The donepezil transdermal system for the treatment of patients with mild, moderate, or severe Alzheimer’s disease: a critical review

ABSTRACT

Introduction

Cholinesterase inhibitors, along with memantine, are the mainstay of symptomatic treatment for AD (Alzheimer’s disease); however, these medications are typically administered orally, which can be difficult for people with AD and their caregivers.

Areas Covered

In this drug profile and narrative review, the authors trace the development of the new FDA-approved transdermal donepezil. The authors discuss the studies showing its bioequivalence with the oral formulation, including two double-blinded placebo controlled non-inferiority trials. The authors also compare the patch to the only other transdermal cholinesterase inhibitor on the market, rivastigmine, and highlight the potential advantages and disadvantages between these two treatments.

Expert opinion

While the patch is bio-equivalent, it is rather large and may not be affordable for some patients. In addition, there is no high dose (e.g. 23 mg) equivalent. Nevertheless, transdermal donepezil will be useful for people with AD and their caregivers, given its effectiveness and potential convenience.

KEYWORDS:

• Alzheimer disease
• donepezil
• transdermal
• cholinesterase inhibitors
• Dementia

Article highlights

• There are three cholinesterase inhibitors, and one NMDA antagonist available in the United States for the treatment of AD (Alzheimer’s disease), and despite the existence of two new treatments for AD, the expense and logistical issues surrounding these two new drugs mean that older drugs will likely be in use for the foreseeable future.

• These medications are helpful to people with AD with regard to cognitive function, but oral formulations present difficulties for patients and caregivers, especially as they require the patient to be cooperative and conscious.

• Rivastigmine is available as a transdermal patch, but it must be applied daily: less frequent dosing may be easier for people to adhere to.

• However, the donepezil transdermal patch, while it need only be applied weekly, is larger, more expensive, and does not come in a high dose option.

• There are several strategies for increasing the permeability of large molecules in transdermal patches: the transdermal donepezil patch uses a unique reservoir of the drug in its salt form that is converted within the patch to the freebase form that is more permeable to the skin.

• Studies support the bioequivalence and noninferiority of the transdermal form with the oral form of donepezil.

• Transdermal donepezil will be useful for people with AD and their caregivers, given its effectiveness and possibly more convenient formulation.

Declaration of interest

G Grossberg serves as a consultant to Acadia, Avanir, Axona, Axsome, Biogen, BioXcel, Eisai, Eli Lilly and Company, Genentech, Karuna, Lundbeck, Otsuka, Roche, and Takeda. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.