Rizatriptan: an update of its use in the management of migraine

Light-Promoted Ni-Catalyzed Cross-Coupling of Aryl Chlorides with Hydrazides: Application to the Synthesis of Rizatriptan

A general and highly efficient photochemical C-N coupling reaction of challenging (hetero)aryl chlorides with hydrazides is reported. Catalyzed by a Ni(II)-bipyridine complex, this reaction provides an efficient tool for the synthesis of arylhydrazines in the presence of a soluble organic amine base without an external photosensitizer. The reaction features a wide substrate range (54 examples) and excellent functional group tolerance. The method has also been successfully applied to the three-step concise synthesis of rizatriptan, an effective drug for migraine and cluster headaches.

Pharmacological and Cellular Significance of Triazole-Surrogated Compounds

:

Heterocyclic compounds have been at the hierarchy position in academia, and industrial arena, particularly the compounds containing triazole-core are found to be potent with a broad range of biological activities. The resistance of triazole ring towards chemical (acid and base) hydrolysis, oxidative and reductive reaction conditions, metabolic degradation and its higher aromatic stabilization energy makes it a better heterocyclic core as therapeutic agents. These triazole-linked compounds are used for clinical purposes for antifungal, anti-mycobacterium, anticancer, anti-migraine and antidepressant drugs. Triazole scaffolds are also found to act as a spacer for the sake of covalent attachment of the high molecular weight bio-macromolecules with an experimental building blocks to explore structure-function relationships. Herein, several methods and strategies for the synthesis of compounds with 1,2,3-triazole moiety exploring Hüisgen, Meldal and Sharpless 1,3-dipolar cycloaddition reaction between azide and alkyne derivatives have been deliberated for a series of representative compounds. Moreover, this review article highlights in-depth applications of the [3+2]-cycloaddition reaction for the advances of triazole-containing antibacterial as well as metabolic labelling agents for the in vitro and in vivo studies on cellular level.

A Randomized Prospective Placebo-Controlled Study of Intravenous Magnesium Sulphate vs. Metoclopramide in the Management of Acute Migraine Attacks in the Emergency Department

The objective of this randomized, placebo-controlled, double-blind study was to determine the effectiveness of intravenous magnesium sulphate and intravenous metoclopramide in the treatment of acute migraine attacks in the Emergency Department when compared with placebo. Adult patients who presented to the Emergency Department with a headache that met International Headache Society (IHS) criteria for acute migraine were infused with either 10 mg of intravenous metoclopramide, 2 g of intravenous magnesium sulphate or normal saline over 10 min. At 0, 15, and 30 min, patients were asked to rate their pain on a standard visual analogue scale. At 30 min, patients were asked in a standard manner about the need for rescue medication. Adverse affects were also recorded. Patients were followed up by telephone within 24 h for any recurrence after discharge. The primary endpoint of the study was the difference in pain relief between the groups at 30 min. Of the 120 patients who met IHS criteria, seven were excluded from the study due to insufficient data. The number of patients, gender, age and initial visual analogue scale (VAS) scores were comparable between groups. Each group experienced more than a 25-mm improvement in VAS score at 30 min. However, there was no significant difference detected in the mean changes in VAS scores for pain. The rescue medication requirement was higher in the placebo group. The recurrence rate in 24 h was similar between the groups. Although patients receiving placebo required rescue medication more than the others, metoclopramide and magnesium have an analgesic effect similar to placebo in migraine attacks.

In Situ Generated HypoIodite Activator for the C2 Sulfonylation of Heteroaromatic N-oxides

A mild approach for direct C2 sulfonylation of heteroaromatic N-oxides with sulfonyl hydrazides affording 2-sulfonyl quinolines/pyridines has been developed. A variety of heteroaromatic N-oxides and sulfonyl hydrazides participate effectively in this transformation which uses hypoiodites (generated in situ from NaI and TBHP) as a means of substrate activators. In this reaction, the N-oxide plays a dual role, acting as a traceless directing group as well as a source of oxygen atom.

Cu- or Fe-catalyzed C–H/C–C bond nitrogenation reactions for the direct synthesis of N-containing compounds

This tutorial account summarizes the recent progress in Cu- or Fe-catalyzed C–H/C–C bond nitrogenation reactions for the direct synthesis of N-containing compounds.

A double-blind, randomized, multicenter, Italian study of frovatriptan versus rizatriptan for the acute treatment of migraine

The objective of this study was to assess patient satisfaction with acute treatment of migraine with frovatriptan or rizatriptan by preference questionnaire. 148 subjects with a history of migraine with or without aura (IHS 2004 criteria), with at least one migraine attack per month in the preceding 6 months, were enrolled and randomized to frovatriptan 2.5 mg or rizatriptan 10 mg treating 1-3 attacks. The study had a multicenter, randomized, double-blind, cross-over design, with treatment periods lasting <3 months. At the end of the study, patients assigned preference to one of the treatments using a questionnaire with a score from 0 to 5 (primary endpoint). Secondary endpoints were pain-free and pain relief episodes at 2 h, and recurrent and sustained pain-free episodes within 48 h. 104 of the 125 patients (83%, intention-to-treat population) expressed a preference for a triptan. The average preference score was not significantly different between frovatriptan (2.9±1.3) and rizatriptan (3.2±1.1). The rates of pain-free (33% frovatriptan vs. 39% rizatriptan) and pain relief (55 vs. 62%) episodes at 2 h were not significantly different between the two treatments. The rate of recurrent episodes was significantly (p<0.001) lower under frovatriptan (21 vs. 43% rizatriptan). No significant differences were observed in sustained pain-free episodes (26% frovatriptan vs. 22% rizatriptan). The number of patients with adverse events was not significantly different between rizatriptan (34) and frovatriptan (25, p=NS). The results suggest that frovatriptan has a similar efficacy to rizatriptan, but a more prolonged duration of action.

Acute treatment of migraine

Acute treatment of migraine has benefited first from major advances in pharmacological science followed in short order, sometimes preceded, by an improved understanding of pathogenesis, especially of headache. This chapter reviews the mechanisms of migraine that provide an understanding of the pharmacology and therapeutic targets for acute migraine medications. General clinical approaches to acute therapy are reviewed, and indices of acceptable acute therapeutic outcomes are discussed. Currently the serotonin (5-HT) 1B/1D agonist group of drugs, triptans, forms the mainstay of acute therapeutic regimens. Other approaches to acute treatment such as simple analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), ergots, and combination medications are reviewed. Finally, the newest acute treatments that are currently exploratory or under clinical investigation are discussed.

A pilot study of rizatriptan and visually-induced motion sickness in migraineurs

BACKGROUND

Limited evidence suggests that rizatriptan given before vestibular stimulation reduces motion sickness in persons with migraine-related dizziness. The present study was designed to test whether rizatriptan is also effective in protecting against visually-induced motion sickness and to test whether rizatriptan blocks the augmentation of motion sickness by head pain.

MATERIAL AND METHODS

Using randomized double-blind, placebo-controlled methodology, 10 females, 6 with migrainous vertigo (V+) and four without vertigo (V-) received 10 mg rizatriptan or placebo two hours prior to being stimulated by optokinetic stripes. Visual stimulation was coupled with three pain conditions: no pain (N), thermally-induced hand pain (H) and temple pain (T). Motion sickness and subjective discomfort were measured.

RESULTS

Motion sickness was less after pre-treatment with rizatriptan for 4 of 10 subjects and more for 5 of 10 subjects. Augmentation of motion sickness by head pain was seen in 6 of 10 subjects; this effect was blunted by rizatriptan in 4 of these 6 subjects. Subjective discomfort was significantly more noticeable in V+ subjects as compared with V- subjects.

CONCLUSIONS

These pilot data suggest that rizatriptan does not consistently reduce visually-induced motion sickness in migraineurs. Rizatriptan may diminish motion sickness potentiation by cranial pain.

Pharmacogenomics and migraine: possible implications

Pharmacogenomics is the science about how inherited factors influence the effects of drugs. Drug response is always a result of mutually interacting genes with important modifications from environmental and constitutional factors. Based on the genetic variability of pharmacokinetic and in some cases pharmacodynamic variability we mention possible implications for the acute and preventive treatment of migraine. Pharmacogenomics will most likely in the future be one part of our therapeutic armamentarium and will provide a stronger scientific basis for optimizing drug therapy on the basis of each patient’s genetic constitution.

Development and validation of a selective and robust LC–MS/MS method for high-throughput quantifying rizatriptan in small plasma samples: Application to a clinical pharmacokinetic study

An analytical method based on liquid chromatography with positive ion electrospray ionization (ESI) coupled to tandem mass spectrometry detection (LC-MS/MS) was developed for the determination of a potent 5-HT(1B/1D) receptor agonist, rizatriptan in human plasma using granisetron as the internal standard. The analyte and internal standard were isolated from 100 microL plasma samples by liquid-liquid extraction (LLE) and chromatographed on a Lichrospher C18 column (4.6mm x 50mm, 5 microm) with a mobile phase consisting of acetonitrile-10mM aqueous ammonium acetate-acetic acid (50:50:0.5, v/v/v) pumped at 1.0 mL/min. The method had a chromatographic total run time of 2 min. A Varian 1200 L electrospray tandem mass spectrometer equipped with an electrospray ionization source was operated in selected reaction monitoring (SRM) mode with the precursor-to-product ion transitions m/z 270-->201 (rizatriptan) and 313.4-->138 (granisetron) used for quantitation. The assay was validated over the concentration range of 0.05-50 ng/mL and was found to have acceptable accuracy, precision, linearity, and selectivity. The mean extraction recovery from spiked plasma samples was above 98%. The intra-day accuracy of the assay was within 12% of nominal and intra-day precision was better than 13% C.V. Following a 10mg dose of the compound administered to human subjects, mean concentrations of rizatriptan ranged from 0.2 to 70.6 ng/mL in plasma samples collected up to 24h after dosing. Inter-day accuracy and precision results for quality control samples run over a 5-day period alongside clinical samples showed mean accuracies of within 12% of nominal and precision better than 9.5% C.V.

Effects on productivity and quality of life of rizatriptan for acute migraine: a workplace study

OBJECTIVE

To evaluate the impact of treatment with rizatriptan 10 mg on jobs and quality of life of patients with migraine.

METHODS

Prospective, open-label study at 27 work sites of 20 companies representing diverse labor sectors in Spain. Eligible patients according International Headache Society (IHS) criteria were recruited for the study by on-site physicians and instructed to treat moderate or severe migraine attacks with one tablet of rizatriptan 10 mg. They were asked to complete the study questionnaires (ML-96, SF-36) at baseline, and then 3 months later.

RESULTS

A total of 259 patients (83 men and 176 women) of a mean age of 39 (range 18 to 61 years) completed the study. Only 7% had taken triptans before for treatment of their migraine attacks. After 3 months of rizatriptan therapy, the use of medical services was significantly lower and all tested domains of quality of life had improved (P<.001). Absenteeism and days worked during migraine attacks also fell significantly during 3 months of rizatriptan therapy as compared with the 3 months before the study (P<.001). The improvement in productivity was reflected in the significant decreases in lost workday equivalents (decrease from 3.32 to 1.21 days; P<.001) and also in the total number of workdays lost (decrease from 5.16 to 1.82 days; P<.001). Two-thirds of patients described the efficacy of oral rizatriptan as excellent or very good (62%), and 89% preferred it over their usual medications for acute treatment of migraine attacks.

CONCLUSION

For this employed population of patients with migraine, treatment with rizatriptan significantly improved parameters measuring direct medical costs, work and productivity, and health-related quality of life. In accordance with these findings, direct and indirect costs related to migraine could be substantially reduced by gathering detailed information about the nature of headache, eliminating triggering factors, and instituting effective treatment of migraine attacks.

A review of rizatriptan, a quick and consistent 5-HT1B/1Dagonist for the acute treatment of migraine

Rizatriptan is a second-generation triptan marketed as 5 and 10 mg tablets and rapidly disintegrating wafer formulations. In > 5000 acute migraine patients enrolled in short-term trials and almost 1800 patients in long-term, open-label trials treating approximately 47000 attacks, rizatriptan was effective and well-tolerated. Controlled head-to-head data and a meta-analysis of 53 randomised, placebo-controlled trials of oral triptans in > 24000 patients have shown that rizatriptan 10 mg offers efficacy advantages over oral sumatriptan 50 and 100 mg and other oral triptans, both in terms of speed of onset of action and consistency. These advantages may reflect its improved pharmacological profile over sumatriptan in terms of higher oral bioavailability and a shorter time to maximum concentration. The wafer formulation offers the convenience of being administered without water. As a result of its superior efficacy profile and generally good tolerability, rizatriptan can be considered as a first-line treatment for acute migraine.

Determination of rizatriptan in human plasma by liquid chromatographic-eletrospray tandem mass spectrometry: application to a pharmacokinetic study

A sensitive liquid chromatographic-tandem mass spectrometry(LC-MS/MS) method was developed for the determination of rizatriptan in human plasma. The analytes were extracted from plasma samples by liquid-liquid extraction, separated on a Zorbax XDB C8 column (150 x 4.6 mm i.d.) and detected by tandem mass spectrometry with an electrospray ionization interface. Zomitriptan was used as the internal standard. The method had a lower limit of quantitation of 50 pg/mL for rizatriptan, which showed more sensitivity and speed of analysis compared with reported methods. The within- and between-day precision was measured to be below 11.71% and accuracy between -5.87 and 0.86% for all quality control samples. This quantitation method was successfully applied to the evaluation of the pharmacokinetic profiles of rizatriptan after single oral administration of 5, 10 and 15 mg rizatriptan tablets to 10 healthy volunteers (five males and five females).

Rizatriptan: a pharmacoeconomic review of its use in the acute treatment of migraine

Rizatriptan (Maxalt; Maxalt-MLT; Maxalt-Melt) is an oral serotonin 5-HT(1B/1D) receptor agonist (triptan) used in the acute treatment of migraine with or without aura in adults. Rizatriptan 5 mg and 10 mg are effective in relieving the symptoms of migraine and the 10 mg dose provided faster pain relief than sumatriptan 50 mg, naratriptan 2.5 mg, ergotamine/caffeine 2 mg/200 mg and possibly zolmitriptan 2.5 mg, while displaying similar tolerability. Two cost-utility analyses performed from a societal perspective indicated that rizatriptan 10 mg was dominant over ergotamine/caffeine 2 mg/200 mg, sumatriptan 50 mg or 100 mg, naratriptan 2.5 mg, zolmitriptan 2.5 mg and analgesic-based usual care in the acute treatment of migraine. In one analysis also performed from the perspective of a healthcare payer, rizatriptan was still dominant over naratriptan, sumatriptan and zolmitriptan. Rizatriptan was cost effective compared with usual care with an incremental cost per quality-adjusted life-year (QALY) gained of 31,845 Can dollars (2002 values) and an incremental cost per additional attack aborted of 49.82 Can dollars. A modelled cost-effectiveness analysis conducted from a healthcare payer's perspective indicated that almotriptan 12.5 mg was more cost effective than rizatriptan 10 mg as a result of better tolerability. The incremental cost per additional successfully treated patient (defined as being sustained pain free without adverse events) with almotriptan was 6.94 US dollars (1999 values). In other nonmodelled cost-effectiveness analyses, rizatriptan 10 mg, eletriptan 40 mg and almotriptan 12.5 mg most consistently displayed the greatest cost effectiveness in different analyses using different clinical endpoints. A modelled analysis of the costs of migraine-related productivity losses in US corporations indicated that the use of rizatriptan rather than usual care to treat migraines could result in annual cost offsets of approximately 84-118 US dollars (2000 values) per employee in lost productivity avoided. An intervention study in Spanish postal service workers demonstrated that replacement of usual care with rizatriptan reduced the mean per-patient cost of lost productivity per migraine attack from 34.47 euros (2001/2002 values) before the intervention to 13.94 euros and 4.59 euros for the first and second post-intervention migraine attacks. In conclusion, rizatriptan is one of the more clinically effective and therefore cost-effective oral triptans available for the acute treatment of migraine. The available data from cost-utility analyses suggest that rizatriptan is more cost effective than ergotamine/caffeine, simple analgesics, naratriptan, zolmitriptan and sumatriptan. The economic value of rizatriptan depends on the payer's perspective, as the greatest savings can be expected to be achieved in terms of reduced migraine-related loss of work productivity compared with less effective treatments. For healthcare payers, the high acquisition cost appears to be at least partly offset by reduced migraine-related healthcare resource use when compared with usual care. The comparative cost effectiveness of the newer triptans requires further elucidation from comprehensive direct comparisons.

Liquid chromatographic method for the determination of rizatriptan in human plasma

A high-performance liquid chromatographic (HPLC) method with fluorescence detection has been developed for the determination of rizatriptan in human plasma. Following a single-step liquid-liquid extraction with methyl tertiarybutyl ether, the analytes were separated using a mobile phase consisting of 0.05% (v/v) triethylamine in water (adjusting to pH 2.75 with 85% phosphoric acid) and acetonitrile (92:8, v/v). Fluorescence detection was performed at an excitation wavelength of 225nm and an emission wavelength of 360nm. The linearity for rizatriptan was within the concentration range of 0.5-50ng/ml. The intra- and inter-day precisions of the method were not more than 8.0%. The lower limit of quantification (LLOQ) was 0.5ng/ml for rizatriptan. The method was sensitive, simple and repeatable enough to be used in pharmacokinetic studies.

[Rizatriptan (Maxalt), a new entity of triptan for migraine: pharmacology and therapeutic relevance]

Rizatriptan is a highly potent, selective serotonin 5-HT(1B/1D)-receptor agonist. Current theories on the mechanism of migraine suggest the central role of vasodilation of intracranial, extracerebral blood vessels and activation of perivascular trigeminal sensory nerves. There abundantly exist 5-HT(1B) receptors in meningeal blood vessels and 5-HT(1D) receptors in the trigeminal ganglia. The therapeutic activity of rizatriptan in migraine can most likely be attributed to agonist effects at 5-HT(1B/1D) receptors on these target sites. Two types of the 10 mg formulation, a tablet (Maxalt) tablet) and an orally disintegrating tablet (Maxalt)RPD tablet), are available. The latter may have a clinical relevance for patients who administer it without liquid. Pharmacokinetic study demonstrated the approximate T(max) of 1.0 or 1.1 h in tablets and 1.3 h in RPD tablets, resulting in early onset for headache relief and also pain free. Bioavailability was estimated to be about 45%. The efficacy and good tolerability and underlying profiles of pharmacokinetics of rizatriptan are almost similar between Japanese and other races, and a reduction in headache response up to 2 h can be attained in a large majority of patients. Several reports have described the favorable clinical profile of rizatriptan in comparison to other triptans. Rizatriptan is thus effective and provides migraine sufferers with an appropriate quality of life.

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.