Rivastigmine exposure provided by a transdermal patch versus capsules

In vitro and Ex vivo study targeting the development of a Lavandula stoechas L. (Ustukhuddūs) loaded Unani Transdermal patch: Implication of Unani Medicine in the treatment of Nisyan (Dementia)

Ustukhuddūs (Lavandula stoechas L.) has been extensively used orally and topically in treating various neurological disorders, including dementia. The optimum potential of traditional dosage forms of Ustukhuddūs is limited for various reasons. Transdermal drug delivery system (TDDS) is a novel means of drug delivery and is known to overcome the drawbacks associated with traditional dosage forms. The current study aimed at fabricating and evaluating Ustukhuddūs hydro-alcoholic extract (UHAE) and essential oil (UEO) loaded matrix-type transdermal patches having a combination of hydrophilic - hydroxyl propyl methyl cellulose (HPMC) and hydrophobic - ethyl cellulose (EC) polymers. ATR-FTIR, DSC, XRD, and SEM analysis were carried out to study drug-polymer interactions, confirming the formation of developed patches and drug compatibility with excipients. We assessed the fabricated patches to evaluate their physicochemical properties, in vitro drug release, and permeation characteristics via ex vivo experiments. The physicochemical characteristics of patches showcased the development of good and stable films with clarity, smoothness, homogeneity, optimum flexibility and free from causing skin irritancy or sensitization. In vitro drug release and ex vivo permeation profile of developed patches were evaluated employing Franz diffusion cells. UHAE and UEO patches exhibited a cumulative drug release of 81.61 and 85.24 %, respectively, in a sustained-release manner and followed non-Fickian release mechanisms. The ex vivo permeation data revealed 66.82 % and 76.41 % of drug permeated from UHAE and UEO patches, respectively. The current research suggests that the formulated patches are more suitable for TDDS and hold potential significance in the treatment of dementia, contributing to enhanced patient compliance, thereby highlighting the implication of Unani Medicine in Nisyan (Dementia) treatment.

Rivastigmine for the management of anticholinergic delirium

INTRODUCTION

Anticholinergic agents are commonly taken in overdose, often causing delirium. The spectrum of anticholinergic delirium ranges from mild agitation to severe behavioural disturbance. Physostigmine is an effective treatment for anticholinergic delirium, but its availability is limited. As rivastigmine is readily available, it has been used to manage anticholinergic delirium; however, there is limited research investigating its use.

METHOD

This was a retrospective review of patients with anticholinergic delirium treated in two toxicology units with rivastigmine (oral capsule or transdermal patch) from January 2019 to June 2023. The primary outcome was the use of further parenteral treatment (sedation or physostigmine) for delirium post rivastigmine administration.

RESULTS

Fifty patients were administered rivastigmine for the management of anticholinergic delirium. The median age was 36 years (interquartile range: 25-49 years) and 27 (54 per cent) were females. Features consistent with anticholinergic toxicity included tachycardia in 44 (88 per cent) and urinary retention requiring catheterisation in 40 (80 per cent). Forty-three patients (86 per cent) were treated with physostigmine before rivastigmine administration. Twenty-two were managed with transdermal rivastigmine (most commonly 9.5 mg/24 hour patch), and 28 with oral rivastigmine 6 mg. Further parenteral sedation and/or physostigmine treatment were required more often in patients given transdermal than oral rivastigmine [16/22 (73 per cent) versus 9/28 (32 per cent), P = 0.010)]. No patients had bradycardia or gastrointestinal symptoms following rivastigmine administration. One patient with a history of epilepsy had a seizure, 1.5 hours post physostigmine administration and 7 hours post transdermal rivastigmine.

DISCUSSION

Rivastigmine has been increasingly used for the management of patients with anticholinergic delirium, due to the lack of availability of physostigmine. In this case series, rivastigmine transdermal patch appeared to be less effective than oral rivastigmine capsules, likely due to its slow onset of action and/or insufficient dose.

CONCLUSION

Rivastigmine can be used to treat anticholinergic delirium. In our case series oral rivastigmine appeared more effective than transdermal rivastigmine.

Evaluation of rivastigmine in Alzheimer's disease

Dementia is the major cause of mortality and morbidity in older adults, with Alzheimer's disease (AD) being the most common cause. AD has a significant impact on economic and psychosocial status. Cholinesterase inhibitors (ChEIs) are currently the mainstay in the management of AD. Rivastigmine is the only ChEI that inhibits both acetylcholinesterase and butyrylcholinesterase enzymes in the brain. This dual inhibition makes it potentially more effective for AD patients. Its availability as both a transdermal formulation and oral capsule, may improve adherence rates and care giver satisfaction compared with other ChEIs. To date, the data from randomized clinical trials and post marketing observational studies have shown evidence for an impact on cognitive functions in AD with good safety and tolerability.

Rivastigmine in Parkinson's Disease Dementia with Orthostatic Hypotension

OBJECTIVE

The purpose of this study was to evaluate if the cognitive benefit of rivastigmine is affected by the presence of orthostatic hypotension (OH) in patients with Parkinson's disease dementia (PDD).

METHODS

We conducted a post hoc analysis on 1,047 patients with PDD from 2 randomized controlled trials comparing rivastigmine versus placebo at week 24 (n = 501) and rivastigmine patch versus capsule at week 76 (n = 546). A drop ≥ 20 mm Hg in systolic blood pressure (SBP) or ≥ 10 in diastolic blood pressure (DBP) upon standing classified subjects as OH positive (OH+); otherwise, OH negative (OH-). The primary end point was the Alzheimer's Disease Assessment Scale - Cognitive subscale (ADAS-Cog) at week 24 and the Mattis Dementia Rating Scale (MDRS) at week 76, using intention-to-treat with retrieved dropout at week 24 and observed cases at week 76, consistent with the original analyses.

RESULTS

Overall safety was comparable between OH+ (n = 288, 27.5%) and OH- (n = 730, 69.7%), except for higher frequency of syncope (9.2%) in the OH+ placebo arm. The placebo-adjusted effect of rivastigmine on ADAS-Cog at week 24 was 5.6 ± 1.2 for OH+ and 1.9 ± 0.9 in OH- (p = 0.0165). Among subjects with OH, the MDRS change from baseline at week 76 was higher for rivastigmine capsules versus patch (10.6 ± 2.9 vs -1.5 ± 3.0, p = 0.031). The overall prevalence of OH was lower for rivastigmine than placebo at week 24 (28.3% vs 44.6%, p = 0.0476).

INTERPRETATION

The cognitive benefit from rivastigmine is larger in patients with PDD with OH, possibly mediated by a direct antihypotensive effect. ANN NEUROL 2021;89:91-98.

Efficacy of acetylcholinesterase inhibitors in Alzheimer's disease

Alzheimer's disease (AD), the most common cause of adult-onset dementia is characterized by a progressive decline of cognitive functions accompanied by behavioral manifestations. The main class of drugs currently used for the treatment of AD are acetylcholinesterase/cholinesterase inhibitors (ChE-Is). The first ChE-I licensed for symptomatic treatment of AD was tacrine. The ChE-Is currently available in the market are donepezil, rivastigmine and galantamine as tacrine is no longer in use, due to its hepatotoxicity. According to mechanism of action the ChE-Is are classified as short-acting or reversible agents such as tacrine, donepezil, and galantamine, as intermediate-acting or pseudo-irreversible agent such as rivastigmine. Overall, the efficacy of the three ChE-Is available in the market is similar and the benefit of administration of these compounds is mild and may not be clinically significant. Due to gastrointestinal side effects of these drugs, medicinal chemistry and pharmaceutical delivery studies have investigated solutions to improve the pharmacological activity of these compounds. In spite of the limited activity of ChE-Is, waiting for more effective approaches, these drugs still represent a pharmacotherapeutic resource for the treatment of AD. Other approaches in which ChE-Is were investigated is in their use in combination with other classes of drugs such as cholinergic precursors, N-methyl-d-aspartate (NMDA) receptor antagonists and antioxidant agents. After many years from the introduction in therapy of ChE-Is, the combination with other classes of drugs may represent the chance for a renewed interest of ChE-Is in the treatment of adult-onset dementia disorders.

Pharmacokinetic Evaluation by Modeling and Simulation Analysis of a Donepezil Patch Formulation in Healthy Male Volunteers

Introduction

This study characterized the pharmacokinetics (PKs) of a donepezil patch formulation currently under development, using mixed effect modeling analysis, and explored optimal patch dosing regimens in comparison with the donepezil oral formulation.

Methods

PK data used in this analysis were from 60 healthy Korean male subjects participating in two Phase I studies, where subjects received single or multiple doses of donepezil of 43.75, 87.5, and 175 mg via patches, and 12 of them received a single oral dose of 10 mg of donepezil, followed by a single dose of donepezil via a patch. Donepezil PKs were analyzed by nonlinear mixed effect modeling using NONMEM software.

Results

A well-stirred model with two-compartment distribution and delayed absorption was chosen as the best model for the oral formulation. The PKs of donepezil after the patch applications were best described by a two-compartment linear model with zero-order absorption (D2) and absorption delay. The relative bioavailability (BA) of donepezil after the patch application compared with oral dosing was described to be affected by the duration of patch application.

Conclusion

PK simulations based on the chosen PK models suggested that, overall, donepezil exposure in plasma is similar whether with 10 mg of oral donepezil every 24 h or a 175 mg patch every 72 h, and likewise with 5 mg of oral donepezil every 24 h or an 87.5 mg patch every 72 h.

An update on the utility and safety of cholinesterase inhibitors for the treatment of Alzheimer's disease

Introduction: Alzheimer's disease (AD) is the most common cause of major neurocognitive disorders with a prevalence in the US of about 5.7 million in 2018. With the disease burden projected to increase dramatically in the coming years, it is imperative to review the current available treatment regimens for their safety and utility. The cholinesterase inhibitors (ChEIs) have continued to play a pivotal role in managing the symptoms and possibly slowing the rate of progression of AD since 1993. Owing to their being a mainstay in the treatment of AD, the safety and efficacy of prescribing these drugs needs to be reviewed often, especially with the approval of new formulations and doses.Areas covered: The three ChEIs currently approved by the FDA are donepezil, rivastigmine and galantamine. This article will review the safety and tolerability of these ChEIs and analyze the potential disease modifying properties of these drugs. The authors have reviewed all recent literature including review articles, meta-analyzes, clinical trials and more.Expert opinion: These ChEIs differ subtly in their mechanisms of action, in their tolerability and safety and FDA-approved indications. All are considered first-line, symptomatic treatments of the various phases of AD and may even have potentially disease-modifying effects.

Percutaneous penetration of drugs applied in transdermal delivery systems: an in vivo based approach for evaluating computer generated penetration models

Human skin is a viable pathway for administration of therapeutics. Transdermal delivery systems (TDS) have been approved by the US-FDA since 1981. To enable the risk assessment of dermal exposure, predictive mathematical models are used. In this work the accuracy of predicted flux of the models is compared to experimental human in vivo data of drugs applied in US-FDA approved TDS. A database of pharmacokinetic data of drugs applied in TDS was used and updated. Three mathematical models (QSAR) were used to calculate predicted fluxes, and compared to the human in vivo data. For more than half of the drugs applied in TDS, the predicted flux by the mathematical models was an underestimation compared to the flux calculated with the experimental in vivo data. The flux was over- or underestimated by a factor 10-100. All mathematical models were significantly correlated with the experimental in vivo data. The process of percutaneous penetration has several influencing factors, TDS minimize some of these factors. Limitations are discussed. Further research is needed, with a focus on validation and standardization of the permeability coefficient. This work offers observations that should give a stimulus for refinement on the appropriate usage and limitations of mathematical models.

Skinfold thickness for rivastigmine patch application in Alzheimer's disease

RATIONALE

Rivastigmine patches are used for patients with Alzheimer's disease (AD), but little is known about the serum concentration of rivastigmine and its metabolite or clinical adherence in relation to skinfold thickness after rivastigmine patch application.

OBJECTIVES

The aim of this study was to examine the association between rivastigmine and NAP 226-90 serum concentration and skinfold thickness and to determine the appropriate skinfold thickness for the use of rivastigmine patch in patients with AD.

METHODS

Patients with AD who continuously used rivastigmine patches (4.6 mg/24 h, 5 cm²) for more than 6 months were recruited. The serum concentrations of rivastigmine and NAP 226-90 were measured. Skinfold thickness was measured using a Lange Skinfold Caliper.

RESULTS

In total, 91 patients with AD (40 men and 51 women) participated in this study on skinfold thickness measurement. Among them, 27 patients were examined for rivastigmine and NAP 226-90 serum concentrations, with mean concentrations of 1.0 ± 0.6 ng/mL and 3.6 ± 3.6 ng/mL, respectively. The skinfold thickness in the subscapular area was significantly negatively correlated with the NAP 226-90 serum concentration (Spearman's rank correlation coefficient = - 0.47, P = .01). In addition, patients with AD and a subscapular skinfold thickness of ≥25 mm exhibited a significantly high risk of decreased Mini-Mental Status Examination score and nonadherence to a rivastigmine patch (odds ratio 3.00; 95% confidence interval = 1.076-8.366, P = .03).

CONCLUSIONS

Subscapular skinfold thickness was significantly negatively correlated with the NAP 226-90 serum concentration and may be considered an appropriate predictor of response and adherence to clinical application of a rivastigmine patch.

An update on the safety of current therapies for Alzheimer's disease: focus on rivastigmine

Alzheimer's disease (AD) is the most common cause of major neurocognitive disorders worldwide. Despite all research efforts, therapeutic options for AD are still limited to two drug classes: cholinesterase inhibitors (ChEIs) and the NMDA-receptor antagonist memantine. Donepezil, rivastigmine and galantamine are the three ChEIs FDA-approved as first-line treatment for AD. Although they share the same mode of action, they differ in terms of their pharmacologic characteristics and route of administration, which can impact their safety and tolerability profile. Rivastigmine, available in both oral and transdermal patch formulations, is a slowly reversible dual inhibitor of acetyl and butyryl cholinesterase, selective for the G1 isoform of acetylcholinesterase, without hepatic metabolism by the CYP-450 system. Despite its unique features, it has been associated with a higher incidence of adverse events in comparison to other ChEIs. The oral form, approved for the treatment of mild to moderate AD, is associated with a higher incidence of gastrointestinal side effects. The transdermal patch formulation approved for use across all stages of AD has been shown to have a better tolerability profile in comparison to both the oral form and even other ChEIs. One important tolerability concern is adverse dermatologic reactions, which are mostly benign, and can be either preventable or manageable. One important safety concern is the risk of treatment overdose by administering multiple patches at the same time, potentially leading to fatal outcomes. This can be prevented by educating patients and caregivers about the proper use of the patch. The goal for the future would be to optimize the patch formulation to increase both efficacy and safety.

Rivastigmine: the advantages of dual inhibition of acetylcholinesterase and butyrylcholinesterase and its role in subcortical vascular dementia and Parkinson's disease dementia

Several studies have demonstrated clinical benefits of sustained cholinesterase inhibition with rivastigmine in Alzheimer's disease (AD) and Parkinson's disease dementia (PDD). Unlike donepezil and galantamine that selectively inhibit acetylcholinesterase (AChE; EC 3.1.1.7), rivastigmine is a unique cholinesterase inhibitor with both AChE and butyrylcholinesterase (BuChE; EC 3.1.1.8) inhibitory activity. Rivastigmine is also available as transdermal patch that has been approved by the US Food and Drug Administration for the treatment of mild, moderate, and severe AD as well as mild-to-moderate PDD. In this review, we explore the role of BuChE inhibition in addition to AChE inhibition with rivastigmine in the outcomes of cognition, global function, behavioral symptoms, and activities of daily living. Additionally, we review the evidence supporting the use of dual AChE-BuChE inhibitory activity of rivastigmine as a therapeutic strategy in the treatment of neurological disorders, with a focus on the role of rivastigmine in subcortical dementias such as vascular dementia (VaD) and PDD. Toward this objective, we performed a literature search in PubMed and Ovid with limits to articles published in the English language before June 2016. The available evidence from the literature suggests that the dual inhibition of AChE and BuChE may afford additional therapeutic potential of rivastigmine in subcortical dementias (subcortical VaD and PDD) with benefits on cognition and behavioral symptoms. Rivastigmine was found to specifically benefit executive dysfunction frequently observed in subcortical dementias; however, large randomized clinical studies are warranted to support these observations.

Comparative evaluation of rivastigmine permeation from a transdermal system in the Franz cell using synthetic membranes and pig ear skin with in vivo-in vitro correlation

In the present study, in vitro permeation experiments in a Franz diffusion cell were performed using different synthetic polymeric membranes and pig ear skin to evaluate a rivastigmine (RV) transdermal drug delivery system. In vitro-in vivo correlations (IVIVC) were examined to determine the best model membrane. In vitro permeation studies across different synthetic membranes and skin were performed for the Exelon(®) Patch (which contains RV), and the results were compared. Deconvolution of bioavailability data using the Wagner-Nelson method enabled the fraction of RV absorbed to be determined and a point-to-point IVIVC to be established. The synthetic membrane, Strat-M™, showed a RV permeation profile similar to that obtained with pig ear skin (R(2)=0.920). Studies with Strat-M™ resulted in a good and linear IVIVC (R(2)=0.991) when compared with other synthetic membranes that showed R(2) values less than 0.90. The R(2) for pig ear skin was 0.982. Strat-M™ membrane was the only synthetic membrane that adequately simulated skin barrier performance and therefore it can be considered to be a suitable alternative to human or animal skin in evaluating transdermal drug transport, potentially reducing the number of studies requiring human or animal samples.

Pharmacokinetic Modeling to Simulate the Concentration-Time Profiles After Dermal Application of Rivastigmine Patch

Rivastigmine is an inhibitor of acetylcholinesterases and butyrylcholinesterases for symptomatic treatment of Alzheimer disease and is available as oral and transdermal patch formulations. A dermal absorption pharmacokinetic (PK) model was developed to simulate the plasma concentration-time profile of rivastigmine to answer questions relative to the efficacy and safety risks after misuse of the patch (e.g., longer application than 24 h, multiple patches applied at the same time, and so forth). The model comprised 2 compartments which was a combination of mechanistic dermal absorption model and a basic 1-compartment model. The initial values for the model were determined based on the physicochemical characteristics of rivastigmine and PK parameters after intravenous administration. The model was fitted to the clinical PK profiles after single application of rivastigmine patch to obtain model parameters. The final model was validated by confirming that the simulated concentration-time curves and PK parameters (Cmax and area under the drug plasma concentration-time curve) conformed to the observed values and then was used to simulate the PK profiles of rivastigmine. This work demonstrated that the mechanistic dermal PK model fitted the clinical data well and was able to simulate the PK profile after patch misuse.

A pilot randomized controlled trial evaluating an integrated treatment of rivastigmine transdermal patch and cognitive stimulation in patients with Alzheimer's disease

OBJECTIVE

To evaluate in a pilot single-blind randomized controlled clinical trial the efficacy of an integrated treatment with rivastigmine transdermal patch (RTP) and cognitive stimulation (CS) in Alzheimer's disease (AD) patients at 6-month follow-up.

METHODS

We enrolled 90 patients with an age ≥65 years admitted to the outpatient Alzheimer's Evaluation Unit with diagnosis of AD. Patients were randomized to enter in the Group-1 (RTP + CS) or in the Group-2 (RTP). All patients at baseline and after 6 months were evaluated with the following tools: Mini Mental State Examination (MMSE), Clinical Dementia Rating (CDR), Hamilton Rating Scale for Depression (HAM-D), Geriatric Depression Scale (GDS-15), Neuropsychiatric Inventory (NPI), Neuropsychiatric Inventory-Distress (NPI-D), and a standardized Comprehensive Geriatric Assessment, including also activities of daily living (ADL), instrumental activities of daily living (IADL), and the Mini Nutritional Assessment (MNA). Mortality risk was assessed using the Multidimensional Prognostic Index (MPI).

RESULTS

At baseline no significant difference was shown between the two groups. After 6 months of follow-up, there were significant differences between Group-1 and Group-2 in: MMSE: +6.39% vs. +2.69%, CDR: +6.92% vs. +1.54%, HDRS-D = -60.7% vs. -45.8%, GDS: -60.9% vs. -7.3%, NPI: -55.2% vs. -32.7%%, NPI-D: -55.1% vs. -18.6%, ADL: +13.88% vs. +5.95%, IADL: +67.59% vs. +18.28%, MNA: +12.02% vs. +5.91%, and MPI: -29.03% vs. -12.90%.

CONCLUSION

The integrated treatment of RTP with CS in AD patients for 6 months improved significantly cognition, depressive and neuropsychiatric symptoms, functional status, and mortality risk in comparison with a group of AD patients receiving only RTP.

Single dose pharmacokinetics of the novel transdermal donepezil patch in healthy volunteers

Background

Donepezil is an acetylcholinesterase inhibitor indicated for Alzheimer’s disease. The aim of this randomized, single-blind, placebo-controlled, single-dose, dose-escalation study was to investigate the safety, tolerability, and pharmacokinetics of the donepezil patch in healthy male subjects.

Methods

Each healthy male subject received a single transdermal donepezil patch (72 hours patch-on periods) of 43.75 mg/12.5 cm², 87.5 mg/25 cm², or 175 mg/50 cm². Serial blood samples were collected up to 312 hours after patch application. The plasma concentrations of donepezil were determined by using a validated liquid chromatography–tandem mass spectrometry method. Pharmacokinetic parameters were obtained by noncompartmental analysis. Tolerability of the patches and performance of the patches (adhesion, skin irritation, residual donepezil content in the patch) were assessed throughout the study.

Results

The study was completed by 36 healthy subjects. After patch application, the maximal plasma donepezil concentration (C_max) and the area under the curve (AUC) increased in a dose-proportional manner. Median time to C_max was ~74–76 hours (~2–4 hours after patch removal), and mean t_1/2β was ~63.77–93.07 hours. The average donepezil residue in the patch after 72 hours was ~73.9%–86.7% of the loading dose. There were neither serious adverse events nor adverse events that lead to discontinuation. Skin adhesion of the patch was good in 97.2% of the subjects. All skin irritations after patch removal were mild and were resolved during the study period.

Conclusion

The donepezil patch appeared to be generally well tolerated and adhesive. Pharmacokinetic analysis of the donepezil patch demonstrated linear kinetics.

[Characteristics of the clinical picture and treatment of moderate or severe Alzheimer's disease]

Alzheimer's disease (AD) is the most frequent cause of dementia and one of the most frequent disease in elderly patients. Pathomorphological data have demonstrated that AD is a sole cause in 40% of patients with dementia and in about 15-20% of cases with vascular comorbidity. We consider the evolution of cognitive and mental disorders in moderate and severe stages of AD and describe new approaches to treatment of late AD stages using high doses of cholinesterase inhibitors (in particular, a new form of rivastigmine transdermal system (15 cm2) releasing 13,3 mg of active substance per day), and combinations of cholinesterase inhibitors and memantine with non-pharmacological correction of behavioral disorders the clinical assessment of treatment efficacy. Attention is drawn to the formation of the adequate level of expectations in caregivers.

Rivastigmine from capsules to patch: therapeutic advances in the management of Alzheimer's disease and Parkinson's disease dementia

OBJECTIVE

To discuss the pharmacology, mechanism of action, and chemical properties of the cholinesterase inhibitor (ChEI) rivastigmine; to provide a rationale for transdermal delivery and supportive clinical data, along with practical guidance on rivastigmine patch use in Alzheimer's disease and Parkinson's disease dementia.

DATA SOURCES

Pivotal studies of rivastigmine capsules and patch were identified using PubMed and the rivastigmine US prescribing information. PubMed searches were performed in 2013 using rivastigmine as a keyword.

STUDY SELECTION

English-language articles related to rivastigmine considered of relevance to primary care physicians were included.

DATA SYNTHESIS

Pharmacologic differences exist between rivastigmine and ChEIs. Clinical studies demonstrate symptomatic efficacy of oral rivastigmine across all stages of Alzheimer's disease and mild-to-moderate Parkinson's disease dementia. However, gastrointestinal adverse events limit access to optimal therapeutic doses. Strategies that lower maximum plasma concentrations (Cmax) and prolong time to Cmax, ie, transdermal delivery, may improve tolerability. Clinical registration studies have demonstrated improved tolerability of rivastigmine 9.5-mg/24-h patch versus 6-mg twice-daily capsules in mild-to-moderate Alzheimer's disease, and a positive benefit-risk profile of 13.3-mg/24-h versus 9.5-mg/24-h patch in patients needing enhanced efficacy. Clinical data comparing 13.3-mg/24-h versus 4.6-mg/24-h patch in severe Alzheimer's disease demonstrated efficacy on cognition and activities of daily living. These data led to approval of rivastigmine patch in severe Alzheimer's disease. Transdermal delivery also has practical advantages, including simple, once-daily administration and a visual indicator of compliance. Potential application site reactions can be minimized and need not be a barrier to treatment.

CONCLUSIONS

In addition to practical advantages, rivastigmine patch may improve clinical outcomes throughout the course of Alzheimer's disease by providing access to high-dose efficacy without compromising tolerability.

Patient adherence to transdermal rivastigmine after switching from oral donepezil: a retrospective claims database study

OBJECTIVE

To examine patient adherence before and after switching from donepezil to the rivastigmine patch.

METHODS

This retrospective cohort study used the MarketScan Commercial and Medicare data sets (2004 to 2009). Patients with a diagnosis of Alzheimer disease who were new donepezil users and were subsequently switched to the rivastigmine patch were included. The proportion of days covered (PDC) and PDC difference between donepezil and the rivastigmine patch were calculated from the time of initiation to the switch, capped at 1 year after the first respective claim. PDC was calculated as the number of days with drugs available divided by the number of days in the respective follow-up periods.

RESULTS

The sample included 772 patients (mean age 77 y; 58% female). The mean time between switching from donepezil to the rivastigmine patch was 579 (SD=317.3) days. The mean PDC for the rivastigmine patch was highest among patients who switched within 3 months (80.4% vs. 90.7%; P=0.04) and within 7 to 9 months (61.3% vs. 71.0%; P=0.05) of initiating donepezil. When adherence was analyzed in increments of 1 year, patients who switched to the rivastigmine patch within the first year of treatment had significantly greater adherence to rivastigmine compared with those who were on donepezil (PDC 69.3% vs. 60.6%; P=0.0004).

CONCLUSIONS

Switching from donepezil to the rivastigmine patch seems to be associated with increased adherence, especially in patients who switched within the first year of initiating donepezil.

A 24-week, randomized, controlled trial of rivastigmine patch 13.3 mg/24 h versus 4.6 mg/24 h in severe Alzheimer's dementia

AIMS

The 24-week, prospective, randomized, double-blind ACTION study investigated the efficacy, safety, and tolerability of 13.3 versus 4.6 mg/24 h rivastigmine patch in patients with severe Alzheimer's disease (AD).

METHODS

Patients had probable AD and Mini-Mental State Examination scores ≥3-≤12. Primary outcome measures were as follows: Severe Impairment Battery (SIB) and AD Cooperative Study-Activities of Daily Living scale-Severe Impairment Version (ADCS-ADL-SIV). Secondary outcomes were as follows: ADCS-Clinical Global Impression of Change (ADCS-CGIC), 12-item Neuropsychiatric Inventory (NPI-12), and safety/tolerability.

RESULTS

Of 1014 patients screened, 716 were randomized to 13.3 mg/24 h (N = 356) or 4.6 mg/24 h (N = 360) patch. Baseline characteristics/demographics were comparable. Completion rates were as follows: 64.3% (N = 229) with 13.3 mg/24 h and 65.0% (N = 234) with 4.6 mg/24 h patch. The 13.3 mg/24 h patch was significantly superior to 4.6 mg/24 h patch on cognition (SIB) and function (ADCS-ADL-SIV) at Week 16 (P < 0.0001 and P = 0.049, respectively) and 24 (primary endpoint; P < 0.0001 and P = 0.025). Significant between-group differences (Week 24) were observed on the ADCS-CGIC (P = 0.0023), not NPI-12 (P = 0.1437). A similar proportion of the 13.3 mg/24 h and 4.6 mg/24 h patch groups reported adverse events (AEs; 74.6% and 73.3%, respectively) and serious AEs (14.9% and 13.6%).

CONCLUSIONS

The 13.3 mg/24 h patch demonstrated superior efficacy to 4.6 mg/24 h patch on SIB and ADCS-ADL-SIV, without marked increase in AEs, suggesting higher-dose patch has a favorable benefit-to-risk profile in severe AD.

Predictors of sustained response to rivastigmine in patients with Alzheimer's disease: a retrospective analysis

OBJECTIVE

The cholinesterase inhibitor rivastigmine is approved for the treatment of mild to moderate Alzheimer's disease. However, it is not possible to predict which individuals will benefit from treatment. This retrospective analysis of an international, 24-week, randomized, double-blind trial aimed to identify the percentage of persons with Alzheimer's disease who have a sustained response with rivastigmine patch, rivastigmine capsules, or placebo; to determine the magnitude of the sustained treatment response; and to investigate baseline patient characteristics predictive of the observed sustained response.

METHOD

Patients who improved on the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and Alzheimer's Disease Cooperative Study-Activities of Daily Living scale (ADCS-ADL) at week 16 and maintained at least the week 16 improvement at week 24 were identified as sustained responders. Treatment differences and baseline predictive factors were assessed in patients demonstrating a 1-, 2-, 3-, 4-, or 5-point sustained improvement. The first patient was screened in November 2003 and the last patient completed the study in January 2006.

RESULTS

More persons with Alzheimer's disease had sustained improvements on the ADAS-cog and ADCS-ADL with rivastigmine versus placebo. Sustained improvements of 4 or 5 points on the ADAS-cog or ADCS-ADL were demonstrated in the 9.5-mg/24-h rivastigmine patch (24% and 36% of patients, respectively) and 12-mg/d capsule groups (28% on both outcome measures). Factors predictive of a sustained response to treatment included baseline Mini-Mental State Examination, ADAS-cog, and ADCS-ADL scores and treatment, country of treatment, and time since first symptom was diagnosed by a physician.

CONCLUSIONS

Understanding factors predictive of sustained cholinesterase inhibitor treatment response should help to optimize Alzheimer's disease management and encourage compliance by allowing more realistic expectations of treatment effects.

3'-R/S-hydroxyvoacamine, a potent acetylcholinesterase inhibitor from Tabernaemontana divaricata

Guided by the acetylcholinesterase inhibiting activity, the bisindole alkaloid 3'-R/S-hydroxyvoacamine was isolated from a stem extract of Tabernaemontana divaricata, a plant used in Thailand in traditional rejuvenation remedies for improving the memory. The structure of the alkaloid was elucidated by extensive use of NMR spectroscopy and the complete assignment of the (1)H and (13)C NMR spectra is reported. The alkaloid acted as a non-competitive inhibitor against AChE with an IC50 value of 7.00±1.99 μM. An HPLC method was developed for the quantitative analysis of the AChE inhibitor. It suggested that there was 12.4% (w/w) of 3'-R/S-hydroxyvoacamine in the alkaloid enriched fraction of T. divaricata stem.

Two cases of Alzheimer's disease showing deterioration of behavioral and psychological symptoms of dementia induced by switching from rivastigmine to donepezil

Rivastigmine, galantamine, and memantine, in addition to donepezil, which has been on the market over 10 years, have been available for the treatment of Alzheimer's disease (AD) since 2011 in Japan, leading a new stage in the medical treatment of AD. We studied two AD patients showing sudden deterioration of behavioral and psychological symptoms of dementia (BPSD) associated with switching from rivastigmine to donepezil after the clinical trial of rivastigmine. In the patients, rivastigmine seemed to be more beneficial than donepezil for the control of BPSD. Although It was not obvious whether their different responses to the two cholinesterase inhibitors were due to the different pharmacological profiles, ie, the presence of inhibition of butyrylcholinesterase in rivastigmine, a particular cholinesterase inhibitor might be more effective in particular AD cases. Further investigations are needed to confirm the difference, and to identify the measures for selecting the most appropriate medication for each AD patient.

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 patches for the treatment of neurologic conditions in elderly patients: a review

OBJECTIVE

The mode of drug delivery can be an important consideration in optimizing drug therapy, as it can affect treatment compliance and outcomes. It is particularly important to develop optimal drug formulations for chronic diseases or conditions in the elderly for which treatment compliance is known to be low. In this review, the features and benefits of transdermal formulations for treating neurologic conditions in elderly patients are described.

DATA SOURCES

English-language articles were identified by searching MEDLINE in November 2010 (there were no search parameters on date of publication) using the search terms transdermal patch, transdermal system, neurology, rivastigmine, rotigotine, selegiline, lidocaine, capsaicin, compliance, and neuropathic pain.

DATA SELECTION

Articles describing the development, use, efficacy, and safety of licensed transdermal patch treatments for neurologic conditions that affect the elderly were included.

DATA EXTRACTION

The features of transdermal systems and comparisons between transdermal and oral formulations for the treatment of specific neurologic conditions in elderly patients were reviewed.

DATA SYNTHESIS

There are 5 transdermal patch systems currently available for neurologic conditions in adults: rivastigmine, rotigotine, selegiline, lidocaine, and capsaicin. These are all modern formulations in matrix patches, developed to provide appropriate drug dosage in an acceptable and well-tolerated form.

CONCLUSIONS

Transdermal patches can offer benefits to patients over oral formulations in terms of ease of use, simple treatment regimens, avoidance of the first-pass effect, and avoidance of high maximum plasma concentrations with rapid changes in drug levels, without the invasive procedures associated with intravenous treatment.

Safety and tolerability of rivastigmine transdermal patch formulation in newly diagnosed patients with Alzheimer's dementia in naturalistic conditions

AIM

The majority of available data on safety and tolerability issues regarding cholinesterase inhibitors used for the treatment of Alzheimer's disease has been available for orally administered formulations. The objective of this prospective, 24 week, observational, non-interventional post-marketing surveillance study was to evaluate the safety and tolerability, as well as the efficacy, of the rivastigmine transdermal patch formulation in newly diagnosed patients with Alzheimer's dementia in naturalistic conditions.

METHODS

Safety and tolerability assessment included the monitoring and recording of adverse events and withdrawals at any time during the study. The efficacy parameter was determined based on the score of the Mini-Mental State Examination.

RESULTS

Out of the 433 patients, 11 patients (2.54%) suffered serious adverse events. Non-serious adverse events were reported in 179 patients (41.34%). As adverse event is defined as any untoward medical occurrence that may present during treatment with a pharmaceutical product but that does not necessarily have a causal relationship with this treatment. The most common adverse event in the present study was a decline in the Mini-Mental State Examination score in 97 patients (22.40%). The second most common non-serious adverse event was a skin reaction in 61 patients (14.09%). Treatment with rivastigmine continued in 139 cases (32.10%) and was discontinued in 40 cases (9.24%). The median Mini-Mental State Examination score observed at the time of inclusion was 21.0, and after 6 months, it was 22.0 (W 63441; P < 0.001). Because of several limitations, the open-label design of the present study necessitates caution when interpreting the results.

CONCLUSIONS

The results of this study suggest that the rivastigmine transdermal patch is safe and tolerable for Alzheimer's dementia patients in naturalistic conditions.

Interindividual variation in transdermal and oral drug deliveries

It is generally assumed that the topical absorption of drugs is subject to more interindividual variation than the oral absorption of drugs. To date, we are unaware of any clinical studies or meta-analyses that compare the interindividual variation of transdermal and oral drug deliveries for a large number of medications. In this research article, the absorption data for 10 medications that can be used as an oral medication or a transdermal patch were compiled, and from the collected data, the interindividual variance was calculated for topical and oral absorption as an overall average and by drug. This research article also briefly reviews the pharmacokinetics and pharmacodynamics of transdermal and oral drug absorption. Our results indicate that there is considerable interindividual variation in topical and oral absorption for the 10 medications investigated. Yet, surprisingly, the calculated overall mean and median coefficient of variation (CV) for topical and oral absorption were comparable (within 10% of each other). Therefore, the interindividual variation in topical and oral absorption may not be as divergent as assumed previously. In a drug-by-drug comparison, certain medications demonstrated considerably more variation when absorbed orally versus topically and vice versa. It is unclear why certain drugs had less variation in absorption when delivered topically versus orally (or vice versa). However, patterns in drug molecular weight (MW) or octanol partition coefficient (log K(OCT) ) could not totally explain these findings. In our analysis, the previously reported correlation between MW or log K(OCT) and interindividual variation in absorption could only be replicated when plotting the topical absorption CV and MW. What became clear from our analysis is that the drug itself is an important variable when considering which route of delivery (oral or topical) will provide the least amount of interindividual variation. Our study had many limitations because of study design, which may have affected our calculations and conclusions. Further experimentation is needed to support and reveal the basic science of skin or drug chemistry that can further explain these findings.

Inhibition of cholinesterase by essential oil from food plant

Inhibition of cholinesterase has attracted much attention recently because of its potential for the treatment of Alzheimer's disease. In this work, the anticholinesterase activities of plant oils were investigated using Ellman's colorimetric method. The results indicate that essential oils obtained from Melissa officinalis leaf and Citrus aurantifolia leaf showed high acetylcholinesterase and butyrylcholinesterase co-inhibitory activities. C. aurantifolia leaf oil revealed in this study has an IC(50) value on acetylcholinesterase and butyrylcholinesterase of 139 ± 35 and 42 ± 5 μg/ml, respectively. GC/MS analysis revealed that the major constituents of C. aurantifolia leaf oil are monoterpenoids including limonene, l-camphor, citronellol, o-cymene and 1,8-cineole.

Association of skin with the pathogenesis and treatment of neurodegenerative amyloidosis

Amyloidosis are a large group of conformational diseases characterized by abnormal protein folding and assembly which results in the accumulation of insoluble protein aggregates that may accumulate systemically or locally in certain organs or tissue. In local amyloidosis, amyloid deposits are restricted to a particular organ or tissue. Alzheimer’s, Parkinson’s disease, and amyotrophic lateral sclerosis are some examples of neurodegenerative amyloidosis. Local manifestation of protein aggregation in the skin has also been reported. Brain and skin are highly connected at a physiological and pathological level. Recently several studies demonstrated a strong connection between brain and skin in different amyloid diseases. In the present review, we discuss the relevance of the “brain–skin connection” in different neurodegenerative amyloidosis, not only at the pathological level, but also as a strategy for the treatment of these diseases.

Topically administered Risedronate shows powerful anti-osteoporosis effect in ovariectomized mouse model

We investigated the therapeutic effect of topical Risedronate (RIS) on a mouse model of estrogen-deficient osteoporosis. Fourteen-week-old female mice were ovariectomized and assigned to 4 groups: SHAM-operated (SHAM), OVX mice treated with vehicle (OVX-V), OVX mice treated with 0.2% RIS (OVX-0.2% RIS), and OVX-mice treated with 0.02% RIS (OVX-0.02% RIS). Topical samples containing RIS were prepared in 10% (w/w) polyethylene glycol (PEG, MW 400) and 80 μg of sample was spread on the mice's mid-backs every 3 days for 5 weeks. Micro-CT analysis of femora demonstrated that OVX-0.2% RIS exhibited a 29% greater bone mineral density and 24% greater bone volume fraction than that of OVX-V group. Investigation of the trabecular bone in OVX-0.2% RIS revealed a 24% higher bone volume (BV/TV), 51% higher trabecular number (Tb.N), and 40% lower trabecular separation (Tb.Sp) compared to OVX-V mice. Additionally, bone phenotypes of tibiae were further confirmed by histological analysis. OVX-0.2% RIS group exhibited a 494% greater BV/TV, 464% less Tb.Sp, 81% greater active osteoclast surface (Oc.S/BS) and 26% less osteoclast number (N.Oc/BS) than that of OVX-V group. Collectively, these results indicated that topical delivery of RIS has powerful pharmaceutical effects on the prevention of osteoporosis and bone turnover.

Rivastigmine transdermal patch and capsule in Alzheimer's disease: influence of disease stage on response to therapy

OBJECTIVES

The cholinesterase inhibitor rivastigmine is approved for the symptomatic treatment of mild to moderate Alzheimer's disease (AD). This exploratory, hypothesis-forming analysis assessed response to rivastigmine according to severity of dementia at baseline.

METHODS

This was a retrospective analysis of a large randomized, placebo-controlled trial (ENA713D2320). AD patients treated with 9.5 mg/24 h rivastigmine patch, 17.4 mg/24 h rivastigmine patch, rivastigmine capsule (12 mg/day), or placebo were stratified according to baseline Mini-Mental State Examination (MMSE) scores: ≥7 to ≤12 (severe disease), ≥13 to ≤15 (moderately severe), ≥16 to ≤18 (moderate), or ≥19 to ≤25 (mild to moderate). Changes from baseline at Week 24 on Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog), Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC), and Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) were assessed.

RESULTS

Based on baseline MMSE scores, 141, 228, 333, and 348 patients had severe, moderately severe, moderate, and mild to moderate dementia. Worsening of ADAS-cog, ADCS-CGIC, and ADCS-ADL scores in patients receiving placebo were greater in patients with more severe dementia. Significant improvements versus placebo were seen with rivastigmine patch and/or capsule on ADAS-cog, ADCS-CGIC, and ADCS-ADL scores in patients with severe, moderately severe, and moderate AD (all p < 0.05). However, no significant improvements were seen in rivastigmine-treated patients with mild to moderate AD.

CONCLUSIONS

Rivastigmine benefits AD patients across dementia stages. Similar to previous cholinesterase inhibitor studies, greatest treatment effects with rivastigmine patch and capsule were seen in patients with more advanced dementia, most likely driven by greater placebo decline in this population.

A 24-week, multicentre, open evaluation of the clinical effectiveness of the rivastigmine patch in patients with probable Alzheimer's disease

BACKGROUND

Cholinesterase inhibitors form the mainstay of treatment for persons with mild-to-moderate Alzheimer's disease (AD). The rivastigmine patch may increase compliance and the proportion of patients maintaining an efficacious dose compared with oral cholinesterase inhibitors.

OBJECTIVE

To investigate the proportion of patients who reached and maintained the target rivastigmine patch dose compared with the target rivastigmine capsule dose reported in clinical trials.

METHODS

This was a multicentre, 24-week, open-label study in persons with probable AD and a Mini-Mental State Examination (MMSE) score of ≥ 10 and ≤ 26. The primary outcome was the proportion of patients (ITT population) treated with 9.5 mg/24 h rivastigmine patch for at least 8 weeks at week 24. Secondary outcomes included week 24 MMSE, Alzheimer's Disease Cooperative Study-Clinical Global Impression of Change (ADCS-CGIC), Trail Making Test Part A (TMT-A) and Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scores.

RESULTS

Overall, 208 participants received treatment and 155 (74.5%) completed the study. Within the ITT population, 147/182 patients (80.8%; 95% CI 75.0-86.5%) were treated for at least 8 weeks with the 9.5 mg/24 h rivastigmine patch; 135/182 patients (74.2%; 95% CI 67.8-80.5%) were treated for at least 8 weeks and completed the study. The most common adverse events were nausea (10.1% of patients), erythema (8.7%), pruritus (8.2%) and vomiting (7.2%). At week 24, patients treated with the rivastigmine patch showed improvements on MMSE, ADCS-ADL, ADCS-CGIC and TMT-A scores. Caregivers reported acceptance, preference and satisfaction with the patch.

CONCLUSION

Transdermal delivery may allow more patients to reach and maintain therapeutic doses of rivastigmine compared with oral rivastigmine.

A 24-week, randomized, double-blind, placebo-controlled study to evaluate the efficacy, safety and tolerability of the rivastigmine patch in Japanese patients with Alzheimer's disease

Background

As of 2010, the rivastigmine patch was licensed for the treatment of Alzheimer's disease (AD) in 64 countries.

Methods

This 24-week, multicenter, randomized, double-blind, placebo-controlled study evaluated the efficacy, safety and tolerability of the 5-cm² (9-mg loading dose; 4.6 mg/24 h delivery rate) and 10-cm² (18-mg loading dose; 9.5 mg/24 h delivery rate) rivastigmine patch in Japanese patients with AD.

Results

In the primary analysis population (intent-to-treat last observation carried forward) at week 24, delayed deterioration was seen with the 10-cm² patch versus placebo on the Japanese version of the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-J cog; p = 0.005) and the Japanese version of the Clinician's Interview-Based Impression of Change plus Caregiver Input (CIBIC plus-J; p = 0.067). Participants receiving the rivastigmine patch showed numerically less decline versus placebo at week 24 on the CIBIC plus-J, although this did not reach statistical significance. Statistical significance for the CIBIC plus-J was met following adjustment for body weight and baseline Mini-Mental State Examination score as dynamic allocation factors (p = 0.042) and on the Disability Assessment for Dementia (DAD; p = 0.024) and Mental Function Impairment (MENFIS; p = 0.016) subscales. Serious adverse events were rare and were consistent with the known safety profile of the rivastigmine patch. Conclusion: The rivastigmine patch has a favorable efficacy and tolerability profile in Japanese patients with AD.

Assessing the cost-effectiveness of the rivastigmine transdermal patch for Alzheimer's disease in the UK using MMSE- and ADL-based models

OBJECTIVE

Assess long-term cost-effectiveness of rivastigmine patch in Alzheimer's disease (AD) management in the UK, using cognitive and functional models based on clinical trial efficacy data.

METHODS

Incremental costs and Quality Adjusted Life Years (QALYs) associated with rivastigmine patch and capsule treatment versus best supportive care (BSC) were calculated using two economic models, one based solely on Mini-Mental State Examination (MMSE) scores, and one also incorporating activities of daily living (ADL) scores. The clinical pathway was populated with data from a clinical trial of rivastigmine patch (9.5 mg/24 h) and capsules (12 mg/day) versus placebo. Costs were based on the UK health and social care costs and basic UK National Health Service (NHS) prices. Disease progression was modelled beyond the trial period over 5 years using published equations to predict natural decline in AD patients. Base case costing variables included drugs, clinical monitoring, and institutionalization.

RESULTS

The MMSE model estimated incremental costs per QALY of £10 579 for rivastigmine patch and £15 154 for capsule versus BSC. The MMSE-ADL model estimated incremental costs per QALY of £9114 for rivastigmine patch and £13 758 for capsules. The main difference between the models was a greater number of institutionalized days avoided for rivastigmine versus BSC estimated by the MMSE-ADL model.

CONCLUSIONS

Both the MMSE and MMSE-ADL models suggest that rivastigmine patch and capsules are cost-effective treatments versus BSC. Incorporating ADL evidence makes a marginal but important difference to estimates in this case. Future economic evaluations of AD treatment should include measures of both cognition and functioning.

Defining optimal treatment with cholinesterase inhibitors in Alzheimer's disease

Despite growing recognition that Alzheimer's disease (AD) represents a global public health and social care crisis, diagnosis is frequently slow and many patients still receive no treatment at all. Of those who do receive treatment, many remain on lower than recommended doses. The Alzheimer's disease International Global Charter promotes awareness and understanding of AD, stressing the importance of optimal treatment. However, the definition of "optimal treatment" is unclear. Since cholinesterase inhibitors became available nearly 20 years ago, clinicians have developed a variety of protocols on the basis of clinical experiences. This review considers what is optimal for several aspects of cholinesterase inhibitor therapy, taking into account initiation strategies, dosages, modes of drug delivery (e.g., oral vs. transdermal), and treatment durations. Regardless of management approach, individuals with AD, their families, and caregivers have a right to a timely diagnosis and access to best available treatment.

Characterization of potent anticholinesterase plant oil based microemulsion

In the present study, essential oils of three edible Thai plants, Cymbopogon citratus (Gramineae), Citrus hystrix (Rutaceae) and Zingiber cassumunar (Zingiberaceae) were comparatively tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities using Ellman's colorimetric method. C. citratus oil exhibited the highest activity with IC(50) values of 0.34±0.07μl/ml and 2.14±0.18μl/ml against BChE and AChE activity, respectively. It was further investigated whether microemulsions of this oil could be obtained. The effects of type of surfactant and co-surfactant as well as pH and ionic strength on the phase behavior of the oil/water system were investigated. Brij 97, Triton X-114, Tween 20 and Tween 85 were employed as surfactant whereas ethanol and hexanol were used as cosurfactants. The size analysis, electrical conductivity measurements and cholinesterase inhibition assays were done in selected microemulsion. The results revealed that the type and concentration of surfactant and co-surfactant exhibited a distinct influence on the C. citratus oil microemulsions. Moreover, the inhibitory activities of the microemulsion formulation were remarkable.

A prospective study on the use of rivastigmine transdermal patch in Alzheimer's dementia in a routine clinical setting

There is not much published literature on the use of rivastigmine patch in a “routine” clinical setting.

Drug profile: transdermal rivastigmine patch in the treatment of Alzheimer disease

Cholinesterase inhibitors constitute one of the mainstays of treatment of Alzheimer disease (AD). Gastrointestinal side effects, difficulty accessing therapeutic doses and poor patient compliance have been identified as barriers to effective treatment with these substances. The rivastigmine transdermal patch provides continuous delivery of drug through the skin into the bloodstream, avoiding the fluctuations in plasma concentration associated with oral administration. This pharmacokinetic profile is associated with reduced side effects, resulting in easier access to expected target doses. These benefits, along with other practical advantages of the transdermal patch, may contribute to enhanced patient compliance. Here, we present a review of the current literature on rivastigmine patch, and offer advice based on our own collective clinical experience. Rivastigmine patch provides an efficient option for managing patients with AD, to be considered among the first line therapies for the disease.

Switching from oral cholinesterase inhibitors to the rivastigmine transdermal patch

Oral cholinesterase inhibitors (ChEIs) are associated with side effects such as nausea and vomiting. The use of transdermal patches for ChEI delivery may help to minimize these problems. The objective of this review was to consider available data from patients switching from oral ChEIs to transdermal rivastigmine treatment, and to suggest practical guidelines for patients wishing to do this. Literature database and reference list searches were performed to identify suitable publications. Data from two clinical trials and a series of open observational studies, in which patients were switched to the rivastigmine patch from oral rivastigmine, donepezil tablets, or galantamine, were evaluated. Adverse events were tabulated. In the studies reported here, nausea was reported in up to 3.2% and vomiting in up to 1.9% of patients switching to the rivastigmine patch from oral rivastigmine. Similar rates (up to 3.8% of patients for nausea and 0.8% of patients for vomiting) were reported when switching to the rivastigmine patch from donepezil tablets, and no nausea or vomiting was reported in a case study of patients switching to the rivastigmine patch from galantamine tablets. Switching regimes used in clinical trials appeared well tolerated. Data support recommendations for patients on high rivastigmine capsule doses to switch directly to the 9.5 mg/24 h rivastigmine patch, while those on lower oral rivastigmine doses should start on the 4.6 mg/24 h patch for 4 weeks before increasing to the 9.5 mg/24 h patch. This latter regimen is recommended for patients on other oral cholinesterase inhibitors if switching is medically indicated or requested by the patient or the caregiver.

Rivastigmine transdermal system for the treatment of mild to moderate Alzheimer's disease

Today patients with mild to moderate Alzhiemer's disease (AD) have a treatment approach choice: oral or transdermal delivery. The aim of this review was to provide a concise, comprehensive overview of the clinically relevant safety, tolerability and efficacy information available for the rivastigmine transdermal system. Relevant articles were identified through a MEDLINE search of publications in the past 3 years using the terms 'rivastigmine' and 'transdermal' or 'patch'. Efficacy, safety and tolerability of the rivastigmine patch vs. placebo were established in a large, international, 24-week, double-blind, randomised clinical trial and subsequent 28-week open-label extension study. Drug exposure with the 9.5 mg/24 h rivastigmine patch was not significantly different to that provided by an oral capsule dose of 12 mg/day. Most frequently observed adverse events were gastrointestinal. In the primary study, incidences of nausea, vomiting and diarrhoea were: 5%, 3% and 3% respectively in the placebo group; 7%, 6% and 6% in the 9.5 mg/24 h rivastigmine patch group; and 23%, 17% and 5% in the 12 mg/day capsule group. Most patients experienced no, slight or mild application-site skin reactions. De novo patients or those taking oral rivastigmine or donepezil may tolerate a switch to rivastigmine patch. By providing drug exposure that is not significantly different to the highest recommended rivastigmine capsule dose (12 mg/day), with less fluctuation over 24 h, rivastigmine patch offers similar efficacy with an improved tolerability profile. The rivastigmine patch provides a viable treatment option for patients with mild to moderate AD.

Safety and tolerability of rivastigmine transdermal patch compared with rivastigmine capsules in patients switched from donepezil: data from three clinical trials

OBJECTIVES

To compare the safety and tolerability of switching patients with mild-to-moderate Alzheimer's disease from donepezil to either rivastigmine capsule or transdermal patch.

METHODS

Three studies investigated the switch from donepezil to rivastigmine; study US13 was a 26-week, single-arm, immediate-switch study; US18 was a 26-week, sequential cohort study (both studies evaluated rivastigmine capsules 3-12 mg/day); study US38 was a 25-week, randomised, parallel-group, open-label study which investigated switch (immediate or after 7 days' withdrawal) from donepezil to rivastigmine transdermal patch (4.6 mg/24 hr). Safety outcomes included adverse events (AEs), discontinuations caused by AEs and serious AEs (SAEs).

RESULTS

Patient groups receiving rivastigmine patch (n = 261) or capsules (n = 331) had mean +/- SD ages of 77.3 +/- 8.0 and 78.1 +/- 7.8 years, dementia durations of 3.9 +/- 2.6 and 3.6 +/- 2.2 years and Mini-Mental State Examination scores of 18.3 +/- 4.00 and 17.9 +/- 4.4 respectively. Overall, 184 (70.5%) and 276 (83.4%) patients experienced at least one AE, and 23 (8.8%) and 55 (16.6%) patients experienced an SAE with the rivastigmine patch and capsules respectively. Of the patients who experienced an AE, 10 (3.8%) and 109 (32.9%) experienced nausea, and 11 (4.2%) and 80 (24.1%) experienced vomiting with the rivastigmine patch and capsules respectively. Discontinuations because of AEs occurred in 64 (19.3%) patients receiving capsules and 38 (14.6%) patients in the transdermal patch group. The most common reasons for discontinuation with the transdermal patch were application site reaction and disease progression, and nausea and vomiting with the capsules.

CONCLUSIONS

The rivastigmine transdermal patch appears to have better tolerability than rivastigmine capsules, with fewer gastrointestinal AEs and discontinuations because of these AEs. Simple daily rotation of patch location will likely reduce the frequency of skin reactions. This post hoc analysis was carried out by Novartis Pharmaceuticals Corporation. Data for the analysis were collected from the US13 study (CENA713B US13), the US18 study (CENA713B US18) and the US38 study (CENA713D US38).

Rivastigmine in Parkinson's disease dementia

Parkinson's disease has now evolved beyond what was considered to be a traditional motor disorder. It is being increasingly recognized that non-motor symptoms such as cognitive impairment, frank dementia, psychosis, depression, autonomic dysfunction and sleep disturbances are just as integral to the disease spectrum. The cholinergic system has been proposed to play a pivotal role in cognitive dysfunction. Based on interpretation of clinical studies in patients with Alzheimer's, cholinesterase inhibitors have also been studied for dementia associated with Parkinson's disease. Most of these include large and small placebo-controlled studies and several pilot studies have indicated that cholinesterase inhibitors have a favorable effect on cognition, psychiatric symptoms and global function in Parkinson's disease dementia. A large randomized placebo-controlled clinical trial showed that rivastigmine had moderate improvement in dementia associated with Parkinson's disease. The magnitude of effects in terms of scores for the cognitive subscale of the Alzheimer's disease assessment scale and Alzheimer's disease cooperative study-clinicians global impression of change were similar to those observed among patients with Alzheimer's disease who were treated with cholinesterase inhibitors. A transdermal patch which gradually releases rivastigmine over the application period is now available for use in mild to moderate dementia associated with Parkinson's disease and Alzheimer's disease.