Iontophoresis Flashcards
What is iontophoresis?
facilitate transdermal delivery of drugs
What current is used with iontophroesis?
low amplitude direct current
What is local delivery of drugs?
delivery into tissue directly below electrode
What is systemic delivery of drugs?
delivery of drugs throughout the body
What medication is most frequently used in iontophoresis?
dexamethasone
What is the depth of penetration for iontophoresis?
3-20mm
What is the depth of penetration of passive delivery of medication?
2-4mm
What must the current amplitude by in iontophoresis?
current must be high enough to overcome combined resistance of electrode and skin
What is the current amplitude of iontophoresis?
1 mA-4mA
How is dosing of iontophoresis determined?
dose described as charge in mA per min (milliamps of current per total time of current)
What are the most common doses of iontophoresis?
40 mA/per and 80 mA per min
What are some adverse effects of direct current?
electrothermal burn
electrochemical burn
How can an electrothermal burn occur?
high amounts of DC pass thru insulator of skin and can heat skin up
strong DC heat skin and create thermal burn
What kind of burn is more likely?
electrochemical burn
What can form inside the body?
acid and base reaction
What can build under the positive electrode?
acid
What can build under the negative electrode?
base- more damaging of the two
How are adverse effects minimized in iontophoresis?
- increase size of negative electrode
- decrease current amplitude or current density
- buffer electrodes
What are battery operated patch electrodes?
very low voltage
very long time (.1mA for 12 hours)
may not overcome skin resistance
What kind of drugs are acceptable to use in iontophoresis?
ionic
stable in solution
ions not altered by electric current
ions are small or moderate in size
Why should ions by small or moderate in size for iontophoresis to work?
because it has to be small enough to be pushed through pores into subcutaneous tissue
Where is the electrode placed in iontophoresis?
drug delivery electrode placed over pathology
What is the max current density at the cathode?
0.5mA/cm2
What is the max current density at the anode?
1.0mA/cm2
What is twice the size rule?
the negative electrode is twice the size of the positive
What should the polarity be?
Polarity of drug delivery electrode should be same as polarity of ionic drug
What should the current amplitude be for iontophoresis?
Highest that is comfortable to patient
Should not exceed 4 mA
What should the treatment time be for iontophoresis?
Calculated after treatment amplitude is determined
Determined by desired dose (generally 40 mA*min)
What is combo?
current and ultrasound
Many high volt pulsed current stimulators offer the possibility of combining electric stimulation with ultrasound during a single treatment
What is the underlying idea of combo?
idea is that you can possibly get an additive or combined therapeutic effect by using the two simultaneously
