The effectiveness of nalbuphine and hydroxyzine for the emergency treatment of severe headache

Migraine, Allergy, and Histamine: Is There a Link?

The relationship between migraines and allergies is controversial. Though they are epidemiologically linked, the underlying pathophysiological connection between them remains unclear. Migraines and allergic disorders have various underlying genetic and biological causes. As per the literature, these conditions are epidemiologically linked, and some common pathophysiological pathways have been hypothesized. The histaminergic system may be the clue to understanding the correlation among these diseases. As a neurotransmitter in the central nervous system with a vasodilatory effect, histamine has a well-documented influence on the allergic response and could be involved in the pathophysiology of migraines. Histamine may influence hypothalamic activity, which may play a major role in migraines or may simply influence their severity. In both cases, antihistamine drugs could prove useful. This review examines whether the histaminergic system, particularly H3 and H4 receptors, may provide a mechanistic link between the pathophysiology of migraines and allergic disorders, two common and debilitating conditions. Identifying their connection could help identify novel therapeutic strategies.

Histamine and Migraine

BACKGROUND

Histamine is an ancient "tissue amine" preceding multicellular organisms. In the central nervous system (CNS), its fibers originate solely from the tuberomammillary nucleus and travel throughout the brain. It is mainly responsible for wakefulness, energy homeostasis, and memory consolidation. Recently, several studies suggest a potential role of histamine in migraine pathogenesis and management.

METHODS

Narrative review of current literature regarding histamine and migraine.

RESULTS

Histamine plays a crucial role in migraine pathogenesis: sustaining the neurogenic inflammation pathway. Interaction between mast cells (MC) and calcitonin-gene related protein (CGRP) results in sensitization of trigeminal afferents and trigeminal ganglia (TG). Histamine binds with differing affinities to four different histaminergic G-protein coupled receptors, activating protein kinases, or triggering calcium release with subsequent mode of actions. Histamine 1 receptor (H₁ R) and histamine 2 receptor (H₂ R) antagonists are frequently used for the treatment of allergy and gastric acid secretion, respectively, but their antagonism is probably ineffective for migraine. Histamine 3 receptor (H₃ R) and histamine 4 receptor (H₄ R) have a threefold higher affinity than H₁ R/H₂ R for histamine and are found almost exclusively on neurons and immune tissues, respectively. H₃ R acts as an autoreceptor or as a heteroreceptor, lowering the release of histamine and other neurotransmitters. This is a potential target for anti-nociception and anti-neurogenic inflammation. To date, several small clinical trials using low dose histamine or N^α -methylhistamine have demonstrated migraine prophylactic efficacy, probably via H₃ R or other undetermined pathways.

CONCLUSION

The histamine system interacts with multiple regions in the CNS and may hypothetically modulate the migraine response. Low dose histamine may be a promising option for migraine prevention.

Diphenhydramine as Adjuvant Therapy for Acute Migraine: An Emergency Department-Based Randomized Clinical Trial

STUDY OBJECTIVE

More than 1 million patients present to US emergency departments (EDs) annually seeking care for acute migraine. Parenteral antihistamines have long been used in combination with antidopaminergics such as metoclopramide to treat acute migraine in the ED. High-quality data supporting this practice do not exist. We determine whether administration of diphenhydramine 50 mg intravenously+metoclopramide 10 mg intravenously results in greater rates of sustained headache relief than placebo+metoclopramide 10 mg intravenously.

METHODS

This was a randomized, double-blind, clinical trial comparing 2 active treatments for acute migraine in an ED. Eligible patients were adults younger than 65 years presenting with an acute moderate or severe headache meeting International Classification of Headache Disorders-2 migraine criteria. Patients were stratified according to presence or absence of allergic symptoms. The primary outcome was sustained headache relief, defined as achieving a headache level of mild or none within 2 hours of medication administration and maintaining this level of relief without use of any additional headache medication for 48 hours. Secondary efficacy outcomes included mean improvement on a 0 to 10 verbal scale between baseline and 1 hour, the frequency with which subjects indicated they would want the same medication the next time they present to the ED with migraine, and the ED throughput time. Sample size calculation using a 2-sided α of .05, a β of .20, and a 15% difference between study arms determined the need for 374 patients. An interim analysis was conducted when data were available for 200 subjects.

RESULTS

Four hundred twenty patients were approached for participation. Two hundred eight eligible patients consented to participate and were randomized. At the planned interim analysis, the data and safety monitoring board recommended that the study be halted for futility. Baseline characteristics were comparable between the groups. Fourteen percent (29/208) of the sample reported allergic symptoms. Of patients randomized to diphenhydramine, 40% (40/100) reported sustained relief at 48 hours, as did 37% (38/103) of patients randomized to placebo (95% confidence interval [CI] for difference of 3%: -10% to 16%). One hour after medication administration, patients randomized to diphenhydramine improved by a mean of 5.1 on the 0 to 10 scale versus 4.8 for those randomized to placebo (95% CI for difference of 0.3: -0.6 to 1.1). Eighty-five percent (84/99) of the patients in the diphenhydramine arm reported they would want the same medication combination during a subsequent ED visit, as did 76% (77/102) of those who received placebo (95% CI for difference of 9%: -2% to 20%). Median ED length of stay was 122 minutes (interquartile range 84 to 180 minutes) in the diphenhydramine group and 139 minutes (interquartile range 90 to 235 minutes) in the placebo arm. Rates of adverse effects, including akathisia, were comparable between the groups.

CONCLUSION

Intravenous diphenhydramine, when administered as adjuvant therapy with metoclopramide, does not improve migraine outcomes.

Histamine in migraine and brain

BACKGROUND

Histamine has been studied in both health and disease since the initial description a century ago. With its vasodilative effect, it was suggested early on to be involved in the pathophysiology of migraine. Over the past 25 years, much has been learned about histamine as a neurotransmitter in the central nervous system. The role of this neurotransmitter system in migraine has not been previously reviewed.

OBJECTIVE

Discuss a potential role of the brain histaminergic system in migraine.

METHODS

Unstructured literature search with a no specific hypothesis-driven approach.

RESULTS

There is substantial evidence that systemically given histamine may elicit, maintain, and aggravate headache. The mechanisms for this are not known, and histamines do not penetrate the blood-brain barrier (BBB). However, circulating histamine may influence hypothalamic activity via the circumventricular organs that lack BBB. In the rat, prolonged activation of meningeal nociceptors induced by dural mast cell degranulation has been observed. Subcutaneous injections of N-alpha-methyl histamine, a catabolite of histamine with high affinity to the histamine H3 receptor, probably have some migraine preventive effect. A negative feedback on histamine release from mast cells in proximity to C-fiber endings has been a postulated mechanism. Most antihistamines have shown to be ineffective as acute medication for migraine. Two centrally acting potent H1 receptor antagonists (cinnarizine and cyproheptadine) have been reported to be efficacious in preventing migraine. However, the proof for this is limited, and their efficacy has been ascribed other actions than the antihistaminergic. In general, lack of specificity and side effects limit the potential use of centrally acting H1 and H2 antagonists. Brain histamine is synthesized by neurons that are restricted to the posterior basal hypothalamus, more specific to the tuberomamillary nucleus (TMN), and that project practically to the whole central nervous system. The posterior hypothalamus is a suspected locus in quo in several primary headaches. Recently, a positron emission tomography study performed in the prodromal phase of migraine attacks supported the idea of initial involvement of this area. In another recent study, the thalamic nuclei receiving trigeminal output was also shown to have direct connections with the ventral TMN. The central histaminergic system plays an important role in the complex sleep-wake cycle, promoting cortical excitability during wakening and attention, and it consolidates the wake state. The period of the day, in the evenings and during the night, when there is reduced susceptibility for migraine attacks corresponds with less central histaminergic firing. Activation of both the H3 and the H4 receptor promotes inhibitory actions on neurons. The H3 receptor causes autoinhibition of the histaminergic neurons themselves, and centrally acting H3 receptor agonist prodrugs have shown to both inhibit neurogenic inflammation in dura, to induce sleep, and to produce antinociception. There are no registered ongoing studies on H3 and H4 receptor ligands in migraine.

CONCLUSION

The role of the central histaminergic system in migraine is largely unexplored, but findings from preclinical research may be linked to several aspects of the disorder. The histaminergic system of the brain may play an important role, especially in the initial phase of an attack, and histamine H3 and H4 receptor ligands may potentially have migraine prophylactic properties. However, the basis for this is still circumstantial, and the evidence is lacking.

Pearls and pitfalls in human pharmacological models of migraine: 30 years' experience

In vitro studies have contributed to the characterization of receptors in cranial blood vessels and the identification of new possible anti-migraine agents. In vivo animal models enable the study of vascular responses, neurogenic inflammation, peptide release and genetic predisposition and thus have provided leads in the search for migraine mechanisms. All animal-based results must, however, be validated in human studies because so far no animal models can predict the efficacy of new therapies for migraine.

Given the nature of migraine attacks, fully reversible and treatable, the headache- or migraine-provoking property of naturally occurring signaling molecules can be tested in a human model. If such an endogenous substance can provoke migraine in human patients, then it is likely, although not certain, that blocking its effect will be effective in the treatment of acute migraine attacks.

To this end, a human in vivo model of experimental headache and migraine in humans has been developed. Human models of migraine offer unique possibilities to study mechanisms responsible for migraine and to explore the mechanisms of action of existing and future anti-migraine drugs. The human model has played an important role in translational migraine research leading to the identification of three new principally different targets in the treatment of acute migraine attacks and has been used to examine other endogenous signaling molecules as well as genetic susceptibility factors. New additions to the model, such as advanced neuroimaging, may lead to a better understanding of the complex events that constitute a migraine attack, and better and more targeted ways of intervention.

Rescue therapy for acute migraine, part 3: opioids, NSAIDs, steroids, and post-discharge medications

OBJECTIVE

The final section of this 3-part review analyzes published reports involving the acute treatment of migraine with opioids, non-steroidal anti-inflammatory drugs (NSAIDs), and steroids in the emergency department (ED), urgent care, and headache clinic settings, as well as post-discharge medications. In the Conclusion, there is a general discussion of all the therapies presented in the 3 sections.

METHOD

Using the terms ("migraine" AND "emergency") AND ("therapy" OR "treatment"), the author searched MEDLINE for reports from ED and urgent care settings that involved all routes of medication delivery. Reports from headache clinic settings were included only if medications were delivered by a parenteral route.

RESULTS

Seventy-five reports were identified that compared the efficacy and safety of multiple acute migraine medications for rescue. Of the medications reviewed in Part 3, opioids, NSAIDs, and steroids all demonstrated some effectiveness. When used alone, nalbuphine and metamizole were superior to placebo. NSAIDs were inferior to the combination of metoclopramide and diphenhydramine. Meperidine was arguably equivalent when compared with ketorolac and dihydroergotamine (DHE) but was inferior to chlorpromazine and equivalent to the other dopamine antagonists. Steroids afford some protection against headache recurrence after the patient leaves the treatment center.

CONCLUSIONS

All 3 opioids most frequently studied - meperidine, tramadol, and nalbuphine - were superior to placebo in relieving migraine pain, although meperidine combined with promethazine was not. Opioid side effects included dizziness, sedation, and nausea. With ketorolac being the most frequently studied drug in the class, NSAIDs were generally well tolerated, and they may provide benefit even when given late in the migraine attack. The rate of headache recurrence within 24-72 hours after discharge from the ED can be greater than 50%. Corticosteroids can be useful in reducing headache recurrence after discharge. As discussed in Parts 1, 2, and 3, there are effective medications for provider-administered "rescue" in all the classes discussed. Prochlorperazine and metoclopramide are the most frequently studied of the anti-migraine medications in the emergent setting, and their effectiveness is superior to placebo. Prochlorperazine is superior or equivalent to all other classes of medications in migraine pain relief. Although there are fewer studies involving sumatriptan and DHE, relatively "migraine-specific" medications, they appear to be equivalent to the dopamine antagonists for migraine pain relief. Lack of comparisons with placebo and the frequent use of combinations of medications in treatment arms complicate the comparison of single agents to one another. When used alone, prochlorperazine, promethazine, metoclopramide, nalbuphine, and metamizole were superior to placebo. Droperidol and prochlorperazine were superior or equal in efficacy to all other treatments, although they also are more likely to produce side effects that are difficult for a patient to tolerate (especially akathisia). Metoclopramide was equivalent to prochlorperazine, and, when combined with diphenhydramine, was superior in efficacy to triptans and NSAIDs. Meperidine was arguably equivalent when compared with ketorolac and DHE but was inferior to chlorpromazine and equivalent to the other neuroleptics. Sumatriptan was inferior or equivalent to the neuroleptics and equivalent to DHE when only paired comparisons were considered. The overall percentage of patients with pain relief after taking sumatriptan was equivalent to that observed with droperidol or prochlorperazine.

Rescue therapy for acute migraine, part 2: neuroleptics, antihistamines, and others

OBJECTIVES

This second portion of a 3-part series examines the relative effectiveness of headache treatment with neuroleptics, antihistamines, serotonin antagonists, valproate, and other drugs (octreotide, lidocaine, nitrous oxide, propofol, and bupivacaine) in the setting of an emergency department, urgent care center, or headache clinic.

METHODS

MEDLINE was searched using the terms "migraine" AND "emergency" AND "therapy" OR "treatment." Reports were from emergency department and urgent care settings and involved all routes of medication delivery. Reports from headache clinics were only included if medications were delivered by a parenteral route.

RESULTS

Prochlorperazine, promethazine, and metoclopramide, when used alone, were superior to placebo. Droperidol and prochlorperazine were superior or equal in efficacy to all other treatments, although they also have more side effects (especially akathisia). Metoclopramide was equivalent to prochlorperazine and, when combined with diphenhydramine, was superior in efficacy to triptans and non-steroidal anti-inflammatory drugs. Meperidine was inferior to chlorpromazine and equivalent to the other neuroleptics. The overall percentage of patients with pain relief after taking droperidol and prochlorperazine was equivalent to sumatriptan.

CONCLUSIONS

Prochlorperazine and metoclopramide are the most frequently studied of the anti-migraine medications in the emergent setting, and the effectiveness of each is superior to placebo. Prochlorperazine is superior or equivalent to all other classes of medications in producing migraine pain relief. Dopamine antagonists, in general, appear to be equivalent for migraine pain relief to the migraine-"specific" medications sumatriptan and dihydroergotamine, although there are fewer studies involving the last two. Lack of comparisons to placebo and the frequent use of combination medications in treatment arms complicate the comparison of single agents to one other.

Standardizing emergency department-based migraine research: an analysis of commonly used clinical trial outcome measures

OBJECTIVES

Although many high-quality migraine clinical trials have been performed in the emergency department (ED) setting, almost as many different primary outcome measures have been used, making data aggregation and meta-analysis difficult. The authors assessed commonly used migraine trial outcomes in two ways. First, the authors examined the association of each commonly used outcome versus the following patient-centered variable: the research subject's wish, when asked 24 hours after investigational medication administration, to receive the same medication the next time they presented to an ED with migraine ("would take again"). This variable was chosen as the criterion standard because it provides a simple, dichotomous, clinically sensible outcome, which allows migraineurs to factor important intangibles of efficacy and adverse effects of treatment into an overall assessment of care. The second part of the analysis assessed how sensitive to true efficacy each outcome measure was by calculating sample size requirements based on results observed in previously conducted clinical trials.

METHODS

This was a secondary analysis of data previously collected in four ED-based migraine randomized trials performed between 2003 and 2007. In each of these trials, subjects were asked 24 hours after administration of an investigational medication whether or not they would want to receive the same medication the next time they came to the ED with a migraine. Odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for sex and medication received, were calculated as measures of association between the most commonly used outcome measures and "would take again." The sensitivity of each outcome measure to treatment efficacy was determined by calculating the sample size that would be required to detect a statistically significant result using estimates of that outcome obtained in two clinical trials.

RESULTS

Data from 378 subjects were used for this analysis. Adjusted ORs for association of "would take again" and other commonly used primary headache outcomes are as follows: achieving a pain-free state by 2 hours, OR = 3.1 (95% CI = 1.8 to 5.4); sustained pain-free status, OR = 4.5 (95% CI = 1.9 to 11.0); and no need for rescue medication, OR = 3.7 (95% CI = 2.1 to 6.6). An improvement on a standardized 11-point pain scale of > or =33% had an adjusted OR = 5.2 (95% CI = 2.2 to 12.4). The best performing alternate outcome, > or =33% improvement, correctly classified 288 subjects and misclassified 77 subjects when compared to "would take again." At least 33% improvement and pain-free by 2 hours required the smallest sample sizes, while sustained pain-free and "would take again" required many more subjects.

CONCLUSIONS

"Would take again" was associated with all migraine outcome measures we examined. No individual outcome was more closely associated with "would take again" than any other. Even the best-performing alternate outcome misclassified more than 20% of subjects. However, sample sizes based on "would take again" tended to be larger than other outcome measures. On the basis of these findings and this outcome measure's inherent patient-centered focus, "would take again," included as a secondary outcome in all ED migraine trials, is proposed.

Double-blind, multicenter trial to compare the efficacy of intramuscular dihydroergotamine plus hydroxyzine versus intramuscular meperidine plus hydroxyzine for the emergency department treatment of acute migraine headache

STUDY OBJECTIVE

To evaluate intramuscular dihydroergotamine in direct comparison with opioid analgesia in the treatment of acute migraine headache.

METHODS

This was a prospective, multicenter, double-blind trial performed in the emergency departments of 11 general hospitals in the United States. One hundred seventy-one patients between the ages of 18 and 60 years who presented to the ED with acute migraine headache were enrolled. Patients were randomly assigned to receive either 1 mg dihydroergotamine (DHE) or 1.5 mg/kg meperidine (MEP) by intramuscular injection. The anti-nauseant hydroxyzine (H) was coadministered in both treatment groups.

RESULTS

One hundred fifty-six patients were evaluable. Treatment groups were comparable in sample size, demographics, and baseline measurements of headache pain. Reduction of headache pain as measured on a 100-mm visual analog scale was 41+/-33 mm (53.5% reduction) for the DHE group, and 45+/-30 mm (55.7% reduction) for the MEP group at 60 minutes after treatment (difference=2.2%; 95% confidence interval [CI] -10%, 14.5%; P=.81). Reduction in the severity of nausea and improvement in functional ability were similar between treatment groups. Central nervous system adverse events were less common in the DHE group (DHE 23.5% versus MEP 37.6%, difference-14.1%: 95% CI -28%, 0%). In particular, dizziness was reported less commonly with DHE than MEP (2% versus 15%, difference=-13%: 95% CI -21%, -5%).

CONCLUSION

In this prospective, double-blind trial of a convenience sample of ED patients randomly assigned to one of two treatment regimens, DHE and MEP were comparable therapies for acute migraine. The use of DHE avoids several problems associated with opioid analgesia, including dizziness.

A prospective, double-blind study of metoclopramide hydrochloride for the control of migraine in the emergency department

STUDY OBJECTIVE

To determine the effectiveness of IV metoclopramide as sole therapy for relieving the pain of acute migraine in the emergency department.

DESIGN

Prospective study. Fifty patients were divided randomly into subjects and placebo controls with blinding of the treating physician and the patient.

PARTICIPANTS

Patients presenting to the ED with migraine requiring parenteral treatment.

INTERVENTIONS

Subjects received 10 mg IV metoclopramide and controls received IV normal saline; patient assessment of relief was followed by means of a numerical scale.

MEASUREMENTS AND MAIN RESULTS

Sixty-seven percent of subjects compared with 19% of controls had effective pain relief within one hour (P less than .001). Subjects achieved mean relief scores of 2.46 compared with 1.69 for controls (P less than .02). No significant side effects were observed.

CONCLUSION

IV metoclopramide as a single agent is effective and safe therapy for migraine in the ED.