Iontophoresis: Definition and Applications
Iontophoresis is a non-invasive technique that uses low-level electrical current to enhance the penetration of ionic drugs or compounds through the skin for therapeutic purposes. 1
Mechanism of Action
- Iontophoresis works through two primary mechanisms: electromigration (movement of charged particles) and electro-osmosis (movement of neutral compounds), which together increase the permeation of both charged and neutral substances through the skin 2
- The process requires placing a charged drug at an electrode with the same polarity, causing the drug to be repelled through the skin when current is applied 1
- Studies have demonstrated that iontophoresis can provide a 20-60 fold increase in drug penetration compared to conventional topical application 1
Clinical Applications
Hyperhidrosis Treatment
- Iontophoresis is considered a safe, efficacious, and cost-effective primary treatment for palmar and plantar hyperhidrosis (excessive sweating of hands and feet) 3
- The technique has shown significant reduction in palmoplantar excessive sweating with minimal side effects through decades of clinical experience 3
Drug Delivery
- Iontophoresis has been successfully used to deliver various medications including:
- Local anesthetics (lidocaine) for procedures such as cutaneous cutdowns, eyelid surgery, and skin biopsies 1
- Corticosteroids for inflammatory conditions 1
- Antiviral medications for herpes simplex and varicella zoster infections 1
- Various antibiotics for localized infections 1
- High molecular weight drugs including peptides such as insulin and hormones 2
Diagnostic Applications
- Pilocarpine iontophoresis is a preferred method for cystic fibrosis detection 1
- In diabetes management, acetylcholine iontophoresis is used in specialized tests like QSART (Quantitative Sudomotor Axon Reflex Test) to evaluate postganglionic sudomotor function 4
Evaluation Methods Using Iontophoresis
- QSART uses acetylcholine iontophoresis to measure sweat production as an increase in humidity through a hygrometer, with results analyzed using area under the curve, maximal sweat production, and sweat onset latency 4
- Silicone impressions use acetylcholine iontophoresis to stimulate sweating for evaluation of sudomotor function 4
- Laser Doppler allows measurement of nerve axon reflex-related vasodilation following acetylcholine iontophoresis, which results from C-fiber stimulation 4
Limitations and Considerations
- Iontophoresis is most effective for conditions at or near the body surface 1
- The American College of Rheumatology conditionally recommends against using iontophoresis for first CMC joint osteoarthritis due to lack of published randomized controlled trials evaluating its efficacy 4
- The technique requires specialized equipment and proper training for optimal results 1
- Modern iontophoretic systems have features that make the process simpler and more efficient for clinical use 1
Recent Advances
- Combinations of iontophoresis with chemical enhancers, electroporation, and sonophoresis have been tested to further increase transdermal drug permeation and decrease possible side effects 2
- Progress in microelectronics, nanotechnology, and device miniaturization is leading to more sophisticated iontophoretic systems with better control of drug delivery 2
- Successful development of systems like the fentanyl E-TRANS iontophoretic system has provided encouraging results for pain management 2
Iontophoresis represents a valuable therapeutic and diagnostic tool that continues to find new applications in medicine, particularly in dermatology and pain management, with ongoing research expanding its potential uses.