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

Development of Optimized Sumatriptan-Prochlorperazine Combined Orodispersible Films Without Disintegrant: in vitro, ex vivo and in vivo Characterization

Sumatriptan succinate and prochlorperazine maleate are a clinically proven combination for treating migraine and associated nausea and vomiting. Classical oral dosage forms are not frequently workable in migraine because of the associated nausea/vomiting, and no effective fixed dose combination is available. Thus, the aim of the study was to optimize a combined sumatriptan-prochlorperazine orodispersible film for rapid release of drugs. Orodispersible films were prepared by solvent casting method using varied amounts of polyvinyl alcohol and glycerol as film former and plasticizer, respectively, along with fixed levels of other ingredients employing central composite design. The optimum film (VF) demonstrated disintegration and total dispersion times as 21 s and 2.3 min, respectively. Tensile strength and Young's modulus were 8.86 ± 0.37 MPa and 24.15 ± 0.07 MPa, respectively. The in vitro T80% of both drugs from the ODF was achieved within 4 min. The film was palatable and disintegrated in 2 min in buccal cavity of human volunteers. Permeation study through goat mucosa demonstrated 100% permeation of both drugs within 15 min. X-Ray diffraction and differential scanning calorimetry supported drugs being amorphous and Fourier transform infrared demonstrated drug-excipient compatibility in optimized film. A judicious combination of sumatriptan succinate and prochlorperazine maleate could be prepared in orodispersible films for the possible relief of migraine.

Bergapten Attenuates Nitroglycerin-Induced Migraine Headaches through Inhibition of Oxidative Stress and Inflammatory Mediators

The present study intended to examine the effect of bergapten and possible mechanisms involved in the treatment of migraine-associated symptoms in the rat model. Five doses of nitroglycerin (10 mg/kg) were injected intraperitoneal to induce migraine headaches in rats with a one-day break between each dose. Treatment groups received nitroglycerin followed after 1 day by bergapten (50 or 100 mg/kg), saline (10 mL/kg), or sumatriptan (50 mg/kg) once daily for 10 days. Behavioral observations were analyzed 2 h after nitroglycerin injections and 1 h 40 min after treatment. The animals were sacrificed 24 h after the last treatment dose. Samples of trigeminal nucleus caudalis (TNC) and cerebral cortex were collected and analyzed for antioxidant activity and expression of inflammatory markers by immunohistochemistry and enzyme-linked immunosorbent assay. Our findings revealed that bergapten notably decreases headache by altering mechanical allodynia, thermal allodynia, light phobicity, and the number of head-scratching incidence in rats. In the cortex and TNC regions, antioxidant factors were restored, and lipid peroxidation was significantly reduced. Furthermore, bergapten decreased the expression of inflammatory markers, such as nuclear factor kappa B (NF-Kb) and tumor necrosis factor-alpha (TNF-α), as evidenced by immunohistochemistry and ELISA. These results suggest that bergapten exhibits headache-relieving activity, possibly mediated through antioxidant and anti-inflammatory pathways.

Cortical spreading depolarisation-induced facial hyperalgesia, photophobia and hypomotility are ameliorated by sumatriptan and olcegepant

Cortical spreading depolarisation (CSD), the neural mechanism underlying migraine aura, may cause headache by sensitising the trigeminal system. Photophobia, the most bothersome accompanying symptom during migraine attacks, is more prevalent in migraine with aura than in migraine without aura. Whether CSD plays a role in developing photophobia remains unknown. Moreover, migraine-induced physical hypoactivity contributes to loss of productivity. We aimed to investigate the development of trigeminal sensitisation, photophobia and locomotive abnormality after KCl-induced CSD using 86 male C57BL/6 mice. Sham-operated mice were used as controls. We confirmed the presence of trigeminal sensitisation and photophobia at 24 h after CSD. CSD-subjected mice also exhibited significantly reduced locomotive activity in both light and dark zones. Hence, the CSD-induced hypomobility was likely to be independent of photophobia. The 5-HT1B/1D agonist, sumatriptan, corrected all these CSD-induced abnormalities. Moreover, dose dependency was demonstrated in the ameliorating effect of the calcitonin gene-related peptide (CGRP) receptor antagonist, olcegepant, on these abnormalities. Sumatriptan and olcegepant improved mouse locomotion with therapeutic lags ranging from 20 to 30 min. Collectively, CSD caused trigeminal sensitisation, photophobia and hypomobility that persisted for at least 24 h by a mechanism involving the 5-HT1B/1D and CGRP activity.

Transdermal Delivery of Sumatriptan Succinate Using Iontophoresis and Dissolving Microneedles

This study focuses on the in vitro transdermal transport of sumatriptan succinate using combined iontophoresis and dissolving polymeric microneedle arrays. Permeation experiments were performed to evaluate the effects of formulation parameters on drug release from polyvinylpyrrolidone systems under mild electrical current (≤500 μA/cm²). The preparations consisted of hydrophilic, positively charged molecules encapsulated in a water-soluble and biocompatible polymeric material. Current densities of 100, 300, and 500 μA/cm² were applied during a 6-h period using silver/silver chloride electrodes. The circular array consisted of 600 needles and occupied a 0.785 cm² area. Tests, carried out with Franz diffusion cells and skin of Göttingen minipigs, showed that small decreases in the polymer concentration led to negligible lag times and marked increases in the cumulative amount of drug permeated in 6 h (Q_6h) and in the flux (J_ss). At 500 μA/cm², Q_6h and J_ss nearly doubled for a microneedle loaded with 5% (w/w) sumatriptan and 20% (w/w) PVP (lag time = 0 min; Q_6h = 2888 μg/cm²; J_ss = 490 μg/cm²/h) relative to a system loaded with 5% (w/w) drug and 30% (w/w) PVP (lag time = 36 min; Q_6h = 1437 μg/cm²; J_ss = 266 μg/cm²/h).

Infrequent or Non-Response to Oral Sumatriptan does not Predict Response to Other Triptans—Review of Four Trials

A migraineur can claim to be an infrequent responder (‘non-responder’) to an oral triptan independent of which triptan he or she is presently using. Four trials of an alternative triptan (zolmitriptan/rizatriptan; eletriptan; naratriptan; almotriptan) in patients with a history of infrequent response to oral sumatriptan were compared and contrasted in terms of study design, patient characteristics, and efficacy and tolerability of the triptan under investigation. Unfortunately, none of the reported studies used an appropriate parallel design, which would have had the non-responding triptan (oral sumatriptan) in one arm and without encapsulation. While the four trials differed in terms of study design (open-label vs. placebo-controlled), definition of sumatriptan ‘non-responder’ (retrospective vs. prospective) and pain intensity at baseline (30% severe to 70% severe), all four demonstrated that lack of response to sumatriptan did not predict lack of response to an alternative triptan. Changing triptans resulted in 2-h pain-relief rates of 25–81% in patients with a history of poor response to sumatriptan. It can be concluded that migraine patients who respond infrequently to sumatriptan should be switched to a different triptan, as lack of response to one triptan does not predict likelihood of responsiveness to another. A review of the available evidence suggests that almotriptan may be one of the most appropriate choices for an alternative triptan.

Anti-migraine effect of Areca Catechu L. nut extract in bradykinin-induced plasma protein extravasation and vocalization in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Areca catechu Linn. (Arecaceae) nut is a popular folk remedy for the treatment of migraine in Kerala and Tamil Nadu states of India.

AIM OF THE STUDY

This study was designed to investigate the effect of hydroalcoholic extract of A. catechu L. nut (ANE) treatment on migraine pain in rat models to strengthen its use as an anti-migraine therapy.

MATERIALS AND METHODS

Bradykinin (0.1 μmol/kg) injection in to left femoral vein of rat produced PPE which was measured with luminescence spectrometer. Vocalizations were produced in rats with 10 μg of bradykinin infusion into common carotid artery. Phonogram was recorded before, during and for 5min after bradykinin injection and sumatriptan was used as a standard anti-migraine drug. In both models, the ANE was orally administered at doses of 250 and 500 mg/kg, 60 min before bradykinin infusion.

RESULTS

The PPE was reduced in both ANE treated groups of rats. The percent fluorescein was significantly increased in positive control group (97.00±1.7%; p<0.0001) compared to negative control (63.87±1.2%). With ANE treatments (250 and 500 mg/kg) PPE was significantly decreased to 88.88±1.4% (p<0.01) and 83.55±0.1% (p<0.0001) compared to positive control group, respectively. On the other hand in the model of vocalization, with 250 and 500 mg/kg ANE treatment, vocalization was significantly reduced to 33.33% and 16.66%, respectively, compared to saline treated rats. The reduction in vocalization is comparable to the reference drug sumatriptan.

CONCLUSION

The findings provide the strong evidence for anti-migraine potential of ANE in rat models of migraine. In summary, therapeutic intervention with ANE treatment could be a promising strategy for prevention of migraine.

Sumatriptan succinate sublingual fast dissolving thin films: formulation and in vitro/in vivo evaluation

Sumatriptan succinate (SS) is a 5-HT1 receptor agonist used in the treatment of migraine having poor bioavailability (15%) due to its extensive first-pass effect. The aim of this work was to prepare SS sublingual fast dissolving thin films (SFDTFs) allowing the drug to directly enter the systemic circulation and bypassing the first-pass metabolism. Plain thin films were prepared using solvent casting technique adopting 2(3) × 3 factorial design to study the effect of polymer and plasticizer type and concentration on mechanical properties and in vitro disintegration time of the plain prepared films using Design-Expert®. Medicated films were prepared after addition of 35 mg SS to each of the two selected plain formulae (F6 and F7) having desirability values above 0.9 showing the values of: 0.038, 0.039 kgf/mm(2) and 156.24, 164.16% and 0.0248, 0.0240 kgf/mm(2) as tensile strength, percent elongation and elastic modulus, respectively. PVP K30 was efficient as crystallization inhibitor in retarding SS crystallization. Pharmacokinetic study of the optimum formula F7 (PVP K30:SS (1:1 w/w)) in healthy human volunteers using LC/MS/MS revealed a shorter tmax (0.25 h) compared to Imitrex® tablet 25 mg (2 h) which is considered promising especially for the rapid relief of acute migraine attacks.

Intranasal delivery of chitosan nanoparticles for migraine therapy

OBJECTIVE

The objective of the research was to formulate and evaluate sumatriptan succinate-loaded chitosan nanoparticles for migraine therapy in order to improve its therapeutic effect and reduce dosing frequency.

MATERIAL AND METHODS

The Taguchi method design of experiments (L9 orthogonal array) was applied to obtain the optimized formulation. The sumatriptan succinate-loaded chitosan nanoparticles (CNPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP) and Tween 80 as surfactant.

RESULTS

The CNPs had a mean size of 306.8 ± 3.9 nm, a zeta potential of +28.79 mV, and entrapment efficiency of 75.4 ± 1.1%. The in vitro drug release of chitosan nanoparticles was evaluated in phosphate buffer saline pH 5.5 using goat nasal mucosa and found to be 76.7 ± 1.3% within 28 hours.

DISCUSSION

The release of the drug from the nanoparticles was anomalous, showing non-Fickian diffusion indicating that drug release is controlled by more than one process i.e. the superposition of both phenomena, a diffusion-controlled as well as a swelling-controlled release. This is clearly due to the characteristics of chitosan which easily dissolves at low pH, thus a nasal pH range of 5.5 ± 0.5 supports it very well. The mechanism of pH-sensitive swelling involves protonation of the amine groups of chitosan at low pH. This protonation leads to chain repulsion, diffusion of protons and counter ions together with water inside the gel, and the dissociation of secondary interactions.

CONCLUSION

The results suggest that sumatriptan succinate-loaded chitosan nanoparticles are the most suitable mode of drug delivery for promising therapeutic action.

A clinical perspective on mucoadhesive buccal drug delivery systems

Mucoadhesion can be defined as a state in which two components, of which one is of biological origin, are held together for extended periods of time by the help of interfacial forces. Among the various transmucosal routes, buccal mucosa has excellent accessibility and relatively immobile mucosa, hence suitable for administration of retentive dosage form. The objective of this paper is to review the works done so far in the field of mucoadhesive buccal drug delivery systems (MBDDS), with a clinical perspective. Starting with a brief introduction of the mucoadhesive drug delivery systems, oral mucosa, and the theories of mucoadhesion, this article then proceeds to cover the works done so far in the field of MBDDS, categorizing them on the basis of ailments they are meant to cure. Additionally, we focus on the various patents, recent advancements, and challenges as well as the future prospects for mucoadhesive buccal drug delivery systems.

Sumatriptan as a treatment for cyclic vomiting syndrome: a clinical trial

BACKGROUND AND OBJECTIVE

Cyclic vomiting syndrome (CVS) is associated with migraine. This study aimed to evaluate the efficacy of sumatriptan in treating CVS.

METHODS

Twelve patients were enrolled in this trial. Sumatriptan was administered either subcutaneously [(age x 4 + 20)/100 x 3 mg] or by nasal spray (NS; 20 mg). Response to the treatment was classified as complete, effective, or noneffective.

RESULTS

Eleven patients, who presented with 35 attacks, were treated by subcutaneous injection of sumatriptan. The treatment was responsive in 19 attacks. The efficacy of sumatriptan was high in attacks that occurred in cases with a family history of migraine compared to those without (p = .0482). Five patients were treated with sumatriptan NS for six attacks. The treatment was completely responsive in two of six attacks. We observed no adverse effects associated with sumatriptan treatment in this trial.

CONCLUSION

We conclude that sumatriptan has potential efficacy in treating of patients with CVS.

Effective prophylactic therapy for cyclic vomiting syndrome in children using valproate

This trial sought to evaluate our experience using the antimigraine prophylactic drug, use of valproate for the prophylactic management of cyclic vomiting syndrome (CVS) in children. Thirteen children diagnosed with severe CVS were enrolled. Prophylactic therapy consisted of valproate administered at a dose of 10-40 mg/kg/day. Upon enrollment in the study, all patients underwent diagnostic tests to rule out organic causes of their symptoms. Vomiting was severe enough in all patients to cause dehydration requiring hospitalization for intravenous rehydration. Nine of 13 patients did not respond to numerous previous medical therapies like propranolol, amitriptyline, cyproheptadine, phenobarbital, phenytoin, and carbamazepine. Three of 13 patients required combination therapy with valproate and phenobarbital. Of the 13 patients, two showed complete resolution of their symptoms, nine had marked improvement in their symptoms, as evidenced by infrequent attacks of reduced severity, and two failed to respond to valproate therapy. Four patients experienced relapse with a decreased dosage of valproate. Side effects associated with long-term valproate administration were not observed. Valproate appears to be effective for the prophylactic management of severe CVS, with 85% of all patients achieving at least a reduction in the frequency of attacks.

Renal Infarction During the Use of Rizatriptan and Zolmitriptan: Two Case Reports

Rizatriptan and zolmitriptan are both used to relieve acute migraine and cluster headaches. The mechanism of action is similar to the other triptans, in that they reverse abnormal cerebral vasodilation through their activity as 5-HT1B receptor agonists. Triptan-induced vasoconstriction is attributed to its activity on peripheral 5-HT1B receptors and has rarely been reported to result in stroke, myocardial infarction and ischemic colitis. We present two cases of renal infarction associated with therapeutic triptan use. The first patient is a 57-year-old man with a history of hypertension that was well controlled on valsartan and hydrochlorothiazide. He was recently diagnosed with cluster headaches and was treated with indomethacin, prednisone, butalbital-acetaminophen-caffeine and hydrocodone without relief. He then received two therapeutic doses of rizatriptan on each of the two days prior to presentation. Subsequently, he presented to the emergency department complaining of nausea, vomiting and right-sided abdominal pain. A computerized tomography (CT) scan of the abdomen and pelvis with intravenous contrast revealed a very large wedge shaped infarction of the right kidney. The second patient is a 34-year-old man with a past medical history significant only for life-long migraine headaches successfully treated for the past six years with zolmitriptan. Shortly after taking one therapeutic dose of zolmitriptan, he presented to the emergency department complaining of nausea and left-sided abdominal pain. A CT scan of the abdomen and pelvis with intravenous contrast revealed multiple wedge-shaped infarctions of the left kidney. Renal infarction was confirmed in both patients by arteriogram of the renal arteries. Although both rizatriptan and zolmitriptan are effective in the treatment of migraine and cluster headaches, they may induce peripheral vasospasm leading to renal infarction.

Mucoadhesive bilayered patches for administration of sumatriptan succinate

The purpose of this study was to develop and optimize formulations of mucoadhesive bilayered buccal patches of sumatriptan succinate using chitosan as the base matrix. The patches were prepared by the solvent casting method. Gelatin and polyvinyl pyrrolidone (PVP) K30 were incorporated into the patches, to improve the film properties of the patches. The patches were found to be smooth in appearance, uniform in thickness, weight, and drug content; showed good mucoadhesive strength; and good folding endurance. A 3(2) full factorial design was employed to study the effect of independent variables viz. levels of chitosan and PVP K30, which significantly influenced characteristics like swelling index, in-vitro mucoadhesive strength, in vitro drug release, and in-vitro residence time. Different penetration enhancers were tried to improve the permeation of sumatriptan succinate through buccal mucosa. Formulation containing 3% dimethyl sulfoxide showed good permeation of sumatriptan succinate through mucosa. Histopathological studies revealed no buccal mucosal damage. It can be concluded that buccal route can be one of the alternatives available for administration of sumatriptan succinate.

Concomitant variations of gastric tone and duodenal motility in humans: results of a placebo-controlled study assessing octreotide and sumatriptan

OBJECTIVE

To describe the concomitant effects of octreotide and sumatriptan on fundic tone and duodenal phase III activity.

MATERIAL AND METHODS

A double-blind study was performed in nine volunteers, studied for 2 h after receiving 50 microg octreotide, 6 mg sumatriptan or placebo. Fundic tone variations were assessed by barostat while antroduodenal motility was studied concomitantly using manometry.

RESULTS

A rapid increase in intrabag volume was observed in all but one subject after both sumatriptan and octreotide administration, while only two subjects exhibited a volume variation after placebo, p<0.01. A significant decrease in the number of phasic contractions was observed after octreotide, while sumatriptan reduced only wave amplitudes (p<0.05). A total of 13 concomitant duodenal phase III-like activities were observed in the duodenum after octreotide, 3 after sumatriptan and 4 after placebo, all followed by spontaneous fundic relaxation with disappearance of phasic contractions, p<0.05. Spontaneous phase III activities were different from phases III-like activities after octreotide in velocity and duration (p<0.05).

CONCLUSIONS

Octreotide induced concomitant fundic relaxation, disappearance of phasic contractions and duodenal phase III-like activity. Sumatriptan relaxed the proximal stomach and reduced the amplitude of fundic phasic contractions without affecting concomitant antroduodenal phase III activity.

Influence of 5-HT1 receptor agonists on feline stomach relaxation

Sumatriptan is known for its stomach relaxing properties in both humans and cats, but the receptor involved has not been characterized. In a barostat study the intragastric volume was monitored in sedated cats at constant pressure. The maximum intragastric volume increase after subcutaneous or intravenous administration of saline or agonists was registered [mean (n=4-5)]. Sumatriptan (0.01-1 mg kg(-1)) induced a dose-dependent intragastric volume increase vs. saline (4-15 vs. 5 ml, respectively) that was sometimes accompanied by retching after 8-10 min. Pre-treatment with nitric oxide-synthase inhibitors and different 5-HT(1) receptor antagonists N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinyl-cyclohexanecarboxamide(WAY-100635), 2-methyl-4-(5-methyl-[1,2,4]oxadiazol-3-yl)-biphenyl-4-carboxylic-acid[4-methoxy-3-(4-methyl-piperazin-1-yl)-phenyl]amide(GR-127935), N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan-amide(5-HTP-DP) and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]piperazine-HCl(NAN-190) did not affect the sumatriptan-induced effect. Alniditan (5-HT(1A/1D) receptor agonist) and flesinoxan (5-HT(1A) receptor agonist) did not induce significant intragastric volume changes. The 5-HT(1F) receptor agonists 5-hydroxy-3-(1-methylpiperidin-4-yl)-1H-indole(BRL-54443) and (R)-(+)-N-(3-dimethylamino-1,2,3,4-tetrahydro-9H-carbazol-6-yl)-4-fluorobenzamide(LY-344864; 0.003-3 mg kg(-1)) however induced a dose-dependent intragastric volume increase (6-36 and 5-26 ml, respectively), no retching was seen. Our results suggest that stimulation of 5-HT(1F) receptors induces feline stomach relaxation. Whether the sumatriptan-induced gastric relaxation in cats is due to interaction with 5-HT(1F) receptors could not be proven absolutely in view of the lack of selective 5-HT(1F) receptor antagonists.

Triptans and CNS side-effects: pharmacokinetic and metabolic mechanisms

Triptans are the treatment of choice for acute migraine. While seemingly a homogenous group of drugs, results from a meta-analysis reveal significant differences in efficacy and tolerability among oral triptans. The incidence of drug-related central nervous system (CNS) side-effects with some triptans is as high as 15% and may be associated with functional impairment and reduced productivity. The occurrence of adverse events associated with triptans in general, and CNS side-effects in particular, may lead to a delay in initiating or even avoidance of an otherwise effective treatment. Potential explanations for differences among triptans in the incidence of CNS side-effects may relate to pharmacological and pharmacokinetic differences, including receptor binding, lipophilicity, and the presence of active metabolites. Of the triptans reviewed, at clinically relevant doses, almotriptan 12.5 mg, naratriptan 2.5 mg and sumatriptan 50 mg had the lowest incidence of CNS side-effects, while eletriptan 40 and 80 mg, rizatriptan 10 mg and zolmitriptan 2.5 and 5 mg had the highest incidence. The most likely explanations for the differences in CNS side-effects among triptans are the presence of active metabolites and high lipophilicity of the parent compound and active metabolites. Eletriptan, rizatriptan and zolmitriptan have active metabolites, while lipophilicity is lowest for almotriptan and sumatriptan. If CNS side-effects are a clinically relevant concern in the individual patient, use of a triptan with a low incidence of CNS side-effects may offer the potential for earlier initiation of treatment and more effective outcomes.

Effect of sumatriptan in different models of pain in rats

The effect of sumatriptan in two standard algesimetric tests and in a model of cephalalgia was evaluated in rats. The pain threshold was measured by the hot-plate and the writhing tests; cephalalgia was produced by injecting bradykinin (10 microg in a volume of 10 microl) into a common carotid artery. Sumatriptan was subcutaneously (s.c.) injected at the doses of 4, 8, 24 or 42 mg/kg; morphine (5 or 10 mg/kg s.c.) and indomethacin (5 or 10 mg/kg s.c) were used as standard analgesic drugs. Sumatriptan had no analgesic activity either in the hot-plate test or in the writhing test. On the other hand, at 24 and 42 mg/kg it dose-dependently reduced the response to the intracarotid injection of bradykinin (vocalization and tachypnea), this effect being prevented by the 5-HT(1B) receptor antagonist, isamoltane. The 5-HT(1D) receptor antagonist BRL15572 prevented the effect of sumatriptan on bradykinin-induced tachypnea, but not the effect of sumatriptan on bradykinin-induced vocalization. These data demonstrate that sumatriptan is significantly effective in a reliable animal model of cephalalgia, while having no systemic analgesic activity.

Synthesis and serotonergic activity of variously substituted (3-amido)phenylpiperazine derivatives and benzothiophene-4-piperazine derivatives: novel antagonists for the vascular 5-HT1B receptor

The synthesis and vascular 5-HT(1B) receptor activity of a novel series of substituted 3-amido phenylpiperazine and 4-(4-methyl-1-piperazinyl)-1-benzo[b]thiophene derivatives is described. Modifications to the amido linked sidechains of the 3-amidophenyl-piperazine derivatives and to the 2-sidechain of the 1-benzo[b]thiophene derivatives have been explored. Several compounds were identified which exhibited affinity at the vascular 5-HT(1B) receptor of pK(B) > 7.0. From the 3-amidophenyl-piperazine series, N-(4-(4-chlorophenyl)thiazol-2-yl-3-(4-methyl-1-piperazinyl)benzamide (30) and from the benzo[b]thiophene-4-piperazine series N-(2-ethylphenyl)-4-(4-methyl-1- piperazinyl)-1-benzo[b]thiophene-2-carboxamide (38) were identified as a highly potent, silent (as judged by the inability of angiotensin II to unmask 5-HT(1B) receptor mediated agonist activity in the rabbit femoral artery) and competitive vascular 5-HT(1B) receptor antagonist. The affinity of compounds from these two series of compounds for the vascular 5-HT(1B) receptor is discussed as well as a proposed mode of binding to the receptor pharmacophore.

Inter-digestive and post-prandial antro-pyloro-duodenal motor activity in humans: effect of 5-hydroxytryptamine 1 receptor agonism

BACKGROUND

Little is known about the effect of 5-hydroxytryptamine 1 (5-HT(1)) receptor agonism on the co-ordinated motor activity of the gastric antrum, pylorus and duodenum under fasting and fed conditions.

AIM

To evaluate the effect of sumatriptan, a 5-HT(1) agonist, on fasting and fed antro-pyloro-duodenal motility.

METHODS

In study 1, antro-pyloro-duodenal motility was recorded for two phase IIIs of the migrating motor complex and then, following either a subcutaneous injection of sumatriptan 6 mg or saline control, for at least one additional phase III in 11 healthy volunteers (21-36 years). In study 2, the post-prandial motility was recorded for 3 h after either a subcutaneous injection of sumatriptan 6 mg or saline control in 10 healthy volunteers (18-36 years).

RESULTS

Sumatriptan prolonged the migrating motor complex cycle (P = 0.009) by increasing the duration of phase II (P = 0.02) but not phases I and III. Post-prandially, sumatriptan reduced the activity index (P = 0.017) by reducing the frequency of co-ordinated motor activity involving the antrum and/or the duodenum (P < 0.05).

CONCLUSION

5-HT(1) receptor agonism increases the periodicity of the migrating motor complex and reduces the occurrence of post-prandial co-ordinated motor activity involving the gastric antrum, pylorus and duodenum.

Triptans and gastric accommodation: pharmacological and therapeutic aspects

In the past decade, several studies have reported a significant delay of gastric emptying induced by the anti-migraine agent sumatriptan (a 5-hydroxytryptamine (5-HT)1B/D receptor agonist) in healthy human beings. In patients with functional dyspepsia, sumatriptan improves gastric accommodation after food consumption and reduce perception of gastric distension, hence relieving epigastric symptoms. Recent studies have established that impaired accommodation after food consumption is a major patho-physiological mechanism in functional dyspepsia and restoration of accommodation is considered to be a potential therapeutic target. The precise site of action of sumatriptan in humans is at present unknown, although recent studies carried out using a canine model indicate that sumatriptan exerts its action on gastric accommodation through 5-HT1B receptors, since both GR127935 and SB216641 (respectively, non selective 5-HT1B/D and selective 5-HT1B receptor antagonists) fully antagonised the effects of sumatriptan. Gastric relaxation and enhanced accommodation to a distending stimulus seem to be a class effect of triptans, since it occurs not only with sumatriptan, but also with second-generation triptans (rizatriptan and naratriptan), at least in a canine model. In dyspeptic patients, administration of triptans would be able to restore gastric accommodation after a meal and to improve symptoms of early satiety, confirming the therapeutic potential of 5-HT1B/D receptor agonists in functional dyspepsia.

Role of 5-HT1B/D receptors in canine gastric accommodation: effect of sumatriptan and 5-HT1B/D receptor antagonists

The 5-HT1B/D receptor agonist sumatriptan has been proposed to treat dyspeptic symptoms, because it facilitates gastric accommodation. It is unknown whether stimulation of 5-HT1B/D receptors is involved. Thus, in four conscious dogs, we compared the effects of sumatriptan alone or combined with N-[4-methoxy-3-(4-methyl-1-piperazinyl) phenyl]-2'-methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)-[1,1-biphenyl]-4-carboxamide hydrocloride (GR-127935), N-[3-[3 (dimethylamino)-ethoxy]-4-methoxyphenyl]-2'-[methyl-4'-(5-methyl-1,2,4-oxadiazol-3-yl)]-[1,1-biphenyl]-4-carboxamide hydrocloride (SB-216641 hydrochloride), or 3-[4-(4-chloro-phenyl)piperazin-1-yl]-1,1-diphenyl-2-propanol hydrochloride (BRL-15572 hydrochloride) (respectively, nonselective 5-HT1B/D, selective 5-HT1B, and selective 5-HT1D receptor antagonists) on gastric accommodation to isobaric distensions performed with a barostat. An exponential and a linear model were used to fit the pressure-volume relationship. An exponential equation fitted the data better than a linear equation. Sumatriptan (800 nmol/kg iv) induced an immediate gastric relaxation (Deltavolume: 112 +/- 44 ml, P < 0.05). After sumatriptan, the pressure-volume curve was shifted toward significantly higher volumes. This effect was fully reversed by GR-127935 or SB-216641 but not by BRL-15572. In conclusion, 5-HT1B receptors seem to play an important role in modulating gastric accommodation to a distending stimulus. An exponential model for pressure-volume curves fits well with the concept of gastric adaptive relaxation.

Identification of the human liver enzymes involved in the metabolism of the antimigraine agent almotriptan

Almotriptan is a novel highly selective 5-hydroxytryptamine(1B/1D) agonist developed for the acute oral treatment of migraine. The in vitro metabolism of almotriptan has been investigated using human liver subcellular fractions and cDNA-expressed human enzymes, to study the metabolic pathways and identify the enzymes responsible for the formation of the major metabolites. Specific enzymes were identified by correlation analysis, chemical inhibition studies, and incubation with various cDNA expressed human enzymes. Human liver microsomes and S9 fraction metabolize almotriptan by 2-hydroxylation of the pyrrolidine group to form a carbinolamine metabolite intermediate, a reaction catalyzed by CYP3A4 and CYP2D6. This metabolite is further oxidized by aldehyde dehydrogenase to the open ring gamma-aminobutyric acid metabolite. Almotriptan is also metabolized at the dimethylaminoethyl group by N-demethylation, a reaction that is carried out by five different cytochrome P450s, flavin monooxygenase-3 mediated N-oxidation, and MAO-A catalyzed oxidative deamination to form the indole acetic acid and the indole ethyl alcohol derivatives of almotriptan. The use of human liver mitochondria confirmed the contribution of MAO-A to the metabolism of almotriptan. Both, the gamma-aminobutyric acid and the indole acetic acid metabolites have been found to be the major in vivo metabolites of almotriptan in humans. In addition, different clinical trials conducted to study the effects of CYP3A4, CYP2D6, and MAO-A on the pharmacokinetics of almotriptan confirmed the involvement of these enzymes in the metabolic clearance of this drug and that no dose changes are required in the presence of inhibitors of these enzymes.

Migraine with aura versus migraine without aura: pain intensity and associated symptom intensities after placebo

OBJECTIVE

To compare the intensity of pain and associated symptoms after placebo administration in patients with migraine with aura and migraine without aura.

BACKGROUND

Studies that evaluate drugs used in the acute treatment of migraine ideally should include a placebo arm. The International Headache Society also recommends stratification according to age and sex but not by the presence versus absence of aura.

METHODS

The study was conducted as part of a placebo controlled randomized survey comparing four active drugs against placebo in the acute treatment of migraine. Patients were blinded as to treatment received. Placebo consisted of 10 mL of normal saline (0.9%) intravenously. Pain intensity was evaluated by a 10-point analogical-verbal scale. Nausea, photophobia, and phonophobia were evaluated by a four-point analogical-verbal scale. For statistical analysis, unpaired t-test with Welch correction was used.

RESULTS

After placebo administration, reduction of symptom intensity (pain, nausea, photophobia, and phonophobia) in patients with migraine without aura was significantly greater than that observed in patients with migraine with aura.

CONCLUSIONS

Our findings suggest that studies comparing placebo against an active drug should use stratification according to the presence versus absence of aura.

Practical approaches to migraine management

Migraine is a recurrent clinical syndrome characterised by combinations of neurological, gastrointestinal and autonomic manifestations. The exact pathophysiological disturbances that occur with migraine have yet to be elucidated; however, cervico-trigemino-vascular dysfunctions appear to be the primary cause. Despite advances in the understanding of the pathophysiology of migraine and new effective treatment options, migraine remains an under-diagnosed, under-treated and poorly treated health condition. Most patients will unsuccessfully attempt to treat their headaches with over-the-counter medications. Few well designed, placebo-controlled studies are available to guide physicians in medication selection. Recently published evidence-based guidelines advocate migraine-specific drugs, such as serotonin 5-HT(1B/1D) agonists (the 'triptans') and dihydroergotamine mesylate, for patients experiencing moderate to severe migraine attacks. Additional headache attack therapy options include other ergotamine derivatives, phenothiazines, nonsteroidal anti-inflammatory agents and opioids. Preventative medication therapy is indicated for patients experiencing frequent and/or refractory attacks.

Almotriptan is an effective and well-tolerated treatment for migraine pain: results of a randomized, double-blind, placebo-controlled clinical trial

Almotriptan is a novel and specific serotonin 5-HT1B/1D agonist for the acute treatment of migraine. This randomized, single-dose, double-blind, multicentre, study assessed the efficacy and safety of oral almotriptan (12.5 mg and 25 mg) in patients with migraine, and compared it with the standard treatment (sumatriptan 100 mg) and placebo. A total of 668 patients treated one migraine attack of moderate or severe intensity with study medication. The primary efficacy assessment was migraine pain relief, improvement from severe or moderate pain to mild or no pain, at 2 h after treatment. Response rates, stratified for variation in baseline pain levels, for both almotriptan doses were equivalent to sumatriptan and significantly better than placebo. Other efficacy assessments confirmed the equivalence of the almotriptan groups with the sumatriptan group. Almotriptan 12.5 mg was as well tolerated as placebo (P=0.493) and significantly better tolerated than sumatriptan (P<0.001), in terms of the overall incidence of adverse events. There was no statistically significant difference in the incidence of adverse events between almotriptan 25 mg and sumatriptan 100 mg (P=0.376). The results from this large clinical study indicate that the new, specific 5-HT1B/1D agonist, almotriptan, is an effective and well-tolerated treatment for migraine pain.

The efficacy and safety of sc alniditan vs. sc sumatriptan in the acute treatment of migraine: a randomized, double-blind, placebo-controlled trial

This double-blind, placebo-controlled, parallel-group, multicentre, multinational, phase-III trial was designed to assess the efficacy and safety of a single subcutaneous injection of placebo, 2 doses of alniditan (1.4 mg and 1.8 mg) and 6 mg of sumatriptan in subjects with acute migraine. A total of 114 investigators from 13 different countries screened 2021 subjects. In total 924 patients were treated with placebo (157), alniditan 1.4 mg (309), alniditan 1.8 mg (141) and sumatriptan 6 mg (317). The lower number of subjects in the alniditan 1.8 mg group is due to the termination of this trial arm after the incidence of a serious adverse event and a subsequent protocol amendment. The number of subjects who were pain free at 2 h (primary endpoint) was: 22 (14.1%) with placebo, 174 (56.3%) with alniditan 1.4 mg, 87 (61.7%) with alnditan 1.8 mg and 209 (65.9%) with sumatriptan 6 mg. Alniditan 1.4 mg was significantly better (P < 0.001) than placebo and sumatriptan was significantly better (P = 0.015) than alniditan 1.4 mg. The number of responders (reduction of headache severity from moderate or severe headache before treatment to mild or absent at 2 h), was 59 (37.8%) on placebo, 250 (80.9%) on alniditan 1.4 mg, 120 (85.1%) on alniditan 1.8 mg, and 276 (87.1%) on sumatriptan. Response was significantly higher (P < 0.001) with alniditan 1.4 mg than with placebo, and significantly lower (P = 0.036) with alniditan 1.4 mg than with sumatriptan. Recurrence rates were: 22 (37.3%) with placebo, 87 (34.8%) with alniditan 1.4 mg, 35 (29.2%) with alniditan 1.8 mg and 108 (39.1%) with sumatriptan. Adverse events occurred in 577/924 (62.4%) subjects, i.e. in 62/157 (39.5%) with placebo, 214/309 (69.3%) with alniditan 1.4 mg, 91/141 (64.5%) with alniditan 1.8 mg and 210/317 (66.2%) with sumatriptan 6 mg. Sumatriptan was significantly better than alniditan 1.4 mg for pain free at 2 h. The difference, however, was small and clinically not important. For alniditan, a dose-dependent adverse event relationship was seen. The safety profile of alniditan 1.4 mg was similar to that of sumatriptan.

[Anti-migraine drug sumatriptan succinate, a 5-HT1B/1D-receptor agonist]

Sumatriptan succinate (SMT) was a highly specific 5-HT1-receptor agonist. It showed high affinity only for 5-HT but no affinity for other neurotransmitter receptors such as muscarinic, dopamine D1, D2, adrenergic alpha 1, alpha 2, and beta. Furthermore, it was highly selective for 5-HT1B/1D-receptor and showed no affinity for 5-HT2 and 5-HT3 receptors. SMT contracted isolated cranial arteries such as basilar, midcerebral, temporal arteries and large arteries in the dura matter, but did not contract coronary, femoral, mesenteric and other arteries. Reflecting these results, SMT induced vasoconstriction of carotid artery, but produced practically no contractile responses in the other arteries mentioned above in anaesthetized animals. These pharmacological characteristics of SMT were different from those of ergot alkaloids, current anti-migraine drugs, which contracted coronary, femoral and other arteries as well. SMT inhibited neurotransmitter release, including CGRP, from trigeminal nerve terminals. Consequently protein extravasation induced by CGRP was inhibited and neurogenic inflammation could be suppressed. It was believed that SMT showed its anti-migraine activity through cranial vasoconstriction via 5-HT1B/1D receptors, since it did not show any analgesic activities. Its clinical efficacy on migraine and cluster headache had been already confirmed in about 100 western countries. Its efficacy was also shown by open trials and placebo controlled double blind tests in Japan.

Zolmitriptan versus sumatriptan for the acute oral treatment of migraine: a randomized, double-blind, international study

This randomized, double-blind, parallel-group study compared the efficacy and tolerability of zolmitriptan (2.5 or 5 mg) and sumatriptan (50 mg) in the acute oral treatment of up to six moderate-to-severe migraine attacks. The intention to treat (ITT) population comprised of 1522 patients: 500 treated with zolmitriptan 2.5 mg (2671 attacks), 514 with zolmitriptan 5 mg (2744 attacks) and 508 with sumatriptan 50 mg (2693 attacks). Overall, the 2-h headache response rates in these groups were 62.9, 65.7 and 66.6%, respectively. There were no statistically significant differences between sumatriptan 50 mg and zolmitriptan 2.5 mg (P = 0.12) or 5 mg (P = 0.80). Approximately 40% of patients in each group reported a 2-h headache response in > or = 80% of attacks. There were no statistically significant differences between the groups in the rates of headache response at 1 h (zolmitriptan 2.5 mg 36.9%, zolmitriptan 5 mg 39.5% and sumatriptan 50 mg 38.0%) or 4 h (70.3, 72.9 and 72.2%, respectively) or in the rates of meaningful migraine relief at 1, 2 or 4 h or sustained (24-h) pain relief. All treatments were well tolerated. In conclusion, zolmitriptan (2.5 or 5 mg) proved similarly efficacious compared with sumatriptan (50 mg), both in terms of response rates and consistency across attacks.

Functional immunohistochemistry of neuropeptides and nitric oxide synthase in the nerve fibers of the supratentorial dura mater in an experimental migraine model

The supratentorial cerebral dura of the albino rat is equipped with a rich sensory innervation both in the connective tissue and around blood vessels, which includes nociceptive axons and their terminals; these display intense calcitonin gene-related peptide (CGRP) immunoreactivity. Stereotactic electrical stimulation of the trigeminal (Gasserian) ganglion, regarded as an experimental migraine model, caused marked increase and disintegration of club-like perivascular CGRP-immunopositive nerve endings in the dura mater and induced an apparent increase in the lengths of CGRP-immunoreactive axons. Intravenous administration of sumatriptan or eletriptan, prior to electrical stimulation, prevented disintegration of perivascular terminals and induced accumulation of CGRP in terminal and preterminal portions of peripheral sensory axons. Consequently, immunopositive terminals and varicosities increased in size; accumulation of axoplasmic organelles resulted in the "hollow" appearence of numerous varicosities. Since triptans exert their anti-migraine effect by virtue of agonist action on 5-HT(1D/B) receptors, we suggest that these drugs prevent the release of CGRP from perivascular nerve terminals in the dura mater by an action at 5-HT(1D/B) receptors. Nitroglycerine (NitroPOHL), given subcutaneously to rats, induces increased beading of nitric oxide synthase (NOS)-immunoreactive nerve fibers in the supratentorial cerebral dura mater, and an apparent increase in the number of NOS-immunoreactive nerve fibers in the dural areas supplied by the anterior and middle meningeal arteries, and the sinus sagittalis superior. Structural alterations of nitroxidergic axons innervating blood vessels of the dura mater support the idea that nitric oxide (NO) is involved in the induction of headache, a well-known side effect of coronary dilator agents.

Oral lysine clonixinate in the acute treatment of migraine: a double-blind placebo-controlled study

Several oral nonsteroidal anti-inflammatory drugs (NSAIDs) are effective to treat migraine attacks. Lysine clonixinate (LC) is a NSAID derived from nicotinic acid that has proven to be effective in various pain syndromes such as renal colic and muscular pain. The aim of this double-blind, placebo-controlled study was to evaluate the efficacy of oral LC compared to placebo in the acute treatment of migraine. Sixty four patients with the diagnosis of migraine, according to the IHS criteria, were studied prospectively. Patients received LC or placebo once the headache reached moderate or severe intensity for 6 consecutive attacks. With regard to the moderate attacks, LC was superior than placebo after 1, 2 and 4 hours. The consumption of other rescue medications after 4 hours was significantly higher in the placebo group. With regard to the severe attacks, there was no difference between the active drug group and the placebo group concerning headache intensity and consumption of other rescue medications. We conclude that the NSAID lysine clonixinate is effective in treating moderately severe migraine attacks. It is not superior than placebo in treating severe migraine attacks.

Hemodynamic and electrocardiographic effects of almotriptan in healthy volunteers

We studied the possible cardiovascular effects of single oral doses of 12.5, 25, and 50 mg of almotriptan, a new triptan for treatment of migraine, in a randomized, double-blind, four-way crossover, placebo-controlled study in 24 healthy volunteers aged 18 to 35 years. Doses were given at 1-week intervals. Cardiovascular effects were assessed by frequent recording of blood pressure and heart rate, 12-lead electrocardiogram (ECG) (recorded at 25 mm/s paper speed and 1 cm/mV and at 50 mm/s and 2 cm/mV), and continuous ECG monitoring for 12 h after each dose. ECG variables, PR, QRS, QT interval, and QT dispersion, were measured. QT intervals were adjusted for heart rate using Bazett's formula. None of the doses of almotriptan differed significantly from placebo with respect to PR, QRS, or QTc intervals, QTc dispersion, heart rate, or continuous ECG monitoring. Almotriptan 12.5 mg did not differ significantly from placebo with respect to systolic or diastolic blood pressure, but almotriptan 25 and 50 mg raised systolic blood pressure by a mean of 2.78 and 4.17 mm Hg, and diastolic blood pressure by 3.77 and 6.11 mm Hg, respectively, during 0 to 4 h after dosing. Thus none of the doses of almotriptan affected the ECG, and the 12.5-mg dose (the expected therapeutic dose) had no hemodynamic effects. Almotriptan in doses of 25 and 50 mg caused a small, dose-related increase in systolic and diastolic blood pressure, as seen with other triptans.

Long-term efficacy and safety of oral almotriptan: interim analysis of a 1-year open study

OBJECTIVE

To assess the long-term tolerability and safety of a single, oral 12.5-mg dose of almotriptan and its efficacy in alleviating pain associated with consecutive migraine episodes occurring during a 12-month period.

BACKGROUND

While sumatriptan appears to be effective for treatment of migraine, the drug has several properties that limit its use. Almotriptan, a new selective 5-HT1B/1D agonist, may be better tolerated over the long term.

METHODS

This 1-year study was conducted on 806 adults between the ages of 18 and 65 years suffering from migraine, either with or without aura. The patients met the criteria for study as outlined by the International Headache Society and were instructed on drug use. Oral almotriptan 12.5 mg was used to treat the attack of any pain severity and a second dose was permitted in case of relapse of pain during the first 24 hours. Rescue medication was provided. Efficacy and tolerability were assessed by a combination of patient reporting and clinical visit evaluations.

RESULTS

Overall, almotriptan was well tolerated. At 2 hours, 81% of attacks were relieved; 56% of the subjects were entirely free of pain. These efficacy data are similar for the first as well as the last attack studied. At analysis, 534 patients had treated their migraines for at least 6 months. About half of all patients experienced at least one adverse event, with 87% of the events being mild or moderate in nature. The most frequent adverse events were back pain (7.23% of patients), bronchitis (5.76%), and influenzalike symptoms (5.62%). Seventy-one percent of the adverse events were not related to almotriptan use.

CONCLUSIONS

Almotriptan at an oral dose of 12.5 mg is safe antimigraine treatment. The safety profile results are similar to those obtained in other controlled triptan clinical studies. Almotriptan is efficacious in moderate-to-severe migraine pain and can be used repeatedly in recurrent episodes. The long-term safety data will be reanalyzed when full data become available.

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.

Functional Dyspepsia: Impaired Fundic Accommodation

Functional dyspepsia is a heterogeneous disorder in which distinct pathophysiological abnormalities are present in subgroups of patients. Accommodation of the proximal stomach to a meal is impaired in 40% of patients with functional dyspepsia. This is associated with symptoms of early satiety and weight loss. The presence of early satiety as a relevant or severe symptom is a good predictor of impaired accommodation. Gastric barostat or proximal gastric ultrasound may confirm the presence of impaired accommodation after a meal. Sophisticated analysis of scintigraphic gastric emptying images or a simple caloric drinking test are under investigation in the diagnosis of impaired accommodation. It seems logical to have patients eat more frequent, smaller sized meals. Cisapride is the only well-evaluated form of pharmacological treatment for this condition, and has been withdrawn from the US market (see Important Note under Treatment, below). Small or preliminary studies suggest some benefit from buspirone or selective serotonin reuptake inhibitors (SSRIs).

Consistent efficacy and tolerability of almotriptan in the acute treatment of multiple migraine attacks: results of a large, randomized, double-blind, placebo-controlled study

In this double-blind study, the efficacy and tolerability of a single dose of almotriptan (6.25 or 12.5 mg) was compared with placebo in the treatment of three consecutive migraine attacks of moderate or severe intensity. Of 1013 randomized patients, 722 evaluable patients completed the study. The total number of attacks relieved (severe or moderate pain reduced to mild or no pain) at 2 h post-dose was significantly higher (P < 0.001) after treatment with almotriptan 6.25 or 12.5 mg compared with placebo (60% and 70% vs. 38%, respectively). Moreover, a consistent response was achieved across and within patients for almotriptan 6.25 or 12.5 mg compared with placebo (pain relief in at least two out of three attacks within 2 h for 64% and 75% vs. 36%, respectively) and less than one-third of the patients relapsed within 24 h. Almotriptan was well tolerated with no significant differences between the almotriptan and placebo treatment groups in the percentage of patients reporting adverse events. Overall, the 12.5-mg dose was associated with the most favourable efficacy/tolerability ratio and is, therefore, the recommended dose.

Naproxen sodium decreases migraine recurrence when administered with sumatriptan

Forty to 78% of the patients using sumatriptan for the acute treatment of migraine may present recurrence at least occasionally. The concomitant use of a NSAID (nonsteroidal anti-inflammatory drug) has been recommended to decrease the recurrence rate. Sixty seven patients that treated successfully 8 migraine attacks with 100 mg of sumatritpan PO and presented recurrence in at least 5 attacks were studied prospectively. The patients received 100 mg of sumatriptan and 550 mg of naproxen sodium PO to treat 4 consecutive moderate or severe migraine attacks. The recurrence rate, once at least 62.5% (5 out of 8 attacks), decreased to 14.2% (38 out of 268 attacks) with the combination of compounds (p<0.0001). We then studied two groups of 13 patients made randomicaly from the 67 initially evaluated, that were given sumatriptan 100 mg plus naproxen sodium 550 mg or placebo, in a double-blind design, to treat 3 other consecutive migraine attacks. Each group of patients treated 39 attacks. The recurrence among the patients taking sumatriptan plus placebo was 59% (23 out of 39 attacks) and the recurrence presented by the group taking sumatriptan plus naproxen was 25.5% (10 out of 39 attacks) (p<0.0003). We concluded that the combination of sumatriptan plus naproxen sodium decreases significantly migraine recurrence presented by patients taking sumatriptan alone.

Influence of a 5HT1 receptor agonist on gastric accommodation and initial transpyloric flow in healthy subjects

Sumatriptan, a 5HT1 receptor agonist, inhibits antral motor activity, delays gastric emptying and relaxes the gastric fundus. The aim of this study was to characterize the effect of sumatriptan on transpyloric flow and gastric accommodation during and immediately after ingestion of a liquid meal using duplex sonography. Ten healthy subjects were investigated twice on separate days. In random order either sumatriptan 6 mg (Imigran 0.5 mL) or a placebo were given s.c. 15 min before ingesting 500 mL of a meat soup. The subjects were examined during the 3-min period before ingestion of the liquid meal, the 3-min spent drinking the meal and 10 min postprandially. Sumatriptan caused a significant widening of both the gastric antrum (P=0.02) and the proximal stomach (P=0.01) 10 min postprandially as compared with placebo. It caused no significant differences in time to initial gastric emptying (P=0.2), but significantly delayed commencement of peristaltic-related transpyloric flow (P=0.04). Sumatriptan had no significant effect on mean abdominal symptom scores, but after sumatriptan there was a significant negative correlation between width of postprandial antral area and postprandial nausea and between width of postprandial antral area and postprandial bloating. We therefore conclude that sumatriptan causes a postprandial dilatation of both the distal and the proximal stomach with no change in dyspeptic symptoms nor in length of time to first gastric emptying. Time to commencement of peristaltic-related emptying is delayed.