Iontophoresis Flashcards
What was iontophoresis originally referred to as?
ion tranfer
What is phonophoresis?
The use of acoustic energy in the form of US to drive whole molecules across the skin into tissues
What is iontophoresis?
The use of a low level direct electric current to transport ions into the tissues
When should iontophoresis be used over phonophoresis?
When ions are suspended in solution and can be carried into the tissue by an electrical current
What is the significance of iontophoresis delivering medication at a constant rate transdermally?
- Decreases absorption lag time
- Increases the delivery rate when compared with passive skin applications
- Can deliver spiked and sustained release of a drug
What are the 5 things rate of delivery depends on?
- Concentration of the ion
- pH of the solution
- Molecular size of the solute
- Current density
- Duration of treatment
The electrode that has the greatest concentration of electrons is _____ charged.
negatively
Describe what happens under the negative electrode (cathode).
Negative ions are repelled and move toward positive electrode, which creates an acidic reaction
The electrode with a lower concentration of electrons is the _____ electrode.
positive
Describe what happens under the positive electrode (anode).
Electrons move toward the negative electrode, which creates an alkaline reaction
What type of reaction is more likely to produce tissue damage?
Alkaline
The force that acts to move ions through the tissues is determined by what 2 things?
- Strength of the electrical field (current density)
- Electrical impedance of tissues to current flow
What determines ion migration?
Current density difference
What are the 3 things in which current density is altered by?
- Changing the size of the electrode
- Increasing current intensity
- Decreasing current intensity
Decreasing the current intensity is recommend under which electrode?
negative
Which electrode should be larger and why?
The negative electrode be larger to reduce current density and potential alkaline reaction at the positive electrode
What types of things are poor conductors?
Skin and Fat
Skin and fat, which are poor conductors provide a _____ resistance to current flow.
greater
Skin and fat, which are poor conductors require ____ current intensities.
higher
The presence of sweat glands _____ impedance.
decreases
How deep does medication penetrate duraing an average treatment?
1-3 mm
What are the 4 things that determine the quantity of ions transferred into tissues?
- Intensity of the current
- Current density at the active electrode
- Duration of the current flow
- Concentration of ions in solution
How can ion transfer be increased?
By increasing intensity and duration of treatment
Increasing the intensity may also increase the risk of what?
burns
What type of medication can be used to decrease inflammation?
Dexamethasone
What type of medication can be used as an anesthetic?
Lidocaine
Iontophoresis can also be used in conjunction with what types of things?
- analgesics
- peptides
- CNS agents
- antiviral agents
- antihypertensive agents
Iontophoresis utilizes a continuous direct current, which ensures what?
the unidirectional flow of ions
Is an alternating current effective for iontophoresis?
Recent studies have shown it to be effective as well. It may help to avoid electrochemical burns
Where should the electrodes be placed for iontophoresis?
The dispersive electrode should be place a few inches away from the treatment electrode
The active (treatment) electrode should have a current density between __ mA/cm2 and __ mA/cm2.
0.1 - 0.5
What should the polarity of the active electrode be?
The same polarity as the active ion of drug
How long is treatment time for iontophoresis?
10-20 minutes
What is current amplitude measured in?
milliampere minutes (mA-minutes)
What is the effective current dosage?
40-80 mA-minutes (suggested 40 mA-minutes)
How do you calculate mA-minutes?
Multiple the current amplitude by the treatment duration
4 mA current x 10 minute Tx = 40 mA-min dose
What can acetate be used for clinically?
Calcium deposits
Acetate has a _____ polarity.
negative
What can dexamethasone be used for clinically?
inflammation
Dexamethasone has a _____ polarity.
negative
What can lidocaine be used for clinically?
as a local anesthetic
Lidocaine has a _____ polarity.
positive
What can tap water be used for clinically?
hyperhidrosis
Tap water has a _____ polarity.
either positive or negative
What can salicylate be used for clinically?
Frozen shoulder, scar tissue, plantar warts, and pother adhesive or edematous conditions
What are some adverse side effects of iontophoresis?
- Erythema
- Itching, tingling, burning
- Minimal blistering
What can dampen the severity of irritation?
The co-delivery of saline and hydrocortisone
What are 5 positive aspects of iontophoresis when it is used as an anesthetic?
- negates the pain
- prevents variation in absorption seen with oral medications
- reduces the chance of over or under-dosage
- can be used to deliver drugs with short half-lives directly to tissue
- it is simple to use and easy to terminate if necessary
