1. Iontophoresis
Chapter 6

2. IONTOPHORESIS
Use of Direct Current to facilitate delivery of ions into the skin for therapeutic purposes.
Mechanism of delivery:
“LIKE CHARGES REPEL”

3. Positive Electrode (anode) delivers + ions
Negative Electrode (cathode) delivers - ions

5. Iontophoreis
Introduction of Ions Into The Body Using Direct Electrical Current
Transports Ions Across A Membrane Or Into a Tissue
It is a Painless, Sterile, Noninvasive Technique
Demonstrated To Have A Positive Effect On The Healing Process

6. Iontophoresis Duration of Tx: Indications Contraindications
Based on intensity desired usually every other day for 3 weeks
Indications
Acute or Chronic Inflam
Arthritis
Myositis
Myofacial Pain Syndromes
Invasive method for delivering drugs
Contraindications
Hypersensitivity to electrical currents
Contraindications to meds.
Pain of unknown origin
Precautions
Prescription
Dosage
Do not reuse electrode
Burns if intensity to great

7. Iontophoresis vs Phonophoresis
Both Techniques Deliver Chemicals To Biologic Tissues
Phonophoresis Uses Acoustic Energy (Ultrasound) To Drive Molecules Into Tissues
Iontophoresis Uses Electrical Current To Transport Ions Into Tissues

8. Pharmacokinetics of Ion Transfer
Transdermal iontophoresis delivers medication at a constant rate so that the effective plasma concentration remains within a therapeutic window for an extended period of time.
Therapeutic window - the plasma concentrations of a drug which should fall between a minimum concentration necessary for a therapeutic effect and the maximum effective concentration above which adverse effects may possibly occur.

9. Pharmacokinetics of Ion Transfer
Iontophoresis appears to overcome the resistive properties of the skin to charged
ions
Iontophoresis decreases absorption lag
time while increasing delivery rate when compared with passive skin application
Iontophoresis provides both a spiked and sustained release of a drug reducing the possibility of developing a tolerance to drug

10. Pharmacokinetics of Ion Transfer
Rate at which an ion may be delivered is determined by a number of factors
The concentration of the ion
The pH of the solution
Molecular size of the solute
Current density
Duration of the treatment

11. Pharmacokinetics of Ion Transfer
Mechanisms of absorption of drugs administered by iontophoresis similar to administration of drugs via other methods
Advantages of taking medication via transdermal iontophoresis relative to oral medications
Concentrated in a specific area
Does not have to be absorbed within the GI tract
Safer than administering a drug through injection

12. Movement of Ions In Solution
Ionization- Soluable compounds dissolve into ions suspended in solutions that are called electrolytes
Electrophoresis- Movement of ions in solution according to the electrically charged currents acting on them.

13. Movement of Ions In Solution
Cathode = Negatively charged electrode
Highest concentration of electrons
Repels negatively charged ions
Attracts positively charged ions
Accumulation of negatively charged ions in a small area creates an acidic reaction

14. Movement of Ions In Solution
Anode = Positively charged electrode
Lower concentration of electrons
Repels positively charged ions
Attracts negatively charged ions
Accumulation of positively charged ions in a small area creates an alkaline reaction

15. Movement of Ions In Solution
Positively charged ions are driven into tissues from positive pole
Negatively charged ions are driven into tissues from negative pole
Knowing correct ion polarity is essential

16. Movement of Ions In Tissue
Force which acts to move ions through the tissues is determined by
Strength of the electrical field
Electrical impedance of tissues to current flow

17. Movement of Ions In Tissue
Strength of the electrical field is determined by the current density
Difference in current density between the active and inactive electrodes establishes a gradient of potential difference which produces ion migration within the electrical field
Active electrode- the one being used to drive the ion into the tissue

18. Movement of Ions In Tissue
Current density may be altered by
Increasing or decreasing current intensity
Changing the size of the electrode
Increasing the size of the electrode will decrease current density under that electrode.

19. Movement of Ions In Tissue
Current density should be reduced at the cathode (negative electrode)
Alkaline reaction (+ions) is more likely to produce tissue damage than acidic reaction(- ions)
Thus negative electrode should be larger (2x) to reduce current density.

20. Movement of Ions In Tissue
Higher current intensities necessary to create ion movement in areas where skin and fat layers are thick further increasing chance of burns around negative electrode
Sweat ducts are primary paths by which ions move through the skin and act to decrease impedance facilitating the flow of direct current as well as ions

21. Movement of Ions In Tissue
The quantity of ions transferred into the tissues through iontophoresis is directly proportional to
Current density at the active electrode
Duration of the current flow
Concentration of ions in solution

22. Movement of Ions In Tissue
Once the ions pass through skin they recombine with existing ions and free radicals in the blood thus forming the necessary new compounds for favorable therapeutic interactions

23. Iontophoresis Techniques

24. Iontophoresis Generators
Produce continuous direct current *
Assures unidirectional flow of ions
*One study has shown that drugs can be delivered using AC current

25. Iontophoresis Generator
Intensity control
1 to 5 mA
Constant voltage output that adjusts to normal variations in tissue impedance thus reducing the likelihood of burns
Automatic shutdown if skin impedance reduces to preset limit

26. Iontophoresis Generator
Adjustable Timer
Up to 25 min

27. Iontophoresis Generator
Lead wires
Active electrode
Inactive electrode

28. Current Intensity
Low amperage currents appear to be more effective as a driving force than currents with higher intensities
Higher intensity currents tend to reduce effective penetration into the tissues
Recommended current amplitudes used for iontophoresis range between 3-5 mA

29. Current Intensity
Increase intensity slowly until patient reports tingling or prickly sensation
If pain or a burning sensation occur intensity is too great and should be decreased
When terminating treatment intensity should be slowly decreased to zero before electrodes are disconnected

30. Current Intensity
Maximum current intensity should be determined by size of the active electrode
Current amplitude usually set so that current density falls between mA/cm2 of the active electrode surface

31. Treatment Duration
Treatment duration ranges between minutes with 15 minutes being an average
Patient should be comfortable with no reported or visible signs of pain or burning
Check skin every 3-5 minutes looking for signs of skin irritation
Decrease intensity during treatment to accommodate decrease in skin impedance to avoid pain or burning

32. Traditional Electrodes
Older electrodes made of tin, copper, lead, aluminum, or platinum backed by rubber
Completely covered by a sponge, towel, or gauze which contacts skin
Absorbent material is soaked with ionized solution
Ion ointment should be rubbed into the skin and covered by some absorbent material.

33. Commercial Electrodes
Sold with most iontophoresis systems
Electrodes have a small chamber covered by a semipermiable membrane into which ionized solution may be injected
The electrode self adheres to the skin

34. Electrode Preparation
To ensure maximum contact of electrodes skin should be shaved and cleaned prior to attachment of the electrodes
Do not excessively abrade skin during cleaning since damaged skin has lowered resistance to current and a burn might occur more easily

35. Electrode Preparation
Attach self-adhering active electrode to skin

36. Electrode Preparation
Attach self-adhering active electrode to skin
Inject ionized solution into the chamber

37. Electrode Preparation
Attach self-adhering active electrode to skin
Inject ionized solution into the chamber
Attach self-adhering inactive electrode to the skin and attach lead wires from generator to each

38. Electrode Placement
Size and shape of electrodes can cause variation in current density (smaller = higher density)
Electrodes should be separated by at least the diameter of active electrode
Wider separation minimizes superficial current density decreasing chance for burns

39. Selecting the Appropriate Ion
Negative ions accumulating at the positive pole or anode
Produce an acidic reaction through the formation of hydrochloric acid
Produce softening of the tissues by decreasing protein density-useful in treating scars or adhesions
Some negative ions can also produce an analgesic effect (salicylates)

40. Selecting the Appropriate Ion
Positive ions that accumulate at the negative pole
Produce an alkaline reaction with the formation of sodium hydroxide
Produce hardening of the tissues by increasing protein density

41. Indications – evidence based
Condition
Ions
Benefit
Reference
Plantar Faciitis
Dex/lido.
Yes
Kahn, 1982, Reidle et all 2000, Montorsi et all 2000, Rothfield et al 1967
Inflamm. Disorders Musc.
Dex
Bertolucci, 1982, Delacerda, 1982Harris, 1982, Pellecchia et al 1994,
TMJ
Dex & dex/lido
Braun 1987; Reid et al 1994;Schiffman et al 1996
Hydrocort/US No
Kahn, 1980
Epicondylitis
Panus et al 1996
Na+ Salcycil.
Demiratas et al 1998
Carpal tunnel
Banta, 1994
Edema
Hualuronidase
Magistro 1964, Boone 1969

42. Iontophoresis: Evidence Based
Condition
Ions
Benefit
Reference
Scar Tissue
Iodine
Yes
Tennenbaum, 1980
Tendon Adhesion
Langley 1984
Subdeltoid Bursa
Magnesium
Weinstein et al 1958
Plantar warts
Salicylate
Gordon et al 1969
Heel Pain
Acetate
Japour et al, 1999
Myositis Oss.
Weider, 1992
Myopathy
Calcium ?
Kahn, 1975
Postsurgical hip pain
Garzione, 1978

43. Biophysical Effects
Dependant on Medication
See following chart

44. Sample Medications

45. Selecting the Appropriate Ion
Inflammation
Dexamethasone (-)
Hydrocortisone (-)
Salicylate (-)
Spasm
Calcium (+)
Magnesium(+)
Analgesia
Lidocaine (+)
Magnesium (+)
Edema
Hyaluronidase(+)
Salicylate (-)
Mecholyl(+)
Open Skin Lesions
Zinc(+)
Scar Tissue
Chlorine(-)
Iodine(-)
Salicylate(-)

46. Treatment Precautions
Problems which might potentially arise from treating a patient using iontophoresis may for the most part be avoided if the athletic trainer
Has a good understanding of the existing condition which is to be treated
Uses the most appropriate ions to accomplish the treatment goal
Uses appropriate treatment parameters and equipment set-up

47. Chemical Treatment Burns
Most common problem is a chemical burn which occurs as a result of direct current itself and not because of the ion being used
Continuous direct current creates migration of ions which alters the normal pH of the skin
Chemical burns typically result from accumulation of sodium hydroxide at cathode
Alkaline reaction causes sclerolysis of local tissues
Decreasing current density by increasing size of cathode can minimize potential for chemical burn

48. Thermal Treatment Burns
Thermal burns may occur due to high resistance to current flow created by poor contact of the electrodes with the skin
Electrodes are not moist enough
Wrinkles in the gauze or paper towels impregnated with the ionic solution
Space between the skin and electrode around the perimeter of the electrode
Body weight resting on top of electrode