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Interictal and postictal contingent negative variation in migraine without aura.

Cortical hyperexcitability is thought to explain the more enhanced contingent negative variation (CNV) amplitudes and impaired CNV habituation that have been found during the interictal period in migraine without aura. These CNV characteristics have been shown to normalize to the level of healthy controls during an attack. This study aimed to replicate the interictal findings, and additionally examine whether migraineurs show reduced CNV amplitudes during the postattack period. Of 12 patients with migraine without aura and their sex- and age-matched healthy controls, CNV characteristics were recorded once in an interictal period, once during the postattack period within 30 hours after an attack that was treated with sumatriptan, and once after an attack that was treated with habitual nonvasoactive medication (counterbalanced). The present results did not confirm the enhanced CNV early and late wave amplitudes or impaired habituation, and cortical hyperexcitability that have previously been reported in the interictal period in patients with migraine without aura. During the postattack period, a decrease in CNV early and late amplitudes was found but only after sumatriptan use. This reduction in CNV amplitudes was most prominent over the frontal cortex and could reflect cortical hypoexcitability, possibly related to a suppression of central catecholaminergic activity by sumatriptan.

Adult↗

Almotriptan increases sustained pain-free outcomes in acute migraine: results from three controlled clinical trials.

OBJECTIVE: Evaluate the effect of almotriptan on sustained pain-free outcome in patients with acute migraine. METHODS: Three randomized, double-blind, placebo-controlled trials of almotriptan for the treatment of acute migraine were examined. Two trials evaluated almotriptan 6.25 mg and 12.5 mg, and the third evaluated almotriptan 12.5 mg and sumatriptan 100 mg. Patients aged 18 to 65 years were instructed to take 1 dose of study medication at the onset of a moderate-to-severe migraine headache. A second dose was allowed for relapse. Sustained pain-free was defined as a decrease in pain severity from moderate or severe at baseline to no pain at 2 hours postdose and without relapse or the use of escape medication between 2 and 24 hours. RESULTS: A total of 1791 adult migraine sufferers were studied. The proportion of patients achieving a sustained pain-free state was significantly (P<.05) higher in the almotriptan 6.25-mg (21.7% to 22.5%) and 12.5-mg (24.6% to 27.6%) groups than in the placebo group (7.5% to 12.1%). The proportion of patients achieving a sustained pain-free state was comparable between almotriptan 12.5 mg (24.6%) and sumatriptan 100 mg (28.5%) and significantly (P<.05) greater than with placebo (12.1%). Among patients with severe baseline pain, a sustained pain-free state was achieved in significantly more patients (P<.05) with almotriptan 12.5 mg (17.3% to 20.9%) than with placebo (3.1% to 3.2%). Among those with moderate baseline pain, a sustained pain-free state was achieved in significantly more patients (P<.01) with almotriptan 12.5 mg (31.3% to 32.0%) than with placebo (10.2% to 16.1%). CONCLUSIONS: Almotriptan 12.5 mg is significantly better than placebo and comparable to sumatriptan 100 mg for achieving a sustained pain-free state.

Acute Disease↗

Tripstar: a comprehensive patient-based approach to compare triptans.

Several second-generation triptans have been introduced that differ in their pharmacologic profiles relative to each other and to sumatriptan. As therapeutic options multiply, clinicians must be able to distinguish among these compounds. Recently, a meta-analysis was conducted on data from 53 double-blind, randomized, placebo- or active-controlled trials involving over 24,000 patients receiving oral triptans. Results indicated that almotriptan 12.5 mg, rizatriptan 10 mg, and eletriptan 80 mg are generally superior to sumatriptan 100 mg based on individual treatment attributes, such as pain relief, sustained pain freedom, consistency of response, and tolerability. Meta-analyses are limited, however, as the analysis can only be performed for individual end points, whereas patients and prescribers balance a variety of treatment attributes when assessing drug acceptability. A flexible overall scoring system ("Tripstar") is proposed that compares triptans to a hypothetical "ideal" using meta-analysis data combined with ratings of the relative importance of clinically relevant treatment criteria. An informal test of the Tripstar model indicated that sumatriptan is most similar to a hypothetical ideal for both mild and severe migraine, primarily due to its high worldwide clinical exposure. However, after exclusion of worldwide exposure as a contributing factor, almotriptan 12.5 mg is most similar to the ideal, principally because of its good tolerability. Further tests of the Tripstar model are planned that will gauge the relative importance of a broader range of attributes.

Acute Disease↗

Persistence of defective serotonergic and GABAergic controls of growth hormone secretion in long-term abstinent alcoholics.

In order to establish whether long-term abstinence from alcohol reverses the defective serotonergic and GABAergic controls of growth hormone (GH) secretion affecting alcoholic patients, the 5-HT1D serotonergic receptor agonist sumatriptan and the GABAergic agent gamma-hydroxybutyric acid (GHB) were administered to 12 normal men (32-49 years) and 22 non-depressed male alcoholic subjects (38-52 years) after 1-2 years of abstinence from alcohol. All subjects were also tested with placebos. Furthermore, tests with GH-releasing hormone (GHRH) and L-arginine (which releases GH from somatostatin inhibition) were performed to determine whether GH secretion in response to its major determinants is preserved in alcoholics. Administration of placebo did not change plasma GH levels in any subject. Similar GH responses were observed in normal controls and alcoholic subjects when GHRH or arginine were administered. A significant GH increase was observed in normal controls after sumatriptan or GHB injection; in contrast, GH secretion was not modified by sumatriptan or GHB administration in alcoholic patients. These data show a persistent selective loss of 5-HT1D receptor and GHB-mediated neurotransmissions in alcoholics that a long-term abstinence from alcohol is unable to restore.

Adult↗

Triptan therapy impacts health and productivity.

New sumatriptan users in a California health plan were surveyed on the impact of migraine using a newly developed migraine impact measure, the Headache Impact Test-6. Productivity and satisfaction with migraine therapy also were assessed. After sumatriptan was initiated, participants reported significantly fewer workdays missed, fewer days worked with headache, and greater productivity while headache symptoms were present. In addition, almost 50% less members used narcotics/opioids, while the frequency, duration, and severity of migraines decreased. Initiation of sumatriptan therapy is associated with improvements in absenteeism and presenteeism, clinical outcomes (Headache Impact Test-6), and satisfaction. The benefits of triptan therapy extend to the employer, who sees a decrease in lost productivity, fewer emergency room visits, and less narcotics use in employees with migraine. Managed care organizations that provide this pharmacotherapy may foster greater satisfaction among members and employer customers.

Adolescent↗

Influence of delaying gastric emptying on meal-related symptoms in healthy subjects.

BACKGROUND: Although delayed gastric emptying is often found in functional dyspepsia, a causal role for delayed emptying in inducing symptoms has not been demonstrated. AIM: To investigate the influence of delaying gastric emptying rate in healthy volunteers on the occurrence of meal-related symptoms. METHODS: Fourteen healthy subjects (six men, mean age 23 +/- 1) underwent gastric emptying studies twice using the 14C octanoic acid and 13C glycin breath test after pre-treatment with saline or sumatriptan 6 mg s.c. Breath samples were taken before meal and at 15-min intervals for a period of 360 min postprandially. At each breath sampling, the subject was asked to grade the intensity (0-6) of four dyspeptic symptoms. RESULTS: Sumatriptan pre-treatment significantly delayed solid but not liquid gastric emptying (t1/2 respectively 159 +/- 11 vs. 112 +/- 9 min, P < 0.005 and 134 +/- 11 vs. 116 +/- 12 min, N.S.). Sumatriptan significantly decreased the mean cumulative symptom score (21.3 +/- 5.5 vs. 8.0 +/- 2.6, P = 0.01), as well as scores for each individual symptom. CONCLUSION: A moderate delay in gastric emptying in health is not associated with an increase of meal-related symptoms. This observation argues against a causal role for delayed gastric emptying in the pathogenesis of dyspeptic symptoms.

Adult↗

Migraine-like headache in bacterial meningitis.

The effect of sumatriptan has not been previously described in the treatment of the headache of meningitis, although this headache has similarities to migraine. This study presents the clinical features of two patients who had fulminant bacterial meningitis with migraine-like headache and who experienced no improvement in headache intensity after administration of sumatriptan 6 mg s.c. On these grounds the lack of response of this type of headache to sumatriptan is discussed.

Adult↗

Prediction of headache response in migraine treatment.

Triptans are efficacious for the acute treatment of migraine attacks. Yet, defining a concentration-effect relation for these compounds is difficult as the dynamics of the migraine attack are not thoroughly understood. The objective of this investigation was to develop a disease model to predict measures of headache in randomized placebo-controlled clinical trials investigating oral sumatriptan as a paradigm compound. A hidden Markov model based on the states of response (no relief, relief, and pain free) and headache scores (observed variable) was used in conjunction with population pharmacokinetics. Model parameters were capable of predicting the course of headache relief, pain-free status and headache recurrence. It was shown that sumatriptan shortens mean transit times between states by up to 5 h. The potency of sumatriptan (EC(50)) was 9 ng/ml. These findings demonstrate the value of combining pharmacokinetic and efficacy information to model disease and characterize time-independent drug properties in a population of migraineurs.

Comorbidity↗

Analysis of the 5-HT receptors mediating contractions in the rabbit isolated renal artery.

1. Using a number of agonist and antagonist compounds, we have attempted to characterize the responses and receptors involved in the effects of 5-hydroxytryptamine (5-HT) in the rabbit isolated renal artery. 2. In vessel segments precontracted with the thromboxane-mimetic agent, U46619 (100 nM), neither 5-HT (10(-8) to 10(-4) M) nor 5-carboxamidotryptamine (5-CT; 10(-8) to 3 x 10(-4) M) caused relaxations like those observed with methacholine. Both 5-HT and 5-CT further increased the tone of the vessels, with pD2 values of 7.1 and 7.9, respectively. 3. In the absence of U46619, both 5-HT (10(-7) to 3 x 10(-3) M) and 5-CT (10(-7) to 10(-3) M) contracted the rabbit renal artery, but with reduced potencies. The contractions to 5-HT were reproducible and the rank order of potency (pD2) of the agonists was: alpha-methyl-5-HT (5.7), sumatriptan (5.3), 5-HT (5.1), 8-hydroxy-2(di-n-propylamino)tetralin (5.0), 5-CT (4.7) and 5-methoxytryptamine (4.3). 1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane, flesinoxan and RU 24969 elicited either only small contractions or none at all. 4. The contractile effect of 5-HT was unaffected by MDL 72222 (10(-6) M) and metergoline (10(-8) and 10(-7) M), was weakly antagonized by ketanserin and phentolamine (pKB: 6.6 and 6.8, respectively), but was effectively antagonized by methiothepin (pKB: 8.6). Responses to 5-CT and sumatriptan were affected by ketanserin, phentolamine and methiothepin similarly to 5-HT-induced responses. 5. Ketanserin was ineffective against noradrenaline-induced contractions, which were antagonized by phentolamine with a pKB of 7.3. The pKB values of phentolamine against 5-HT, 5-CT or sumatriptan were about half a log unit lower than against noradrenaline.6. In vascular preparations treated with cocaine (3 x 10- I M), the potency (pKB) of phentolamine as an antagonist of the responses to noradrenaline (7.6) and 5-HT (6.7) did not differ significantly from the values in untreated preparations. However, the difference between the pKB values of phentolamine against the two agonists was now about one log unit.7. Pretreatment of the vascular strips with 6-hydroxydopamine (1.5 x 10- 3M) did not significantly affect responses to 5-HT or 5-CT, but almost eliminated those to tyramine. Cocaine (3 x 10- 5M) slightly potentiated noradrenaline-induced contractions, but did not significantly affect those induced by 5-HT.8. These data suggest that: (i) 5-HT receptors mediating vasodilatation are not present in the rabbit renal artery smooth muscle or endothelium; (ii) the contractile effect of 5-HT does not involve the release of noradrenaline from sympathetic nerve stores; (iii) the 5-HT receptor in the rabbit renal artery is not of the 5-HT2, 5-HT3 or 5-HT4 type. The pharmacological properties of this receptor most closely resemble those described for the heterogeneous 5-HT1-like category.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

Time-dependent blockade of neurogenic plasma extravasation in dura mater by 5-HT1B/D agonists and endopeptidase 24.11.

1. The delayed effects of stimulating the trigeminal ganglion unilaterally in rats and guinea-pigs were assessed by measuring the leakage of radiolabelled albumin from blood into the dura mater at intervals for up to 120 min after a 5 min stimulation period (5 Hz, 0.6 mA, 5 ms). 2. [125I]-albumin (50 microCi kg-1) was injected i.v. as a tracer 0, 20, 50, 80 or 110 min after stimulation and the animals were killed 10 min later. Extravasation of plasma protein developed for up to 90 min poststimulation. 3. To examine the mechanism underlying delayed plasma protein extravasation, CP-93,129 (5-HT1B receptor agonist, 460 nmol.kg-1), sumatriptan (5-HT1B/D receptor agonist, 24 nmol kg-1), or neutral endopeptidase 24.11 (1 nmol kg-1) were administered 45 or 75 min after trigeminal stimulation and 5 min before radiolabelled albumin. The extravasation response was reduced at 45 min. CP-23,129 also blocked extravasation when injected 25 min after capsaicin administration (1 mumol kg-1). 4. If the tracer was injected 5 min prior to electrical trigeminal stimulation, endopeptidase 24.11 (1 nmol kg-1) given 10 min before stimulation blocked the leakage (as reported previously for CP-93,129 or sumatriptan). All three compounds blocked the leakage when administered 30 min (but not 60 min) poststimulation in this paradigm. 5. The data support the previously made contention that neuropeptide release from sensory fibres mediates the plasma extravasation response following trigeminal ganglion stimulation, and that release and plasma leakage continue many minutes beyond the stimulation period. Hence, drugs that inhibit neuropeptide release (CP-93,129, sumatriptan), or enhance breakdown of neuropeptide mediators(endopeptidase 24.11) block the delayed extravasation response. Extravasation developing later than 45 min poststimulation was not neurogenically mediated.

Animals↗

Presence of vasoconstrictor 5HT1-like receptors revealed by precontraction of rabbit isolated mesenteric artery.

1. A series of 5-hydroxytryptamine (5-HT) receptor agonists including 5-HT, 5-carboxamidotryptamine (5-CT) and sumatriptan produced little or no contraction of rabbit isolated mesenteric arteries under resting tone conditions, even at concentrations up to 10(-4) M. 2. When the same agonists were retested in mesenteric artery preparations pre-contracted with the thromboxane-mimetic, U46619, each demonstrated concentration-related vasoconstrictor activity. 5-CT and 5-HT were especially potent and effective in this model giving EC50 values of 4.3 x 10(-9) M and 1.6 x 10(-8) M respectively and maximum effects equivalent to those of KCl 80 mM. In preparations precontracted by U46619 (conditions retained throughout the rest of the study) the order of agonist potency was 5-CT > 5-HT > RU 24969 = sumatriptan > 8-hydroxy-2-(di-n-propylamino)tetralin (8-OHDPAT) > cisapride. 3. The vasoconstrictor effects of 5-CT were competitively antagonized by methiothepin (pA2 8.20) but resistant to antagonism by a range of other 5-HT receptor antagonists, i.e. pindolol (5-HT1A/5-HT1B), propranolol (5-HT1B), spiperone (5-HT2A), ondansetron (5-HT3), ICS 205930 (5-HT3/5-HT4) and SDZ 205557 (5-HT4). 5-CT responses were slightly antagonized by a high concentration of ritanserin (5-HT2A/5-HT2C). Responses to 5-HT and sumatriptan were also antagonized by methiothepin with similar affinity (pA2/pKB values congruent to 8.0). 4. Metergoline and rauwolscine (10(-7)-10(-6) M) antagonized the effects of 5-CT in a non-competitive fashion giving pKBapp values of 7.13 (metergoline) and 6.86 (rauwolscine). 5. Vasoconstrictor responses to 5-HT were not modified in the presence of ritanserin (3 x 10-7 M) orspiperone (3 x 10-7 M) and only modestly antagonized by ketanserin (10-6 M) suggesting that 5-HT2Areceptors do not make a significant contribution in this model.6. Hence, precontraction of rabbit mesenteric arteries reveals potent vasoconstrictor effects of 5-HT and related agonists. Based on the agonist potency order and the antagonist studies performed, the receptor subtype responsible has the characteristics of a 5-HT1-like (probably 5-HTlD) receptor. This study therefore demonstrates a particularly striking example of vasoconstrictor synergy involving 5-HT1-like receptors.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

Pharmacological profile of the receptors that mediate external carotid vasoconstriction by 5-HT in vagosympathectomized dogs.

1. 5-Hydroxytryptamine (5-HT) can produce vasodilatation or vasoconstriction of the canine external carotid bed depending upon the degree of carotid sympathetic tone. Hence, external carotid vasodilatation to 5-HT in dogs with intact sympathetic tone is primarily mediated by prejunctional 5-HT1-like receptors similar to the 5-HT1D subtype, which inhibit the carotid sympathetic outflow. The present investigation is devoted to the pharmacological analysis of the receptors mediating external carotid vasoconstriction by 5-HT in vagosympathectomized dogs. 2. Intracarotid (i.c.) infusions for 1 min of 5-HT (0.3, 1, 3, 10, 30 and 100 micrograms) resulted in dose-dependent decreases in both external carotid blood flow and the corresponding conductance; both mean arterial blood pressure and heart rate remained unchanged during the infusions of 5-HT. These responses to 5-HT were resistant to blockade by antagonists at 5-HT2 (ritanserin) and 5-HT3/5-HT4 (tropisetron) receptors, but were partly blocked by the 5-HT1-like and 5-HT2 receptor antagonist, methiothepin (0.3 mg kg-1); higher doses of methiothepin (1 and 3 mg kg-1) caused little, if any, further blockade. These methiothepin (3 mg kg-1)-resistant responses to 5-HT were not significantly antagonized by MDL 72222 (0.3 mg kg-1) or tropisetron (3 mg kg-1). 3. The external carotid vasoconstrictor effects of 5-HT were mimicked by the selective 5-HT1-like receptor agonist, sumatriptan (3, 10, 30 and 100 micrograms during 1 min, i.c.), which produced dose-dependent decreases in external carotid blood flow and the corresponding conductance; these effects of sumatriptan were dose-dependently antagonized by methiothepin (0.3, 1 and 3 mg kg-1), but not by 5-HT1D-like receptor blocking doses of metergoline (0.1 mg kg-1). 4. The above vasoconstrictor effects of 5-HT remained unaltered after administration of phentolamine, propranolol, atropine, hexamethonium, brompheniramine, cimetidine and haloperidol, thus excluding the involvement of alpha- and beta-adrenoceptors, muscarinic, nicotinic, histamine and dopamine receptors. Likewise, inhibition of either 5-HT-uptake (with fluoxetine) or cyclo-oxygenase (with indomethacin), depletion of biogenic amines (with reserpine) or blockade of calcium channels (with verapamil) did not modify the effects of 5-HT. 5. Taken together, the above results support our contention that the external carotid vasoconstrictor responses to 5-HT in vagosympathectomized dogs are mainly mediated by activation of sumatriptan-sensitive 5-HT1-like receptors. It must be emphasized, notwithstanding, that other mechanisms of 5-HT, including an interaction with a novel 5-HT receptor (sub)type and/or an indirect action that may lead to the release of a known (or even unknown) neurotransmitter substance cannot be categorically excluded.

Animals↗

Psychological status during migraine attack and interval before and after treatment with a selective 5-HT1-agonist.

The study recorded the quantitative changes in psychological status during migraine attack and interval in 20 migraine patients. It further determined their psychological status after administration of the selective 5-HT1-agonist sumatriptan and placebo during migraine interval and migraine attack. psychological status was classified with the aid of an adjective list enabling quantitative description of 15 essential aspects of the subjects' current disposition. The results demonstrate a drastic deterioration in psychological status during an acute migraine attack as compared to the migraine interval and plainly show how badly migraine affects the patients, as almost all the aspects of psychological status are impaired. Administration of placebo did not significantly influence current disposition either in the migraine interval or during the attack. Sumatriptan minimally increased inactivity and dizziness during the migraine interval. During an attack sumatriptan completely normalized current disposition within 30 minutes by significantly improving the impaired dimensions. it is conceivable that this rapid normalization is due to the reduction in pain severity and is only a secondary effect of the rapid alleviation of pain. It is also possible that a direct effect of the selective 5-HT1-agonist on the central nervous system may be the cause of this rapid normalization of current disposition.

Adult↗

Terminating migraine with allodynia and ongoing central sensitization using parenteral administration of COX1/COX2 inhibitors.

OBJECTIVE: To determine whether delayed infusion of COX1/COX2 inhibitors (ketorolac, indomethacin) will stop migraine in allodynic patients, and suppress ongoing sensitization in central trigeminovascular neurons in the rat. BACKGROUND: The majority of migraineurs seeking secondary or tertiary medical care develop cutaneous allodynia during the course of migraine, a sensory abnormality mediated by sensitization of central trigeminovascular neurons in the spinal trigeminal nucleus. Triptan therapy can render allodynic migraineurs pain free within a narrow window of time (20 to 120 minutes) that opens with the onset of pain and closes with the establishment of central sensitization. Can drugs that tackle ongoing central sensitization render allodynic migraineurs pain free after the window for triptan therapy has expired? METHODS: Patients exhibiting migraine with allodynia were divided in two groups (n=14, each): group 1 received delayed sumatriptan injection (6 mg) 4 hours after onset of attack--which failed to render them pain free-and ketorolac infusion (two 15-mg boluses) 2 hours later; group 2 received delayed ketorolac monotherapy 4 hours after onset of attack. Pain intensity (visual analog scale) and skin sensitivity (quantitative sensory testing) were measured when the patients were migraine free (baseline); 4 hours after onset of migraine (just before treatment); 2 hours after sumatriptan; 1 hour after ketorolac. In the rat, we tested whether infusion of ketorolac (0.4 mg/kg) or indomethacin (1 mg/kg) will block ongoing sensitization in peripheral and central trigeminovascular neurons. The induction of sensitization (using topical application of inflammatory soup on the dura) and its suppression by COX1/COX2 inhibitors were assessed by monitoring changes in spontaneous activity and responses to mechanical and thermal stimuli. RESULTS: Patients had normal skin sensitivity in the absence of migraine, and presented cutaneous allodynia 4 hours after onset of migraine. In group 1, all patients continued to exhibit allodynia 2 hours after sumatriptan treatment, and none of them became pain free. However, 71% and 64% of the patients in groups 1 and 2, respectively, were rendered free of pain and allodynia within 60 minutes of ketorolac infusion. Nonresponders from both groups, in contrast to the responders, had had a history of opioid treatment. In the rat, infusion of COX1/COX2 inhibitors blocked sensitization in meningeal nociceptors and suppressed ongoing sensitization in spinal trigeminovascular neurons. This inhibitory action was reflected by normalization of neuronal firing rate and attenuation of neuronal responsiveness to mechanical stimulation of the dura, as well as mechanical and thermal stimulation of the skin. CONCLUSIONS: The termination of migraine with ongoing allodynia using COX1/COX2 inhibitors is achieved through the suppression of central sensitization. Although parenteral administration of COX1/COX2 inhibitors is impractical as routine migraine therapy, it should be the rescue therapy of choice for patients seeking emergency care for migraine. These patients should never be treated with opioids, particularly if they had no prior opioid exposure.

Adolescent↗

Donitriptan decreases jugular venous oxygen saturation in rats in the absence of cranial vasoconstriction: an overlooked mechanism of antimigraine action?

The aim of the present study was to determine whether donitriptan and sumatriptan decreased jugular venous oxygen saturation and increased carbon dioxide partial pressure in venous blood. However, previous studies conducted with these compounds cannot discriminate whether the decrease of venous oxygen saturation is dependent of cranial vasoconstrictor. In the present study, vehicle (n = 10), donitriptan (2.5, 10, and 40 microg/kg; n = 8) or sumatriptan (630 microg/kg; n = 8) were infused into the carotid artery in the anesthetized rat. Regional blood flows were evaluated in the presence of donitriptan (10 microg/kg; n = 6) or vehicle (n = 6). Jugular venous oxygen saturation was significantly decreased by donitriptan (from 10 microg/kg) with maximal changes of -32.9 +/- 8.0%. Jugular carbon dioxide partial pressure was increased by donitriptan, reaching maximal changes of 17.7 +/- 4.6% (P < 0.05 versus vehicle). Similarly, sumatriptan significantly decreased venous oxygen saturation and increased jugular carbon dioxide partial pressure. These changes induced by donitriptan are abolished by the 5-hydroxytryptamine (5-HT)(1B/1D) receptor antagonist GR 127935 (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 dihydrochloride). In addition, donitriptan was devoid of significant effects on systemic arterial pressure, heart rate, or regional blood flows, including systemic arterial-jugular venous anastomotic, systemic, or cranial. The results demonstrate that donitriptan increases cerebral oxygen consumption by 5-HT(1B/1D) receptor activation in the absence of cranial vasoconstriction.

Animals↗

Endothelium-dependent relaxant responses to selective 5-HT(1B/1D) receptor agonists in the isolated middle cerebral artery of the rat.

The vasomotor effects of triptans in the middle cerebral artery (MCA) of rats were studied using the pressurised arteriography method and in vitro vessel baths. Using the arteriograph, MCAs from Sprague-Dawley rats were mounted on two glass micropipettes, pressurised to 85 mm Hg and luminally perfused. Luminally added 5- hydroxytryptamine (5-HT), sumatriptan and rizatriptan induced maximal dilatations of 22 +/- 4, 10 +/- 2 and 13 +/- 5%, respectively, compared to the resting diameter. The relaxant effect of sumatriptan was blocked by the 5- HT(1B/1D) receptor selective antagonist GR 55562 (10(-6)M). The use of N(omega)-nitro-L-arginine and charybdotoxin revealed that the dilatation involved both nitric oxide and endothelially derived hyperpolarising factor. Thus, the earlier demonstrated expression of 5-HT(1B/1D) immunoreactivity in the endothelium may well translate into a relaxant response to 5-HT and triptans. Using the vessel bath technique, MCA segments were mounted on two metal wires. The relaxant responses to sumatriptan could not be reproduced using this model; instead, weak contractile responses (6 +/- 3% of submaximal contractile capacity) were observed. The difference in observations between the experimental models may be related to the maintenance of shear stress in the arteriograph.

Animals↗

Eletriptan: pharmacological differences and clinical results.

The potential advantages of eletriptan lie firstly in its lipophilicity reflected as an increased rate of absorption and Tmax compared to sumatriptan. This is manifested in a modest advantage over sumatriptan in terms of speed of onset, 2 h headache response and 2 h pain free. However, eletriptan has not yet been shown to have an advantage over the other triptans for lack of head-to head comparisons. It does not appear to have an advantage over sumatriptan for headache recurrence. The second advantage is the partial agonist activity at the 5-HT(1B) receptor, reducing the potential for cardiovascular side-effects compared to the other triptans. Although no serious cardiovascular events have yet been recognized, eletriptan should still be used with extreme caution for patients with cardiovascular risk factors.

Humans↗

Ergotamine, dihydroergotamine: current uses and problems.

In randomized clinical trials oral ergotamine was found superior to placebo but inferior to oral sumatriptan 100mg. In contrast rectal ergotamine was found to have higher efficacy (73% headache relief) than rectal sumatriptan (63% headache relief). Intranasal dihydroergotamine (DHE) was found superior to placebo but less effective than subcutaneous and intranasal sumatriptan. In general, the use of the more specific drugs, the triptans, causing less adverse events and being more effective, is preferable to the use of the ergotamine in the acute treatment of migraine. If ergotamine is to be used the rectal route is preferable. The rectal dose of ergotamine should be tailored to the individual patient. The intranasal dose of DHE , between 1 and 2 mg, should also be tailored to the individual patient. In order to avoid drug-induced headache ergotamine and DHE should not be used daily.

Analgesics, Non-Narcotic↗