Chapter 6: Iontophoresis

OBJECTIVES

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. The expansion of available medications for delivery via iontophoresis has drawn new attention to this therapeutic modality. Iontophoresis has several advantages as a treatment technique that involves little to no patient discomfort, is a 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 the majority of medications used in iontophoresis require a physician's prescription for use. Typically the patient is responsible for filling the prescription and bringing the medication to the treatment session. Clinicians must be aware of state law that may regulate the ability of a clinical setting to store medication for individual patients. Medications prescribed for one patient cannot be used for other patients, so the traditional practice of clinics having a single prescription of medication shared amongst all patients should be avoided.

IONTOPHORESIS VERSUS PHONOPHORESIS

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

BASIC MECHANISMS OF ION TRANSFER

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 ...