Practical considerations for optimal transdermal drug delivery

Purpose. The properties of various transdermal drug delivery system (TDDS) products are reviewed, with safety recommendations and guidance on addressing questions frequently posed by patients and caregivers. Summary. Drug delivery via a TDDS can offer many advantages over other methods of administration, but those benefits can be compromised by improper use or alteration of medication patches or a lack of awareness of the properties of different patch types (reservoir, matrix, drug-in-adhesive). To assess current TDDS technologies and recommended practices for safe and effective use of medication patches, a literature search for articles on commonly used TDDS products available in the United States was conducted; supplemental information was obtained from package inserts and through direct communication with manufacturers. In addition to recommendations on the site and duration of TDDS application and proper patch disposal, clinicians must consider (1) potential problems with cutting patches as a method of dosage adjustment, (2) safety concerns related to the electric conductivity of metal-containing patches, (3) appropriate strategies for managing patch adhesion failures, and (4) the advisability of writing on patches for medication safety or compliance reasons. Clinicians should also be prepared to counsel patients about TDDS-specific recommendations on the avoidance of sunlight and other external heat sources during the use of a medication patch. Conclusion. Practical considerations related to transdermal drug delivery include the appropriateness of cutting patches, the implications of their containing metallic components, and whether they may be covered with tape or written on. Manufacturers of patches provide some useful information on these topics.