IONTOPHORESIS
Reading: Cameron pgs 272-276
• Use of Direct Current to facilitate delivery of
ions into the skin for therapeutic purposes.
• Mechanism of delivery:
“LIKE CHARGES REPEL”
Positive Electrode (anode)
delivers (+) ions
Negative Electrode (cathode)
delivers - ions
Historical Highlights
• Concept first developed & researched
over a century ago.
• Therapeutic use for more than 70 years.
• Popularity & usage was declining until
Joseph Kahn PhD,PT had 9 publications
from 1973 to 1983.
• Most case studies & clinical commentaries
Kahn, J. Case Report: Lithium lontophoresis for Gouty Arthritis. J Orthop Sports Phys Ther
1982;4(2):113-114.
Contemporary Use
• In PT: primarily for treating localized
inflammatory conditions in superficial
tissues
– Use corticosteroids,
(usually dexamethasone)
• Multiple uses of other non-steroidal ions
both within & outside PT
• Ex: Dentistry, Dermatology, Emergency
Dept, Ophthalmology
Ionto: Advantages over injection
• non-invasive; less risk of infection
• less pain & anxiety
• less drug into systemic circulation;
decreased side effects
• Less risk of local collagen
catabolism*
* assuming use of corticosteroid
Ionto: Advantages over drug PO
• avoids “first-pass” elimination by
liver.
• less drug into systemic circulation;
decreased side effects.
• potentially greater concentration of
drug in the target area
• supervised; maximizes compliance.
Ionto: Disadvantages
• risk skin irritation or burn
• depth of penetration known to vary b/c of
variation of current density, skin
impedence, skin/fat thickness, and
ionization/pH
• greater risk of local collagen catabolism
than oral administration*
• Action of drug – localized
immunosuppression*
* assuming use of corticosteroid
Treatment Parameters
(when using a DC stimulator eg. “dose controller”)
• Current: DC; “high current, short duration”
• Amplitude: 0.5 to 4.0 mA is the range
• depends on pt. tolerance, polarity, electrode size
• Dosage: 40 to 80 mA-min
• Dosage Formula: amplitude X time = mA min
• Time: calculated by the unit, you set the dosage
• The dispersive pad should be put
about 6 inches away from the active
pad on the same side of the body.
Parameters cont. . .
• Polarity – use the same polarity as the drug ion
• Rx frequency: every other day at the most
• steroid effects can be delayed & last
several days
• allows time for skin to recover
• minimize risk of side effects
• cost effective
• Rx number: 4 - 7 max
• More than 7 treatments in a short period of time
can produce detrimental effects such as skin
and connective tissue break-down.
Parameters cont. . .
• Due to continuous stim using
DC, no need for dealing with:
– Waveform
– Ramp-surge
– Frequency
– Width
– Amplitude, Time, & Polarity abide
Treatment Guidelines (Skin Safety)
• Amplitude: the patient feels a slight tingling, itching
or mild stinging. Check the skin under both
electrodes after ~ 5 minutes.
• Mildly red skin under the electrodes is a normal reaction
due to vasodilation & heat buildup.
• DC can cause mast cells to release histamine =
small bumps/vesicles and maybe petechiae.
These reactions are normal and resolve
within hours.
• If the skin is bright red or if many small vesicles are
forming, should decrease the amplitude and check
skin again after a few minutes. In some cases,
may terminate
Many factors affect skin reaction
• The patient's skin type & sensitivity to DC
current
• Current density: not > 0.5 mA/cm2
• Heat build-up; Chemical build-up
• Skin pigmentation: skin response harder
to judge.
Skin safety cont..
• Caution you about increasing the
amplitude after accommodation
occurs.
– Counterbalance with repeated skin
checks
• Some clinicians end the treatment by
application of a skin lotion containing
lanolin or aloe vera.
Contraindications & Precautions
• E-stim standard contraindications &
precautions apply
• Pt. allergic to ions/drugs
• Impaired skin sensation is a precaution
• No thermal modalities immediately before or
after. Why??
• No conductive gel before Ionto. Why??
• Diabetes is a precaution due to decreased
peripheral sensation and secondary to
localized immunosuppression caused by
corticosteroid.
Most Common Ion in PT
• Dexamethasone Sodium Phosphate
• 0.4% aqueous solution
• 0.4% = 0.004 g/ml = 4 mg/ml
• corticosteroid for anti-inflammatory
• effects; polarity is (-)
Additional Ions
(know name, polarity, usage)
•
•
•
•
•
•
•
Acetic Acid (-) dissolve Ca deposits
Calcium Chloride (+) ms. relaxant
Hyaluronidase (+) disperse edema; not acute
Iodine (-) softens adhesions & scar tissue
Magnesium Sulfate (+) ms. relaxant
Sodium Salicylate (-) ms. & joint pain
Lidocaine (+) local anesthetic
• Example pharmacy services
Equipment & Supplies
• Drug ion dissolved in aqueous solution or
suspended in ointment
• Absorbent & buffered electrode
• Iontophoresis devices
• Dupel DC stimulator by EMPI is what we will use
– Numerous other brands of DC stimulators exist
• Patch products: Iontopatch, ActionPatch
• Newest – Hybresis by EMPI
Dupel by EMPI
Phoresor II and look-a-likes
Patch (Integrated) Systems
• Current: DC, “low current, long duration”
• Amplitude: ~0.2 mA and less (if constant voltage)
• Dosage: 40 to 80 mA-min
– more convenient for clinicians and perhaps
patients because in-clinic wear time is greatly
decreased. Efficacy??
Iontopatch by Birch Medical
Action Patch by EMPI
HYBRESIS by EMPI
Effectiveness Factors
• Dosage: mA-min
• Little evidence exists that different
combinations of amplitude & duration provide
equivalent amounts of ion transfer; some
evidence that 4mA X 10 min is best. 40
mAmin is a commonly accepted standard.
• Preparation of skin
• must be clean; no competing ions.
• Depth of target tissue
• skin thickness, fat layer, overlying tissues
• Electrode Contact
Depth of ion penetration
• Believed to occur primarily thru pores
(sweat & oil) & hair follicles
• Passsive diffusion and local
circulation are required to shuttle the
drug deeper, to the cells of the target
tissue
• Research – effect is often inferred
based on clinical effectiveness (pain,
ROM, MMT, function)
• max depth of ion penetration is largely
unknown in humans (8-10mm in mammals)