Pharmacokinetics of sumatriptan nasal spray in children

Population Pharmacokinetics of an Intranasally Administered Combination of Oxymetazoline and Tetracaine in Healthy Volunteers

The primary objective of the current investigation was to establish the pharmacokinetic characteristics of oxymetazoline and tetracaine's primary metabolite, para-butylaminobenzoic acid (PBBA), after the intranasal administration of oxymetazoline/tetracaine. Thirty-six subjects contributing a total of 1791 plasma concentration results from 2 open-label trials were utilized. Model development was achieved using data from the second trial (N = 24) in which 0.3 mg oxymetazoline/18 mg tetracaine was administered. External model validation utilized data from the first trial (N = 12), which included doses of 0.3 mg oxymetazoline/18 mg tetracaine and 0.6 mg oxymetazoline/36 mg tetracaine. Oxymetazoline and PBBA dispositions were described by a 2-compartment model with first-order absorption. An allometric model for body weight was included on volumes and clearances to describe unexplained between-subject variability. The final oxymetazoline parameter estimates were k_a 4.41 h^-1 ; peripheral volume 418 L; clearance 66.4 L/h; central volume 6.97 L; and intercompartmental clearance 419 L/h for a 70-kg subject. The final PBBA parameter estimates were k_a 8.51 h^-1 ; peripheral volume 32.0 L; clearance 16.7 L/h; central volume 29.8 L; and intercompartmental clearance 2.43 L/h for a 70-kg subject. Between-subject variability ranged from 14% to 39% for oxymetazoline and from 10% to 94% for PBBA.

Pharmacological treatment of acute migraine in adolescents and children

Migraine is a common disease in children and adolescents. The incidence of migraine has increased alarmingly in the general population during recent decades. Migraine causes considerable individual suffering and impaired quality of life. Therefore, appropriate management is essential. In this article, the treatment of acute migraine in children and adolescents will be reviewed. Only a few randomized controlled studies have been published and high placebo rates are a major problem for proving superiority of active drugs. Generally, acetaminophen (paracetamol) and ibuprofen are accepted as drugs of first choice, even though the evidence is poor for the former and limited for latter. Among 14 studies on triptans in adolescents, 9 showed some superiority over placebo with respect to pain relief and pain freedom, and among 6 studies in children, 5 suggest some superiority over placebo. Sumatriptan nasal spray and zolmitriptan nasal spray have been approved for adolescents in Europe; almotriptan has been approved for adolescents in the USA, as has rizatriptan for patients aged 6-17 years. A recent study demonstrated the efficacy of a fixed combination of sumatriptan and naproxen in adolescents with migraine. In conclusion, evidence for the pharmacological treatment of acute migraine in children is very poor and evidence for adolescents is better but still limited.

The use of triptans for pediatric migraines

Migraine headaches frequently occur in the pediatric population, with a prevalence of 3% in children 2-7 years of age, 4-11% in children 7-11 years of age, and 8-23% in children 11 years of age and older. Migraine without aura is more than twice as common as migraine with aura in children. Headaches are the third leading cause of emergency room referrals and rank in the top five health problems of children. The 2004 American Academy of Neurology's treatment parameter for migraine in children and adolescents recommended that nasal sumatriptan be considered for acute treatment; however, data were lacking to make a decision regarding the available oral triptans at that time. The more recently released European guidelines discuss three different triptans for use in children but no specific triptan was recommended. Currently, six of the seven available triptans have been studied for efficacy and safety in the pediatric population; however, only a few well controlled clinical studies have been conducted. Sumatriptan has the most available data on outcomes in general, with nasal sumatriptan showing the most positive results. Nasal sumatriptan is approved in children older than 12 years of age in Europe. Oral sumatriptan does not show any clinical benefit versus placebo in children. Rizatriptan and zolmitriptan have conflicting efficacy and safety data, with most studies favoring the use of oral rizatriptan and nasal zolmitriptan. Almotriptan is the first triptan to obtain a US FDA indication in adolescents with migraines lasting 4 or more hours. This approval was based upon two studies, one large clinical trial and one very small, open-label, pilot study. At this time, there are insufficient data to recommend naratriptan and eletriptan for first- or second-line use in pediatric patients with migraines. There are currently no efficacy data for frovatriptan in pediatric patients, which limits its use in this population. Adverse effects of triptans and pharmacokinetic data in children and adolescents are similar to those in adults. The triptan class should be considered as an acute treatment option for children and adolescents with migraines, although their use is mostly 'off-label'. Of the available triptans, there are more positive efficacy data for sumatriptan and zolmitriptan nasal sprays, and rizatriptan and almotriptan tablets than for the other triptans.

Sumatriptan succinate transdermal delivery systems for the treatment of migraine

We have successfully obtained sumatriptan transdermal systems with different polymer compositions: methyl cellulose (MC), polyvinyl pyrrolidone (PVP) and a polyvinyl pyrrolidone (PVP)-polyvinyl alcohol (PVA) mixture. The systems contained 1,2-propylenglycol (MC) or sorbitol as a plasticizer (PVP and PVP-PVA), methacrylate copolymer as an adhesive agent, and an occlusive liner. Azone (5%, w/w) was incorporated into all the systems as a percutaneous enhancer. Transdermal systems are thin, transparent and non-adhesive when in a dry state. The permeation of sumatriptan succinate across pig ear skin was studied using the systems prepared. The formulation with MC polymer produced a statistically significant increment with respect to the PVP and PVP-PVA formulations (p < 0.05). Azone incorporation into the systems produced an increment in the sumatriptan flux values of all three transdermal systems with respect to those of the controls (p < 0.05). In addition, the application of iontophoresis to the wet methyl cellulose-Azone formulation produced a much higher increase of sumatriptan transdermal flux.

Sumatriptan nasal spray in the acute treatment of migraine in adolescents and children

About 4-10% of children and adolescents suffer from migraine. In the last few years, several studies have been performed to assess the efficacy and safety of triptans for the acute treatment of migraine in children and adolescents. Only sumatriptan nasal spray has been approved for the treatment of acute migraine with or without aura in adolescents aged 12-17 years in Europe. This review describes the results of the studies with sumatriptan nasal spray that have been performed in children and adolescents, including a study performed in the Netherlands.

Population pharmacokinetic studies in pediatrics: issues in design and analysis

The current review addresses the following 3 frequently encountered challenges in the design and analysis of population pharmacokinetic studies in pediatrics: (1) body size adjustments during the development of pharmacostatistical models, (2) design and validation of limited sampling strategies, and (3) the integration of historical priors in data analysis and trial simulation. Size adjustments with empiric approaches based on body weight or body surface area have frequently proven as a pragmatic tool to overcome large size differences in a pediatric study population. Allometric size adjustments, however, provide a more mechanistic, physiologically based approach that, if used a priori, allows delineation of the effect of size from that of other covariates that show a high degree of collinearity. The frequent lack of dense data sets in pediatric clinical pharmacology because of ethical and logistic constraints in study design can be overcome with the application of D-optimality-based limited sampling schemes in combination with Bayesian and nonlinear mixed-effects modeling approaches. Empirically based dose selection and clinical trial designs for pediatric clinical pharmacology studies can be improved by applying clinical trial simulation techniques, especially if they integrate adult and pediatric in vitro and/or in vivo data as historic priors. Although integration of these concepts and techniques in population pharmacokinetic analyses is not only limited to pediatric research, their application allows researchers to overcome some major hurdles frequently encountered in pharmacokinetic studies in pediatrics and, thus, provides the basis for additional clinical pharmacology research in this previously insufficiently studied fraction of the general population.