Following completion of this chapter, the student will be able to:
- Differentiate between iontophoresis and phonophoresis.
- Explain the basic mechanisms of ion transfer.
- Establish specific iontophoresis application procedures and techniques.
- Identify the different ions most commonly used in iontophoresis.
- Choose the appropriate clinical applications for using an iontophoresis technique.
- Establish precautions and concerns for using iontophoresis treatment.
Iontophoresis is a therapeutic technique that involves the introduction of ions into the body tissues by means of a direct electrical current.1 Originally referred to as ion transfer, it was first described by LeDuc in 1903 as a technique of transporting chemicals across a membrane using an electrical current as a driving force.2 Since that time, the use and popularity of iontophoresis has varied. Recently new emphasis has been placed on iontophoresis, and it has become a commonly used technique in clinical settings. Iontophoresis has several advantages as a treatment technique in that it is a painless, sterile, noninvasive technique for introducing specific ions into a tissue that has been demonstrated to have a positive effect on the healing process.3
Although specific statutes relative to the use of iontophoresis vary from state to state, the clinician must be aware that most of the medications used in iontophoresis require a physician's prescription for use.
It is critical to point out the difference between iontophoresis and phonophoresis since the two techniques are often confused and occasionally the two terms are erroneously interchanged. It is true that both techniques are used to deliver chemicals to various biologic tissues. Phonophoresis, which is discussed in detail in Chapter 10, involves the use of acoustic energy in the form of ultrasound to drive whole molecules across the skin into the tissues, whereas iontophoresis uses an electrical current to transport ions into the tissues.97
Clinical Decision-Making Exercise 6–1
A physician sends the clinician a prescription for using topical hydrocortisone to treat plantar fasciitis but does not specify whether phonophoresis or iontophoresis should be used. What should determine the clinician's decision to use one or the other?
Pharmacokinetics of Iontophoresis
In an ideal drug delivery system, the goal is to maximize the therapeutic effects of a drug while minimizing adverse effects and simultaneously providing a high degree of patient compliance and acceptability.4 Transdermal iontophoresis delivers medication at a constant rate so that the effective plasma concentration remains within a therapeutic window for an extended period of time. The therapeutic window refers to the plasma concentrations of a drug, which should fall between a minimum concentration necessary for a therapeutic effect and the maximum effective concentration above which adverse effects may possibly occur.4 Iontophoresis is able to facilitate the delivery of charged and high-molecular-weight compounds that cannot be effectively delivered by simply applying them to the skin. It is useful since it appears ...