INP104: a drug evaluation of a nonoral product for the acute treatment of migraine.

Migraine is a highly prevalent, disabling neurological disorder that is also associated with gastrointestinal symptoms, autonomic dysfunction and allodynia. Despite the availability of multiple acute agents for migraine, an unmet need remains for effective, well-tolerated drugs that are nonoral and noninvasive. Here, we provide a drug evaluation of INP104, a novel drug-device combination product of dihydroergotamine (DHE) mesylate - a molecule with a long history of efficacy familiar to headache specialists - which is delivered to the difficult-to-reach upper nasal space where it is rapidly and consistently absorbed via Precision Olfactory Delivery (POD®). In clinical trials, INP104 exhibited favorable pharmacokinetics, a well-tolerated safety profile, and rapid symptom relief, highlighting its potential as a suitable acute therapy for migraine.

Migraine is a very common headache disorder that often presents with pain and gastrointestinal symptoms. There are many available treatments for migraine, but some patients still need an option that works well for them, that is noninvasive, or does not need to be taken orally. Here we provide a drug evaluation of INP104, an approved acute treatment for migraine that combines a drug and a device: the medication dihydroergotamine (DHE) mesylate, which has been used for decades for treating acute symptoms of migraine, and the Precision Olfactory Delivery (POD^®) device, which delivers DHE mesylate to the hard-to-reach upper regions of the nose. Targeting this region helps medication to be absorbed faster and more consistently. In clinical trials, INP104 demonstrated favorable drug properties, came with few adverse events, and provided fast relief from migraine symptoms.

A Phase 1, Randomized, Open-Label, Safety, Tolerability, and Comparative Bioavailability Study of Intranasal Dihydroergotamine Powder (STS101), Intramuscular Dihydroergotamine Mesylate, and Intranasal DHE Mesylate Spray in Healthy Adult Subjects.

OBJECTIVE: To investigate and compare the safety and the pharmacokinetics of dihydroergotamine (DHE) after administration of intranasal DHE powder (STS101), intranasal DHE spray (Migranal® ), and intramuscular (IM) DHE injection in healthy subjects. METHODS: This was a 2-part, active-controlled, 3-period crossover study over 3 weeks, separated by 1-week washout periods. In part 1, 3 ascending dosage strengths of STS101 (1.3, 2.6, and 5.2 mg) were administered to 15 healthy subjects with no history of migraine. In part 2, 27 healthy subjects were administered 1 dose each of STS101 5.2 mg, Migranal DHE Mesylate Liquid Nasal Spray 2.0 mg, and IM DHE Mesylate 1.0 mg in a randomized order. Liquid chromatography, tandem mass spectrometry was used to determine plasma levels of DHE and its major metabolite, 8'OH-DHE. Pharmacokinetic parameters (Cmax , Tmax , AUC0-2 h , AUC0-48 h , AUC0-inf , and t1/2 ) for DHE and metabolite were calculated. Geometric means and 90% confidence intervals of log-transformed data were calculated and the ratio of means compared. Safety was evaluated by monitoring adverse events, vital signs, electrocardiograms, subjective and objective assessments of nasal signs and symptoms, and changes in laboratory parameters. The study is registered as NCT03874832. RESULTS: Forty-three subjects were enrolled and received study medication. Forty completed all study activities, 14 in part 1 and 26 in part 2. In part 1, DHE plasma levels showed a dose-dependent increase, with STS101 5.2 mg reaching a mean Cmax of 1870 pg/mL with a Tmax of 23 minutes. In part 2, STS101 5.2 mg showed rapid absorption, achieving mean DHE plasma concentrations of 1230 and 1850 pg/mL at 10 and 15 minutes after administration, respectively. In comparison to Migranal, STS101 5.2 mg showed approximately 2-fold higher Cmax (2175 vs 961 pg/mL), AUC0-2 h (2979 vs 1316 h × pg/mL), and AUC0-inf (12,030 vs 6498 h × pg/mL), respectively. The mean AUC0-inf of STS101 5.2 mg was comparable to IM DHE (12,030 vs 13,650 h × pg/mL). STS101 5.2 mg showed substantially lower variability compared to Migranal for Cmax (41% vs 76%), AUC0-2 h (39% vs 75%), and AUC0-inf (39% vs 55%). The incidence of treatment emergent AEs (TEAEs), all mild and transient, reported in parts 1 and 2 combined was 9/15 (60%), 5/15 (33%), and 16/41 (39%) of the subjects after 1.3, 2.6, and 5.2 mg STS101, respectively, and 4/26 (15%) and 5/27 (19%) of the subjects after IM DHE and Migranal, respectively. CONCLUSION: STS101 showed rapid absorption, achieving effective DHE plasma concentrations within 10 minutes. It achieved substantially higher Cmax , AUC0-2 h and AUC0-inf , compared to Migranal suggesting potentially better efficacy than Migranal. Its variability was better than Migranal, thus offering improved consistency of response. AUC0-inf was comparable to IM DHE, suggesting prolonged action and low recurrence. Additionally, the Cmax was sufficiently low to avoid any significant nausea reported with IV DHE. Thus, STS101 is an easy to administer, non-injected, acute treatment for migraine, with a favorable tolerability profile and is expected to provide rapid and consistent freedom from pain and associated migraine symptoms without recurrence.

Development and in vitro/in vivo evaluation of dihydroergotamine mesylate loaded maltodextrin-pullulan sublingual films.

Dihydroergotamine mesylate (DHE), ergotamine derivative, has been offered for clinical use to stop or treat symptoms of an emerging migraine as injection for more than a half century. It is shown that bioavailability of DHE greatly changes between the subjects and up to 99% of the orally absorbed dose may be cleared by first pass metabolism. The aim of this study was to design and optimize DHE fast-dissolving sublingual films for migraine treatment. For this purpose pullulan and maltodextrin was chosen as film-forming polymers and propylene glycol as plasticizer. For optimization process Box Behnken design was used. The formed films were free from air bubbles, cuttings, or cracks. Disintegration, mechanical strength and dissolution of films were compared. It is found that pullulan and maltodextrin formed films with the most desired properties at the concentration of 1.5% and 2%. The application of optimum formulation to rabbits showed that bioavailability of formulation is about 23.35% with a tmax 20 min. Due to this fast onset of action and higher bioavailability than oral administration, it is suggested that the polymer combinations of pullulan and maltodextrin formed successful films and were considered as an alternative dosage form for DHE in migraine therapy.

Dihydroergotamine mesylate-loaded dissolving microneedle patch made of polyvinylpyrrolidone for management of acute migraine therapy.

Migraine is a widespread neurological disease with negative effects on quality of life and productivity. Moderate to severe acute migraine attacks can be treated with dihydroergotamine mesylate (DHE), an ergot derivative that is especially effective in non-responders to triptan derivatives. To overcome limitations of current DHE formulations in subcutaneous injection and nasal spray such as pain, adverse side effects and poor bioavailability, a new approach is needed for DHE delivery enabling painless self-administration, quick onset of action, and high bioavailability. In this study, we developed a dissolving microneedle patch (MNP) made of polyvinylpyrrolidone, due to its high aqueous solubility and solubility enhancement properties, using a MNP design previously shown to be painless and simple to administer. DHE-loaded MNPs were shown to have a content uniformity of 108±9% with sufficient mechanical strength for insertion to pig skin ex vivo and dissolution within 2min. In vivo pharmacokinetic studies were carried out on hairless rats, and DHE plasma levels were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The area under curve (AUC) value after DHE delivery by MNP (1259±917ng/mL min) was not significantly different (p>0.05) as compared to subcutaneous injection, with a relative bioavailability of 97%. Also, appreciable plasma levels of DHE were seen within 5min for both delivery methods and tmax value of MNPs (38±23min) showed no significant difference (p>0.05) compared to subcutaneous injection (24±13min). These results suggest that DHE-loaded MNPs have promise as an alternative DHE delivery method that can be painlessly self-administered with rapid onset and high bioavailability.

In Vitro Metabolism Evaluation of the Ergot Alkaloid Dihydroergotamine: Application of Microsomal and Biomimetic Oxidative Model.

Dihydroergotamine is a semisynthetic natural product derived from ergotamine, an ergot alkaloid. It is used to treat migraines, a neurological disease characterized by recurrent moderate to severe headaches. In this work, the in vitro metabolism of dihydroergotamine was evaluated in a biomimetic phase I reaction, aiming to verify all possible formed metabolites. Dihydroergotamine was submitted to an in vitro metabolism assay using rat liver microsomes, and the metabolites were analyzed by HPLC-MS/MS. The biomimetic reactions were performed with Jacobsen catalyst for scaling up production of oxidized metabolites. Two hydroxylated metabolites were isolated and characterized by MS/MS and 1H NMR analysis.

Orally inhaled dihydroergotamine: a review.

Orally inhalable dihydroergotamine (iDHE), before the US Food and Drug Administration in 2013 for consideration for approval for acute treatment of episodic migraine in adults, is a user-friendly formulation of an older medication. Dihydroergotamine (DHE) has a heterogeneous receptor profile, central penetration, and persistent receptor binding that may account for its clinical prolonged benefits in acute treatment of migraine. The same features may result in the ability of DHE to reverse central sensitization and allodynia and to maintain efficacy deep into attacks. These characteristics make DHE particularly useful in treating migraine upon awakening, prolonged migraine and status migrainosus, menstrually related migraine, and for bridging patients out of medication-overuse headache/chronic migraine. The inhalable formulation has helpful pharmacokinetics, with a lower maximal serum concentration than intravenous DHE which may account for minimal nausea, and less binding to the potentially toxic serotonin2B receptor. The inhaler itself is designed for delivery of reproducible aliquots of intrapulmonary DHE with only nominal need for patient coordination. The inhalable form allows for bypassing the gastrointestinal tract in the setting of migraine nausea or vomiting, and greatly reduces first-pass effect. No drug-related serious adverse events were reported during the Phase 3 study of iDHE. Product taste and nausea were the most common side effects in both the Phase 3 regulatory trial and in the safety extension trial. Limitations for use of iDHE are those for any ergot or triptan, ie, contraindication in the setting of vascular disease. In addition, iDHE is metabolized by the cytochrome P450 3A4 liver enzymatic system. Inhalable DHE provides the promise of a new formulation of a valued medication with important clinical features, useful deep into attacks in a variety of situations.

Assessing acute systemic effects of an inhaled drug with serial echocardiography: a placebo-controlled comparison of inhaled and intravenous dihydroergotamine.

OBJECTIVE: MAP0004 is an investigational product which delivers dihydroergotamine (DHE) through the lung via a breath-synchronized metered dose inhaler. The objective of this study was to compare the acute effects of orally inhaled and intravenous (IV) DHE to placebo on maximum change and area under the curve for pulmonary arterial systolic pressure (PASP). RESEARCH DESIGN AND METHODS: A randomized, double-blind, placebo-controlled, 3-period, crossover study of 24 health adults. Trial registration NCT01089062. Study assessments included pharmacokinetics, electrocardiograms (ECG), and validated echocardiographic (Doppler)-derived measures of PASP by echocardiogram. The primary endpoint was the absolute change in calculated PASP using area under the curve, 0 to 2 hours (AUC(0-2h)). RESULTS: The change in PASP with IV DHE was significantly different than MAP0004 and placebo (AUC(0-2h)2857, 2624, and 2453 mmHg*min, respectively). After a second dose of MAP0004, AUC(0-4h) remained lower with MAP0004 than with a single dose of IV DHE. Adverse events were more common with IV DHE than with MAP0004 or placebo. None of the treatments produced clinically significant changes in PASP or other cardiac parameters. Changes in PASP were significantly smaller with MAP0004 compared with IV DHE. CONCLUSION: These results indicate the effects 1 mg of orally inhaled DHE on the cardiovascular system are less than with 1 mg of IV DHE, and that serial echocardiography can be a useful noninvasive means of assessing acute systemic effects.

Assessment of the consistency of absorption of dihydroergotamine following oral inhalation: pooled results from four clinical studies.

BACKGROUND: MAP0004 is an investigational orally inhaled dihydroergotamine (DHE) delivered via a TEMPO(®) metered dose inhaler that was effective in the acute treatment of migraine in a large Phase 3 trial. Rapid and consistent absorption of DHE is important for efficacy in the acute treatment of migraine. METHODS: The pharmacokinetic parameters from four recent clinical studies, with doses including the proposed clinical dose of 1.0 mg nominal (0.65 mg emitted) MAP0004, were assessed for the consistency and speed of absorption of DHE. RESULTS: Across these studies, MAP0004 administration resulted in rapid DHE absorption, with a median time of maximum concentration (C(max)) of approximately 10 min. The C(max) and area under the curve from time zero to 2 hr associated with the MAP0004 1.0 mg nominal dose were also similar between the three studies with this dose. C(max) values after 1.0 mg MAP0004 administration were consistently lower than for 1.0 mg intravenous DHE administration, and C(max) appeared to correlate with incidence of nausea. In these studies, DHE absorption through the lung was fast, consistent, and not associated with any unique tolerability issues for this route of administration. CONCLUSIONS: These results provide evidence of the consistency of absorption that can be achieved with the use of an appropriate metered dose inhaler, which may translate into a predictable therapeutic response.

Effects of a supratherapeutic dose of investigational orally inhaled dihydroergotamine (MAP0004) on QT interval: a randomized, double-blind, active- and placebo-controlled crossover study in healthy volunteers.

BACKGROUND: MAP0004 is an orally inhaled investigational drug containing dihydroergotamine (DHE). Although DHE has been used for 60 years with no reported cardiac arrhythmias, a thorough QT study had not previously been performed with DHE. OBJECTIVE: The objective of this study was to assess the effects of MAP0004 on the QT interval as required for regulatory approval of a new product. METHODS: This randomized, double-blind, placebo-controlled, 3-period crossover study enrolled healthy volunteers. Subjects were assigned to receive, in randomized sequence, MAP0004 at a supratherapeutic dose (3-fold the clinically effective dose) (3.0 mg), moxifloxacin 400 mg, or inactive vehicle, each administered with 1 placebo capsule. Triplicate ECGs were performed continuously at baseline (day 0), before dosing, and over 24 hours after dosing in each treatment period. The effect on the QT interval was assessed using the Fridericia (QTcF) and individualized (QTcI) correction formulas. RESULTS: Fifty-four healthy adults (20 men, 34 women; mean age, 28 years) completed the trial and had measurable plasma levels of DHE after MAP0004 administration. The largest observed mean difference in QTcI between MAP0004 and placebo was 0.08 msec, and the largest 1-sided 95% upper confidence bound was 2.24 msec, both at 30 minutes after dosing. In contrast, moxifloxacin increased the mean QTcI between 9.57 and 11.28 msec relative to placebo, with a 1-sided lower 95% CL between 7.23 and 8.96 msec, confirming that the assay sensitivity was sufficient to detect MAP0004-related effects. Nausea (27.8%) was common following MAP0004 administration but apparently did not influence the QTc interval. CONCLUSIONS: A supratherapeutic dose of MAP0004 was not associated with prolonged QTc intervals. At the proposed clinical dose (1.0 mg), MAP0004 is unlikely to affect the QT interval. MAP0004 and its primary metabolite showed no evidence for prolongation of the QTc interval in healthy subjects according to the criteria required from regulatory agencies. ClinicalTrials.gov identifier: NCT01191723.

Dihydroergotamine, ergotamine, methysergide and sumatriptan - basic science in relation to migraine treatment.

The 5-hydroxytryptamine (5-HT) receptor family mediates the effects of several drugs highly effective in migraine primarily by activating 5-HT(1B) , 5-HT(1D) , and 5-HT(1F) receptors. Ergotamine, dihydroergotamine, and methysergide, as well as the "triptan" sumatriptan, are all agonists for these receptors. The receptor profile and degree of selectivity of these four drugs differ, which is reflected by their side effects that limit their use in the acute and prophylactic treatment of migraine. The acute antimigraine efficacy of these remedies is very much dependent on the formulation used where, in general, parenteral formulations are more effective in reliving the symptoms of a migraine attack.

Lack of drug interaction between the migraine drug MAP0004 (orally inhaled dihydroergotamine) and a CYP3A4 inhibitor in humans.

BACKGROUND: Dihydroergotamine (DHE), a proven migraine treatment, currently has product labeling warning against concomitant use of CYP3A4 inhibitors because of potential drug interactions. However, no reported studies of such interactions with DHE administered by any route are available. METHODS: The pharmacokinetics (PK) of MAP0004, an investigative inhaled DHE formulation, were assessed in human subjects with and without CYP3A4 inhibition by ketoconazole to evaluate the potential for drug interaction, elevation of DHE levels, and increased adverse effects. RESULTS: After MAP0004 alone vs. MAP0004 plus ketoconazole, the DHE maximum concentrations (C(max)) and area-under-the-curve (AUC(0-48) and AUC(0-∞)) were not statistically significantly different nor was the C(max) of the primary metabolite, 8'-OH-DHE. A difference in 8'-OH-DHE AUCs was observed between MAP0004 with and without ketoconazole; however, the concentrations were very low. MAP0004 was well tolerated after both treatments. CONCLUSIONS: This study demonstrated that CYP3A4 inhibition had little to no effect on DHE PK after MAP0004 administration, apparently because of its high systemic and low gastrointestinal bioavailability. CYP3A4 inhibition slowed elimination of the metabolite 8'-OH-DHE, but concentrations were too low to be pharmacologically relevant.

Randomized, double-blind, placebo-controlled study of the safety, tolerability and pharmacokinetics of MAP0004 (orally-inhaled DHE) in adult asthmatics.

BACKGROUND: MAP0004 (a proprietary formulation of dihydroergotamine mesylate [DHE]) for inhaled delivery is being developed for acute migraine treatment. Because asthma and migraine often occur as co-morbid conditions, it is considered important to study the safety of MAP0004 in a population of asthmatic adults and to confirm that the pharmacokinetics of DHE, when inhaled by asthmatic subjects, were comparable to a population of healthy volunteers. The safety, tolerability, and pharmacokinetics of orally-inhaled MAP0004 administered by the Tempo inhaler were studied in adult asthmatics. SCOPE: This was a randomized, double-blind, placebo-controlled study of two doses of inhaled MAP0004. Eligible subjects were randomized in a 2 : 1 ratio to MAP0004 or placebo and observed for 4 h after each dose. Pharmacokinetic parameters were determined pre-dose and up to 36 h post-dose. FINDINGS: Among 19 subjects, geometric mean AUC(0-36) was 6754 pg.h/mL and geometric mean AUC(0-inf) was 7483 pg.h/mL. Geometric mean t(max) was 9.6 min, geometric mean C(max) was 3174 pg/mL, and geometric mean t((1/2)) was 9.5 h. Overall, 13 of 19 (68%) subjects reported at least one adverse event, most commonly nausea, vomiting, dysgeusia, and headache. CONCLUSION: MAP0004 results in rapid and efficient systemic absorption in asthmatic subjects. Systemic DHE concentrations were similar to those previously reported in healthy subjects, and no clinically relevant safety issues were observed. While this small study was suitable for pharmacokinetic analysis and conclusions, MAP0004 use in migraineurs with concomitant stable asthma should be supported by larger studies of longer duration to confirm that it does not present additional safety risks compared to non-asthmatic migraineurs.

Intrapulmonary and intravenous administrations of dihydroergotamine mesylate have similar cardiovascular effects in the conscious dog.

BACKGROUND AND PURPOSE: The effects of intrapulmonary artery (i.p.a.) administration of dihydroergotamine mesylate (DHE) were evaluated. EXPERIMENTAL APPROACH: Conscious beagle dogs (n=4) were given DHE via the i.p.a. or i.v. route as two 0.014 mg kg(-1) doses and a 0.14 mg kg(-1) dose given 60 min apart. A recovery period of > or =45 h occurred before crossover to the alternative route. Physiological parameters were monitored by telemetry or direct measurement, and venous blood samples were collected for pharmacokinetic assessments. KEY RESULTS: No meaningful differences between i.v. and i.p.a. treatments were observed for heart rate, systemic pressures and vascular pressures. Aortic resistance increased 8, 27 and 70%, respectively, following three doses of i.v. DHE compared with 11, 37 and 57%, respectively, with i.p.a. DHE. Carotid artery resistance increased 22, 40 and 87%, respectively, following three doses of i.v. DHE, compared with 17, 45 and 67%, respectively, following i.p.a. DHE. Increases in coronary artery resistance were of similar magnitude following i.v. and i.p.a. DHE administration. Increases in left ventricular systolic and diastolic pressures were seen following all doses of i.v. and i.p.a. DHE. Changes following DHE 0.014 mg kg(-1) were minimal and not clinically significant. With DHE 0.14 mg kg(-1) by either route, emesis was the most common adverse event. CONCLUSIONS AND IMPLICATIONS: DHE has comparable effects delivered via simulated deep inhalation (i.p.a.) or i.v. administration. The risk of cardiovascular complications is unlikely to be greater following inhalation of DHE.

Safety and pharmacokinetics of dihydroergotamine mesylate administered via a Novel (Tempo) inhaler.

OBJECTIVE: We investigated the pulmonary absorption of dihydroergotamine (DHE) mesylate and compared the safety, pharmacokinetic, and metabolic profile of 4 different doses of orally inhaled DHE delivered by the Tempo Inhaler (MAP Pharmaceuticals Inc., Mountain View, CA, USA) with 1.0 mg intravenously (IV) administered DHE in 18 healthy subjects. METHODS: Safety was measured by monitoring adverse events, vital signs, electrocardiograms, spirometry, and changes in biochemical and hematological laboratory values. Liquid chromatography, tandem mass spectrometry was used to determine plasma DHE levels while C(max), t(max), AUC(0-6), AUC(0-48), AUC(0-inf), and t(1/2) of parent DHE and the major bioactive metabolite, 8'OH-DHE. Pharmacokinetic parameters and qualitative spectrograms for DHE and metabolites for all treatment groups were compared after inhaled DHE (MAP0004) and IV DHE 1.0 mg. Geometric means and 90% confidence intervals of log-transformed data were calculated and the ratio of means compared. RESULTS: Inhaled DHE resulted in rapid systemic absorption with pharmacokinetic parameters of both parent DHE and 8'OH-DHE similar to those achieved after a 3-minute IV infusion. Post-peak (t(max) approximately 12 minutes) DHE concentrations achieved after 4 actuations ( approximately 0.88 mg respirable dose) of MAP0004 were comparable to those detected after IV administration. The systemic exposure to DHE after 6 actuations of MAP0004 was slightly greater than that achieved after IV administration (geometric mean AUC(0-inf) ratio = 1.24). CONCLUSION: The 4-actuation delivery was well tolerated and provided systemic levels of DHE and 8'OH-DHE slightly lower than IV administration and predicted levels.

Pharmacology of dihydroergotamine and evidence for efficacy and safety in migraine.

Dihydroergotamine mesylate (DHE), an ergot alkaloid, has been extensively utilized and studied in the treatment of episodic and chronic migraine. This article reviews the pharmacokinetics, pharmacodynamics, and clinical efficacy and safety of DHE, particularly in comparison to ergotamine tartrate (ET), a similar ergot alkaloid with a long history of use in the treatment of migraine. Structural differences between these 2 compounds account for clinically important distinctions in their pharmacokinetic, pharmacodynamic, and adverse event profiles. DHE is a significantly less potent arterioconstrictor than is ET, which makes it a potentially much safer drug. In addition, DHE is associated with a markedly lower incidence of medication-withdrawal headache, nausea, and vomiting than is ET. The safety and efficacy data presented here are derived from clinical trials and case series involving DHE administered by intravenous infusion, intramuscular or subcutaneous injection, or intranasal spray.

Sensitive and specific liquid chromatographic-tandem mass spectrometric assay for dihydroergotamine and its major metabolite in human plasma.

A sensitive and specific procedure for the simultaneous determination of dihydroergotamine (DHE) and its 8'-hydroxylated metabolite (8'-OH-DHE) in human plasma was developed and validated. The analytes were extracted from plasma samples by liquid-liquid extraction, separated through a Zorbax C18 column (50x2.1 mm I.D.) and detected by tandem mass spectrometry with an electrospray ionization interface. Caroverine was used as the internal standard. The method has a lower limit of quantitation (LOQ) of 10.0 and 11.0 pg/ml for DHE and 8'-OH-DHE, respectively. The intra- and inter-run precision was measured to be below 9.1% for both DHE and 8'-OH-DHE. The inter-run accuracy was within 4% for the analytes. The overall extraction recoveries of DHE and 8'-OH-DHE were determined to be about 58 and 52% on average, respectively. The chromatographic run time was approximately 2.5 min. More than 120 samples could be assayed daily with this method, including sample preparation, data acquisition and processing. The method developed was successfully used to investigate plasma concentrations of DHE and 8'-OH-DHE in a pharmacokinetic study of volunteers who received DHE orally.

Dihydroergotamine: discrepancy between arterial, arteriolar and pharmacokinetic data.

AIMS: To investigate the peripheral vascular effects and pharmacokinetics of dihydroergotamine (DHE) 0.5 mg after a single subcutaneous administration in humans. METHODS: A double-blind, placebo-controlled cross-over study was performed in 10 healthy male subjects. A wash-out period of 2 weeks separated the two study periods. During each period, just before and at regular intervals after drug administration, vascular measurements were performed and venous blood samples were drawn. Vessel wall properties were assessed at the brachial artery, by ultrasound and applanation tonometry. Blood pressure and heart rate were recorded with an oscillometric device. Forearm blood flow was measured with venous occlusion plethysmography. For all parameter-time curves the area under the curve (AUC) was calculated. Differences in AUC after placebo and DHE (DeltaAUC) were analysed and the time-course of the difference assessed. DHE pharmacokinetics were analysed according to a two-compartment open model with an absorption phase. RESULTS: AUC for blood pressure, heart rate and forearm vascular resistance did not change after DHE. Brachial artery diameter and compliance decreased (P < 0.01); DeltaAUC (95% confidence interval) equalled -8.81 mm h (-12.97/-4.65) and -0.98 mm2 kPa(-1) h (-1.61/-0.34), respectively. Diameter decreased (P < 0.05) from 1 until 24 h after DHE (peak decrease 9.7% at 10 h); compliance from 2 until 32 h (24.8% at 2 h). Time to reach maximum plasma concentration of DHE averaged 0.33 +/- 0.08 h (+/- s.e.mean); terminal half-life was 5.63 +/- 1.15 h. CONCLUSIONS: DHE decreased diameter and compliance of the brachial artery whereas forearm vascular resistance remained unchanged. Thus, DHE acts on conduit arteries without affecting resistance arteries. Furthermore, a discrepancy was demonstrated between the plasma concentrations of DHE which rapidly reach peak levels and quickly decline, and its long lasting vasoconstrictor activity.

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.

Determination of dihydroergotamine in human plasma by high-performance liquid chromatography with fluorescence detection.

Dihydroergotamine, a 5-hydroxytryptamine antagonist, is used for the treatment of vascular headaches. A high-performance liquid chromatography assay with fluorescence detection is described for the determination of dihydroergotamine in plasma. The assay was validated over the concentration range 0.1-10 ng/ml plasma and applied to the analysis of plasma samples from subjects treated intramuscularly and intranasally with 2 mg of dihydroergotamine.