Pharmacokinetics and pharmacodynamics of the triptan antimigraine agents: a comparative review

Sex Hormones and Calcitonin Gene-Related Peptide in Women With Migraine: A Cross-sectional, Matched Cohort Study

BACKGROUND AND OBJECTIVES

Sex hormones may modulate calcitonin gene-related peptide (CGRP) release in the trigeminovascular system. We studied CGRP concentrations in plasma and tear fluid in female participants with episodic migraine (EM) and a regular menstrual cycle (RMC), female participants with EM and combined oral contraception (COC), and female participants with EM in the postmenopause. For control, we analyzed 3 corresponding groups of age-matched female participants without EM.

METHODS

Participants with an RMC had 2 visits: during menstruation on menstrual cycle day 2 ± 2 and in the periovulatory period on day 13 ± 2. Participants with COC were examined at day 4 ± 2 of the hormone-free interval (HFI) and between days 7 and 14 of hormone intake (HI). Postmenopausal participants were assessed once at a random time point. Plasma and tear fluid samples were collected at each visit for determination of CGRP levels with an ELISA.

RESULTS

A total of 180 female participants (n = 30 per group) completed the study. Participants with migraine and an RMC showed statistically significantly higher CGRP concentrations in plasma and tear fluid during menstruation compared with female participants without migraine (plasma: 5.95 pg/mL [IQR 4.37-10.44] vs 4.61 pg/mL [IQR 2.83-6.92], p = 0.020 [Mann-Whitney U test]; tear fluid: 1.20 ng/mL [IQR 0.36-2.52] vs 0.4 ng/mL [IQR 0.14-1.22], p = 0.005 [Mann-Whitney U test]). In contrast, female participants with COC and in the postmenopause had similar CGRP levels in the migraine and the control groups. In migraine participants with an RMC, tear fluid but not plasma CGRP concentrations during menstruation were statistically significantly higher compared with migraine participants under COC (p = 0.015 vs HFI and p = 0.029 vs HI, Mann-Whitney U test).

DISCUSSION

Different sex hormone profiles may influence CGRP concentrations in people, with current or past capacity to menstruate, with migraine. Measurement of CGRP in tear fluid was feasible and warrants further investigation.

Metabolism of sumatriptan revisited

Scientific literature describes that sumatriptan is metabolized by oxidative deamination of its dimethylaminoethyl residue by monoamine oxidase A (MAO A) and not by cytochrome P450 (CYP)-mediated demethylation, as is usual for such structural elements. Using recombinant human enzymes and HPLC-MS analysis, we found that CYP enzymes may also be involved in the metabolism of sumatriptan. The CYP1A2, CYP2C19, and CYP2D6 isoforms converted this drug into N-desmethyl sumatriptan, which was further demethylated to N,N-didesmethyl sumatriptan by CYP1A2 and CYP2D6. Otherwise, sumatriptan and its two desmethyl metabolites were metabolized by recombinant MAO A but not by MAO B to the corresponding acetaldehyde, with sumatriptan being only a poor substrate for MAO A compared to the N-demethylated and the N,N-didemethylated derivatives.

Childhood cancer confers increased risk of migraine - A Danish nationwide register study

BACKGROUND

Investigations of migraine among childhood cancer survivors have predominantly relied on self-reported information and hospital discharge diagnoses. Alone, both approaches are liable to bias. We used Danish nationwide registers to obtain data on both prescriptions of acute migraine medications (antimigraines) and hospital discharge diagnoses of migraine to assess the relative risk of migraine across a wider spectrum of migraine presentations than previously studied.

METHODS

We followed a Danish population-based cohort of 7771 individuals with childhood cancer diagnosed in the period from Jan 1st, 1978 to Dec 31st, 2017, for risk of prescription antimigraine initiation and for risk of hospitalization due to migraine. Rates of hospitalization were assessed for the entire follow-up period whereas rates of antimigraine initiations were assessed in the period from Jan 1st, 1997, to Dec 31st, 2017. Relative to the general population without childhood cancer, standardized incidence ratios (SIRs) were calculated for each outcome.

RESULTS

Individuals exposed to childhood cancer were at increased risk of antimigraine initiation (SIR of 1.24, 95% CI: 1.11-1.38) and of migraine hospitalization (SIR of 2.44, 95% CI: 1.87-3.12) from the day of their cancer diagnosis and up to 40 years after.

CONCLUSIONS

Individuals diagnosed with childhood cancer have a higher risk of migraine of varying presentations, in addition to migraine resulting in hospitalization as previously reported. This potentially preventable problem warrants clinical attention.

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

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

Naratriptan is as effective as sumatriptan for the treatment of migraine attacks when used properly. A mini-review

BACKGROUND

Naratriptan, marketed in a low oral dose of 2.5 mg, is generally regarded as a less-effective triptan with a slower onset of action than most other triptans in the treatment of migraine attacks. In this review, naratriptan will be compared with sumatriptan, the standard triptan.

METHODS

Papers on pharmacodynamics and pharmacokinetics and results from comparative clinical trials with oral and subcutaneous naratriptan versus other triptans were retrieved from PubMed.

RESULTS

Naratriptan and sumatriptan have similar effects in relevant animal models. In a randomized controlled trial, oral naratriptan 2.5 mg is less effective than oral sumatriptan 100 mg after both 2 h and 4 h. In contrast, oral naratriptan 10 mg has a similar time-effect curve as oral sumatriptan 100 mg, in both its steepness and the efficacy at 2 h and 4 h. Subcutaneous naratriptan 10 mg (88% pain free at 2 h) was in one trial superior to subcutaneous sumatriptan 6 mg (55% pain free at 2 h).

CONCLUSION

Naratriptan was marketed for the treatment of migraine attacks as the "gentle triptan" in a low oral dose of 2.5 mg, a dose with no more adverse events than placebo. This low dose results in the slow onset of action and low efficacy of oral naratriptan, but in high doses oral naratriptan is similar to oral sumatriptan. Based on one randomized controlled trial, subcutaneous naratriptan has probably the greatest effect of any triptan.

Drug interactions and risks associated with the use of triptans, ditans and monoclonal antibodies in migraine

PURPOSE OF REVIEW

The aim of this study was to review current evidence concerning potential risks and interactions associated with concomitant use of drugs indicated for the abortive treatment of migraine, namely triptans and ditans, and more recently developed drugs used for the preventive treatment. The latter drug class encompasses monoclonal antibodies (mAbs), which target either calcitonin gene-related peptide (CGRP) or its receptor.

RECENT FINDINGS

To date, no pharmacokinetic interactions between these drug classes have been reported. However, patients who suffer from triptan- (or ditan-) induced medication overuse headache or those who are nonresponders to triptans might respond less effectively to mAbs. Caution is warranted when coadministrating these drugs in migraine patients with comorbid cardiovascular disease or with an increased cardiovascular risk profile.

SUMMARY

In this review, the main mechanisms of action of triptans, ditans and mAbs targeting CGRP or its receptor are summarized as well as the current evidence on their individual risks. Studies on risks and interactions in case of concomitant use of triptans, ditans and mAbs in migraine patients are relatively scarce. Therefore, these aspects have been considered from a theoretical and hypothetical point of view by taking both their overlapping target, CGRP, and contraindications into account.

Twenty-five years of triptans - a nationwide population study

BACKGROUND

The efficacy of triptans as the main acute treatment strategy for migraine headache at the population-wide level needs to be understood to inform clinical decision-making. We summarise key trends in triptan use using more than 25 years of Danish nationwide data.

METHODS

We conducted a nationwide register-based cohort study based on all Danish residents with access to public healthcare between 1 January 1994 and 31 October 2019 and summarise informative trends of all purchases of triptans in Denmark in the same period. Complete purchase records of Sumatriptan, Naratriptan, Zolmitriptan, Rizatriptan, Almotriptan, Eletriptan, and Frovatriptan were used.

FINDINGS

Over a 25-year period, triptan use increased from 345 to 945 defined daily doses (DDD) per 1000 inhabitants per year and the yearly prevalence of triptan use increased from 5.17 to 14.57 per 1000 inhabitants. Between 2014 and 2019, 12.3% of the Danish migraine population purchased a triptan. Following their initial purchase, 43% of patients had not repurchased triptans within 5 years. At most, 10% of patients indicating triptan discontinuation tried more than one triptan. The prevalence of triptan overuse, defined as having purchased at least 20 DDDs of triptans per month for 3 consecutive months, increased in parallel with the prevalence of triptan use, prevalent in 56 of every 1000 triptan users every year between 2014 and 2019.

INTERPRETATION

In a cohort with access to free clinical consultations and low medication costs, we observed low rates of triptan adherence, likely due to disappointing efficacy and/or unpleasant side effects rather than economic considerations. Triptan success continues to be hindered by poor implementation of clinical guidelines and high rates of treatment discontinuance.

Fabrication of polyvinyl alcohol based fast dissolving oral strips of sumatriptan succinate and metoclopramide HCL

Migraine is a throbbing condition, usually associated with nausea and vomiting and requires concurrent administration of anti-migraine along with anti-emetic therapy. The current study was undertaken with an aim to fabricate fast dissolving oral strips (FDOSs) containing Sumatriptan succinate (anti-migraine) and Metoclopramide HCl (anti-emetic) in combination without involving any superdisintegrant. Hydrophilic polymer polyvinyl alcohol (PVA) was used alone with three concentrations of 100, 125, and 150 mg using variable concentrations of glycerol. The solvent casting technique was employed to formulate FDOSs and were evaluated for surface morphology, mechanical properties, surface pH, % moisture content, disintegration time (DT), total dissolving time (TDT), drug contents, and dissolution profile. PVA (150 mg) with 5% glycerol concentration gave best formulation results. FDOSs have exhibited good tensile strength with smooth and uniform surface morphology. DT was ranged from 7.7 to 28 s; while TDT was from 26.4 to 77.6 s. Both polymer and plasticizer concentrations were found to be influencing the characteristics of the strips. Dissolution studies were carried out in distilled water for 15 min and all the formulations have shown released more than 50% drug within first 2 min thereby highlighting the usefulness of FDOSs for the delivery of both drugs in combination significantly. Optimized combination of ingredients was found to be suitable for the formulation of FDOSs for simultaneous delivery of Metoclopramide HCl and Sumatriptan succinate.

Sex-Specific Pharmacotherapy for Migraine: A Narrative Review

Migraine is a common neurological disorder characterized by recurrent headache episodes that accompany sensory-motor disturbances, such as higher sensitivity to touch and light, extremity heaviness or weakness, and speech or language disabilities. Worldwide, migraine is one of the top 10 causes of disability and hence poses a huge economic burden to society. On average, migraine occurs in 12% of population but its occurrence is sexually dimorphic, as it is two to three times more prevalent in women than in men. This female to male ratio of migraine prevalence is age- and sex hormone-dependent. Advancements in understanding migraine pathogenesis have also revealed an association with both genetics and epigenetics. The severity of migraine, in terms of its attack duration, headache intensity, frequency, and occurrence of migraine-associated symptoms, has generally been reported to be greater in women. Sex differences in migraine disability and comorbidities, such as psychiatric disorders, have also been noted in some population-based studies. However, research on sex-related differences in response to migraine treatments is relatively scarce. Although a general observation is that women consume more medication than men for migraine treatment, strategies for the use of abortive and preventive medications for migraine are generally similar in both sexes. This narrative review summarizes available findings on sexually distinct responses to abortive and prophylactic pharmacotherapy of migraine. Basic experimental data and clinical findings will be presented, and potential mechanisms underlying sex-based responses will be discussed to highlight the importance and value of sex-based treatment in migraine research and practice.

Economic burden of migraine in Latvia and Lithuania: direct and indirect costs

BACKGROUND

Migraine is a primary headache disorder which affects all aspects of life. The financial burden of migraine imposed on the society might be substantial. This study aims at estimating the economic cost of migraine in Latvia and Lithuania, including both direct and indirect costs. Direct costs encompass the costs of migraine-related health care resource utilization. Indirect costs are related to productivity loss, the potential or expected earnings lost due to migraine.

METHODS

Direct cost is assessed by using the prevalence method, a widely used cost-of-illness approach. The prevalence rate of migraine and the migraine-related health care resource utilization are proxied from the literature, whereas unit cost of medical services and procedures are retrieved from national databases and providers. For estimating the indirect cost of migraine, we follow the human capital approach. We quantify three components of indirect costs: reduced labour force participation, absence from work and reduced productivity while at work. The number of unemployed migraineurs, days missed from work and days lost due to impairment while at work are drawn from the literature. Unemployment rate and average income in Latvia and Lithuania are then inserted to assess indirect costs.

RESULTS

We find that the mean per-person total cost of migraine is €801 annually in Latvia, and €721 in Lithuania. In both countries around 30% of total cost is direct cost; cost related to a wide array of migraine-related medical services and interventions. The total cost of migraine is €112.26 million in Latvia, corresponding to 0.42% of Latvia's GDP. The total cost of migraine is €149.62 million in Lithuania, corresponding to 0.35% of Lithuania's GDP. In both countries two thirds of total cost is related to lost workdays due to absenteeism and presenteeism.

CONCLUSIONS

The financial burden of migraine imposed on the society is substantial in Latvia and Lithuania. Improvements in care for patients with migraine, such as easier access to structured headache assessment services, wider availability of various procedures and preventive medications would significantly increase direct costs. Nevertheless, this cost increase might be far outweighed by lower migraine-related productivity loss, especially as the prevalence of migraine is the highest in the most productive years of life.

Using Microemulsion as Carrier for Drug Transdermal Delivery: The Effect of Surfactants and Cosurfactants

BACKGROUND

The purpose of this study was to evaluate the effect of types of surfactants and cosurfactants on physicochemical properties and permeability of sumatriptan-loaded microemulsions through rat skin.

METHODS

Different types of surfactants and cosurfactants were used to prepare drug-loaded microemulsions. The physicochemical characters and permeability parameters of these formulations were measured.

RESULTS

The experimental microemulsions with varying components had small droplet size ranging from 24.6 nm to 2568.8 nm, low viscosity ranging from 7.49 to 43.34 cps and significant permeation enhancement ratio ranging from 23.0 to 98.6 when compared to the control group.

CONCLUSION

The composition and proportion of surfactants and cosurfactants were key factors for the physiochemical properties of drug-loaded microemulsions. The cumulative transdermal amount of the microemulsion containing mixture surfactant of Laureth-3/Laureth-23 was higher than that of the microemulsion with a mixture of Tween 80/Span 20. In the selected cosurfactant, diethylene glycol monoethyl ether (DEGMEE) showed highest permeation enhancement. Thermodynamic stability tests revealed that the experimental microemulsion was a stable enough formulation to be considered as a suitable carrier for sumatriptan.

Preparation and Optimization of Fast-Disintegrating Tablet Containing Naratriptan Hydrochloride Using D-Optimal Mixture Design

Optimization of a lyophilized fast-disintegrating tablet (LFDT) formulation containing naratriptan hydrochloride, an antimigraine drug, was the foremost objective of the study, aiming in achieving fast headache pain relief. The Design-Expert® v10 software was used to generate formulations using D-optimal mixture design with four components: gelatin (X₁), hydrolyzed gelatin (X₂), glycine (X₃), and mannitol (X₄) of total solid material (TSM) w/w. The effect of the relative proportion of each component was determined on friability (Y₁), hardness (Y₂), and in vitro disintegration time (Y₃), which was then applied for formulation optimization. In addition, their effect on tablet porosity was determined via scanning electron microscopy (SEM). Drug-excipient interaction was evaluated using differential scanning calorimetry (DSC). A comparative dissolution study against the conventional tablets was studied. Accelerated stability study was carried out in (Al/Al) and (Al/PVC) blister packs. An in vivo pharmacokinetic study was carried out to compare the optimized formulation and the conventional tablets. The optimized formulation's responses were 0.30%, 3.4 kg, and 6.12 s for Y₁, Y₂, and Y₃, respectively. No drug-excipient interaction was specified via DSC. The optimized formulation exhibited porous structure as determined via SEM. Dissolution study demonstrated complete dissolution within 1.5 min. Study indicated stability for 78 months in (Al/Al) blister packs. In vivo pharmacokinetic study demonstrated that C_max, AUC_last, and AUC_inf were significantly higher for the developed formulation. As well, the T_max was 1 h earlier than that of convenient tablet. An LFDT would achieve a faster onset of action for naratriptan compared to other formulations.

Migraine Treatment: Current Acute Medications and Their Potential Mechanisms of Action

Migraine is a common and disabling primary headache disorder with a significant socioeconomic burden. The management of migraine is multifaceted and is generally dichotomized into acute and preventive strategies, with several treatment modalities. The aims of acute pharmacological treatment are to rapidly restore function with minimal recurrence, with the avoidance of side effects. The choice of pharmacological treatment is individualized, and is based on the consideration of the characteristics of the migraine attack, the patient's concomitant medical problems, and treatment preferences. Notwithstanding, a good understanding of the pharmacodynamic and pharmacokinetic properties of the various drug options is essential to guide therapy. The current approach and concepts relevant to the acute pharmacological treatment of migraine will be explored in this review.

Pharmacokinetics and tolerability of eletriptan hydrobromide in healthy Korean subjects

Background

Migraine is one of the most common headache disorders that greatly affect the quality of life. Selective serotonin (5-HT) receptor agonists such as triptamine-based drugs called triptans are used for treatment of migraine.

Purpose

This study aimed to evaluate the pharmacokinetic (PK) and tolerability profiles of eletriptan hydrobromide (eletriptan HBr), a selective 5-hydroxytryptamine (also known as serotonin) 1B/1D receptor agonist, in Koreans and compare the results to those observed in non-Koreans in a previously published study.

Patients and methods

A randomized, open-label, single, and repeated-dose study was conducted in 16 healthy Korean male subjects using a four-treatment, four-period, and four-sequence crossover design (NCT01139515). The subjects received one of the following four treatments in each period: a single dose of 20, 40, 80 mg eletriptan HBr or a repeated oral dose of 40 mg 2 h apart. Blood samples were collected before and up to 26 h after dosing for quantification of plasma eletriptan concentration by high-performance liquid chromatography tandem–mass spectrometry. The PK parameters were estimated using noncompartmental methods. Ethnicity differences between Korean and non-Korean subjects were identified using geometric mean ratios and 90% confidence intervals (CIs) of dose-normalized maximum plasma concentration (C_max) and dose-normalized area under the plasma concentration versus time curve from 0 h to the last measurable concentration (AUC_0–t).

Results

After single-dose administration of eletriptan HBr to Korean subjects, the mean C_max and AUC_0–t increased linearly with dose. Comparable total systemic exposures were observed in the 2 h apart 40 mg repeated and single 80 mg dose. The geometric mean ratios (90% CIs) of the dose-normalized C_max and AUC_0–t of Korean subjects were similar to those of non-Korean subjects reported in the literature. The adverse events observed were transient and mild in severity.

Conclusion

Eletriptan HBr showed linear PK and was well tolerated in Korean subjects. The PK and tolerability of eletriptan HBr did not differ between Korean and non-Korean subjects.

17-β-Estradiol induces spreading depression and pain behavior in alert female rats

AIMS

Test the putative contribution of 17-β-estradiol in the development of spreading depression (SD) events and head pain in awake, non-restrained rats.

MAIN METHODS

Female, Sprague-Dawley rats were intact or underwent ovariectomy followed one week later by surgery to place electrodes onto the dura to detect epidural electroencephalographic activity (dEEG). dEEG activity was recorded two days later for 12 hours after systemic administration of 17-β-estradiol (180 μg/kg, i.p.). A separate set of rats were observed for changes in exploratory, ambulatory, fine, and rearing behaviors; periorbital allodynia was also assessed.

KEY FINDINGS

A bolus of 17-β-estradiol significantly elevated serum estrogen levels, increased SD episodes over a 12-hour recording period and decreased rearing behaviors in ovariectomized rats. Pre-administration of ICI 182,780, an estrogen receptor antagonist, blocked 17-β-estradiol-evoked SD events and pain behaviors; similar results were observed when the antimigraine therapeutic sumatriptan was used.

SIGNIFICANCE

These data indicate that an estrogen receptor-mediated mechanism contributes to SD events in ovariectomized rats and pain behaviors in both ovariectomized -and intact- rats. This suggests that estrogen plays a different role in each phenomenon of migraine where intense fluctuations in concentration may influence SD susceptibility. This is the first study to relate estrogen peaks to SD development and pain behaviors in awake, freely moving female rats, establishing a framework for future preclinical migraine studies.

Clinical Profile and Practice Experience of Almotriptan

Patients expect their acute migraine treatment to have a rapid onset of action, achieve complete pain relief that is sustained for 24 h, and to have a good tolerability profile. Almotriptan has a favourable pharmacokinetic profile that translates clinically to a rapid onset of action and consistent absorption regardless of age, sex, food intake and status of the acute migraine attack. In addition, almotriptan is not associated with any clinically relevant drug-drug interactions. Pain-free status at 2 h postdose is achieved by approximately 39% of patients receiving almotriptan in clinical trials. Recurrence of headaches within 24 h is low with almotriptan (< 22%). Almotriptan has a sustained pain-free rate of 25-27%, which in a meta-analysis of triptans was superior to sumatriptan 100 mg. Almotriptan therapy is associated with a low incidence of adverse events, including those affecting the central nervous system and chest.

What Do Patients Want from Acute Migraine Treatment?

Clinical observations have shown that migraine is a progressive disorder, both within an acute attack, and within the disease itself. Rates of diagnosis for migraine have increased in the last decade, but more than half of migraineurs remain undiagnosed. Patient expectations of migraine therapies have also increased (patients require rapid and sustained pain relief with a treatment that has good tolerability), and can differ greatly from those of physicians. Management decisions should be made with these expectations in mind, to enhance patient outcomes and compliance with treatment. Improved understanding of acute migraine attack pathophysiology has led to the strategy of early treatment to modify both the progression of the current attack and, potentially, the progression of the disease itself in the individual. The triptans are effective acute migraine therapies. Each agent has its own distinct profile of efficacy and tolerability, enabling individualization of treatment.

Longitudinal changes in neurodevelopmental outcomes between 18 and 36 months in children with prenatal triptan exposure: findings from the Norwegian Mother and Child Cohort Study

OBJECTIVE

This study sought to determine whether changes in neurodevelopmental outcomes between 18 and 36 months of age were associated with prenatal exposure to triptan medications, a class of 5-HT receptor agonists used in the treatment of migraine.

METHOD

Using data from the Norwegian Mother and Child Cohort Study, a prospective birth cohort that includes nearly 40% of all pregnancies in Norway from 1999 to 2008, we identified 50 469 mother-child dyads who met inclusion criteria and were present for at least one follow-up assessment at 18 or 36 months postpartum. Neurodevelopment was assessed using the Child Behaviour Checklist, the Emotionality, Activity, and Shyness Questionnaire, and the Ages and Stages Questionnaire. We used generalised estimating equations to evaluate change from 18 to 36 months for children prenatally exposed to triptans, relative to contrast groups, and used marginal structural models with inverse probability of treatment and censoring weights to address time-varying exposure and confounding as well as loss to follow-up.

RESULTS

Among eligible participants (n=50 469), 1.0% used a triptan during pregnancy, 2.0% used triptans prior to pregnancy only, 8.0% reported migraine without triptan use and 89.0% had no history of migraine. Children with prenatal triptan exposure had greater increases in emotionality (r-RR 2.18, 95% CI 1.03 to 4.53) and activity problems (r-RR 1.70, 95% CI 1.02 to 2.8) compared to children born to mothers who discontinued triptan use prior to pregnancy.

CONCLUSION

Prenatal triptan exposure was associated with changes over time in externalising-type behaviours such as emotionality and activity, but not with internalising-type behaviours.

A Comparison of the Pharmacokinetics and Tolerability of the Anti-Migraine Compound Almotriptan in Healthy Adolescents and Adults

This study was designed to assess and compare the pharmacokinetics and tolerability of almotriptan, a 5-HT1B/1D agonist used to treat migraine attacks, in adolescents and adults. Healthy adolescents ( n = 18) and adults ( n = 18) received a single 12.5-mg dose of almotriptan after fasting overnight. Plasma and urinary almotriptan concentrations were measured by high-performance liquid chromatography. Pharmacokinetic parameters of almotriptan were determined by non-compartment analysis. The 90% confidence interval (CI) approach was employed to assess age effects. Mean Cmax, tmax, area under the curve (AUC 0-∞), half-life, and percentage excreted in urine were nearly identical for the two populations. Mean oral (CLPO) and renal (CLR) clearances were similar between the age groups; however, weight-corrected CLPO was approximately 32% higher (90% CI 16, 51) in adolescents compared with adults. The higher weight-corrected CLPO appeared to offset increases in exposure expected on the basis of lower body weight in adolescents. The findings were the same when a subgroup ( n = 9) of 12-14-year old children was compared with adults. The type, incidence and severity of adverse events were similar between the two age groups and were consistent with those reported previously during adult clinical trials. Based on these pharmacokinetic and tolerability findings, no dose adjustment for almotriptan would be required when treating patients as young as 12 years old.

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

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

Cytochrome P450 and Non-Cytochrome P450 Oxidative Metabolism: Contributions to the Pharmacokinetics, Safety, and Efficacy of Xenobiotics

The drug-metabolizing enzymes that contribute to the metabolism or bioactivation of a drug play a crucial role in defining the absorption, distribution, metabolism, and excretion properties of that drug. Although the overall effect of the cytochrome P450 (P450) family of drug-metabolizing enzymes in this capacity cannot be understated, advancements in the field of non-P450-mediated metabolism have garnered increasing attention in recent years. This is perhaps a direct result of our ability to systematically avoid P450 liabilities by introducing chemical moieties that are not susceptible to P450 metabolism but, as a result, may introduce key pharmacophores for other drug-metabolizing enzymes. Furthermore, the effects of both P450 and non-P450 metabolism at a drug's site of therapeutic action have also been subject to increased scrutiny. To this end, this Special Section on Emerging Novel Enzyme Pathways in Drug Metabolism will highlight a number of advancements that have recently been reported. The included articles support the important role of non-P450 enzymes in the clearance pathways of U.S. Food and Drug Administration-approved drugs over the past 10 years. Specific examples will detail recent reports of aldehyde oxidase, flavin-containing monooxygenase, and other non-P450 pathways that contribute to the metabolic, pharmacokinetic, or pharmacodynamic properties of xenobiotic compounds. Collectively, this series of articles provides additional support for the role of non-P450-mediated metabolic pathways that contribute to the absorption, distribution, metabolism, and excretion properties of current xenobiotics.

Eletriptan in the management of acute migraine: an update on the evidence for efficacy, safety, and consistent response

Migraine is a multifactorial, neurological and disabling disorder, also characterized by several autonomic symptoms. Triptans, selective serotonin 5-HT1B/1D agonists, are the first-line treatment option for moderate-to-severe headache attacks. In this paper, we review the recent data on eletriptan clinical efficacy, safety, and tolerability, and potential clinically relevant interactions with other drugs. Among triptans, eletriptan shows a consistent and significant clinical efficacy and a good tolerability profile in the treatment of migraine, especially for patients with cardiovascular risk factors without coronary artery disease. It shows the most favorable clinical response, together with sumatriptan injections, zolmitriptan and rizatriptan. Additionally, eletriptan shows the most complex pharmacokinetic/dynamic profile compared with the other triptans. It is metabolized primarily by the CYP3A4 hepatic enzyme and therefore the concomitant administration of CYP3A4-potent inhibitors should be carefully evaluated. A relatively low risk of serotonin syndrome is given by the co-administration with serotoninergic drugs. No clinically relevant interaction has been found with drugs used for migraine prophylactic treatment or other acute drugs, with the exception of ergot derivatives that should not be co-administered with eletriptan.

OCT1 mediates hepatic uptake of sumatriptan and loss-of-function OCT1 polymorphisms affect sumatriptan pharmacokinetics

The low bioavailability of the anti-migraine drug sumatriptan is partially caused by first-pass hepatic metabolism. In this study, we analyzed the impact of the hepatic organic cation transporter OCT1 on sumatriptan cellular uptake, and of OCT1 polymorphisms on sumatriptan pharmacokinetics. OCT1 transported sumatriptan with high capacity and sumatriptan uptake into human hepatocytes was strongly inhibited by the OCT1 inhibitor MPP(+) . Sumatriptan uptake was not affected by the Met420del polymorphism, but was strongly reduced by Arg61Cys and Gly401Ser, and completely abolished by Gly465Arg and Cys88Arg. Plasma concentrations in humans with two deficient OCT1 alleles were 215% of those with fully active OCT1 (P = 0.0003). OCT1 also transported naratriptan, rizatriptan, and zolmitriptan, suggesting a possible impact of OCT1 polymorphisms on the pharmacokinetics of other triptans as well. In conclusion, OCT1 is a high-capacity transporter of sumatriptan and polymorphisms causing OCT1 deficiency have similar effects on sumatriptan pharmacokinetics as those observed in subjects with liver impairment.

Improvement of transdermal delivery of sumatriptan succinate using a novel self-dissolving microneedle array fabricated from sodium hyaluronate in rats

The purpose of the present study was to develop an alternative transdermal formulation containing sumatriptan succinate (SS) for the treatment of migraine. Novel self-dissolving SS-loaded microneedle arrays (MNs) were fabricated from sodium hyaluronate and their efficacy for transdermal delivery of SS was characterized. The resulting MNs maintained their skin piercing abilities for at least 30 min after being placed at a high relative humidity of 75%. Rapid release of SS from the MNs was also observed in vitro. Optical coherence tomography images demonstrated that MNs were able to successfully pierce into rat skin without any bending or cracking, and needles were completely dissolved within 1 h. MNs significantly increased transepidermal water loss; however, skin barrier function gradually recovered to control levels within 24 h, in contrast to the skin damage observed after tape stripping treatment. These findings indicated that the micropores created by MNs quickly resealed, and that the skin damage was reversible. Furthermore, a dose-dependent plasma concentration of SS was obtained after transdermal delivery using SS-loaded MNs in rats. Absorption of SS delivered by MNs was similar to that observed after subcutaneous injection and was associated with high bioavailability (ca. 90%), which was much higher than that produced by oral administration. These findings suggested that application of SS-loaded MNs to the skin provided an effective alternative approach to enhance the transdermal delivery of SS without serious skin damage, and would be likely to improve patient compliance.

The influence of genetic constitution on migraine drug responses

Objective

Specific acute treatments of migraine are 5HT1B/D receptor agonists; triptans and ergotamine, but only two-thirds of patients respond well without side effects. No migraine-prophylactic drugs are specific to migraine. Prophylactic drugs are selected by time-consuming “trial and error.” Personalized treatment is therefore much needed. The objective of this study was to test the effect of 12 single nucleotide polymorphisms (SNPs) significantly associated with migraine on migraine drug responses.

Methods

Semi-structured migraine interviews including questions on drug responses, blood samples and genotyping were performed on 1806 unrelated migraine cases recruited from the Danish Headache Center. Association analyses were carried out using logistic regression, assuming an additive model for the genetic effect. The effect on drug responses was tested for a combined genetic score and for each of the 12 SNPs. Significant findings were subsequently tested in an independent replication sample of 392 unrelated Danish migraine cases.

Results

A single risk variant, rs2651899 in PRDM16, was significantly associated with efficacy of triptans with an odds ratio (OR) of treatment success of 1.3, and a higher combined genetic score was significantly associated with efficacy of triptans with an OR of success of up to 2.6. A number of SNPs showed nominal preferential association with the efficacy of triptans and others with prophylactic drugs. Analyses of triptans and ergotamine complemented each other and gave a stronger signal when analyzed together. The associations between response to triptans and genetic load and rs2651899 were partially confirmed in the independent sample.

Conclusion

We show for the first time an association between genetic constitution and migraine drug response. This is a first step toward future individualized medicine.

Efficacy of early vs. late use of frovatriptan combined with dexketoprofen vs. frovatriptan alone in the acute treatment of migraine attacks with or without aura

Early triptan use after headache onset may help improve the efficacy of acute migraine treatment. This may be particularly the case when triptan therapy is combined with a nonsteroidal anti-inflammatory drug (NSAID). The objective of this is to assess whether the combination of frovatriptan 2.5 mg + dexketoprofen 25 or 37.5 mg (FroDex25 and FroDex37.5) is superior to frovatriptan 2.5 mg alone (Frova) in the acute treatment of migraine attacks in patients who took the drug within 30 min from the onset of pain (early use) or after (late use). A total of 314 subjects with a history of migraine with or without aura were randomized into a double-blind, multicenter, parallel group, pilot study to Frova, FroDex25 or FroDex37.5 and were required to treat at least one migraine attack. In the present post hoc analysis, traditional migraine endpoints were compared across study drugs for subgroups of the 279 patients of the full analysis set according to early (n = 172) or late (n = 107) drug use. The proportion of patients pain free at 2 h in the early drug use subgroup was 33 % with Frova, 50 % with FroDex25 and 51 % with FroDex37.5 mg (p = NS combinations vs. monotherapy), while in the late drug use subgroup was 22, 51 and 50 % (p < 0.05 FroDex25 and FroDex37.5 vs. Frova), respectively. Pain-free episodes at 4 h were 54 % for early and 34 % for late use of Frova, 71 and 57 % with FroDex25 and 74 and 68 % with FroDex37.5 (p < 0.05 for early and p < 0.01 for late use vs. Frova). The proportion of sustained pain free at 24 h was 26 % under Frova, 43 % under FroDex25 mg and 40 % under FroDex37.5 mg (p = NS FroDex25 or 37.5 vs. Frova) in the early drug intake subgroup, while it was 19 % under Frova, 43 % under FroDex25 mg and 45 % under FroDex37.5 mg (p < 0.05 FroDex25 and FroDex37.5 vs. Frova) in the late drug intake subgroup. Risk of relapse at 48 h was similar (p = NS) among study drug groups (Frova: 25 %, FroDex25: 21 %, and FroDex37.5: 37 %) for the early as well as for the late drug use subgroup (14, 42 and 32 %). FroDex was found to be more effective than Frova taken either early or late. The intrinsic pharmacokinetic properties of the two single drug components made FroDex combination particularly effective within the 2–48-h window from the onset of the acute migraine attack. The efficacy does not seem to be influenced by the time of drug use relative to the onset of headache.

Sublingual Delivery of Frovatriptan: An Indication of Potential Alternative Route

Frovatriptan, a 5-HT1B and 5-HT1D receptor agonist, is used for the treatment of acute migraine attack. This molecule is classified into second line therapy because of its slow onset of action (peak response obtained after 4 hours of administration) and low bioavailability (25%). Moreover, its therapy is the most costly among all triptans. Attempt has been made in present work to suggest a way out to fasten its onset of action and to enhance its bioavailability. Prepared tablets were evaluated by physicochemical tests, in vitro permeation studies, ex vivo permeation studies, and histopathological studies. Suitable mathematical calculations were performed to calculate the minimum amount of bioavailability that could be enhanced. Tablets containing chitosan (5% w/w) were found to give optimum results. Prepared tablets can double the bioavailability of frovatriptan and can initiate its response within 10 minutes of its administration. Suggestive alternative has the potential to increase the efficacy of frovatriptan for treating acute migraine attack.

Effect of N-salicyloyltryptamine (STP), a novel tryptamine analogue, on parameters of cell viability, oxidative stress, and immunomodulation in RAW 264.7 macrophages

Immunomodulatory actions exerted by some classes of tryptamines, such as benzoyltryptamine analogues, suggest these molecules as promising candidates to develop new therapies to treat conditions associated to acute and chronic pain and inflammation. N-salicyloyltryptamine (STP) was observed to act as an anticonvulsive agent and exert antinociceptive effects in mouse. In the present work, we performed a screening of cytotoxic, cytoprotective, immunomodulatory, and redox properties of STP in RAW 264.7 macrophages challenged with hydrogen peroxide and LPS. Our results show that STP presents no cytotoxicity in the range of 0.001 to 1 μg/mL, but doses of 50 and 100 μg/mL caused loss of cell viability (IC(50) = 22.75 μg/mL). Similarly, STP at 0.001 to 1 μg/mL did not cause oxidative stress to RAW 264.7 cells, although it did not prevent cell death induced by H(2)O(2) 0.5 mM. At 1 μg/mL, STP reversed some redox and inflammatory parameters induced by LPS. These include thiol (sulfhydryl) oxidation, superoxide dismutase activation, and morphological changes associated to macrophage activation. Besides, STP significantly inhibited LPS-induced TNF-α and IL-1β release, as well as CD40 and TNF-α protein upregulation. Signaling events induced by LPS, such as phosphorylation of ERK 1/2 and IκBα and p65 nuclear translocation (NF-kB activation) were also inhibited by STP. These data indicate that STP is able to modulate inflammatory parameters at doses that do not interfere in cell viability.

Naratriptan mitigates CGRP1-associated motor neuron degeneration caused by an expanded polyglutamine repeat tract

Spinal and bulbar muscular atrophy (SBMA) is a motor neuron disease caused by the expansion of the CAG triplet repeat within the androgen receptor (AR) gene. Here, we demonstrated that pathogenic AR upregulates the gene encoding calcitonin gene-related peptide α (CGRP1). In neuronal cells, overexpression of CGRP1 induced cellular damage via the activation of the c-Jun N-terminal kinase (JNK) pathway, whereas pharmacological suppression of CGRP1 or JNK attenuated the neurotoxic effects of pathogenic AR. The depletion of CGRP1 inactivated JNK and suppressed neurodegeneration in a mouse model of SBMA. Naratriptan, a serotonin 1B/1D (5-hydroxytryptamine 1B/1D, or 5-HT1B/1D) receptor agonist, decreased CGRP1 expression via the induction of dual-specificity protein phosphatase 1 (DUSP1), attenuated JNK activity and mitigated pathogenic AR-mediated neuronal damage in cellular and mouse SBMA models. These observations suggest that pharmacological activation of the 5-HT1B/1D receptor may be used therapeutically to treat SBMA and other polyglutamine-related neurodegenerative diseases.

Method development and validation of almotriptan in human plasma by HPLC tandem mass spectrometry: application to pharmacokinetic study

A simple, sensitive and selective method has been developed for quantification of Almotriptan (AL) in human plasma using Almotriptan-d(6) (ALD6) as an internal standard. Almotriptan and Almotriptan-d(6) were detected with proton adducts at m/z 336.1→201.1 and 342.2→207.2 in multiple reaction monitoring (MRM) positive mode, respectively. The method was linear over a concentration range of 0.5-150.0 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) for Almotriptan were 0.2 pg/mL and 0.5 ng/mL, respectively. Liquid-liquid extraction was used followed by MS/MS (ion spray). The method was shown to be precise with an average within-run and between-run variation of 0.68 to 2.78% and 0.57 to 0.86%, respectively. The average within-run and between-run accuracy of the method throughout its linear range was 98.94 to 102.64% and 99.43 to 101.44%, respectively. The mean recovery of drug and internal standard from human plasma was 92.12 ± 4.32% and 89.62 ± 6.32%. It can be applied for clinical and pharmacokinetic studies.

Preparation and evaluation of tubular micelles of pluronic lecithin organogel for transdermal delivery of sumatriptan

The present work focuses on the preparation and evaluation of lecithin organogel system of thermoreversible polymer pluronic F127, which would enhance the stability and absorption of sumatriptan succinate across the skin. Formulations were developed with and without co-surfactant (pluronic F127). The prepared organogels were evaluated for its appearance, organoleptic characteristics, and feel upon application, homogeneity, occlusivenes, washability, pH, viscosity, spreadability, gel transition temperature of formulations. The formulations were also evaluated for drug content, in vitro drug diffusion properties and skin irritation testing. In vivo evaluation of formulations was carried out by hot plate and writhing test method, and finally the optimized formulation was subjected to stability studies. The developed formulations were easily washable, smooth in feel, and showed no clogging which indicate superior texture of system. Formulation, containing pluronic showed greater spreadability and higher drug diffusion rate as compared to pluronic free organogel. Drug content of organogel formulations was in the range of 94-97%. The pH of the formulations was 6.48 ± 0.5 and 6.98 ± 0.1, reflecting no risk of skin irritation. Pluronic not only enhances the stability of organogel by increasing the viscosity (from 6,541 ± 234.76 to 7,826 ± 155.65 poise) but also increases the release of drug from 67.39 ± 1.53% to 74.21 ± 1.7%. The sumatriptan exhibits higher and long lasting antinociceptive effect as indicated by the persistent increase in reaction time in hot plate and inhibited abdominal contraction in acetic acid-induced writhing test (p < 0.05). The prepared optimized formulation was found to be stable without any significant changes at room temperature.

Efficacy and tolerability of rizatriptan for the treatment of acute migraine in sumatriptan non-responders

Objective: The study was carried out to assess the efficacy and tolerability of rizatriptan orally disintegrating tablet (ODT) for treating acute migraine in patients who are non-responders to sumatriptan.

Background: Many migraineurs report dissatisfaction with sumatriptan efficacy. It is unclear whether sumatriptan 100 mg non-responders will respond to other triptans.

Methods: This was a randomized, placebo-controlled, double-blind study in adults with >1-year history of ICHD-II (International Classification of Headache Disorders, second edition) migraine who reported that they generally do not respond to sumatriptan (≥50% unsatisfactory response). In the baseline phase, participants treated a single moderate/severe migraine attack with open-label generic sumatriptan 100 mg. Those who continued to experience moderate/severe pain at two hours post-dose were eligible to enter the double-blind treatment phase, during which participants treated three migraine attacks in crossover fashion (two with rizatriptan 10-mg ODT, one with placebo) after being randomly assigned to one of three treatment sequences (1 : 1 : 1 ratio). The primary endpoint was two-hour pain relief.

Results: A total of 102 (94%) participants treated at least one study migraine. Pain relief at two hours was significantly greater with rizatriptan compared with placebo (51% vs. 20%, p < .001). Response rates also favored rizatriptan on two-hour pain freedom (22% vs. 12%, p = .013) as well as 24-hour sustained pain relief (38% vs. 14%, p < .001) and sustained pain freedom (20% vs. 11%, p = .036). Treatment was generally well tolerated.

Conclusion: Rizatriptan 10-mg ODT was superior to placebo at providing two-hour pain relief and two-hour pain freedom in the treatment of acute migraine in those who do not respond to sumatriptan 100 mg. Rizatriptan was generally well tolerated in this population.

Transdermal delivery of sumatriptan for the treatment of acute migraine

SUMMARY

Migraine is a common, multisymptom disorder that can severely impact the daily activities of migraineurs. Triptans (primarily sumatriptan) are the most commonly prescribed treatment for migraine and are considered a relatively safe and effective initial therapy. Unfortunately, current sumatriptan formulations (i.e., oral, nasal, subcutaneous) may be associated with limitations that can result in patients' delaying or avoiding treatment. For oral formulations, these limitations include difficulty in taking an oral medication due to the nausea and vomiting that often accompany migraine, and inconsistent absorption, whereas nasal and subcutaneous formulations may be associated with low bioavailability and an undesirable rate of adverse events, respectively. An alternative to current formulations is transdermal drug delivery, particularly iontophoresis. Transdermal delivery has several advantages over current formulations, including avoidance of the gastrointestinal tract, controlled and sustained delivery, and convenient administration. This article reviews the in vitro, in vivo, and preclinical data supporting the use of iontophoresis for the delivery of sumatriptan, as well as the recent clinical data for Zelrix (NuPathe Inc., Conshohocken, PA), an iontophoretic sumatriptan patch currently in phase III development for the treatment of migraine.

Eletriptan

Migraine is a multifactorial chronic central nervous system disorder, characterized by recurrent disabling attacks of moderate-to-severe headache. Symptomatic acute treatment of migraine should provide rapid and effective relief of the headache pain. The introduction of the 5-HT(1B/1D) receptor agonists (triptans) expanded the armamentarium for acute migraine pain treatment. Eletriptan is a second-generation triptan with favorable bioavailability and half-life, a high affinity for 5-HT(1B/1D) receptors and selectivity for cranial arteries. Eletriptan (40 and 80 mg) has been shown to be effective as early as 30 min after administration and well tolerated when compared to placebo. In comparative clinical trials, eletriptan 40 and 80 mg were superior or equivalent to other triptans and have shown a very high safety and tolerability profile across the studies performed. Eletriptan showed the most favorable cost-effectiveness profile when compared with other agents in its class.

Safety and tolerability of short-term preventive frovatriptan: a combined analysis

OBJECTIVE

To assess the safety and tolerability profile of the 5-HT(1B/1D) agonist frovatriptan (Frova(R), Endo Pharmaceuticals Inc., Chadds Ford, PA, USA) when used as a 6-day regimen for the short-term prevention of menstrual migraine scheduled over multiple perimenstrual periods.

BACKGROUND

Two randomized controlled trials have established the efficacy of a 6-day regimen of frovatriptan for reducing the incidence and severity of menstrual migraine over 1 to 3 perimenstrual periods; long-term data are needed to further assess the safety and tolerability profile of this regimen.

METHODS

Two multinational trials were included in the analysis: Study 1 was a randomized, placebo-controlled double-blind parallel trial (3 perimenstrual periods treated) with an open-label extension (3 additional perimenstrual periods treated), and Study 2 was a long-term (12 perimenstrual periods treated over 12-15 months) open-label study. Enrolled women experienced menstrual migraine defined as predictable migraine attacks that started -2 days to +3 (Study 1) or +4 (Study 2) days relative to the first day of menses and that occurred in at least 2 out of 3 menstrual cycles. Frovatriptan or placebo was given 2 days before anticipated menstrual migraine and continued for 6 days. Adverse events, serious adverse events, vital signs, cardiovascular events, electrocardiograms, and laboratory parameters were assessed and recorded periodically and summarized using descriptive statistics. Adverse event data from Study 1 and Study 2 were compared using event rates.

RESULTS

The demographic characteristics of the 2 study populations were similar: the mean age was approximately 38 years, > or =94% of participants were white, and 85% reported menstrual migraine began on days -2 to +1 of the menstrual cycle. The mean reported history of menstrual migraine was approximately 11 years. A large percentage of the respective safety populations completed each study or study period: 87% (362/416) and 88% (273/309) completed the double-blind period and open-label periods of Study 1, respectively, and 59% (308/525) completed treatment of 12 perimenstrual periods in Study 2. Major reasons for discontinuation in Study 1 included adverse events (5%, double-blind period) and "other" (10% double-blind period and 5% open-label period). In Study 2, major reasons for discontinuation included patient request (17.3%) and adverse event (10.2%). The most common treatment emergent adverse events in the double-blind period of Study 1 (placebo vs frovatriptan twice daily) were upper respiratory infection (9% vs 9%), nausea (6% vs 8%), dizziness (7% vs 7%), fatigue (4% vs 7%), dysmenorrhea (3% vs 7%), influenza (3% vs 6%), neck pain (4% vs 6%), and migraine (4% vs 4%). With the exception of migraine (which was reported using a different method in each study), prevalence rates for Studies 1 and 2 were numerically similar. The most frequently reported cardiovascular adverse events during double-blind treatment (placebo vs frovatriptan twice daily) were chest discomfort (2% and 3%), chest pain (2% and 2%), and hypertension (0 and 2%). The corresponding adverse event rates in Study 2 were 2% (chest pain), 3% (chest discomfort), and 3% (hypertension). In both studies, most adverse events were of mild or moderate intensity and their incidence numerically declined with each perimenstrual period/cycle, as did the incidence of menstrual migraine. The observed rate of intercurrent migraine in Study 2 over 12 perimenstrual periods was 1.5 per month, compared with 1.7 at baseline. There was no observable increase in the first occurrence of migraine in the 5 days following the perimenstrual period, indicating a lack of rebound headache.

CONCLUSIONS

During treatment of up to 12 perimenstrual periods over a 12- to 15-month period, the safety and tolerability of frovatriptan for short-term prevention of menstrual migraine was similar to that observed with acute use of triptans. Adverse events were generally mild or moderate in severity, there was no evidence of an increased risk of cardiovascular adverse events relative to acute treatment, and rebound headache was not evident. A short-term regimen with frovatriptan presents a safe and viable treatment option for preventing predictable migraine such as menstrual migraine.

Postmarketing migraine survey of frovatriptan: effectiveness and tolerability vs previous triptans, NSAIDs or a combination

OBJECTIVE

Compare the effectiveness and tolerability of current therapy with frovatriptan 2.5-mg tablets (in 1-3 migraines) in patients with migraine previously using other triptans, analgesics/nonsteroidal anti-inflammatory drugs (NSAIDs), or triptans and NSAIDs (T+NSAIDs).

RESEARCH DESIGN AND METHODS

Subanalysis of a postmarketing survey study in patients with migraine managed at primary care facilities in Germany.

MAIN OUTCOME MEASURES

A total of 5025 patients rated the effectiveness and tolerability of previous therapy (triptans; T+NSAIDs; NSAIDs) and current therapy with frovatriptan; physicians rated only frovatriptan effectiveness and tolerability (1 = Very Good, 2 = Good, 3 = Satisfactory, 4 = Poor).

RESULTS

Of 7107 patients initially surveyed, 5025 were identified for this subanalysis as previously using NSAIDs (n = 2890), triptans (n = 1418) or T + NSAIDs (n = 717). The mean (SD) age was 42.3 (11.9) years. At baseline, patients who previously used NSAIDs reported significantly fewer migraines per month, lower migraine severity, shorter migraine duration, and poorer ratings for effectiveness and tolerability versus responses from patients previously using triptans or T + NSAIDs (P < 0. 001 for each). Patient effectiveness ratings of Very Good or Good for previous therapy occurred in 49% (n = 691 of 1411) of patients using triptans, 27% (n = 195 of 716) of patients using T + NSAIDs, and 11% (n = 303 of 2866) of patients using NSAIDs (P < 0.04 between each group). Most patients rated current therapy with frovatriptan as Very Good or Good for effectiveness (86%, triptans; 83%, T + NSAIDs; 94%, NSAIDs) and tolerability (95%; 95%; 97%). Most physicians rated frovatriptan as Very Good or Good for effectiveness (87%; 86%; 95%) and tolerability (96%; 96%; 98%). Within-patient comparisons confirmed that frovatriptan had improved effectiveness (P < 0.001) and tolerability ratings (P < 0.001) in all three groups versus previous therapies.

CONCLUSIONS

Intrapatient comparisons showed that most patients with migraine reported significantly improved effectiveness and tolerability ratings with frovatriptan versus previous acute therapies.

Scheduled short-term prevention with frovatriptan for migraine occurring exclusively in association with menstruation

OBJECTIVE

This post hoc subgroup analysis evaluated scheduled short-term preventive frovatriptan therapy for women with migraine occurring exclusively in association with menstruation (occurring day -2 to +3; day 1 = menses start, no migraines outside this window).

BACKGROUND

A previously published randomized, double-blind, placebo-controlled 3-way crossover trial assessed the efficacy and safety of a scheduled 6-day preventive regimen with frovatriptan for the treatment of menstrual migraine; the study population included women experiencing both menstrual and non-menstrual migraine and women experiencing only menstrual migraine.

METHODS

Women received each treatment (placebo, frovatriptan 2.5 mg once daily, and frovatriptan 2.5 mg twice daily) once over 3 perimenstrual periods in randomized sequence. For this subset analysis, screening questions were used to identify women with migraine occurring exclusively in association with menstruation. Efficacy was evaluated by occurrence and severity of migraine, functional impairment, and rescue medication use. Adverse events and tolerability were also assessed.

RESULTS

Among 179 patients, the mean age (SD) was 37.3 (7.7) years and mean menstrual migraine history was 10.6 (8.7) years. Significantly fewer women experienced menstrual migraine during treatment with frovatriptan twice daily (37.7%, P < .001) or once daily (51.3%, P = .002) than during treatment with placebo (67.1%); a significant dose response was noted (P = .01, twice daily vs once daily). Significant treatment differences were also found for several secondary endpoints, but the data from this post hoc analysis must be interpreted with caution. Frovatriptan was well tolerated and most adverse events were mild or moderate and similar to those reported with the acute treatment of migraine with frovatriptan; the most common adverse events were nausea, dizziness, and headache.

CONCLUSIONS

Scheduled short-term preventive frovatriptan therapy effectively reduced the occurrence of menstrual migraine in women with attacks occurring exclusively in association with menstruation.

The triptans

The migraine-specific triptans have revolutionized the treatment of migraine and are currently the drugs of choice to treat a migraine attack in progress. Over the past 15 years, triptans were released in rapid succession, with each one demonstrating some specific pharmacokinetic properties that may be translated into clinical advantages. Triptans share many similarities, but also have important differences from one another. Accordingly, herein we discuss the class of the triptans. We first define the trigeminovascular system and its importance in migraine pain, then discuss the mechanism of action of the triptans and contrast the evidence supporting the use of different triptans. We close with our view of the future and hopes for the next generation of antimigraine therapies.

Indolealkylamines: biotransformations and potential drug-drug interactions

Indolealkylamine (IAA) drugs are 5-hydroxytryptamine (5-HT or serotonin) analogs that mainly act on the serotonin system. Some IAAs are clinically utilized for antimigraine therapy, whereas other substances are notable as drugs of abuse. In the clinical evaluation of antimigraine triptan drugs, studies on their biotransformations and pharmacokinetics would facilitate the understanding and prevention of unwanted drug-drug interactions (DDIs). A stable, principal metabolite of an IAA drug of abuse could serve as a useful biomarker in assessing intoxication of the IAA substance. Studies on the metabolism of IAA drugs of abuse including lysergic acid amides, tryptamine derivatives and beta-carbolines are therefore emerging. An important role for polymorphic cytochrome P450 2D6 (CYP2D6) in the metabolism of IAA drugs of abuse has been revealed by recent studies, suggesting that variations in IAA metabolism, pharmaco- or toxicokinetics and dynamics can arise from distinct CYP2D6 status, and CYP2D6 polymorphism may represent an additional risk factor in the use of these IAA drugs. Furthermore, DDIs with IAA agents could occur additively at the pharmaco/toxicokinetic and dynamic levels, leading to severe or even fatal serotonin toxicity. In this review, the metabolism and potential DDIs of these therapeutic and abused IAA drugs are described.

Parenteral vs. oral sumatriptan and naratriptan: plasma levels and efficacy in migraine. a comment

The clinical efficacy in migraine was compared for oral and subcutaneous sumatriptan and naratriptan. Doses of the two administration forms were chosen as resulting in comparable blood concentrations. Subcutaneous administrations of the drugs were superior for efficacy than the oral forms. This most likely due to a quicker rise in blood concentrations after subcutaneous injections.. In designing new therapies for migraine one should aim at a quick absorption of the drug, which will probably result in an increased efficacy.

Sorbitan ester organogels for transdermal delivery of sumatriptan

The partial phase behavior, rheological, and drug release characteristics of an organogel (OG) composed of water, isooctane and sorbitan esters, sorbitan monopalmitate (Span-40) and poly(oxyethylene)sorbitan monostearate (Polysorbate-60) were studied. Phase diagrams showed decreasing areas of optically isotropic organogel region depending on the surfactant ratio, Kw and drug incorporation. The nonbirefringent, clear isotropic solution suggested the reverse micellar/microemulsion nature of the organogel without any molecular ordering. The increase in drug concentration in OGs leads to increase in the viscosity and sol-gel transition temperature (Tg). Fractal dimension (df) values calculated for different compositions suggested that the density of the tubular network increases with increasing drug concentration in OGs. The release rate of the drug from OGs was found to be non-Fickian through the dialysis membrane. The permeation rate of sumatriptan from pig skin was 0.231 mg/h/cm2 (781.9 nmol/h/cm2). The study indicates potential of OG as a reservoir system for transdermal drug delivery.

A Unique Iontophoretic Patch for Optimal Transdermal Delivery of Sumatriptan

PURPOSE

Migraines affect approximately 10% of the adult population worldwide. The purpose of this study was to assess the pharmacokinetic and safety profile of a novel iontophoretic sumatriptan delivery system, NP101, which uses an electrical current to propel sumatriptan across intact skin and into underlying tissue. Four unique prototype iontophoretic sumatriptan patch conditions were compared to a 6 mg subcutaneous injection and an oral 50 mg tablet of sumatriptan succinate.

MATERIALS AND METHODS

This was a randomized, single-center, single-dose, six-period Phase I study.

RESULTS

Patches were well tolerated with fewer adverse events than the subcutaneous injection. Adverse events that were more prevalent for NP101 than other formulations included localized sensations and reactions at the patch site. A linear relationship was observed between total applied current and sumatriptan delivery. Patches delivering 6 and 12 mA per h yielded favorable sumatriptan systemic profiles, delivering drug at a rate that maintained plasma levels above the target level (> or = 10 ng/ml) for greater than 7 h.

CONCLUSIONS

This study met the initial objective to define the dose-current relationship in humans as well as delimiting specific current and current density targets for a well tolerated patch design that can deliver therapeutic drug levels for longer periods than currently possible.