Iontophoresis

Question 1

what is iontophoresis?

Answer 1

the transcutaneous delivery of medications (in the form of ions) via the application of direct electrical current

Question 2

when is iontophoresis commonly used?

Answer 2

in rehabilitation to apply dexamethasone (an anti-inflammatory corticosteroid)

Question 3

how deep into the skin does iontophoresis penetrate?

Answer 3

uncertain

most studies have demonstrated approx 1-2 cm

Question 4

what are the indications for iontophoresis?

Answer 4

analgesia, calcium deposits, fungal infection, hyperhidrosis, inflammation, ischemia, keloids, muscle spasm, myositis ossificans, plantar warts, scar tissue and wounds

Question 5

what is the current strength of iontophoresis?

Answer 5

0.1-4 milliAmperes

Question 6

what sized ions are more easily transported across the skin barrier?

Answer 6

small

Question 7

what is the transport mechanism of iontophoresis?

Answer 7

transport of ions through the skin is enhance by imposed electrical fields

Question 8

what charge ion will an anode drive?

Answer 8

positive

Question 9

what charge ion will a cathode drive?

Answer 9

negative

Question 10

what are the components of iontophoresis?

Answer 10

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)

Question 11

When are ions driven through the skin?

Answer 11

only if a polarity match exists between the charged ions and the electrode under which they are placed (like poles repel)

Question 12

what are the physiological mechanisms?

Answer 12

electromigration
electroporation
electroosmosis

Question 13

what is electromigration?

Answer 13

electrical repulsion of ions

Question 14

what is electroporation?

Answer 14

ES increase porosity of superficial skin (especially in the striatum corneum)

Question 15

what is electroosmosis?

Answer 15

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

Question 16

what are the 3 mechanisms?

Answer 16

1. electrical repulsion of like charges
2. electroporation, increasing openings in skin surface for ions
3. electroosmosis or movements of water and sodium toward the cathode, creating a stream by which ions are moved

Question 17

what increases with current density?

Answer 17

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)

Question 18

what are the three routes of penetration through the skin?

Answer 18

sweat glands
oil glands
hair follicles

Question 19

what are the advantages of iontophoresis?

Answer 19

better than oral meds if the patient is vomiting
better than nasal delivery
better than injections (which may cause pain, bleeding, infection, traumatic injury)

Question 20

what are the disadvantages of iontophoresis?

Answer 20

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

Question 21

how can you minimize burns?

Answer 21

increasing the size of the cathode relative to the anode
decrease the current density (using larger electrodes)
increasing the space between the electrodes

Question 22

what are the anode reactions?

Answer 22

attracts C-
forms HCl
Process- sclerotic
effects- skin hardens

Question 23

what are the cathode reactions?

Answer 23

attracts Na+
forms NaOH
process- sclerolytic
effects- skin softens (increase risk of electrical burn)

Question 24

what is the current dosage?

Answer 24

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

Question 25

what are electrode considerations?

Answer 25

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)

Question 26

what are the general considerations of iontophoresis?

Answer 26

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

Question 27

what are the recommended parameter settings for iontophoresis?

Answer 27

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

Question 28

what is dexamethasone and why should it be used?

Answer 28

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

Question 29

what is lidocaine and why should it be used?

Answer 29

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

Question 30

what is naproxen?

Answer 30

non-steroidal | effective in reducing pain in lateral epicondylitis

Question 31

what is fentanyl?

Answer 31

``` obtained with MD orders in hospital synthetic opiate analgesic control of post operative pain more effective than placebo comparable effects of IV morphine ```

Question 32

what is the procedure for the use of iontophoresis machine?

Answer 32

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

Question 33

what are post- treatment considerations?

Answer 33

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

Question 34

what are the contraindications for iontophoresis?

Answer 34

``` drug allergies skin sensitivity reaction to specific ions metal in or near treatment area cuts or broken skin be wary of tattoos ```

Question 35

what are ES precautions?

Answer 35

cardiac disease impaired mentation or sensation malignant tumors skin irritation or open wounds

Question 36

what are ES contraindications?

Answer 36

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

Question 37

how can you apply iontophoresis in conjunction with other agents?

Answer 37

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

Question 38

how do you document use of iontophoresis?

Answer 38

``` the area of the body treated patient positioning specific stimulation parameters electrode placement treatment duration patient response condition of skin and surrounding area ```

Question 39

what is the difference between phonophoresis and iontophoresis?

Answer 39

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