Safety is paramount

Hello Bloggers, now that the dosage guidelines have been discussed, a very important topic to cover is the safety issues. We must take extreme caution when applying iontophoresis because the adverse effects can be severe and permanent. Before the application you must inform your patient about the risks and precautions of iontophoresis.

During your consultation, it is imperative you find out if the patient has any of the usual contraindications for e-stim. However additional contraindications do exist for iontophoresis and a few are outlined here for you. The direct current involved in iontophoresis may cause adverse vision effects when the electrodes are placed over the temporal or orbicular region, thus a different approach for drug administration must be taken when the condition is around these areas (Belanger, 2010). It is also an absolute contraindication if the patient is hypersensitive or allergic to the therapeutic ion being discussed.

The main safety precaution that must be dealt with and thus calculated before the application of iontophoresis is current density (CD). CD is the amount of current amplitude applied against the electrode conductive surface area. The CD limit differs depending on whether the administration is via the cathode, 0.5 mA/cm², or the anode, 1.0 mA/cm²  (Belanger, 2010). The discrepancies between the cathode and anode guidelines are due to the migration of positive ions at the cathode resulting in an alkalitic reaction, leading to an increased risk of chemical burn (Mcgraw Hill). As the process of drug admission is hypothesized to occur through sweat pores and hair follicles (Robertson, Ward, Low & Reed, 2006), CD may be inadvertently increased if the electrodes are placed over an area with low pore density. If the CD exceeds what the skin can withstand; tingling or painful sensations in the entire limb; erythema; skin necrosis; and chemical or thermal burns may occur (Batheja, Kaushik, Hu & Michniak-Kohn, 2007). However, if you exceed this limit by a substantial margin, more serious permanent damage to skin pigmentation may be the outcome.  

A feature of iontophoresis that has been observed and discussed is that skin resistance reduces after 10 minutes of 0.16mA current (Gazelius). Thus increasing application time, and conversely reducing current amplitude, is associated with its own risks for skin irritation. Although this is not within our control, we should make sure that our application is within the safe limits.

Now that we have discussed safety in application, next we’ll endeavor to describe the process of electrode positioning and application.

 REFERENCES:

Batheja, P., Kaushik, D., Hu, L., & Michniak-Kohn, B. (2007). Transdermal Iontophoresis. Touch Briefings, 46-48.

Belanger, A. (2010). Therapeutic Electrophysical Agents: Evidence Based Practice. (2^nd ed.) Wolters Kluwer Health: Lippincott Williams & Wilkins.

Gazelius, B. (n.d.) Periflux Systems, Iontophoresis. PeriMed.

McGraw Hill Higher Education. (2011). Department of Physical Education and Exercise Science. Retrieved March, 20, 2012 from <http://catalogs.mhhe.com>