirone hydrochloride, 1% w/v chitosan hydrochloride and 5% w/v hydroxypropyl β-cyclodextrin (HP-β-CD) in 5 ml of 0.5% sodium chloride solution. The formulation was nasally administered to rats and the plasma and brain concentration compared with that for buspirone hydrochloride solution after intravenous and intranasal (Bus-plain) administration. The brain drug uptake was also confirmed by gamma scintigraphic study.

Key findings

The nasal Bus-chitosan formulation improved the absolute bioavailability to 61% and the plasma concentration peaked at 30 min whereas the peak for nasal Bus-plain formulation was 60 min. The AUC0-480 in brain after nasal administration of Bus-chitosan formulation was 2.5 times that obtained by intravenous administration (711 ± 252 ng/g vs 282 ± 110 ng/g); this was also considerably higher than that obtained with the intranasal Bus-plain formulation (354 ± 80 ng/g). The high percentage of direct drug transport to the brain (75.77%) and high drug targeting index (&gt;1) confirmed the direct nose to brain transport of buspirone following nasal administration of Bus-chitosan formulation.

Conclusions

These results conclusively demonstrate increased access of buspirone to the blood and brain from intranasal solution formulated with chitosan and HP-β-CD.

Efficacy and safety of transnasal butorphanol for pain relief after anal surgery

AIM: To compare the analgesic properties and efficacy of transnasal butorphanol with intramuscular meperidine after anal surgery.

METHODS: Sixty patients who underwent fistulectomy were enrolled in the study from January 2006 to December 2007. They were randomly divided into transnasal butorphanol (n = 30) or intramuscular meperidine (n = 30) treatment groups. Assessment of postoperative pain was made using a visual analogue scale (VAS). The VAS score was recorded 6 h after the completion of surgery, before receiving the first dose of analgesic, 60 min after analgesia and the next morning. Any adverse clinical effects such as somnolence, dizziness, nausea or vomiting were recorded. Satisfaction with narcotic efficacy, desire to use the particular analgesic in the future and any complaints were recorded by patients using questionnaires before being discharged.

RESULTS: Forty-two men and eighteen women were included in the study. There were no significant differences in VAS scores between the groups within 24 h. Length of hospital stay and the incidence of adverse effects between the groups were similar. In addition, most patients were satisfied with butorphanol nasal spray and wished to receive this analgesic in the future, if needed.

CONCLUSION: Butorphanol nasal spray is effective for the relief of pain after fistulectomy. However, it offered patients more convenient usage and would be suitable for outpatients.

Instilled or injected purified natural capsaicin has no adverse effects on rat hindlimb sensory-motor behavior or osteotomy repair

BACKGROUND

A novel formulation of > or = 98% pure capsaicin (4975) is currently undergoing clinical investigation using novel routes of delivery to provide selective analgesia lasting weeks to months with a single dose. We conducted this study to assess the safety and effects of instilled and injected 4975 in rat models of wound healing osteotomy repair and sensory-motor nerve function.

METHODS

Adult male and female Sprague-Dawley rats were used. To assess the effects of 4975 on nerve or muscle, 0.0083 or 0.025 mg 4975 or vehicle (25% polyethylene glycol-300) was applied to exposed sciatic nerve, or 0.1 mg 4975 or vehicle was injected into the surrounding muscle (Group 1). To assess the effect of 4975 on bone healing, an osteotomy was made in one femur and 0.5 mg of 4975 or vehicle was instilled into the site (Group 2). Behavioral testing was performed on both groups of rats and histological evaluation of the sciatic nerve, and surrounding soft tissue and bone was done at days 3, 14, and 28 after surgery. Femurs from osteotomy rats were assessed using peripheral quantitative computed tomography and biomechanical testing. Standard statistical tests were used to compare groups.

RESULTS

Rats with direct application of 4975 to the sciatic nerve and surrounding muscle were no different from the controls in nociceptive sensory responses (F = 0.910, P = 0.454), grip strength (F = 0.550, P = 0.654), or histology of the muscle or sciatic nerve. In osteotomy rats, there were no statistical differences between 4975 and vehicle-treated rats for bone area (H = 2.858, P = 0.414), bone mineral content (F = 0.945, P = 0.425), or bone mineral density (F = 0.87, P = 0.462) and no difference in soft tissue healing. There were neither differences in bone stiffness (F = 1.369, P = 0.268) nor were there noticeable differences in the macro- or microscopic appearance of the right femur osteotomy healing site and surrounding soft tissues between the control group and the 4975-treated animals.

CONCLUSION

A single, clinically relevant application of instilled or injected 4975 has no observable adverse effect on wound and bone healing after osteotomy or on the structural integrity of exposed muscle and nerve.

Discovery of (R)-4-(8-fluoro-2-oxo-1,2-dihydroquinazolin-3(4H)-yl)-N-(3-(7-methyl-1H-indazol-5-yl)-1-oxo-1-(4-(piperidin-1-yl)piperidin-1-yl)propan-2-yl)piperidine-1-carboxamide (BMS-694153): a potent antagonist of the human calcitonin gene-related peptide receptor for migraine with rapid and efficient intranasal exposure

Calcitonin gene-related peptide (CGRP) has been implicated in the pathogenesis of migraine. Early chemistry leads suffered from modest potency, significant CYP3A4 inhibition, and poor aqueous solubility. Herein, we describe the optimization of these leads to give 4 (BMS-694153), a molecule with outstanding potency, a favorable predictive toxicology profile, and remarkable aqueous solubility. Compound 4 has good intranasal bioavailability in rabbits and shows dose-dependent activity in validated in vivo and ex vivo migraine models.

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.

DHE in the pharmacotherapy of migraine: potential for a larger role

Despite a large array of currently marketed, frequently effective drugs for the acute treatment of migraine headache, comprising various classes and formulations, predictably reliable treatment for most headache types is often lacking. Dihydroergotamine mesylate (DHE) is a comparatively safe and effective therapy for migraine headache that could potentially be used for a broader range of headache types than occurs at present. The features of DHE supporting this assertion include (1) effectiveness in terminating severe, long-lasting headaches, (2) rapid onset of action, (3) very low rates of headache recurrence, (4) minimal risk of medication-overuse headache, and (5) in the nasal spray formulation, suitability for outpatients (especially patients who are very nauseated or vomiting, potentially obviating the need for an office or hospital visit for acute care). Conditions or circumstances for which there are data supporting the expanded use of DHE include menstrual migraine, migraine with central sensitization and cutaneous allodynia, medication-overuse headache, migraine recurrence, and status migrainosus. The introduction of the intranasal formulation of DHE provides both pharmacologic and patient-convenience advantages for use in migraine therapy. This article reviews the rationale for the use of DHE in these common, often difficult-to-treat migraine forms.

Nasal delivery of antimigraine drugs: clinical rationale and evidence base

The intranasal route of administration for antimigraine drugs offers many theoretical and practical advantages. A drug that is administered intranasally is absorbed by the highly vascular mucous membranes of the nose, which allows for rapid delivery of un-metabolized drug to the central nervous system. The onset of action is thus considerably earlier than with oral administration requiring gastrointestinal absorption. The intranasal route also provides several practical advantages, such as greater acceptability to patients because of the noninvasive mode of delivery, the ability to take medication when severe nausea or vomiting is present, and a better adverse event profile. Three antimigraine drugs are available in intranasal formulation: dihydroergotamine, sumatriptan, and zolmitriptan. This article reviews the pharmacology, efficacy, safety, and tolerability of these agents. All are well tolerated by patients and have demonstrated efficacy in the treatment of migraine headache. Each of these drugs has a unique pharmacokinetic and pharmacodynamic profile, which may support a clinical preference for one intranasal agent over another in treating patients with specific headache features.

Intranasal delivery: physicochemical and therapeutic aspects

Interest in intranasal (IN) administration as a non-invasive route for drug delivery continues to grow rapidly. The nasal mucosa offers numerous benefits as a target issue for drug delivery, such as a large surface area for delivery, rapid drug onset, potential for central nervous system delivery, and no first-pass metabolism. A wide variety of therapeutic compounds can be delivered IN, including relatively large molecules such as peptides and proteins, particularly in the presence of permeation enhancers. The current review provides an in-depth discussion of therapeutic aspects of IN delivery including consideration of the intended indication, regimen, and patient population, as well as physicochemical properties of the drug itself. Case examples are provided to illustrate the utility of IN dosing. It is anticipated that the present review will prove useful for formulation scientists considering IN delivery as a delivery route.

Cluster headache treatment dilemmas: the experts respond

When conventional treatment approaches to cluster headache are unsuccessful, expert recommendations are relevant but may not be easily accessible to treating clinicians. We conducted a study of expert recommendations in response to standardized vignettes. Ten expert headache clinicians were asked what treatment they would recommend for a hypothetical 55-year-old male cluster headache patient in the following five situations: 1) known coronary artery disease with response only to sumatriptan; 2) strictly unilateral headaches unresponsive to preventive treatment; 3) effective abortive treatment not covered by insurance; 4) patient request to obtain methysergide from Canada; and 5) headaches responsive only to steroid treatment.

Central Sensitization Theory of Migraine: Clinical Implications

The clinical science of migraine headache continues to evolve. Theories of the pathophysiology of migraine have progressed from the early vascular basis of migraine to more complex current theories that emphasize the centrality of neuronal dysfunction. The most recently articulated theory of migraine is the central sensitization hypothesis, which proposes that altered processing of sensory input in the brainstem, principally the trigeminal nucleus caudalis, could account for many of the temporal and symptomatic features of migraine, as well as its poor response to triptan therapy when such treatment is initiated hours after the onset of pain. Both preclinical and clinical data support the central sensitization theory. A critical clinical implication of this theory is that drugs that are capable of either aborting or arresting the process of central sensitization, most prominently dihydroergotamine, may have a unique role in the treatment of migraine. An additional, and highly practical, implication is based upon the finding that cutaneous allodynia-pain arising from innocuous stimulation of the skin, as in hair brushing or the application of cosmetics-is an easily identifiable marker of central sensitization. Thus, the presence or absence of cutaneous allodynia can be integrated into the routine clinical assessment of migraine and utilized as a determinant of treatment. Future basic and clinical research on central sensitization is likely to be of ongoing importance to the field.

Sphenopalatine Endoscopic Ganglion Block: A Revision of a Traditional Technique for Cluster Headache

The diagnosis of chronic cluster headache (CH), the most painful form of headache, is based on typical clinical features characterized by strictly unilateral pain with no side shift and ipsilateral oculofacial autonomic phenomena. The attacks occur several times a day for periods of 1 to 2 months in the episodic form of the disease or less frequently on a daily basis in the chronic form. The pathogenesis of CH involves the activation of parasympathetic nerve structures located within the sphenopalatine ganglion (SPG), which explains many of the associated symptoms, whereas the activation of the ipsilateral hypothalamic gray matter may explain its typical circadian and circannual periodicity. A number of surgical approaches have been tried in cases of chronic CH resistant to pharmacologic therapy, of which SPG blockade has been shown to have certain efficacy. We have adopted a new technique based on endoscopic ganglion blockade that approaches the pterigo-palatine fossa by way of the lateral nasal wall and consists of the injection of a mixture of local anesthetics and corticosteroids, which was performed in 20 selected patients with chronic CH, according to the International Headache Society criteria (18 male, 2 female; mean age 40 yr), who were selected for SPG blockade because they were totally drug resistant. The symptoms improved significantly, but always only temporarily, in 11 cases. These results should be considered rather good because, unlike other frequently used techniques, SPG blockade is not invasive and should therefore always be attempted before submitting patients to more invasive surgical approaches.

Evaluation of the efficacy of intravenous acetaminophen in the treatment of acute migraine attacks: a double-blind, placebo-controlled parallel group multicenter study

The efficacy of intravenous acetaminophen (1000mg) in the treatment of acute migraine attacks as an alternative to parenteral application of lysine acetylsalicylate or triptans was investigated, using a multi-center, randomized, double-blind, placebo controlled study design. Migraine diagnosis was made according to the International Headache Society Classification. Sixty patients were included in three headache outpatient centers (Neurology Departments of the Universities of Regensburg, Münster and München). In the acute migraine attack patients were treated intravenously with either 1000mg paracetamol (acetaminophen) or placebo. The primary end point was pain-free after 2h. Secondary efficacy criteria were pain-free after 24h or pain relief after 2hours and after 24hours. With regard to the efficacy criteria, 37% of patients reported pain relief or painfree after two hours, 12 patients after treatment with acetaminophen and 10 patients after treatment with placebo. Out of these, 3 patients in the acetaminophen and 4 patients in the placebo group were painfree. After 24hours 86% of the patients reported pain relief: 24 treated with acetaminophen and 27 treated with placebo. The results indicate, that 1000mg intravenous acetaminophen is not superior to placebo in treating severe acute migraine attacks.

Intranasal medications for the treatment of migraine and cluster headache

Intranasal medications for the treatment of headache have recently received increased attention. This paper reviews intranasal formulations of a variety of available medications (dihydroergotamine mesylate [dihydroergotamine mesilate], sumatriptan, zolmitriptan, butorphanol, capsaicin and lidocaine [lignocaine]) and one experimental medication (civamide, a cis-isomer of capsaicin) for the treatment of migraine and cluster headache. Although the efficacy of intranasal agents varies with the product used, intranasal delivery may be both convenient and more effective than other modes of drug delivery for a variety of reasons: (i) intranasal administration bypasses small bowel gastrointestinal tract absorption, which is often significantly delayed during the acute phase of a migraine attack; (ii) nauseated patients may prefer non-oral formulations as they decrease the chance of vomiting and are more rapidly effective; (iii) intranasal administration causes no pain or injection site reaction and is easier and more convenient to administer than injection or suppository and so may be used earlier in a migraine attack, resulting in better efficacy; (iv) intranasal medication produces the same number or fewer adverse events than injections; and (v) intranasal formulations offer a more rapid onset of action than oral medications, for some of the above reasons and, as such, may be more useful in patients with cluster headache, although this needs to be verified. However, it is important to emphasise that a preference study showed that most patients prefer oral tablets to an intranasal formulation. Also, some nasal preparations have significant adverse effects or are not well absorbed and therefore do not work consistently; others are more challenging to administer as a result of their delivery apparatus. Nevertheless, it is our opinion that nasal preparations increase therapeutic options and may result in faster response times and better efficacy than oral formulations and better patient satisfaction than injectable preparations.