Early clinical experience with subcutaneous GR43175 in acute migraine: an overview

Role of KATPChannels in the Regulation of Rat Dura and Pia Artery Diameter

The aim of the present study was to examine the effect of KATPchannel openers pinacidil and levcromakalim on rat dural and pial arteries as well as their inhibition by glibenclamide. We used an in-vivo genuine closed cranial window model and an in-vitro organ bath. Glibenclamide alone reduced the dural but not the pial artery diameter compared with controls. Intravenous pinacidil and levcro-makalim induced dural and pial artery dilation that was significantly attenuated by glibenclamide. In the organ bath pinacidil and levcromakalim induced dural and middle cerebral artery relaxation that was significantly attenuated by glibenclamide. In conclusion, KATPchannel openers induce increasing diameter/relaxation of dural and pial arteries after intravenous infusion in vivo and on isolated arteries in vitro. Furthermore, dural arteries were more sensitive to KATPchannel openers than pial arteries.

Migraine recurrence is not associated with depressive or anxiety symptoms. Results of a randomized controlled trial

In order to investigate the plausible association of migraine recurrence with anxiety and depressive symptoms, a multicentre, randomized, double-blind, placebo-controlled, crossover clinical trial was conducted using sumatriptan as a vehicle drug. Migraineurs were randomly assigned to receive either 50 mg sumatriptan or placebo for three consecutive migraine attacks, and then cross over to the other treatment for three more migraine attacks. The primary measurements were the observed rate of migraine recurrence in relation to (i) patient's mood condition, measured by the Hamilton rating scales for depression and anxiety and (ii) patient's general health and functioning measured by the Symptom Checklist (SCL)-90-R. Migraine recurrence was defined as any migrainous headache that occurred within 24 h post treatment, only when pain free at 2 h was achieved. The analysis of efficacy was performed on 376 migraine attacks treated with sumatriptan and 373 attacks treated with placebo. Recurrence ratio was 14.1% and 5.1%, respectively ( P = 0.045). The number needed to treat for pain free at 2 h post dose was 5.4. Recurrence was not affected by Hamilton scores for depression or anxiety, SCL-90-R scores or treatment. Apparently, depressive or anxiety symptoms do not influence headache recurrence in acute pharmaceutical migraine treatment, but further investigation is required.

Sumatriptan-naproxen fixed combination for acute treatment of migraine: a critical appraisal

Nonsteroidal anti-inflammatory drugs (NSAIDs), including naproxen and naproxen sodium, are effective yet nonspecific analgesic and anti-inflammatory drugs, which work for a variety of pain and inflammatory syndromes, including migraine. In migraine, their analgesic effect helps relieve the headache, while their anti-inflammatory effect decreases the neurogenic inflammation in the trigeminal ganglion. This is the hypothesized mechanism by which they prevent the development of central sensitization. Triptans, including sumatriptan, work early in the migraine process at the trigeminovascular unit as agonists of the serotonin receptors (5-HT receptors) 1B and 1D. They block vasoconstriction and block transmission of signals to the trigeminal nucleus and thus prevent peripheral sensitization. Therefore, combining these two drugs is an attractive modality for the abortive treatment of migraine. Sumatriptan-naproxen fixed combination tablet (Treximet [sumatriptan-naproxen]) proves to be an effective and well tolerated drug that combines these two mechanisms; yet is far from being the ultimate in migraine abortive therapy, and further research remains essential.

What can be learned from the history of recurrence in migraine? A comment

Recurrence was first recognised as a clinical problem in 1989 with the advent of sumatriptan. The history of recurrence in early sumatriptan randomised clinical trials is described. Recurrence has been ascribed to patient-dependent factors but experience with ergot alkaloids suggested that recurrence can also be treatment-dependent. Possible mechanisms for recurrence are discussed.

History of the Use of Ergotamine and Dihydroergotamine in Migraine From 1906 and Onward

Dale showed in 1906 in a seminal work that ergot inhibits the pressor effect of adrenaline. Stoll at Sandoz isolated ergotamine from ergot in 1918. Based on the belief that migraine was due to increased sympathetic activity, ergotamine was first used in the acute treatment of migraine by Maier in Switzerland in 1925. In 1938 Graham and Wolff demonstrated the parallel decrease of temporal pulsations and headache after ergotamine i.v. This inspired the vascular theory of Wolff: an initial cerebral vasoconstriction followed by an extracranial vasodilation. Dihydroergotamine (DHE) was introduced as an adrenolytic agent in 1943. It is still in use parenterally and by the nasal route. Before the triptan era ergotamine and DHE had widespread use as the only specific antimigraine drugs. From 1950 the world literature on ergotamine was dominated by two adverse events: ergotamine overuse headache and the relatively rare overt ergotism. Recently, oral ergotamine, which has an oral bioavailability of < 1%, has been inferior to oral triptans in randomized clinical trials. A European Consensus in 2000 concluded that ergotamine is not a drug of first choice. In an American review of 2003 it was suggested that ergotamine may be considered in the treatment of selected patients with moderate to severe migraine.

High efficacy and low frequency of headache recurrence after oral sumatriptan. The Oral Sumatriptan Italian Study Group

This multicentre, double-blind study compared (100 mg) sumatriptan administered orally with placebo in treating an acute attack of migraine; 238 patients were studied over a 48-h period. Four hours after treatment, 92 of the 142 evaluable sumatriptan patients (65%) showed significant reductions (P < 0.001) in headache severity, clinical disability and accompanying symptoms compared with 32 of the 80 evaluable placebo-treated patients (40%). The duration of attack prior to taking medication and the history of persistent migraine do not influence the observed difference between the two treatment regimens (sumatriptan and placebo), which remained statistically significant (P < 0.001) in both cases. The incidence of headache recurrence in patients who experienced relief 4 h after initial treatment was low, occurring in 16 (17%) and 4 (13%) of the sumatriptan- and placebo-treated patients, respectively. Only patients with a history of migraine attacks lasting longer than 24 h suffered headache recurrences, and these recurrences were not consistent with the International Headache Society definition of migraine. Treatment with sumatriptan was well tolerated.

Sumatriptan for the treatment of migraine attacks--a review of controlled clinical trials

Sumatriptan, a 5HT1-like receptor agonist, is a completely new treatment principle for migraine. In an extensive international programme of controlled clinical trials, sumatriptan, 6 mg subcutaneously and 100 mg orally, was superior to placebo in reducing headache and associated symptoms. The response rate for subcutaneous sumatriptan (70-84% after 1 h and 81-87% after 2 h) was higher than for oral sumatriptan (50-67% after 2 h). Additional doses did not increase efficacy. Oral sumatriptan was superior to Cafergot (2 mg ergotamine plus 200 mg caffeine) and somewhat better than aspirin (900 mg) plus metoclopramide (10 mg). Recurrence of migraine occurred in approximately 40% of attacks. Side effects were generally mild and short-lived in the controlled clinical trials. However, in clinical practice sumatriptan has subsequently caused rare cases of heart ischemia and sumatriptan is contraindicated in patients with a history of ischemic heart disease.

The 5-HT1-like agonist sumatriptan has a significant effect in chronic tension-type headache

Subcutaneous treatment of chronic tension-type headache with 2 mg and 4 mg sumatriptan, a selective 5-hydroxytryptamine1-like receptor agonist, was compared with placebo in a double-blind crossover study of 36 patients. The effect was evaluated using a 6-point verbal relief rating scale and by visual analog scale ratings of headache intensity before and for 2 h after treatment. Sumatriptan induced a modest but significantly greater headache relief than placebo, whereas no significant difference was found between the two doses of sumatriptan. Headache relief following sumatriptan was significant after 60 min and still seemed to be increasing after 120 min when the examination terminated. Three possible mechanisms of action of sumatriptan in tension-type headache are discussed.

Treatment of migraine attacks with subcutaneous sumatriptan: first placebo-controlled study. The Subcutaneous Sumatriptan International Study Group

The results of the very first large-scale placebo-controlled dose-response trial with the novel selective 5-hydroxytryptamine1-like (5HT1-like) receptor agonist sumatriptan are presented. We studied the efficacy and tolerability of subcutaneous injections of 1 mg, 2 mg and 3 mg of sumatriptan in alleviating migraine attacks in a double-blind, placebo-controlled, parallel-group, multicentre clinical trial. Six-hundred and ninety patients were randomized and 685 received study medication. At 30 min, reduction of headache severity to mild or none (primary efficacy endpoint) was achieved in 22% (95% CI: 15-28%) of placebo-treated patients and in 39% (CI: 31-46%) of patients treated with 1 mg sumatriptan, 44% (CI: 36-51%) treated with 2 mg sumatriptan and 55% (CI: 48-63%) treated with 3 mg sumatriptan. Differences from placebo were 17% (CI: 8-27%) for 1 mg sumatriptan, 22% (CI: 13-32%) for 2 mg sumatriptan and 34% (CI: 24-44%) for 3 mg sumatriptan (p < 0.001 for all three comparisons). Other migraine symptoms were also more effectively treated by sumatriptan than by placebo. Subsequently, an open-label 3 mg dose subcutaneous sumatriptan was given to partial or non-responders. Thirty minutes after this open dose the response rate to sumatriptan had improved to between 70 and 80%. Adverse events after sumatriptan were minor and short-lived. We conclude that subcutaneous sumatriptan is well tolerated in doses up to 3 + 3 mg and may rapidly abort migraine attacks.

Clinical effects and mechanism of action of sumatriptan in migraine

Sumatriptan is a novel, highly effective drug against migraine and cluster headache attacks. It shows a remarkably selective pharmacological profile in animals. Determination of its mechanism of action in human should further the understanding of the pathophysiology of migraine and cluster headache. We, therefore, review current knowledge on the clinical and pharmacological effects of sumatriptan. Important pharmacological actions of sumatriptan are (i) poor penetration of the blood-brain barrier suggesting a peripheral point of action; (ii) 5-HT1-like/5-HT1d receptor-mediated vasoconstriction of large cerebral arteries and dural vessels; and (iii) blockade of neurogenic dural inflammation via 5-HT1d autoreceptor-mediated inhibition of vasoactive neuropeptides within the trigeminovascular system. Future research will tell which mechanism is involved in the pathophysiology of migraine and cluster headache.

Treatment of acute cluster headache with sumatriptan

BACKGROUND

Attacks of cluster headache are difficult to treat. Sumatriptan, an agonist of 5-hydroxytryptamine1-like receptors, has proved effective in the treatment of migraine. The clinical similarities between migraine and cluster headache and positive results from an open pilot study in patients with cluster headache indicated that sumatriptan should be evaluated more rigorously in the treatment of this condition.

METHODS

We conducted a randomized, double-blind, placebo-controlled crossover study to assess the efficacy and tolerability of sumatriptan in 49 patients with cluster headache. The patients received, in random order, a subcutaneous injection of 6 mg of sumatriptan for one cluster-headache attack and placebo for another attack. The results for the two attacks could be fully evaluated for 39 patients. A response to treatment was defined as complete or almost complete relief of headache (no pain or mild pain) within 15 minutes after the injection.

RESULTS

In the 39 patients, the severity of headache decreased in 74 percent of the attacks within 15 minutes of treatment with sumatriptan, as compared with 26 percent of the attacks for which placebo was given (P less than 0.001). Thirty-six percent of the patients were free of pain within 10 minutes after the administration of sumatriptan, as compared with 3 percent after placebo (P less than 0.001); by 15 minutes these numbers had increased to 46 percent and 10 percent, respectively (P less than 0.001). Thirteen percent of the patients required oxygen as an additional treatment 15 minutes after receiving sumatriptan, as compared with 49 percent of those who received placebo. The severity of functional disability and the incidence of ipsilateral conjunctival injection also decreased more in response to sumatriptan than placebo. Sumatriptan was well tolerated, and there were no serious adverse events.

CONCLUSIONS

Sumatriptan is an effective and well-tolerated treatment for acute attacks of cluster headache.

Treatment of migraine attacks with sumatriptan

BACKGROUND

The headache in migraine attacks may be caused by dilatation of certain cranial arteries or arteriovenous anastomoses, by neurogenic dural plasma extravasation, or by both of these mechanisms. Sumatriptan, a novel selective agonist of 5-hydroxytryptamine-like receptors, blocks these phenomena. We investigated its efficacy in migraine.

METHODS

We studied 639 patients with migraine attacks in a randomized, double-blind, placebo-controlled, parallel-group clinical trial. We assessed the effect of subcutaneous injections of 6 or 8 mg of sumatriptan or placebo on the severity of headache and associated migrane symptoms 30, 60, and 120 minutes after treatment. Patients who were not free of pain after 60 minutes subsequently received placebo if they had initially received placebo or 8 mg of sumatriptan, and 6 mg of sumatriptan or placebo if they had initially received 6 mg of sumatriptan.

RESULTS

After 60 minutes, the severity of headache was decreased in 72 percent (95 percent confidence interval, 68 to 76 percent) of the 422 patients given 6 mg of sumatriptan, 79 percent (95 percent confidence interval, 71 to 87 percent) of the 109 patients given 8 mg of sumatriptan, and 25 percent (95 percent confidence interval, 17 to 33 percent) of the 105 patients given placebo (data on 3 patients could not be evaluated). As compared with the placebo group, 47 percent (95 percent confidence interval, 38 to 57 percent) more patients who had received 6 mg of sumatriptan and 54 percent (95 percent confidence interval, 43 to 65 percent) more patients who had received 8 mg of sumatriptan had a decrease in the severity of headache (P less than 0.001 for both comparisons). After 120 minutes, 86 to 92 percent of the 511 patients treated with sumatriptan (202 assigned to 6 mg plus placebo, 203 to 6 mg plus 6 mg, and 106 to 8 mg plus placebo) had improvement in the severity of headache, as compared with only 37 percent of the 104 patients who received placebo once or twice (P less than 0.001 for all comparisons). Twenty-one patients were excluded from the analysis because of missing data (19) or protocol violations (2). The response rates did not differ significantly among the sumatriptan regimens. Adverse events were minor and transient in all groups.

CONCLUSIONS

We conclude that a single 6-mg dose of sumatriptan given subcutaneously is a highly effective, rapid-acting, and well-tolerated treatment for migrane attacks. The administration of a second dose 60 minutes later to patients not responding well to an initial dose affords little additional benefit.

Migraine pain associated with middle cerebral artery dilatation: reversal by sumatriptan

The combination of measurements of regional cerebral blood flow (rCBF) and blood velocity in the middle cerebral arteries (MCA) by transcranial doppler sonography was used to investigate cerebrovascular involvement in migraine. Ten migraine patients with unilateral headache were studied during an attack and when they had been free of attacks for 5 days (non-attack). On both occasions they were given as intravenous infusion of sumatriptan (2 mg), a 5-HT1-like receptor agonist, which relieved the symptoms within 30 min without affecting rCBF. The MCA velocity was normal on both sides on the non-attack day and on the unaffected side during the attack. However, during the attack the MCA velocity on the headache side was significantly lower than that on the non-headache side (45 vs 61 cm/s:mean difference 16.3 [95% confidence interval 10.3-22.3]; p = 0.02). The MCA velocity on the headache side returned to normal after treatment with sumatriptan and recovery. Since rCBF in the MCA supply territory was unaffected, the lower velocity can be explained only by dilatation of the MCA. The mean MCA diameter increase was estimated to be 20%. Thus, headache was associated with intracranial large arterial dilatation on the headache side. Sumatriptan predominantly had effects on the distended artery, which suggests that the 5-HT receptor system has a role in the pathogenesis of migraine.

Migraine headaches

Once the definitive diagnosis of migraine has been formulated, the physician has many options available for abortive and prophylactic therapy. Nonpharmacologic modalities, including behavioral modification methods such as biofeedback training, may also be considered. Migraine does not necessarily have to disrupt the lives of those afflicted. The patient with mixed headache presents a more difficult diagnostic and therapeutic problem. These patients can also be helped when the disorder is identified, and inpatient therapy for these patients may be required.

Clinical experience with oral sumatriptan: a placebo-controlled, dose-ranging study. Oral Sumatriptan Dose-defining Study Group

A double-blind, placebo-controlled multicentre study was carried out to evaluate the efficacy and tolerability of 100, 200 and 300 mg sumatriptan, a selective 5-hydroxytryptamine (5-HT)1-like receptor agonist, given in an oral dispersible form in the acute treatment of migraine attacks. A total of 1130 patients were recruited from 51 centres in eight countries and the efficacy results are presented from an interim analysis of 538 cases. Tolerability was evaluated in 227 patients. At 2 h, an improvement in headache severity from moderate or severe to mild or none was reported by 67% of patients who received 100 mg sumatriptan, 75% receiving 200 mg and 69% of patients receiving 300 mg sumatriptan, compared with 22% of patients who received placebo (P less than 0.001 all doses sumatriptan vs placebo). Adverse events were generally mild and transient, and appeared to be dose-related; the adverse event profile of 100 mg sumatriptan was similar to that of placebo. Overall, nausea/vomiting and "bitter taste" were the most common complaints. The proportion of patients withdrawn due to adverse events was similar in the placebo and 100 mg sumatriptan treatment groups (2% and 3%, respectively). It is concluded that 100 mg sumatriptan given orally is well tolerated with an anti-migraine efficacy comparable to that provided by the two higher doses.

Subcutaneous sumatriptan in the acute treatment of migraine. Sumatriptan International Study Group

Two double-blind, randomized, placebo-controlled multicentre studies were carried out to assess the efficacy and tolerability of subcutaneous (s.c.) injections of 1-3 mg and 1-8 mg sumatriptan, respectively, in the acute treatment of migraine. Data are presented from a total of 519 patients. In both studies, the primary endpoint of efficacy was a reduction in headache severity from severe or moderate to mild or no headache. All doses of sumatriptan were significantly more effective than placebo in relieving symptoms, and the response appeared to be dose-related; an effective response to treatment was achieved within 30 min in 73% of patients treated with 6 mg sumatriptan and 80% of patients treated with 8 mg sumatriptan s.c., compared with 22% for placebo. Sumatriptan was well tolerated and the majority of adverse events were mild and transient. The most frequent complaint was irritation and pain at the site of injection. No changes in laboratory values were noted and ECG readings were unaltered by treatment. On the basis of these results, the 6 mg subcutaneous dose has been selected for further evaluation in large-scale studies.

Pharmacology of antimigraine drugs

The drugs used in migraine therapy can be divided into two groups: agents that abort an established migraine attack and agents used prophylactically to reduce the number of migraine attacks. Both groups have drugs that are specific for migrainous headaches and that are non-specific, and are used to treat the accompanying headache (analgesics), vomiting (anti-emetics), anxiety (sedatives and anxiolytics), or depression (antidepressants). The main drugs with specific action on migraine include ergot alkaloids (ergotamine, dihydroergotamine), agonists (sumatriptan) or partial agonists (methysergide) at a specific subtype of 5-HT1-like receptors, beta-adrenoceptor antagonists (propranolol, metoprolol), calcium antagonists (flunarizine) and anti-inflammatory agents (indomethacin). The pharmacological basis of therapeutic action of several of these drugs is not well understood. In the case of the ergot alkaloids and 5-HT1-like receptor agonists, however, it is likely that the antimigraine effect is related to the potent and rather selective constriction of the large arteries and arteriovenous anastomoses in the scalp and dural regions. In addition, these drugs inhibit plasma extravasation into the dura in response to trigeminal ganglion stimulation, but it is possible that this effect is related to the selective vasoconstriction in the extracerebral vascular bed. The selectivity of the pharmacological effects of these antimigraine drugs (constriction of the extracerebral arteries and arteriovenous anastomoses, poor penetration into the central nervous system and the absence of an antinociceptive effect even after intrathecal administration) strongly suggests that excessive dilatation in the extracerebral cranial vasculature, probably initiated by a neuronal event, is an integral part of the pathophysiology of migraine.