This is based on the electrical principle that like charges repel. Iontophoresis is commonly used to treat pain, inflammation, spasms, and calcium deposits, all dependent on the type of medication being used. Transmembrane transport also occurs between the cells due the concentration gradients formed during and after the treatment. The literature has shown depths of penetration up to 6-20mm subcutaneously, possibly as a result of these two mechanisms.
Further research is necessary.
Vasodilation of the blood vessels occurs as a result of the heat, thereby increasing local blood flow to the area. Hyperemia, or reddening of the skin thus occurs. These are normal side effects of iontophoresis and the symptoms should subside within one hour. The effects are usually more pronounced and last longer under the negative electrode as a result of the increased release of hydrogen from the sodium hydroxide reactions. Patient may be sitting prone, supine, or sidelying.