Treating attention-deficit/hyperactivity disorder with a stimulant transdermal patch: the clinical art

Implantable and transdermal polymeric drug delivery technologies for the treatment of central nervous system disorders

The complexity of the brain and the membranous blood-brain barrier (BBB) has proved to be a significant limitation to the systemic delivery of pharmaceuticals to the brain rendering them sub-therapeutic and ineffective in the treatment of neurological diseases. Apart from this, lack of innovation in product development to counteract the problem is also a major contributing factor to a poor therapeutic outcome. Various innovative strategies show potential in treating some of the neurological disorders; however, drug delivery remains the most popular. To attain therapeutic drug levels in the central nervous system, large, intolerable systemic doses are generally administered. The major factors responsible for the success maintenance therapy of neurological diseases included controlled and sustained release of neurotherapeutics, reduced frequency of administration, higher bioavailability, and patient compliances. Conventional oral or injectable formulations cannot satisfy all the requirements in many circumstances. This article reviews the therapeutic implantable polymeric and transdermal devices employed in an attempt to effectively achieve therapeutic quantities of drug across the BBB over a prolonged period, to improve patient disease prognosis.

Atomoxetine pharmacogenetics: associations with pharmacokinetics, treatment response and tolerability

Atomoxetine is indicated for the treatment of attention deficit hyperactivity disorder and is predominantly metabolized by the CYP2D6 enzyme. Differences in pharmacokinetic parameters as well as clinical treatment outcomes across CYP2D6 genotype groups have resulted in dosing recommendations within the product label, but clinical studies supporting the use of genotype guided dosing are currently lacking. Furthermore, pharmacokinetic and clinical studies have primarily focused on extensive as compared with poor metabolizers, with little information known about other metabolizer categories as well as genes involved in the pharmacodynamics of atomoxetine. This review describes the pharmacogenetic associations with atomoxetine pharmacokinetics, treatment response and tolerability with considerations for the clinical utility of this information.

Transdermal patches: the emerging mode of drug delivery system in psychiatry

Adherence to prescribed psychiatric and nonpsychiatric medication is a serious issue in people with mental illness that can contribute to poor health outcomes. Some of the factors influencing adherence include side effects of medication and the ease of use. With mental healthcare provision increasingly focusing on a community model of health delivery, there seems to be a renewed interest in addressing complex dilemmas of safety and adherence to treatment. The use of alternative methods of safely delivering medication in innovative ways may resolve some of these difficulties. There has been little discussion about the wider use of transdermal patches in the field of psychiatry in published literature. This article describes the findings from the literature on key principles underlying transdermal delivery strategies, the scope of clinical use in psychiatric illness and explores its challenges and advantages.

Transdermal rivastigmine: management of cutaneous adverse events and review of the literature

Alzheimer's disease is a chronic neurodegenerative disorder resulting in part from the degeneration of cholinergic neurons in the brain. Rivastigmine, a cholinesterase inhibitor, is commonly used as a treatment for dementia due to its ability to moderate cholinergic neurotransmission; however, treatment with oral rivastigmine can lead to gastrointestinal adverse effects such as nausea and vomiting. Transdermal administration of rivastigmine can minimize these adverse effects by providing continuous delivery of the medication, while maintaining the effectiveness of the oral treatment. While the transdermal form of rivastigmine has been found to have fewer systemic adverse effects compared with the oral form, cutaneous reactions, such as contact dermatitis, can lead to discontinuation of the drug in its transdermal form. Lack of patient compliance with regard to applying the patch to the designated site, applying the patch for the correct length of time or rotating patch application sites increases the risk of cutaneous adverse reactions. This article outlines the diagnosis and management of irritant contact dermatitis and allergic contact dermatitis secondary to transdermal rivastigmine. The large majority of reactions to transdermal patches are of an irritant type, which can be diagnosed clinically by the presence of a pruritic, erythematous, eczematous plaque strictly confined to the borders of the patch. In contrast, an allergic reaction can be differentiated by the presence of vesicles and/or oedema, erythema beyond the boundaries of the transdermal patch and lack of improvement of the lesion 48 hours after removal of the offending treatment. By encouraging the patient to follow a regular rotation schedule for the patch, and using lipid-based emollients for irritant dermatitis and pre- and post-treatment topical corticosteroids for allergic dermatitis, cutaneous reactions can often be alleviated and patients can continue with their medication regimen. Other simple changes to a patient's treatment routine, including minimizing the use of harsh soaps, avoiding recently shaven or damaged areas of skin and carefully removing the patch after use, can help to further decrease the risk of dermatitis development.

Evaluating elevated release liner adhesion of a transdermal drug delivery system (TDDS): a study of Daytrana™ methylphenidate transdermal system

BACKGROUND

Complaints from healthcare providers that the adhesive on the Daytrana™ methylphenidate transdermal drug delivery system (TDDS) adhered to the release liner to such an extent that the release liner could not be removed prompted this study. Daytrana™ has a packaging system consisting of a moisture-permeable pouch contained within a sealed tray containing a desiccant; the tray is impermeable to ambient moisture. The objective of this project was to determine if the Daytrana™ packaging system influenced the difficulty in removing the release liner.

METHOD

Both a sealed tray and an open tray containing sealed pouches were placed into an environmental chamber at 25°C and 60% relative humidity for 30 days; afterwards, release liner removal testing using a peel angle of 90° and a peel speed of 300 mm/min was performed.

RESULTS

TDDS from open chamber trays required less force to remove the release liner than did TDDS from closed chamber trays. For the 10 mg/9 h TDDS and the 15 mg/9 h TDDS (the dosages examined), there were substantial differences in release liner removal force between an old lot and a new lot for closed chamber trays but not for open chamber trays.

CONCLUSION

The results demonstrate that for this particular TDDS, storage conditions such as humidity influence release liner adhesion. This project also demonstrates that, to ensure adequate product quality, adhesion needs to become an important design parameter, and the design of a TDDS should consider the ability to remove the release liner under anticipated storage conditions.

Switching from oral extended-release methylphenidate to the methylphenidate transdermal system: continued attention-deficit/hyperactivity disorder symptom control and tolerability after abrupt conversion

OBJECTIVE

To evaluate symptom control and tolerability after abrupt conversion from oral extended-release methylphenidate (ER-MPH) to methylphenidate transdermal system (MTS) via a dose-transition schedule in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

In a 4-week, prospective, multisite, open-label study, 171 children (164 intent-to-treat) with diagnosed ADHD aged 6-12 years abruptly switched from a stable dose of oral ER-MPH to MTS in nominal dosages of 10, 15, 20, and 30 mg using a predefined dose-transition schedule. After the first week on the scheduled dose, the dose was titrated to optimal effect. The primary effectiveness outcome was the change from baseline (while taking ER-MPH) to week 4 in ADHD-Rating Scale-IV (ADHD-RS-IV) total scores. Adverse events (AEs) were assessed throughout the study.

RESULTS

Most subjects (58%) remained on the initial MTS dose defined by the dose-transition schedule; 38% increased and 4% decreased their MTS dose for optimization. MTS dose optimization resulted in significantly better ADHD-RS-IV total (mean +/- SD) scores at week 4 than at baseline (9.9 +/- 7.47 vs. 14.1 +/- 7.48; p < 0.0001). The most commonly reported AEs included headache, decreased appetite, insomnia, and upper abdominal pain. Four subjects (2.3%) discontinued because of application site reactions and three discontinued because of other AEs.

CONCLUSIONS

Abrupt conversion from a stable dose of oral ER-MPH to MTS was accomplished using a predefined dose-transition schedule without loss of symptom control; however, careful titration to optimal dose is recommended. Most AEs were mild to moderate and, with the exception of application site reactions, were similar to AEs typically observed with oral MPH. Limitations of this study included its open-label sequential design without placebo, which could result in spurious attribution of improvement to the study treatment and precluded superiority determinations of MTS over baseline ER-MPH treatment. The apparent superiority of MTS was likely due to more careful titration and clinical monitoring rather than the product itself. ClinicalTrials.gov: NCT00151983.

Practical management of cutaneous reactions to the methylphenidate transdermal system: recommendations from a dermatology expert panel consensus meeting

BACKGROUND

Psychostimulants remain the most-used medications for attention-deficit/hyperactivity disorder (ADHD). The methylphenidate transdermal system (MTS) is the first stimulant patch dosage formulation to be approved by the US Food and Drug Administration for the treatment of the symptoms of ADHD in children aged 6 to 12 years. The MTS patch is approved to be applied once daily to the hip and worn for 9 hours. While cutaneous reactions may occur with any formulation of medication, they are more likely with transdermal administration.

OBJECTIVE

The purpose of this commentary was to describe the types of cutaneous reactions that have been reported with transdermal systems in general, review the cutaneous adverse events seen in clinical trials with the MTS specifically, and provide practical management suggestions for prevention and treatment of these potential cutaneous reactions.

METHODS

In September 2007, a group of child psychiatrists, pediatricians, developmental pediatricians, and pediatric neurologists who treat ADHD and have had experience in their practices with MTS convened to discuss cutaneous reactions in relation to its use. Information collected from this meeting and from the clinical trials database of the sponsor was reviewed by a panel of 3 dermatologic clinical experts in contact dermatitis and 1 pediatric dermatologist. The panel's recommendations form the basis for this report.

CONCLUSIONS

Mild to moderate erythema is a common cutaneous effect with MTS use, and is generally not a cause for discontinuation if seen in isolation. Irritant contact dermatitis is relatively common and can be reduced and treated by alternating patch application sites, moisturizing, gentle skin care, and application of topical corticosteroids at the previous patch sites if needed. Allergic contact dermatitis (ACD) and allergic contact urticaria are rare when MTS is worn as directed in the prescribing information. MTS should be discontinued if ACD is suspected.

Psychopharmacology and preschoolers: a critical review of current conditions

Rates of prescriptions for very young children have increased notably in the last 20 years. These changes have occurred in the context of increasing attention to early childhood mental health, availability of medications perceived to be safer than older medications, application of the medical model to the mental health care of young children, as well as other cultural shifts. Psychopharmacological treatment for any patient, but especially very young children, requires consideration of central nervous system (CNS) and metabolic development and issues of diagnostic validity and should be guided by an empirical literature. In young children, this literature is quite limited. In this article, the authors review developmental issues involved in psychopharmacological treatment and present existing literature and practical guidelines for common preschool diagnoses, recognizing that for some disorders, the extant literature does not support even consideration of medications.

An update on central nervous system stimulant formulations in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

To review recent literature on the different stimulant preparations regarding efficacy and safety in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) and describe advantages and disadvantages of the many available dosage formulations.

DATA SOURCES

Literature retrieval was performed through PubMed/MEDLINE (2005-December 2008) using the terms methylphenidate, amphetamines, central nervous system stimulants, and attention-deficit/hyperactivity disorder. In addition, reference citations from publications identified were reviewed and drug manufacturers were contacted for any possible additional references.

STUDY SELECTION AND DATA EXTRACTION

Double-blind clinical trials found using the search criteria listed above were included for review. Open-label studies and studies prior to 2005 were included if no double-blind trials were published for that formulation within the time period reviewed.

DATA SYNTHESIS

The literature reviewed here demonstrates the efficacy and safety of stimulant medications in children and adolescents with ADHD. However, there are 19 different formulations of stimulants, leading to confusion and errors in prescribing and dispensing of these drugs. Knowing and understanding the advantages and disadvantages of the different formulations can lead to individualized treatment. Formulations like Concerta, Focalin-XR, Adderall-XR, and Vyvanse provide the convenience of once-daily dosing. Each of these provides varying amount of stimulants at different times of the day. Vyvanse has a unique delivery system that may lower the risk of patients abusing their medication. Daytrana gives patients more control over their dosing by being able to choose when the patch is removed; it is also a feasible alternative for children who cannot swallow pills. For patients who cannot swallow tablets or capsules, the capsules of Focalin-XR, Adderall-XR, Metadate-CD, and Ritalin-LA can be opened and sprinkled on applesauce.

CONCLUSIONS

Stimulants are effective medications to treat the symptoms of ADHD. The multiple available dosage forms allow for individualization of treatment.

[What's new about hyperactivity disorder in children?]

This article presents a review of the treatments for children suffering from attention deficit hyperactivity available in France. Multimodal treatment of French hyperactive child includes psycho stimulant medication (short and long acting methylphenidate) and parent training, speech therapy, psychomotor therapy and academic training.