what is iontophoresis?
the transcutaneous delivery of medications (in the form of ions) via the application of direct electrical current
when is iontophoresis commonly used?
in rehabilitation to apply dexamethasone (an anti-inflammatory corticosteroid)
how deep into the skin does iontophoresis penetrate?
uncertain
most studies have demonstrated approx 1-2 cm
what are the indications for iontophoresis?
analgesia, calcium deposits, fungal infection, hyperhidrosis, inflammation, ischemia, keloids, muscle spasm, myositis ossificans, plantar warts, scar tissue and wounds
what is the current strength of iontophoresis?
0.1-4 milliAmperes
what sized ions are more easily transported across the skin barrier?
small
what is the transport mechanism of iontophoresis?
transport of ions through the skin is enhance by imposed electrical fields
what charge ion will an anode drive?
positive
what charge ion will a cathode drive?
negative
what are the components of iontophoresis?
polarity - black wire is negative and red wire is positive treatment electrode (active/ delivery- medication is injected into the pad) and dispersive electrode (inactive- contains gel or saline)
When are ions driven through the skin?
only if a polarity match exists between the charged ions and the electrode under which they are placed (like poles repel)
what are the physiological mechanisms?
electromigration
electroporation
electroosmosis
what is electromigration?
electrical repulsion of ions
what is electroporation?
ES increase porosity of superficial skin (especially in the striatum corneum)
what is electroosmosis?
human skin has a net negative charge
direction of ionic flow is from anode to cathode
anodic delivery is assisted by electroosmosis (+) current flows easier
cathodic delivery is impeded
what are the 3 mechanisms?
- electrical repulsion of like charges
- electroporation, increasing openings in skin surface for ions
- electroosmosis or movements of water and sodium toward the cathode, creating a stream by which ions are moved
what increases with current density?
permeability of skin
response may be more pronounced under the cathode due to alkaline reaction from formation of NaOH (increased skin pH)
cathode usually has greater skin response
anode usually more uncomfortable (smaller electrodes)
what are the three routes of penetration through the skin?
sweat glands
oil glands
hair follicles
what are the advantages of iontophoresis?
better than oral meds if the patient is vomiting
better than nasal delivery
better than injections (which may cause pain, bleeding, infection, traumatic injury)
what are the disadvantages of iontophoresis?
acidic and alkaline reactions can cause significant discomfort, tingling, skin irritation, itching, chemical burns, redness
acidic reaction- thickening of skin under the anode
alkaline reaction- softening of skin under the cathode
how can you minimize burns?
increasing the size of the cathode relative to the anode
decrease the current density (using larger electrodes)
increasing the space between the electrodes
what are the anode reactions?
attracts C-
forms HCl
Process- sclerotic
effects- skin hardens
what are the cathode reactions?
attracts Na+
forms NaOH
process- sclerolytic
effects- skin softens (increase risk of electrical burn)
what is the current dosage?
higher the amplitude, shorter the treatment time
lower is usually more comfortable
current amplitude is determined by patient comfort, time is then calculated by the machine
electrodes determine dosage most often 40mA-80mA
can go as high has 120mA-min
what are electrode considerations?
if electrodes are manufactured, they will be buffered for optimal medication intake (the size of the electrode is fixed and the pole is determined by the ion used)
home-made/ sponge electrodes will nit be buffered (anode will be smaller and pH will not be proper throughout the treatment)
what are the general considerations of iontophoresis?
electrode placement and size-type dependent
active electrode over area of inflammation-palpate
electrode size should be large enough so current density does not exceed (cathode: 0.5 mA/cm2 and anode 1.0 mA/cm2)
drug delivery electrode polarity: same as active ion of the drug
current amplitude: varies
treatment time: determined by machine
what are the recommended parameter settings for iontophoresis?
current type/ waveform: direct current
pulse frequency: N/A
pulse duration: N/A
Amplitude: to patient tolerance not greater than 4mA
Dosage: 40-120 mA-min
treatment time: calculated by device
electrode configuration: active target area; dispersive- remote area
polarity (active electrode)- same as drug ion
what is dexamethasone and why should it be used?
a corticosteroid with inflammatory effects
recommended for tendonitis and bursitis
works well for lateral epicondylitis and plantar fasciitis
applications: ions negative polarity- medication placed under cathode
what is lidocaine and why should it be used?
topical anesthetic drug
recommended for children as localized anesthesia
effect in relieving pain, well tolerated and cost effective
application: ions have positive polarity- medication placed under anode
what is naproxen?
non-steroidal
effective in reducing pain in lateral epicondylitis
what is fentanyl?
obtained with MD orders in hospital synthetic opiate analgesic control of post operative pain more effective than placebo comparable effects of IV morphine
what is the procedure for the use of iontophoresis machine?
need MD prescription
patient should have own medication
explanation of procedure including side effects and sensations
inspect skin integrity and color
palpate
skin prep (remove hair/ alcohol swab/ soap and water)
electrode prep and placement
determine polarity and dosage (to patient comfort)
start treatment
monitor every 3-5 minutes for burns/ skin irritation
what are post- treatment considerations?
check skin irritation
re-evaluate treatment area from previous treatment
frequency of treatment dependent on ion selected and underlying condition
effectiveness of treatment determined within 3-5 treatment sessions
what are the contraindications for iontophoresis?
drug allergies skin sensitivity reaction to specific ions metal in or near treatment area cuts or broken skin be wary of tattoos
what are ES precautions?
cardiac disease
impaired mentation or sensation
malignant tumors
skin irritation or open wounds
what are ES contraindications?
demand pacemakers or unstable arrhythmias
over the carotid sinus/ trans cervical area
venous/arterial thrombosis or thrombophlebitis
over the pelvis, abdomen, trunk and low back during pregnancy
how can you apply iontophoresis in conjunction with other agents?
should not be applied after a physical agent that can alter skin permeability (heat, ice, US)
use of heat will: cause vasodilation, increased blood flow, accelerate drug to disperse away from targeted tissue
how do you document use of iontophoresis?
the area of the body treated patient positioning specific stimulation parameters electrode placement treatment duration patient response condition of skin and surrounding area
what is the difference between phonophoresis and iontophoresis?
PHONO- ultrasound, molecular transport, creme based, local/systemic effects, via process of cavitation
IONTO- DC current, ion transport, liquid solution, local/systemic effects, repelling electrical charge
