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Are triptans with enhanced lipophilicity used for the acute treatment of migraine associated with an increased consulting rate for depressive illness?

1997, sumatriptan-treated migraineurs had significantly higher depression PCRs (22.3%) compared with non-triptan users (19.3%), a difference of 6.4% (95% confidence interval (CI) 4.6-8.4%, P < 0.001). In the year (April 1997 to March 1998) following the launch of the TELs, depression PCRs were significantly higher among patients using these compounds compared with sumatriptan-treated patients (5.1%, CI 1.8-12.0%, P < 0.05). However, after taking account of prior depression (odds ratio (OR) 6.45, 95% CI 3.63-11.43), TELs were not significantly associated with depression (OR 0.27, 95% CI 0.03-2.13). Furthermore, rates of newly diagnosed depression after treatment were similar in the two triptan groups (sumatriptan 4.2%; TELs 3.9%). Although, the TELs are being prescribed to patients with higher pre-existing rates of depression, they are not associated with subsequently increased consulting for depressive illness compared with patients taking sumatriptan. This study highlights the potential to use GPRD to test targeted hypotheses exploring pharmacovigilance issues for patients using new medicines.

Cohort Studies↗

Effect of high-dose intravenous eletriptan on coronary artery diameter.

The goal of this study was to evaluate the coronary vasoconstrictive effects of high doses of eletriptan compared with a standard dose of sumatriptan. Patients with no clinically significant coronary artery disease were randomized to receive high-dose intravenous eletriptan (n = 24) vs a standard dose of sumatriptan (n = 18; 6 mg subcutaneously) vs placebo (n = 18). Serial angiograms were obtained. The primary non-inferiority analysis found equivalence between the mean maximum change in left anterior descending coronary artery diameter for eletriptan, -22%[95% confidence interval (CI) -26, -19], and sumatriptan, -19% (95% CI -22, -16). The change due to placebo was -16% (95% CI -20, -12). No individual cases of clinically significant vasoconstriction were observed. The results confirm that eletriptan has a broad cardiovascular safety margin, with plasma concentrations comparable to three to five times the Cmax of an oral 80-mg dose associated with modest vasoconstriction equivalent to standard therapeutic doses of sumatriptan.

Adult↗

Studies on the mechanism of 5-HT1 receptor-induced smooth muscle contraction in dog saphenous vein.

1. We have investigated the mechanism of smooth muscle contraction evoked by activation of 5-HT1-like receptors in dog isolated saphenous vein. 2. In the presence of the 5-HT2 receptor antagonist, ritanserin (0.1 microM), concentration-effect curves (10 nM-300 microM) for 5-hydroxytryptamine (5-HT)-induced smooth muscle contraction were biphasic. This could be attributed to a direct action on 5-HT1-like receptors at low concentrations of 5-HT (10 nM-10 microM) and an indirect (through the release of noradrenaline from sympathetic neurones) activation of postjunctional alpha-adrenoceptors at higher 5-HT concentrations. In contrast, concentration-effect curves (100 nM-100 microM) for sumatriptan-induced contractions were not biphasic, and were due solely to activation of 5-HT1-like receptors. 3. Smooth muscle contractions evoked either by low concentrations of 5-HT or by sumatriptan were abolished by removal of extracellular calcium and were markedly inhibited, but not abolished, by the calcium channel blocker, verapamil (1-30 microM). In contrast, contractions evoked by high concentrations of 5-HT were markedly less sensitive to removal of extracellular calcium or to verapamil. 4. 5-HT and sumatriptan also inhibited (to a maximum of about 50%) prostaglandin E2 (PGE2, 5 microM)-stimulated adenosine 3':5'-cyclic monophosphate (cyclic AMP) formation. This effect was mimicked by the alpha 2-adrenoceptor agonist, azepexole (B-HT933) but not by the alpha 1-adrenoceptor agonist, methoxamine.5. In contrast to mediation of smooth muscle contraction, the 5-HT1-like receptor-mediated inhibition of PGE2-stimulated cyclic AMP formation evoked by 5-HT or sumatriptan was not attenuated by removal of extracellular calcium or by verapamil (1 microM).6. A directly-acting inhibitor of adenylyl cyclase, 2',3'-dideoxyadenosine (1 mM) inhibited PGE2-stimulated cyclic AMP formation but did not produce smooth muscle contraction.7. These results suggest that contractile responses of dog isolated saphenous vein arising through activation of 5-HT1-like receptors are associated with both an influx of extracellular calcium ions (to a large extent via voltage-dependent channels) and an inhibition of adenylyl cyclase. However, although these two responses are coupled to the same receptor, they appear to be independent.

Adenylyl Cyclase Inhibitors↗

Onset of effect of 5-HT1B/1D agonists: a model with pharmacokinetic validation.

OBJECTIVE: To quantitate onset of effect of all formulations of sumatriptan, and to investigate whether this is related to rate, not extent, of drug absorption. METHODS: From published literature, for 4 formulations of sumatriptan and matching placebos, response rates were modeled using a simple logarithmic equation, with a being a parameter of curve convexity and B, a location parameter (equal to response rate at 2 hours [the standard regulatory parameter]). The average rate of drug absorption (A) was estimated by dividing the maximal drug concentration by the time needed to achieve it (Cmax/Tmax). Least mean square correlation was then performed between the therapeutic gains and therapeutic ratios of curve convexity and rate of drug absorption. RESULTS: -Models closely fitted observed response rates (2 hours or less). Curve convexity correlated with rate of drug absorption. Sumatriptan response rates (0 to 2 hours) for formulations correlated with rate, not extent, of drug absorption. The range of rates of onset of effect among different routes of administration was greater than that for tablets with 4-fold differences in dose size. CONCLUSION: Onset of effect is related to rate of absorption of sumatriptan. There is greater scope for improving onset of effect using an alternative route of administration than by increasing the oral dose.

Dose-Response Relationship, Drug↗

Involvement of two different pathways in the motor effects of erythromycin on the gastric antrum in humans.

BACKGROUND: During the interdigestive state in humans, erythromycin 40 mg induces a premature activity front that starts in the stomach, while erythromycin 200 mg induces a prolonged period of enhanced antral contractile activity. AIMS: To study the involvement of a cholinergic pathway in the motor effects of erythromycin using the muscarinic antagonist atropine and the neural 5-HT1 receptor agonist sumatriptan. METHODS: In 30 healthy volunteers, fasted antroduodenojejunal motor activity was studied by stationary manometry. Placebo (n = 10), atropine (15 micrograms/kg intravenous bolus plus 15 micrograms/kg/h over 30 minutes; n = 10), or sumatriptan (6 mg subcutaneously; n = 10) was administered, followed by infusion of erythromycin 40 mg or 200 mg. RESULTS: After placebo, erythromycin 40 mg induced a premature activity front with gastric onset after 19.1 (1.7) minutes in all volunteers. After atropine, erythromycin 40 mg failed to induce a premature activity front during a 60 minute period in all volunteers (p < 0.001), while sumatriptan prevented the induction of a premature activity front during a 60 minute period in all but one volunteer (p < 0.005). The number of antral contractions and their mean amplitude in the 60 minutes after erythromycin 200 mg did not differ significantly after atropine or sumatriptan versus placebo. CONCLUSIONS: The antral motor effects of erythromycin in humans are mediated via different pathways. The induction of a premature activity front is mediated through activation of an intrinsic cholinergic pathway, while the induction of enhanced antral contractile activity may be mediated via a pathway potentially involving activation of a muscular receptor.

Anti-Bacterial Agents↗

Defective 5-HT 1-receptor-mediated neurotransmission in the control of growth hormone secretion in Parkinson's disease.

In order to gain a better insight in the serotonergic disorder affecting the parkinsonian brain, the growth hormone (GH) response to the 5-HT 1 serotonergic receptor agonist sumatriptan was tested. Sumatriptan was injected subcutaneously in 10 de novo parkinsonian patients (aged 58-69 years) and in 9 age-matched normal controls. On different occasions, subjects were also tested with GH-releasing hormone (GH-RH; 1 micrograms/kg body weight in an intravenous bolus) and L-arginine (30 g in 50 ml normal saline over 30 min), which releases GH from somatostatin inhibition, to determine whether GH secretion in response to alternate secretagogues is preserved in Parkinson's disease. In addition, a control test with the administration of normal saline instead of drug treatments was performed. Plasma GH levels were recorded over 2 h in all tests. Placebo administration did not change plasma GH levels in any subject. Similar GH responses were observed in normal controls and parkinsonian patients when GH-RH or arginine were administered. A significant GH increase was observed in normal controls after sumatriptan injection; in contrast, GH secretion was not modified by sumatriptan administration in parkinsonian patients. These data show that Parkinson's disease is associated with an impairment in the 5-HT1-receptor-mediated serotonergic transmission in the control of GH secretion, suggesting that this specific defect might alter other serotonergic-mediated mechanisms in the parkinsonian brain.

Aged↗

Coronary side-effect potential of current and prospective antimigraine drugs.

BACKGROUND: The antimigraine drugs ergotamine and sumatriptan may cause angina-like symptoms, possibly resulting from coronary artery constriction. We compared the coronary vasoconstrictor potential of a number of current and prospective antimigraine drugs (ergotamine, dihydroergotamine, methysergide and its metabolite methylergometrine, sumatriptan, naratriptan, zolmitriptan, rizatriptan, avitriptan). METHODS AND RESULTS: Concentration-response curves to the antimigraine drugs were constructed in human isolated coronary artery segments to obtain the maximum contractile response (Emax) and the concentration eliciting 50% of Emax (EC50). The EC50 values were related to maximum plasma concentrations (Cmax) reported in patients, obtaining Cmax/EC50 ratios as an index of coronary vasoconstriction occurring in the clinical setting. Furthermore, we studied the duration of contractile responses after washout of the acutely acting antimigraine drugs to assess their disappearance from the receptor biophase. Compared with sumatriptan, all drugs were more potent (lower EC50 values) in contracting the coronary artery but had similar efficacies (Emax <25% of K+-induced contraction). The Cmax of avitriptan was 7- to 11-fold higher than its EC50 value, whereas those of the other drugs were <40% of their respective EC50 values. The contractile responses to ergotamine and dihydroergotamine persisted even after repeated washings, but those to the other drugs declined rapidly after washing. CONCLUSIONS: All current and prospective antimigraine drugs contract the human coronary artery in vitro, but in view of low efficacy, these drugs are unlikely to cause myocardial ischemia at therapeutic plasma concentrations in healthy subjects. In patients with coronary artery disease, however, these drugs must remain contraindicated. The sustained contraction by ergotamine and dihydroergotamine seems to be an important disadvantage compared with sumatriptan-like drugs.

Adolescent↗

Different approaches to valuing the lost productivity of patients with migraine.

OBJECTIVE: To calculate and compare the human capital approach (HCA) and friction cost approach (FCA) methods for estimating the cost of lost productivity of migraineurs after the initiation of sumatriptan from a US societal perspective. DESIGN: Secondary, retrospective analysis to a prospective observational study. SETTING: A mixed-model managed care organisation in western Pennsylvania, USA. PATIENTS: Patients with migraine using sumatriptan therapy. INTERVENTIONS: Patient-reported questionnaires collected at baseline, 3 and 6 months after initiation of sumatriptan therapy. OUTCOME MEASURES: The cost of lost productivity estimated with the HCA and FCA methods. RESULTS: Of the 178 patients who completed the study, 51% were full-time employees, 13% were part-time, 18% were not working and 17% changed work status. Twenty-four percent reported a clerical or administrative position. From the HCA, the estimated total cost of lost productivity for 6 months following the initiation of sumatriptan was $US117905 (1996 values). From the FCA, the six-month estimated total cost of lost productivity ranged from $US28329 to $US117905 (1996 values). CONCLUSIONS: This was the first study to retrospectively estimate lost productivity of patients with migraine using the FCA methodology. Our results demonstrate that depending on the assumptions and illustrations employed, the FCA can yield lost productivity estimates that vary greatly as a percentage of the HCA estimate. Prospective investigations are needed to better determine the components and the nature of the lost productivity for chronic episodic diseases such as migraine headache.

Absenteeism↗

Present and future of 5-HT receptor agonists as antimigraine drugs.

Serotonin (5-hydroxytryptamine; 5-HT) is thought to play an important role in the pathogenesis of migraine. The discovery of the 5-HT1B/1D/1F agonist sumatriptan constitutes a substantial advance in the acute treatment of migraine, though it displays a number of nonnegligible shortcomings. Today, a number of second-generation drugs derived from tryptamine are under advanced clinical development or are about to be marketed worldwide for the acute treatment of migraine. These tryptamine derivatives display partial agonist properties at 5-HT1B/1D receptors. It is not yet clearly established whether these agents represent a major improvement over sumatriptan in therapeutic effectiveness. Most of them also show affinity for 5-ht1F binding sites and have better oral pharmacokinetics than sumatriptan. The acute antimigraine effects of this second-generation of triptans seem to be obtained in largely the same way as with sumatriptan: by cranial vasoconstriction and inhibition of trigeminovascular activation from both peripheral and central projections. Future directions in migraine therapy should focus on agents that exhibit high intrinsic activity at 5-HT1B/1D receptors, offer a good safety profile, and demonstrate long-lasting action which might also be considered in migraine prophylaxis.

Animals↗

Pharmacology and efficacy of eletriptan for the treatment of migraine attacks.

Sumatriptan, a 5-HT 1B/1D agonist, was introduced 10 years ago and was the most effective therapy for migraine attacks at that time. Eletriptan is a new 5-HT 1B/1D agonist with high potency and selectivity at 5-HT 1B/1D receptors. It is effective in animal models in which the vascular and neurogenic mechanisms implicated in migraine were measured. Eletriptan is selective for the intracranial blood vessels over other extracranial vasculature, in particular coronary arteries. Eletriptan has a rapid and complete oral absorption and a good oral bioavailability in migraineurs. In comparative trials 20 mg, 40 mg and 80 mg eletriptan, 100 mg sumatritpan and placebo were compared for the treatment of migraine attacks. All three doses of eletriptan were statistically superior to placebo for headache response and headache-free patients. The 80 mg dose of eletriptan was also superior to sumatriptan 100 mg. Headache recurrence, defined as return of moderate or severe headache within 24 hours of dosing and following a headache response at two hours after initial dosing, occurred in 33% of the patients following 100 mg sumatriptan and in 28%, 34% and 32% after 20 mg, 40 mg and 80 mg eletriptan. In another large trial, headache response rates were significantly higher for both doses of eletriptan (64% for 40 mg and 67% for 80 mg) than for two doses of sumatriptan (50% for 50 mg and 53% for 100 mg). Eletriptan 40 mg or 80 mg was also superior to ergotamine plus caffeine (Cafergot). In summary, eletriptan is a highly effective and fast-acting drug for the treatment of acute migraine attacks.

Double-Blind Method↗

Patient satisfaction with rizatriptan versus other triptans: direct head-to-head comparisons.

This study summarises the impact of treatment with rizatriptan 10 mg versus other 5-HT 1B/1D receptor agonists (triptans) on patient satisfaction with medication. Rizatriptan is a potent, selective 5-HT1B/1D receptor agonist shown to be fast, effective and well tolerated in the acute treatment of migraine. We investigated patients' overall satisfaction with treatment in studies in which direct comparisons with other triptans were made. Data from five double-blind, placebo-controlled trials in which rizatriptan 10 mg was compared with another triptan were included in the analysis. Rizatriptan 10 mg was compared with sumatriptan 100 mg in one parallel study (n = 916), sumatriptan 50 mg in two crossover studies (n = 1599), naratriptan 2.5 mg in one parallel study (n = 502), and zolmitriptan 2.5 mg in one parallel study (n = 701). Satisfaction was reported by patients on a seven-point scale ranging from 'completely satisfied, couldn't be better' to 'completely dissatisfied, couldn't be worse' at 2 hours after dosing. The percent of patients in the top two 'satisfied' categories (completely or very satisfied) were analysed. More patients on rizatriptan 10 mg were completely or very satisfied compared with sumatriptan 100 mg (33% vs 26%, p < 0.05), sumatriptan 50 mg (40% vs 35%, p < 0.05), naratriptan 2.5 mg (33% vs 19%, p < 0.01), and zolmitriptan 2.5 mg (38% vs 30%, p < 0.05). In all five studies more patients treated with rizatriptan 10 mg or other triptans were completely or very satisfied with treatment than patients receiving placebo (p < 0.001, except naratriptan vs placebo p = 0.004). The results, combined with the superior efficacy profile (fast, effective, well tolerated) of rizatriptan 10 mg, should enhance the treatment of migraine headache and lead to improved therapeutic intervention in clinical practice.

Adolescent↗

Regulation of 5-hydroxytryptamine release from rat midbrain raphe nuclei by 5-hydroxytryptamine1D receptors: effect of tetrodotoxin, G protein inactivation and long-term antidepressant administration.

Our study was undertaken to characterize the functional properties of 5-hydroxytryptamine (5-HT)1D receptors in the rat midbrain raphe nuclei. In a first series of experiments, designed to assess whether 5-HT1D receptors are coupled to Gi/o proteins, the intracerebral injection of pertussis toxin into the dorsal raphe as well as incubation of midbrain raphe slices with the alkylating agent N-ethyl-maleimide (NEM) reduced the efficacy of the 5-HT1B/1D agonist sumatriptan to inhibit the electrically evoked overflow of [3H]5-HT from preloaded slices. Furthermore, preincubation with NEM also reduced the efficacy with which the 5-HT1B/1D antagonist GR 127935 enhanced evoked overflow of [3H]5-HT. These results indicate that, in rat midbrain raphe nuclei, 5-HT1D receptors are linked to Gi/o proteins. In an attempt to determine whether 5-HT1D receptors are located on 5-HT neurons, the inhibitory effect of sumatriptan and of the nonselective 5-HT agonist 5-carboxyamidotryptamine on K(+)-evoked overflow of [3H]5-HT was assessed in the presence of the Na+ channel blocker tetrodotoxin. Neither the inhibitory effect of sumatriptan nor that of 5-carboxyamidotryptamine were reduced by the addition of tetrodotoxin to the superfusion medium, suggesting that these 5-HT1D receptors are located on 5-HT neurons and may be considered autoreceptors. In a third series of experiments, rats were treated for 21 days either with the selective 5-HT reuptake inhibitor paroxetine (10 mg/kg/day, s.c.) or the reversible type A monoamine oxidase inhibitor befloxatone (0.75 mg/kg/day, s.c.) and superfusion experiments were performed after a 48-hr washout period. 5-HT1D receptors, similarly to 5-HT1A autoreceptors, desensitize after long-term treatment with a selective 5-HT reuptake inhibitor or a reversible type A monoamine oxidase inhibitor because the efficacy of sumatriptan and of 8-OH-DPAT to inhibit the electrically evoked overflow of [3H]5-HT was reduced after the administration of either drug.

Animals↗

[Drug treatment of migraine attacks. Pharmacological considerations].

In the 1990s, the Decade of the Brain, significant progress has been made in our understanding of the pathophysiological events that take place during a migraine attack. Simultaneously, a big step forward has been made as regards drug therapy. The development of the 5-Hydroxy Tryptamine ID (5HT1D)-agonist sumatriptan has changed the lives of many migraine sufferers. This review describes attack management with analgesics, non-steroidal anti-inflammatory drugs (NSAIDs), ergotamines and sumatriptan. Adverse events associated with ergotamines and use of sumatriptan are focused upon, with special attention to the pharmacokinetic and pharmacodynamic aspects of both these drugs. Sumatriptan has both vascular and neurogenic effects, both of which may be necessary for a good clinical outcome.

Analgesics↗

Autoradiographic characterisation and localisation of 5-HT1D compared to 5-HT1B binding sites in rat brain.

The regional distribution and the pharmacology of the binding sites labelled with the novel 5-hydroxytryptamine (serotonin) 5-HT1B/1D selective radioligand serotonin-O-carboxy-methyl-glycyl-[125I]tyrosinamide (abbreviated [125I]GTI for the sake of simplicity) was determined using quantitative autoradiography in rat brain. The distribution of [125I]GTI binding sites was largely comparable to that of [125I]iodocyanopindolol ([125I] ICYP) which labels 5-HT1B binding sites (in the presence of 8-OH-DPAT (8-hydroxy-[2N-dipropylamino]tetralin) and isoprenaline, to prevent binding to 5-HT1A and beta-adrenoceptor binding sites), although a detailed analysis revealed differences. The pharmacology of the [125I]GTI binding sites was analysed using compounds known to display high affinity for and/or distinguish between 5-HT1B and 5-HT1D sites: 5-carboxamidotryptamine (5-CT), sumatriptan, CP 93129 (5-hydroxy-3(4-1,2,5,6-tetrahydropyridyl)-4-azaindole), (-)pindolol, PAPP (4[2-[4-[3-(trifluoromethyl)phenyl]-1- piperazinyl]ethyl]benzeneamine), rauwolscine, and 8-OH-DPAT. The displacement of [125I]GTI by 5-CT was monophasic. By contrast, the selective 5-HT1B compound CP 93129 and (-)pindolol produced biphasic curves showing a majority of high affinity sites in the globus pallidus and the substantia nigra, whereas PAPP and sumatriptan (which are somewhat 5-HT1D selective) produced biphasic curves indicating a minority of high affinity sites in these areas. In addition, by blocking the 5-HT1B sites with 100 nM CP 93129, the remaining population of [125I]GTI binding sites could be studied and was found to have high affinity for PAPP, rauwolscine and 8-OH-DPAT. The pharmacological profile of the major binding component was typical of the 5-HT1B type: 5-CT > CP 93129 > or = (-)pindolol > sumatriptan > or = PAPP > rauwolscine. The profile of the minor component of [125I]GTI binding is best characterised as that of a 5-HT1D site: 5-CT > PAPP > or = sumatriptan > rauwolscine > (-)pindolol > or = CP 93129. The localisation of the non 5-HT1B [125I]GTI binding sites was characterised by blocking the 5-HT1B receptors with 100 nM CP 93129. Low densities of the 5-HT1D recognition sites were found to be present in globus pallidus, ventral pallidum, caudate-putamen, subthalamic nucleus, entopeduncular nucleus, substantia nigra (reticular part), nuclei of the (normal and accessory) optic tract, different nuclei of the geniculate body and frontoparietal cortex, although higher densities of 5-HT1B sites were always observed in the same structures.(ABSTRACT TRUNCATED AT 400 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Neuroeffector functions of sensory fibres: implications for headache mechanisms and drug actions.

The results of recent investigations designed to elucidate the neuroeffector functions of sensory fibres, the cause of migraine headache and the mechanism of action of antimigraine drugs are reviewed and discussed. Neurogenic inflammation (vasodilatation and neurogenic plasma extravasation) is one explanation for the development of headaches and the blood flow changes which occur during migraine headache. Numerous studies have recently been carried out on rats and guinea-pigs into the effects of antimigraine agents, including ergot alkaloids, sumatriptan and non-steroidal anti-inflammatory drugs (NSAIDs), on neurogenic plasma protein extravasation in the dura mater induced by electrical stimulation of trigeminal ganglia or systemic administration of capsaicin. It is known that the dura mater is able to produce headaches in man. Ergot alkaloids have been shown to block neurogenic inflammation via a C-fibre dependent neuronal mechanism. Sumatriptan appears to act fairly similarly although, whereas the ergot alkaloids are non-selective for either 5-hydroxytryptamine (5-HT; serotonin) receptors or 5-HT1, sumatriptan is selective for 5-HT1 receptors. The antimigraine action of NSAIDs may be via either an effect on blood vessels or an effect on the nerve fibre. The antimigraine effects of ergot alkaloids, sumatriptan and NSAIDs are discussed in the light of the common vasoconstrictor actions of these agents and knowledge that vasodilatation is apparently not responsible for migraine headache pain in most cases.

Animals↗

A novel 5-HT receptor or a combination of 5-HT receptor subtypes may mediate depression of a spinal monosynaptic reflex in vitro.

The monosynaptic reflex (MSR), recorded in vitro from the neonatal rat spinal cord, was depressed by 5-hydroxytryptamine (5-HT) and 5-HT receptor agonists. The results, together with our previous findings, indicate an apparent rank order of potency: 5-carboxamidotryptamine (5-CT) > sumatriptan > methysergide > 5-HT >> 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) > 5-methoxytryptamine (5-MeOT) = 1-[3-(trifluoromethyl)phenyl]-piperazine (TFMPP) > alpha-methyl-5-hydroxytryptamine (alpha-Me 5-HT) >> (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). The equipotent molar ratios were 5-CT 0.12, sumatriptan 0.4, methysergide 0.72, 5-HT 1.0, 8-OH-DPAT 13.3, 5-MeOT 26.7, TFMPP 31, alpha-Me 5-HT 402 and DOI > 3333. Time for peak depression from start of agonist application was 3-4 min for 5-HT, 5 min for sumatriptan and 5-MeOT, 5-7 min for alpha-Me 5-HT and 12 min for 8-OH-DPAT. The half-time for recovery from peak depression was 1.5 +/- 0.3 min for 5-HT, 2.8 +/- 0.3 min for 5-MeOT, 5.3 +/- 1.5 min for sumatriptan, 13 +/- 2.9 min for 8-OH-DPAT and > 30 min for alpha-Me 5-HT. 8-OH-DPAT induced depression of the reflex (IC50 0.85, 0.7-1.0 microM, geometric mean and 95% confidence limits) was blocked by spiperone (1 microM, apparent pA2 6.3) suggesting mediation via 5-HT1A receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Low dose zolmitriptan as a 5-HT neuroendocrine challenge agent in humans.

The 5-HT1B/D agonist sumatriptan has been used in a number of studies as a neuroendocrine challenge agent. Whether its neuroendocrine effects are centrally mediated is unclear, however, since sumatriptan shows minimal penetration of the central nervous system. Zolmitriptan shows a greater penetration into the central nervous system than sumatriptan, and has recently been shown to be an effective challenge agent. In order to determine the neuroendocrine, temperature and side effects of a 2.5 mg oral dose of zolmitriptan, 17 healthy volunteers underwent a placebo controlled, repeated measures, double blind neuroendocrine challenge. Zolmitriptan or placebo were administered, and cortisol, growth hormone, prolactin, blood pressure and temperature, were measured over four hours after the dose of zolmitriptan. Zolmitriptan at this dose was well tolerated by all subjects, with minimal side effects and only minor effects on blood pressure. There was a significant increase in serum growth hormone after zolmitriptan compared to placebo, however there were no significant effects on cortisol, prolactin or oral temperature. The neuroendocrine effects of 2.5 mg of orally administered zolmitriptan are similar to previously reported effects of sumatriptan, with minimal side effects.

Adult↗

Receptor specificity and trigemino-vascular inhibitory actions of a novel 5-HT1B/1D receptor partial agonist, 311C90 (zolmitriptan).

1. 311C90 (zolmitriptan zomig: (S)-4[[3-[2-(dimethylamino)ethyl]-1H-indol-5-yl]methyl]-2-oxazolidinone) is a novel 5-HT1B/1D receptor agonist with proven efficacy in the acute treatment of migraine. Here, we describe the receptor specificity of the drug and its actions on trigeminal-evoked plasma protein extravasation into the dura mater of the anaesthetized guinea-pig. 2. At the "5-HT1B-like' receptor mediating vascular contraction (rabbit saphenous vein), the compound was a potent (p[A50] = 6.79 +/- 0.06) partial agonist achieving 77 +/- 4% of the maximum effect to 5-hydroxytryptamine (5-HT). In the same experiments, sumatriptan (p[A50] = 6.48 +/- 0.04) was half as potent as 311C90 and produced 97 +/- 2% of the 5-HT maximum effect. Studies in which receptor inactivation methods were used to estimate the affinity (pKA) and efficacy relative to 5-HT (tau rel) for each agonist confirmed that 311C90 exhibits higher affinity than sumatriptan (pKA = 6.63 +/- 0.04 and 6.16 +/- 0.03, respectively) and that both drugs are partial agonists relative to 5-HT (tau rel = 0.61 +/- 0.03 and 0.63 +/- 0.10, respectively, compared to 5-HT = 1.0). 3. Consistent with its effects in rabbit saphenous vein, 311C90 also produced concentration-dependent contractions of primate basilar artery and human epicardial coronary artery rings. In basilar artery, agonist potency (p[A50] = 6.92 +/- 0.07) was similar to that demonstrated in rabbit saphenous vein, again being 2-3 fold higher than for sumatriptan (p[A50] = 6.46 +/- 0.03). Both agonists produced about 50% of the maximum response obtained with 5-HT in the same preparations. In rings of human coronary artery, the absolute potency of 311C90 and sumatriptan was higher than in primate basilar artery (p[A50] = 7.3 +/- 0.1 and 6.7 +/- 0.1, respectively), but maximum effects relative to 5-HT were lower (37 +/- 8% and 35 +/- 7%, respectively). In both types of vessel, the inability of 5-HT1B/1D agonists to achieve the same maximum as the endogenous agonist 5-HT is explained by the additional presence of 5-HT2A receptors. 4. 311C90 displayed high affinity at human recombinant 5-HT1D (formerly 5-HT1D alpha) and 5-HT1B (formerly 5-HT1D beta) receptors in transfected CHO-K1 cell membranes (pIC50 values = 9.16 +/- 0.12 and 8.32 +/- 0.09, respectively). In intact cells, the drug produced concentration-dependent inhibition of forskolin-stimulated adenylyl cyclase (p[A50] = 9.9 and 9.5, respectively) achieving the same maximum effect as 5-HT. Excepting human recombinant 5-HT1A and 5-ht1F receptors at which the drug behaved as an agonist with modest affinity (pIC50 = 6.45 +/- 0.11 and 7.22 +/- 0.12, respectively), 311C90 exhibited low, or no detectable affinity (pKi or pKB < or = 5.5) at numerous other monoamine receptors, including other 5-HT receptor subtypes. 5. When administered to anaesthetized guinea-pigs ten minutes before unilateral electrical stimulation of the trigeminal ganglion (1.2 mA, 5 Hz, 5 ms, 5 min), 311C90 (3-30 micrograms kg-1, i.v.) caused a dose-dependent inhibition of [125I]-albumin extravasation within the ipsilateral dura mater. At the same doses, the drug also produced dose-dependent falls in cranial vascular conductance (32.3 +/- 7.5% at 30 micrograms kg-1), as measured in the ear by laser doppler flowmetry. 6. These results show that 311C90, a novel member of the 5-HT1B/1D agonist drug class, exhibits a high degree of pharmacological specificity. Its potent partial agonist action at "5-HT1B-like' receptors in intracranial arteries, coupled with potent agonism at 5-HT1D and 5-HT1B receptors and an ability to inhibit neurogenic plasma protein extravasation in the dura, are consistent with its utility as an effective acute treatment for migraine.

Animals↗