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

Rizatriptan is an orally active serotonin 5-HT(1) receptor agonist that potently and selectively binds to 5-HT(1B/1D) subtypes. Earlier clinical trials demonstrated that rizatriptan 5 or 10mg is more effective than placebo at providing pain relief and a pain-free state, relieving associated symptoms of migraine, normalising functional ability and improving patient quality of life, and showed that rizatriptan provides faster freedom from pain and reduces nausea to a greater extent than oral sumatriptan. More recently, rizatriptan 10mg was shown to be more effective than zolmitriptan 2.5mg or naratriptan 2.5mg at producing a pain-free state 2 hours postdose. Furthermore, compared with naratriptan, significantly more patients who received rizatriptan were pain free or had pain relief from 1 hour onwards. The number of patients with normal functional ability at 2 hours was significantly higher after rizatriptan than after naratriptan or zolmitriptan. Rizatriptan was also generally more effective than zolmitriptan or naratriptan at relieving migraine-associated symptoms. Rizatriptan is generally well tolerated and adverse events are usually mild and transient. The most common adverse events associated with rizatriptan in recent randomised trials were asthenia/fatigue, dizziness, somnolence and nausea. There was a trend towards a lower incidence of adverse events with rizatriptan compared with zolmitriptan (31.2 vs 38.8%). However, rizatriptan was associated with a significantly higher incidence of adverse events than naratriptan (39 vs 29%). The incidence of chest pain was similar after the administration of rizatriptan, zolmitriptan or naratriptan (2 to 4%). CONCLUSION: Rizatriptan is an effective drug for the acute treatment of moderate or severe migraine. Oral rizatriptan 5 and 10mg have shown greater efficacy than placebo in providing pain relief, an absence of pain, relief from associated symptoms, normal functional ability and an improvement in patient quality of life. Earlier results showed that rizatriptan provides faster freedom from pain and reduces nausea to a greater extent than oral sumatriptan. More recent studies have shown that rizatriptan 10mg provides faster pain relief and a higher percentage of patients with an absence of pain and normal functional ability at 2 hours than naratriptan 2.5mg or zolmitriptan 2.5mg. The efficacy of rizatriptan is retained when used in the long term and the drug is generally well tolerated. Although well designed studies comparing rizatriptan with almotriptan, eletriptan and frovatriptan would further define the position of rizatriptan, current data suggest rizatriptan should be considered as a first-line treatment option in the management of migraine.     

Spotlight on rizatriptan in migraine

Rizatriptan is an orally active serotonin 5-HT(1) receptor agonist that potently and selectively binds to 5-HT(1B/1D) subtypes. Earlier clinical trials demonstrated that rizatriptan 5 or 10mg is more effective than placebo at providing pain relief and a pain-free state, relieving associated symptoms of migraine, normalising functional ability and improving patient quality of life, and showed that rizatriptan provides faster freedom from pain and reduces nausea to a greater extent than oral sumatriptan. More recently, rizatriptan 10mg was shown to be more effective than zolmitriptan 2.5mg or naratriptan 2.5mg at producing a pain-free state 2 hours postdose. Furthermore, compared with naratriptan, significantly more patients who received rizatriptan were pain free or had pain relief from 1 hour onwards. The number of patients with normal functional ability at 2 hours was significantly higher after rizatriptan than after naratriptan or zolmitriptan. Rizatriptan was also generally more effective than zolmitriptan or naratriptan at relieving migraine-associated symptoms. Rizatriptan is generally well tolerated, and adverse events are usually mild and transient. The most common adverse events associated with rizatriptan in recent randomised trials were asthenia/fatigue, dizziness, somnolence and nausea. There was a trend towards a lower incidence of adverse events with rizatriptan compared with zolmitriptan (31.2 vs 38.8%). However, rizatriptan was associated with a significantly higher incidence of adverse events than naratriptan (39 vs 29%). The incidence of chest pain was similar after the administration of rizatriptan, zolmitriptan or naratriptan (2-4%). In conclusion, rizatriptan is an effective drug for the acute treatment of moderate or severe migraine. Oral rizatriptan 5 and 10mg have shown greater efficacy than placebo in providing pain relief, an absence of pain, relief from associated symptoms, normal functional ability and an improvement in patient quality of life. Earlier results showed that rizatriptan provides faster freedom from pain and reduces nausea to a greater extent than oral sumatriptan. More recent studies have shown that rizatriptan 10mg provides faster pain relief and a higher percentage of patients with an absence of pain and normal functional ability at 2 hours than naratriptan 2.5mg or zolmitriptan 2.5mg. The efficacy of rizatriptan is retained when used in the long term, and the drug is generally well tolerated. Although well designed studies comparing rizatriptan with almotriptan, eletriptan and frovatriptan would further define the position of rizatriptan, current data suggest that rizatriptan should be considered as a first-line treatment option in the management of migraine.     

Rizatriptan: a new 5-HT1B/1D receptor agonist for the treatment of migraine

Rizatriptan (MAXALT MK-0462) is a new 5-HT(1B/1D) receptor agonist for the acute treatment of migraine. The marketed 10 mg and 5 mg oral doses are rapidly and consistently effective in relieving headache pain with associated migraine symptoms, and in enabling patients to return to their normal activities of daily living. Rizatriptan 10 mg is more effective than rizatriptan 5 mg. Compared to oral sumatriptan, the established agent in this class, rizatriptan has a shorter Tmax and greater bioavailability. In comparative clinical trials, the probability of having pain relief sooner was higher for rizatriptan 10 mg than for sumatriptan 100 mg or 50 mg. Over the 2 h after dosing, rizatriptan 10 mg was also superior to sumatriptan 100 mg and 50 mg on a range of other outcome measures. Both doses of rizatriptan are well-tolerated. The most common side-effects are dizziness, drowsiness, and asthenia/fatigue, which are short-lasting and of mild or moderate severity. In summary, rizatriptan is an effective and well-tolerated acute treatment for migraine, which may offer some advantages over oral sumatriptan.     

Rizatriptan: pharmacological differences from sumatriptan and clinical results

Rizatriptan and sumatriptan are selective 5-HT(1B/1D) receptor agonists for theacute treatment of migraine. For oral formulations, the time to maximum plasma concentration is reached earlier with rizatriptan than with sumatriptan (1 h versus 2-2.5 h) and rizatriptan has greater bioavailability than sumatriptan (45% versus 15%). These pharmacological advantages appear to translate into a faster onset of action and a better overall response for oral rizatriptan versus oral sumatriptan. The two drugs have been directly compared in randomized, double-blind, placebo-controlled clinical trials of patients with moderate or severe migraine attacks. Rizatriptan 10 mg was generally superior to sumatriptan on a measure of time-to-pain-relief within 2 h, where pain relief was defined as a reduction of pain to mild or none (odds ratio for rizatriptan versus sumatriptan 100 mg = 1.21; odds ratios for rizatriptan 10 mg versus sumatriptan 50 mg = 1.14 and 1.10 in two studies). Rizatriptan 10 mg was also superior to sumatriptan on the International Headache Society recommended endpoint of the percentage of patients pain free at 2 h (40% for rizatriptan 10 mg, 33% for sumatriptan 100 mg, and 35% for sumatriptan 50 mg). Further advantages for rizatriptan were seen on stringent outcome measures of the percentage of patients who were completely free of all symptoms at 2 h, patient satisfaction with medication at 2 h, and 24-h sustained pain-free response. 5-HT(1B/1D) receptor agonists are contraindicated in patients with coronary artery disease because of their potential to cause vasoconstriction. In clinical trials which excluded such patients, rizatriptan and sumatriptan were both well-tolerated. The most common side-effects on both drugs occurred in <10% of patients and consisted of dizziness, drowsiness, and asthenia/fatigue. The adverse events were usually mild or moderate in severity and short-lasting.     

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.     

Efficacy of almotriptan 12.5 mg in achieving migraine-related composite endpoints: a double-blind, randomized, placebo-controlled study in patients controlled study in patients with previous poor response to sumatriptan 50 mg

BACKGROUND: Triptans are not identical and migraine sufferers respond differently to different triptans. Few studies have evaluated the efficacy of switching triptans in migraine patients who have shown poor response to another agent. OBJECTIVE: To investigate the efficacy and tolerability of almotriptan 12.5 mg in patients who did not achieve 2-h pain relief with sumatriptan 50 mg. METHODS: This double-blind, placebo-controlled study recruited patients with IHS-defined migraine and at least 2 previous unsatisfactory responses to sumatriptan. Those who did not achieve pain relief (moderate or severe pain decreasing to mild or no pain) 2 h after taking oral sumatriptan 50 mg on an open-label basis for the treatment of their first migraine attack during this trial (Attack 1) were randomized to receive either oral almotriptan 12.5 mg or placebo for the treatment of their next migraine attack (Attack 2). RESULTS: Of 302 patients receiving sumatriptan 50 mg for the treatment of their first migraine attack, 221 (73%) did not achieve 2-h pain relief and were randomized to almotriptan 12.5 mg or placebo for the treatment of Attack 2. The majority (70%) of randomized patients treating their headache in Attack 2 reported severe pain at baseline characterizing this as a difficult-to-treat population. In the intent-to-treat population (n = 198), significantly more patients in the almotriptan group compared with the placebo group achieved 2-h complete relief (free from pain and migraine-associated symptoms) at 2 h (17.1% vs. 4.4%; p < 0.05) and sustained pain free (20.9% vs. 9.0%; p < 0.05). Adverse events of mild-to-moderate intensity occurred in 7.1% of patients in the almotriptan group compared to 5.1% in the placebo group (not statistically different). CONCLUSION: Almotriptan is more effective than placebo and similarly well-tolerated for the acute treatment of migraine in patients who responded poorly to oral sumatriptan.     

A review of rizatriptan, a quick and consistent 5-HT1B/1D agonist 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.     

A review of rizatriptan,a quick and consistent 5-HT1B/1D agonist 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 ~ 47,000 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 > 24,000 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.     

Triptans in migraine: a comparative review of pharmacology, pharmacokinetics and efficacy

Triptans are a new class of compounds developed for the treatment of migraine attacks. The first of the class, sumatriptan, and the newer triptans (zolmitriptan, naratriptan, rizatriptan, eletriptan, almotriptan and frovatriptan) display high agonist activity at mainly the serotonin 5-HT1B and 5-HT1D receptor subtypes. As expected for a class of compounds developed for affinity at a specific receptor, there are minor pharmacodynamic differences between the triptans. Sumatriptan has a low oral bioavailability (14%) and all the newer triptans have an improved oral bioavailability and for one, risatriptan, the rate of absorption is faster. The half-lives of naratriptan, eletriptan and, in particular, frovatriptan (26 to 30h) are longer than that of sumatriptan (2h). These pharmacokinetic improvements of the newer triptans so far seem to have only resulted in minor differences in their efficacy in migraine. Double-blind, randomised clinical trials (RCTs) comparing the different triptans and triptans with other medication should ideally be the basis for judging their place in migraine therapy. In only 15 of the 83 reported RCTs were 2 triptans compared, and in 11 trials triptans were compared with other drugs. Therefore, in all placebo-controlled randomised clinical trials, the relative efficacy of the triptans was also judged by calculating the therapeutic gain (i.e. percentage response for active minus percentage response for placebo). The mean therapeutic gain with subcutaneous sumatriptan 6mg (51%) was more than that for all other dosage forms of triptans (oral sumatriptan 100mg 32%; oral sumatriptan 50mg 29%: intranasal sumatriptan 20mg 30%; rectal sumatriptan 25mg 31%; oral zolmitriptan 2.5mg 32%; oral rizatriptan 10mg 37%; oral eletriptan 40mg 37%; oral almotriptan 12.5mg 26%). Compared with oral sumatriptan 100mg (32%), the mean therapeutic gain was higher with oral eletriptan 80mg (42%) but lower with oral naratriptan 2.5mg (22%) or oral frovatriptan 2.5mg (16%). The few direct comparative randomised clinical trials with oral triptans reveal the same picture. Recurrence of headache within 24 hours after an initial successful response occurs in 30 to 40% of sumatriptan-treated patients. Apart from naratriptan, which has a tendency towards less recurrence, there appears to be no consistent difference in recurrence rates between the newer triptans and sumatriptan. Rizatriptan with its shorter time to maximum concentration (tmax) tended to produce a quicker onset of headache relief than sumatriptan and zolmitriptan. The place of triptans compared with non-triptan drugs in migraine therapy remains to be established and further RCTs are required.     

Efficacy of almotriptan 12.5 mg in achieving migraine-related composite endpoints: a double-blind,randomized, placebo-controlled study in patients with previous poor response to sumatriptan 50 mg

ABSTRACT

Background: Triptans are not identical and migraine sufferers respond differently to different triptans. Few studies have evaluated the efficacy of switching triptans in migraine patients who have shown poor response to another agent.

Objective: To investigate the efficacy and tolerability of almotriptan 12.5?mg in patients who did not achieve 2‐h pain relief with sumatriptan 50?mg.

Methods: This double-blind, placebo-controlled study recruited patients with IHS-defined migraine and at least 2 previous unsatisfactory responses to sumatriptan. Those who did not achieve pain relief (moderate or severe pain decreasing to mild or no pain) 2?h after taking oral sumatriptan 50?mg on an open-label basis for the treatment of their first migraine attack during this trial (Attack 1) were randomized to receive either oral almotriptan 12.5?mg or placebo for the treatment of their next migraine attack (Attack 2).

Results: Of 302 patients receiving sumatriptan 50?mg for the treatment of their first migraine attack, 221 (73%) did not achieve 2‐h pain relief and were randomized to almotriptan 12.5?mg or placebo for the treatment of Attack 2. The majority (70%) of randomized patients treating their headache in Attack 2 reported severe pain at baseline characterizing this as a difficult-to-treat population. In the intent-to-treat population (n = 198), significantly more patients in the almotriptan group compared with the placebo group achieved 2‐h complete relief (free from pain and migraine-associated symptoms) at 2?h (17.1% vs. 4.4%; p < 0.05) and sustained pain free (20.9% vs. 9.0%; p < 0.05). Adverse events of mild-to-moderate intensity occurred in 7.1% of patients in the almotriptan group compared to 5.1% in the placebo group (not statistically different).

Conclusion: Almotriptan is more effective than placebo and similarly well-tolerated for the acute treatment of migraine in patients who responded poorly to oral sumatriptan.     

Rizatriptan, a novel 5-HT1B/1D agonist for migraine: single- and multiple-dose tolerability and pharmacokinetics in healthy subjects

Rizatriptan is a novel 5-HT1D/1B agonist for relief of migraine headache. The pharmacokinetics, metabolite profiles, and tolerability of rizatriptan were examined in a multiple-dose study in healthy subjects. Rizatriptan (N = 24) (or placebo, N = 12) was administered as a single 10 mg dose, followed 48 hours later by administration of one 10 mg dose every 2 hours for three doses on 4 consecutive days, corresponding to the maximum daily dose for a migraine attack. The AUC of rizatriptan and its active N-monodesmethyl metabolite after three 10 mg doses was approximately threefold greater than the plasma concentrations following a single 10 mg dose. Metabolite profiles were similar after single and multiple doses. Adverse events during rizatriptan were mild and transient; similar events occurred during placebo, with a somewhat reduced incidence. Diastolic blood pressure tended to increase compared with placebo (approximately 5 mmHg), particularly on the first multiple-dose day (p < .01 vs. placebo). In conclusion, rizatriptan is well tolerated by healthy subjects during multiple-dose administration, with no unexpected accumulation of drug in plasma.     

Cost-effectiveness analysis of rizatriptan and sumatriptan versus Cafergot in the acute treatment of migraine

BACKGROUND: Both ergotamine and selective serotonin 5-HT(1B/1D) receptor agonists ('triptans') are currently used in the treatment of moderate to severe migraine. Ergotamine is a traditional therapy with a lower drug acquisition cost compared with triptans. It has been shown that triptans are more efficacious than ergotamine, but the higher acquisition costs and shorter duration of action are disadvantages of triptans compared with ergotamine. OBJECTIVE: The purpose of this study was to provide a comparison of the cost-effectiveness of rizatriptan 10 mg and sumatriptan 50 mg tablets with that of a fixed-dose combination of ergotamine tartrate plus caffeine (Cafergot) in the treatment of an acute migraine attack. The cost-effectiveness of rizatriptan in comparison with sumatriptan was also assessed. METHODS: Three separate decision tree models were developed (model 1: rizatriptan vs Cafergot; model 2: sumatriptan vs Cafergot; model 3: rizatriptan vs sumatriptan). The time horizon was 1 year. Cost-effectiveness analysis was conducted from the societal perspective using cost and effectiveness estimates from the literature. All costs were converted to US dollars (2003). The cost-effectiveness ratio was expressed as incremental cost per quality-adjusted life-year (QALY) gained. RESULTS: Base case evaluation showed that both rizatriptan and sumatriptan dominated Cafergot. The net annual saving associated with use of rizatriptan was US dollars 622.98 per patient, with an incremental QALY of 0.001. Use of sumatriptan resulted in a saving of US dollars 620.90 and an increase in QALY. The cost-effective ratios were not sensitive to changes in key variables such as efficacy, utility, drug costs, hospitalisation cost and patient preference over alternative therapies. The study further showed that rizatriptan is more cost effective than sumatriptan, as evidenced by its lower cost and greater effectiveness. Sensitivity analysis showed that the cost-effectiveness ratios were sensitive to moderate changes in drug efficacy. CONCLUSION: Rizatriptan and sumatriptan were less costly and more effective than Cafergot in the treatment of an acute migraine attack. Rizatriptan was somewhat less costly and more effective than sumatriptan. Additional quality-of-life studies are needed to confirm the benefits of using triptans in the management of migraine.     

Migraine pharmacotherapy with oral triptans: a rational approach to clinical management

The recent clinical development of a number of migraine specific 5-HT_1B/1Dagonist triptans with enhanced lipophilicity (TELs), relative to the first drug of this class sumatriptan, and with a range of different metabolic, pharmacokinetic and receptor affinity profiles, provides the potential for critically different clinical profiles. Eletriptan, naratriptan, rizatriptan and zolmitriptan display both increased stability to first pass metabolic inactivation by monoamine oxidase (MAO-A) and enhanced lipophilicity (4- to >> 120-fold more than sumatriptan), leading to increased oral bioavailability (2- to 5-fold more than the 14% reported for oral sumatriptan). Central penetration and increased receptor affinity and selectivity for the neuronal (5-HT_1D) receptor also combine to allow for lower total oral dosing (i.e., unit doses of 15 mg or less compared with 50 - 300 mg doses of sumatriptan) and reduced peripheral exposure to the coronary vasoconstrictor (5-HT_1B) receptor. The notable exception being eletriptan, where an active P-glycoprotein blood-brain barrier efflux system effectively negates these benefits and requires an 80 mg oral dose. Differences in the metabolic balance between hepatic P450 (especially CYP 1A2) and MAO-A inactivation lead to potential drug interactions for all TELs with the oral contraceptive pill (OCP), fluvoxamine and the quinilone antibiotics (with increased triptan levels). An important but complex MAO-A interaction between a metabolite of propranolol and rizatriptan mandates dosage reduction (to 5 mg) for rizatriptan in the presence of propranolol treatment. There is also an absolute contraindication for the concurrent administration of the MAO-A inhibitor moclobemide and rizatriptan. All the new-marketed TELs have potential clinical benefits and were well-tolerated relative to sumatriptan. Both rizatriptan (10 mg) and zolmitriptan (2.5 mg and 5 mg) demonstrate at least equivalent efficacy to sumatriptan 25, 50 and 100 mg, respectively, making them suitable first line agents for moderate or severe migraine headaches. Rizatriptan has the fastest onset of effect of the TELs. Naratriptan would appear to have lower recurrent headache rate than sumatriptan, rizatriptan or zolmitriptan. Therefore, for headaches of long duration and with a tendency to recur naratriptan may be the most appropriate treatment. Thus, knowledge of the metabolic, pharmacokinetic and clinical profiles of the TELs facilitates the selection of a triptan which allows optimisation of the clinical benefits for individual patients, minimising the risk of drug interactions and a minimally effective dose to reduce potential adverse events (AEs).     

Migraine pharmacotherapy with oral triptans: a rational approach to clinical management

The recent clinical development of a number of migraine specific 5-HT1B/1D agonist triptans with enhanced lipophilicity (TELs), relative to the first drug of this class sumatriptan, and with a range of different metabolic, pharmacokinetic and receptor affinity profiles, provides the potential for critically different clinical profiles. Eletriptan, naratriptan, rizatriptan and zolmitriptan display both increased stability to first pass metabolic inactivation by monoamine oxidase (MAO-A) and enhanced lipophilicity (4- to > 120-fold more than sumatriptan), leading to increased oral bioavailability (2- to 5-fold more than the 14% reported for oral sumatriptan). Central penetration and increased receptor affinity and selectivity for the neuronal (5-HT1D) receptor also combine to allow for lower total oral dosing (i.e., unit doses of 15 mg or less compared with 50-300 mg doses of sumatriptan) and reduced peripheral exposure to the coronary vasoconstrictor (5-HT1B) receptor. The notable exception being eletriptan, where an active P-glycoprotein blood-brain barrier efflux system effectively negates these benefits and requires an 80 mg oral dose. Differences in the metabolic balance between hepatic P450 (especially CYP 1A2) and MAO-A inactivation lead to potential drug interactions for all TELs with the oral contraceptive pill (OCP), fluvoxamine and the quinilone antibiotics (with increased triptan levels). An important but complex MAO-A interaction between a metabolite of propranolol and rizatriptan mandates dosage reduction (to 5 mg) for rizatriptan in the presence of propranolol treatment. There is also an absolute contraindication for the concurrent administration of the MAO-A inhibitor moclobemide and rizatriptan. All the new-marketed TELs have potential clinical benefits and were well-tolerated relative to sumatriptan. Both rizatriptan (10 mg) and zolmitriptan (2.5 mg and 5 mg) demonstrate at least equivalent efficacy to sumatriptan 25, 50 and 100 mg, respectively, making them suitable first line agents for moderate or severe migraine headaches. Rizatriptan has the fastest onset of effect of the TELs. Naratriptan would appear to have lower recurrent headache rate than sumatriptan, rizatriptan or zolmitriptan. Therefore, for headaches of long duration and with a tendency to recur naratriptan may be the most appropriate treatment. Thus, knowledge of the metabolic, pharmacokinetic and clinical profiles of the TELs facilitates the selection of a triptan which allows optimisation of the clinical benefits for individual patients, minimising the risk of drug interactions and a minimally effective dose to reduce potential adverse events (AEs).     

Effects of a fast disintegrating/rapid release oral formulation of sumatriptan on functional ability in patients with migraine

BACKGROUND: A new oral form of sumatriptan has been developed to facilitate tablet disintegration and drug dispersion and to mitigate the effects of gastric stasis that can accompany migraine. OBJECTIVE: To evaluate the effects on functional ability of the new fast disintegrating/rapid release formulation of sumatriptan. METHODS: Sumatriptan 50 mg (n = 137), 100 mg (n = 142), or placebo (n = 153) was administered early when pain was mild for the acute treatment of a single migraine attack in a randomized, double-blind, parallel-group, placebo-controlled clinical trial. For this report, main health-outcomes endpoints (which were secondary endpoints for this clinical trial that was primarily designed to assess pain-free efficacy) included functional ability measured through 2 h postdose on a 5-point scale and lost time equivalents, a composite measure of migraine-associated time missed from activities, and reduced effectiveness at activities through 24 h postdose. RESULTS: Normal functional ability was restored in a significantly (p < 0.05) greater percentage of patients treated with sumatriptan than placebo beginning 45 min postdose for sumatriptan 100 mg and 1 h postdose for sumatriptan 50 mg. During the 24 h after initial dosing, the median (range) lost time equivalents for the combination of paid work activities and activities outside of paid work were significantly lower in the groups treated with sumatriptan (1.1 [0-10] sumatriptan 100 mg; 0.8 [0-36] sumatriptan 50 mg) compared with placebo (2.9 [0-24]) (p < or = 0.01 each sumatriptan group versus placebo). The corresponding mean +/- SD values for lost time equivalents were 1.9 +/- 2.3 and 2.5 +/- 4.7 for sumatriptan 100 mg and 50 mg, respectively, compared with 3.5 +/- 4.3 for placebo. CONCLUSION: A new oral sumatriptan formulation confers rapid, sustained restoration of functional ability in the acute treatment of migraine so that patients can return rapidly to normal functioning at work and outside of work.     

Cost effectiveness of oral triptan therapy: a trans-national comparison based on a meta-analysis of randomised controlled trials

OBJECTIVE: The objective of this study was to appraise the relative cost effectiveness of oral triptan therapy in the management of acute migraine, comparing the results obtained using drug cost data from six different countries, USA, UK, Canada, Germany, Italy and The Netherlands. METHOD: A meta-analysis of randomised placebo controlled trials of single dose oral triptans was carried out in order to calculate aggregate Numbers Needed to Treat (NNT) for each triptan and dose. Cost effectiveness ratios were then derived for each treatment by applying mean drug acquisition costs for each country to these NNTs. Using a graphical plot for each country, incremental cost effectiveness comparisons were then made versus sumatriptan 100 mg, the most commonly used oral triptan. RESULTS: When analysed in terms of 2-h pain one country to another. When compared to free outcomes, rizatriptan 10 mg and eletriptan 40 and 80 mg were the most effective oral triptans. Rizatriptan 10mg has the most advantageous absolute cost effectiveness ratio in all six countries studied, although levels of statistical significance compared to other agents varied from sumatriptan 100mg, rizatriptan 10 mg and eletriptan 40 mg are most consistently the cost effective treatment choices, both being cost dominant in five out of six countries studied. CONCLUSIONS: There are systematic differences in triptan efficacy that have an impact on treatment choice. Differences in pricing structure between countries mean that hierarchies of cost effectiveness will vary. Country-specific data should therefore be examined before defining treatment strategies.     

Efficacy and safety of sumatriptan 50 mg in patients not responding to standard care, in the treatment of mild to moderate migraine. The Sumatriptan 50 mg Italian Study Group

The tolerability and efficacy of oral sumatriptan 50 mg for the treatment of mild to moderate migraine attacks were assessed in a double-blind, multicenter placebo-controlled study on a group of patients who had not responded sufficiently to analgesic preparations. Three-hundred-and-twenty-eight migraine sufferers treated a first migraine attack with a nontriptan standard care medication: a mixture containing phenazone, butalbital and caffeine (optalidon) or indomethacin plus prochlorperazine plus caffeine (difmetre) or paracetamol 100 mg (tachipirine), depending on their habits. Of these patients, 32.6% reported headache relief with this treatment and were not included in phase II of the study. The 219 patients not reporting relief during the first phase of the study entered the second phase and were randomized to sumatriptan 50 mg or to placebo; 167 of these patients treated a second attack according to the protocol and were evaluated for efficacy. Of the patients with migraine taking sumatriptan, 58% reported headache relief compared with 35% of placebo-treated patients (p = 0.008). The reduction of nausea and vomiting was significantly better in the sumatriptan group. No differences were detected for the recurrence rate, while rescue medication was used more by the placebo group. The safety profile of sumatriptan 50 mg was confirmed. This study demonstrates the usefulness of this dose of oral sumatriptan against the pain and the accompanying symptoms of mild and moderate migraine.     

Influence of β-adrenoceptor antagonists on the pharmacokinetics of rizatriptan, a 5-HT1B/1D agonist: differential effects of propranolol, nadolol and metoprolol

AIMS: Patients with migraine may receive the 5-HT1B/1D agonist, rizatriptan (5 or 10 mg), to control acute attacks. Patients with frequent attacks may also receive propranolol or other beta-adrenoceptor antagonists for migraine prophylaxis. The present studies investigated the potential for pharmacokinetic or pharmacodynamic interaction between beta-adrenoceptor blockers and rizatriptan. METHODS: Four double-blind, placebo-controlled, randomized crossover investigations were performed in a total of 51 healthy subjects. A single 10 mg dose of rizatriptan was administered after 7 days' administration of propranolol (60 and 120 mg twice daily), nadolol (80 mg twice daily), metoprolol (100 mg twice daily) or placebo. Rizatriptan pharmacokinetics were assessed. In vitro incubations of rizatriptan and sumatriptan with various beta-adrenoceptor blockers were performed in human S9 fraction. Production of the indole-acetic acid-MAO-A metabolite of each triptan was measured. RESULTS: Administration of rizatriptan during propranolol treatment (120 mg twice daily for 7.5 days) increased the AUC(0, infinity) for rizatriptan by approximately 67% and the Cmax by approximately 75%. A reduction in the dose of propranolol (60 mg twice daily) and/or the incorporation of a delay (1 or 2 h) between propranolol and rizatriptan administration did not produce a statistically significant change in the effect of propranolol on rizatriptan pharmacokinetics. Administration of rizatriptan together with nadolol (80 mg twice daily) or metoprolol (100 mg twice daily) for 7 days did not significantly alter the pharmacokinetics of rizatriptan. No untoward adverse experiences attributable to the pharmacokinetic interaction between propranolol and rizatriptan were observed, and no subjects developed serious clinical, laboratory, or other significant adverse experiences during coadministration of rizatriptan with any of the beta-adrenoceptor blockers. In vitro incubations showed that propranolol, but not other beta-adrenoceptor blockers significantly inhibited the production of the indole-acetic acid metabolite of rizatriptan and sumatriptan. CONCLUSIONS: These results suggest that propranolol increases plasma concentrations of rizatriptan by inhibiting monoamine oxidase-A. When prescribing rizatriptan to migraine patients receiving propranolol for prophylaxis, the 5 mg dose of rizatriptan is recommended. Administration with other beta-adrenoceptor blockers does not require consideration of a dose adjustment.     

Sumatriptan. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in the acute treatment of migraine and cluster headache.

Sumatriptan is a serotonin1 (5-HT1) receptor agonist, which is effective in the acute treatment of migraine headache. Its antimigraine activity is believed to derive from selective vasoconstriction of cranial blood vessels which are dilated and distended during migraine headache and/or from inhibition of neurogenically mediated inflammation in the dura mater. In placebo-controlled comparative studies, sumatriptan reduced migraine headache from 'moderate or severe' to 'mild or none' within 2 hours in 50 to 73% of patients following oral administration of 100 or 200 mg, and within 1 hour in 70 to 80% of patients following subcutaneous doses of 6 to 8 mg or intranasal doses 20 mg into each nostril. In addition, sumatriptan alleviated the accompanying symptoms of nausea, vomiting, and photophobia/phonophobia more effectively than placebo, and permitted higher percentages of patients to resume normal daily activities. Sumatriptan 100 mg orally was more effective in the acute treatment of migraine than oral combination therapy consisting of ergotamine 2 mg plus caffeine 200 mg or aspirin 900 mg plus metoclopramide 10 mg. Pooled data from nearly 5000 patients treated with either oral or subcutaneous sumatriptan in clinical trials indicate that it is well tolerated. However, migraine recurrence within 24 or 48 hours of initial symptom resolution developed in approximately 40% of patients treated with sumatriptan, irrespective of route of administration. It is likely that migraine recurrence is related to the short half-life of the drug (approximately 2 hours). Future studies should attempt to ascertain whether additional doses of sumatriptan will help prevent migraine recurrence in patients with attacks of long duration and if so, should determine the optimum interval between dosages. In conclusion, sumatriptan is an important addition to the range of drugs currently available for acute treatment of migraine. It provides rapid relief from debilitating symptoms in a high percentage of patients, particularly after subcutaneous administration. At this stage in its development a number of questions remain to be answered - most notably whether repeat doses will help prevent recurrent attacks and which patients are most likely to respond to therapy. Nevertheless, sumatriptan presently offers a combination of efficacy and tolerability that is unique in this particular clinical setting.     

Almotriptan: a review of its use in migraine

Almotriptan is a selective serotonin 5-HT(1B/1D) receptor agonist ('triptan'). Its efficacy and tolerability have been assessed in a number of randomised, controlled trials in over 4800 adults with moderate or severe attacks of migraine. Oral almotriptan has a rapid onset of action (significant headache relief is observed 0.5 hours after administration of a 12.5mg dose) and efficacy is sustained in most patients who respond by 2 hours. The drug is significantly more effective than placebo as measured by a number of parameters including 2-hour headache response and pain-free response rates. Other symptoms of migraine, including nausea, photophobia and phonophobia, are also alleviated by almotriptan. The efficacy of oral almotriptan appears to be maintained over repeated doses for multiple attacks of migraine treated over a long period (up to 1 year). High headache response rates were reported over all attacks without tachyphylaxis. For the relief of single attacks of migraine, oral almotriptan 12.5mg had similar efficacy to oral sumatriptan 50mg. Patients given almotriptan report less concern with adverse effects than patients given sumatriptan. The lower incidence of chest pain following treatment with almotriptan than with sumatriptan may lead to a reduction in direct costs, with fewer patients requiring management of chest pain. Almotriptan is well tolerated. Most adverse events were of mild or moderate intensity, transient, and generally resolved without intervention or the need for treatment withdrawal. The most common adverse events associated with oral almotriptan 12.5mg treatment were dizziness, paraesthesia, nausea, fatigue, headache, somnolence, skeletal pain, vomiting and chest symptoms. The incidence of adverse events did not differ from placebo and decreased in the longer term. Almotriptan can be coadministered with drugs that share a common hepatic metabolic path; in addition, dosage reduction is required only in the presence of severe renal or hepatic impairment. CONCLUSIONS: Almotriptan is an effective drug for the acute treatment of moderate or severe attacks of migraine in adults. An oral dose of almotriptan 12.5mg has shown greater efficacy than placebo; current data indicate that efficacy is similar to that of oral sumatriptan 50mg, and is maintained in the long term (相似文献