Iontophoresis simply means the transport of ions through tissue.1 Practitioners have attempted to treat pain sites by this method for several years by the use of electric currents.2 However, these attempts have never been widely adopted primarily due to inadequate instruments that provided relatively poor penetration of medication into tissue and the use of medication that had marginal pharmacologic effects. Today, new electromagnetic instruments are capable of driving medication deep into tissue and, most critically, high potency corticoid hormones provide an effective immunologic and healing effect. This report describes the hormones and the electromagnetic devices used by the author. The use of electromagnetic techniques and high potency corticoid hormones are simple to implement and they can even be inexpensively used at home by patients.
What Happened to the Old Iontophoresis?
The deficiencies of yesterday’s iontophoretic techniques are instructive and should provide a message to today’s practitioner that “things are now different.” There are two fundamental reasons for the heretofore limited use of iontophoresis. First, the fundamental purpose of iontophoresis is to drive medication from the skin surface to a pain site that may rest two to five inches below the skin surface. A pain site contains a host of biologic elements including inflammatory markers, retained electrical charges, opioid receptors, and blood-lymph drainage (see Figure 1). Medication agents administered by iontophoresis in the past were usually weak metals, salicylates, or corticoid preparations that were simply not potent enough to have much effect. The second reason that iontophoresis has never been widely adopted is that the commercial instruments marketed for this purpose were inadequate to the task. They usually utilized low intensity, low frequency electric currents and attempted to administer medical agents under a very small skin contact pad that may not have been larger than one-half inch on a side. In summary, the iontophoresis attempts of yesteryear were a good start that has progressively evolved into a system of effective delivery and pharmacologic activity.
High Potency Hormones
I have systematically attempted to iontophoretically administer a number of corticoid, androgenic, and anti-inflammatory agents and have settled on two high potency corticoids after noting excellent skin penetration and good clinical response when administered by various electromagnetic instruments. Here are my choices of iontophoretic agents:
- Prednisone: 40mg in 1 ounce of base cream
- Medroxyprogesterone: 40 mg in 1 ounce of base cream.
Today’s compounding pharmacies are creating a number of very innovative mixtures and concentrations of topical agents. Some will very likely have great merit when used as iontophoretic agents. It should be noted that any topical agent which shows therapeutic benefit will have that benefit enhanced if it is applied under any one of a number of electromagnetic instruments that are now commercially available.
What Base Should Be Used?
My criteria for a base cream is simple. Will it dissolve rapidly when rubbed on the skin? Although some base gels for topical compounds are popular with compounding pharmacies, base agents for iontophoresis require only that the base cream be able to dissolve hormones and will diffuse rapidly into the skin when applied under an electromagnetic instrument.
The New Electromagnetic Instruments
Many of the new electromagnetic instruments now available are ideally suited for iontophoretic treatments. Instruments that use electric currents have the ability to deliver currents of different intensities and frequencies. Of critical importance is that many of the new electromagnetic instruments deliver their current or photon wave in pulses. The pulse action of an electric current or electromagnetic wave appears to enhance the penetration of medication into deep pain sites.
An electric current creates a series of photon waves in the electromagnetic spectrum (see Figure 2). Pain practitioners should be aware of this spectrum and know that radio, ultrasound, infrared, and laser waves are all fundamentally related. Their basic unit of mass is the photon. The waves can clinically differ in their intensity and frequency and can be delivered in pulses.
Benefits of these electromagnetic in-struments include cell growth, increased vascular perfusion, dispersion of sequest-ered electrical charges, and reduction of edema and inflammation.2,3 Simply put, when these instrument are used for iontophoresis as described here, not only does the patient get the benefit of the basic electromagnetic current or wave but the added benefit of a high potency corticoid hormone. It is important that the electromagnetic instruments on the commercial market carry a US Food and Drug Administration (FDA) clinical indication for various pain problems. When used for iontophoresis, the treatment is an off-label use and the patient should be so informed.
Pulsed Radio Frequency
A pulsed radiofrequency instrument (Provant®, Scottsdale, Arizona) has had considerable success in treating the pain of surface wounds such as those caused by diabetes, trauma, or vascular disease. It has a square skin contact plate about 8" on a side that lays nicely over a relatively flat anatomical area such as the lumbar spine, cheek, or chest wall (see Figure 3).
An instrument is available in a probe about the size of a pencil that delivers a microcurrent of electricity (Alpha-Stim®, Mineral Wells, TX). The topical hormone can be placed over a small skin surface area such as the thumb or cervical area and the this instrument can make skin contact in these areas while a plate or patch cannot do so (see Figure 4).
There are now pulsed electric current instruments (H-wave®, Huntington Beach, CA and Impulse TENS®, Vista, CA) whose intensity and frequency can be adjusted upward as needed. They also have contact pads which measure about two to three inches in diameter and are large enough to administer hormones beneath them (see Figure 5).
Infrared and Ultrasound
These devices have long histories in pain treatment and are now available at low prices for at-home use. No serious side-effects are known. Consequently, these simple instruments are suitable patient self-administration. The waves in these instruments are not usually pulsed, so the penetration of hormones into the pain site may be limited (see Figure 6).
Treatment Procedures and Precautions
About one quarter to half an ounce of hormone cream is applied to the skin directly over the pain site. The topical hormone dosage, therefore, is only about 5 to 20mg of prednisone or medroxyprogesterone. The electromagnetic instrument is then applied for 10 to 30 minutes.