chap 6- iontophoresis
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8/7/2019 Chap 6- Iontophoresis
http://slidepdf.com/reader/full/chap-6-iontophoresis 1/42
8/7/2019 Chap 6- Iontophoresis
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Iontophoresis
8/7/2019 Chap 6- Iontophoresis
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Iontophoreis
Introduction of Ions Into The Body UsingDirect Electrical Current
Transports Ions Across A Membrane Or Into a TissueIt is a Painless, Sterile, Noninvasive
TechniqueDemonstrated To Have A Positive EffectOn The Healing Process
8/7/2019 Chap 6- Iontophoresis
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Iontophoresis vs Phonophoresis
Both Techniques Deliver Chemicals ToBiologic Tissues
Phonophoresis Uses Acoustic Energy(Ultrasound) To Drive Molecules IntoTissues
Iontophoresis Uses Electrical Current ToTransport I ons Into Tissues
8/7/2019 Chap 6- Iontophoresis
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Pharmacokinetics of Ion Transfer
Transdermal iontophoresis deliversmedication at a constant rate so that the
effective plasma concentration remainswithin a therapeutic window for an extendedperiod of time.
j Therapeutic window - the plasmaconcentrations of a drug which should fallbetween a minimum concentration necessaryfor a therapeutic effect and the maximumeffective concentration above which adverseeffects ma ossibl occur.
8/7/2019 Chap 6- Iontophoresis
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Pharmacokinetics of Ion Transfer
Iontophoresis appears to overcome theresistive properties of the skin to charged io
Iontophoresis decreases absorption lag timwhile increasing delivery rate when compar with passive skin application
Iontophoresis provides both a spiked andsustained release of a drug reducing thepossibility of developing a tolerance to drug
8/7/2019 Chap 6- Iontophoresis
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Pharmacokinetics of Ion Transfer
R ate at which an ion may be deliveredis determined by a number of factors
j The concentration of the ionj The pH of the solutionj Molecular size of the solutej
Current densityj Duration of the treatment
8/7/2019 Chap 6- Iontophoresis
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Pharmacokinetics of Ion Transfer Mechanisms of absorption of drugsadministered by iontophoresis similar to administration of drugs via other methods
Advantages of taking medication viatransdermal iontophoresis relative to oral
medicationsj Concentrated in a specific areaj Does not have to be absorbed within the G I tractj
Safer than administering a drug through injection
8/7/2019 Chap 6- Iontophoresis
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8/7/2019 Chap 6- Iontophoresis
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Movement of Ions In Solution
Cathode = Negatively charged electrodej Highest concentration of electronsj Repels negatively charged ionsj Attracts positively charged ionsj Accumulation of negatively charged ions in a
small area creates an a cidic reaction
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Movement of Ions In Solution
Anode = Positively charged electrodej L ower concentration of electronsj Repels positively charged ionsj Attracts negatively charged ionsj Accumulation of positively charged ions in a
small area creates an alkaline reaction
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Movement of Ions In Solution
Positively charged ions are driven intotissues from positive pole
Negatively charged ions are driven intotissues from negative poleKnowing correct ion polarity is essential
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Movement of Ions In Tissue
F orce which acts to move ions throughthe tissues is determined by
j Strength of the electrical fieldj Electrical impedance of tissues to current
flow
8/7/2019 Chap 6- Iontophoresis
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Movement of Ions In Tissue
Strength of the electrical field isdetermined by the current density
j Difference in current density between theactive and inactive electrodes establishesa gradient of potential difference whichproduces ion migration within the electricalfield
j Active electrode- the one being used to drivethe ion into the tissue
8/7/2019 Chap 6- Iontophoresis
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Movement of Ions In Tissue
Current density may be altered byj Increasing or decreasing current intensityj Changing the size of the electrode
Increasing the size of the electrode willdecrease current density under that electrode.
8/7/2019 Chap 6- Iontophoresis
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Movement of Ions In Tissue
Current density should be reduced atthe cathode (negative electrode)
Alkaline reaction (+ions) is more likely toproduce tissue damage than acidic reaction(-ions)Thus negative electrode should be larger (2x)
to reduce current density.
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Movement of Ions In Tissue
Higher current intensities necessary tocreate ion movement in areas whereskin and fat layers are thick further increasing chance of burns aroundnegative electrode
Sweat ducts are primary paths by whichions move through the skin and act todecrease impedance facilitatingthe flow of direct current as well asions
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Movement of Ions In Tissue
The quantity of ions transferred into thetissues through iontophoresis is directlyproportional to
j Current density at the active electrodej Duration of the current flow
j Concentration of ions in solution
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Movement of Ions In Tissue
O nce the ions pass through skin theyrecombine with existing ions and freeradicals in the blood thus forming thenecessary new compounds for favorable therapeutic interactions
8/7/2019 Chap 6- Iontophoresis
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Iontophoresis Techniques
8/7/2019 Chap 6- Iontophoresis
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Iontophoresis Generators
j Produce continuousdirect current *
j Assures unidirectionalflow of ions
± *One study has shownthat drugs can bedelivered using AC
current
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Iontophoresis
Generator j Intensity control
j 1 to 5 mAj
Constant voltageoutput that adjusts tonormal variations intissue impedancethus reducing the
likelihood of burnsj Automatic shutdown
if skin impedancereduces to preset
limit
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Iontophoresis
Generator j Adjustable Timer
j Up to 25 min
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Iontophoresis
Generator j L ead wires
j Active electrodej Inactive electrode
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Current Intensity
Low amperage currents appear to bemore effective as a driving force than
currents with higher intensitiesHigher intensity currents tend to reduceeffective penetration into the tissues
R ecommended current amplitudes usedfor iontophoresis range between 3-5 mA
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Current Intensity
Increase intensity slowly until patientreports tingling or prickly sensation
If pain or a burning sensation occur intensity is too great and should bedecreased
When terminating treatment intensityshould be slowly decreased to zerobefore electrodes are disconnected
8/7/2019 Chap 6- Iontophoresis
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Current Intensity
Maximum current intensity should bedetermined by size of the active
electrodeCurrent amplitude usually set so thatcurrent density falls between 0.1-0.5mA/cm 2 of the active electrodesurface
8/7/2019 Chap 6- Iontophoresis
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Treatment Duration
Treatment duration ranges between 10-20 minutes with 15minutes being an averagePatient should be comfortable with noreported or visible signs of pain or burning
Check skin every 3-5 minutes lookingfor signs of skin irritationDecrease intensity during treatment to
accommodate decrease in skin
8/7/2019 Chap 6- Iontophoresis
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Traditional Electrodes
O lder electrodes made of tin, copper,lead, aluminum, or platinum backed by
rubber Completely covered by a sponge, towel,or gauze which contacts skin
Absorbent material is soaked withionized solutionIon ointment should be rubbed into theskin and covered by some absorbent
8/7/2019 Chap 6- Iontophoresis
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Commercial Electrodes
Sold with most iontophoresis systemsElectrodes have a small chamber covered by
a semipermiable membrane into whichionized solution may be injectedThe electrode self adheres to the skin
8/7/2019 Chap 6- Iontophoresis
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8/7/2019 Chap 6- Iontophoresis
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Electrode Preparation
Attach self-adhering activeelectrode to skin
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Electrode Preparation
Attach self-adhering activeelectrode to skinInject ionized solution intothe chamber
8/7/2019 Chap 6- Iontophoresis
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Electrode Preparation
Attach self-adhering activeelectrode to skinInject ionized solution intothe chamber Attach self-adheringinactive electrode to the
skin and attach lead wiresfrom generator to each
8/7/2019 Chap 6- Iontophoresis
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8/7/2019 Chap 6- Iontophoresis
http://slidepdf.com/reader/full/chap-6-iontophoresis 36/42
Selecting the Appropriate Ion
N egative ions accumulating at the positivepole or anode
j Produce an acidic reaction through theformation of hydrochloric acidj Produce softening of the tissues by decreasing
protein density-useful in treating scars or adhesions
j Some negative ions can also produce ananalgesic effect (salicylates)
8/7/2019 Chap 6- Iontophoresis
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Selecting the Appropriate Ion
Positive ions that accumulate at thenegative pole
j Produce an alkaline reaction with theformation of sodium hydroxidej Produce hardening of the tissues by
increasing protein density
8/7/2019 Chap 6- Iontophoresis
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Selecting the Appropriate IonInflammation
j Dexamethasone (-)j Hydrocortisone (-)
j Salicylate (-)Spasm
j Calcium (+)j Magnesium(+)
Analgesiaj L idocaine (+)j Magnesium (+)
Edemaj Hyaluronidase(+)j Salicylate (-)
j Mecholyl(+)Open Skin L esions
j Z inc(+)
Scar Tissuej Chlorine(-)j Iodine(-)j Salicylate(-)
8/7/2019 Chap 6- Iontophoresis
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Treatment Precautions
Problems which might potentially arisefrom treating a patient usingiontophoresis may for the most part beavoided if the athletic trainer
j Has a good understanding of the existingcondition which is to be treated
j Uses the most appropriate ions toaccomplish the treatment goalj Uses appropriate treatment parameters
and equipment set-up
8/7/2019 Chap 6- Iontophoresis
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Chemical Treatment Burns
Most common problem is a chemical burnwhich occurs as a result of direct currentitself and not because of the ion beingused
j Continuous direct current creates migration of ions which alters the normal pH of the skin
j Chemical burns typically result fromaccumulation of sodium hydroxide at cathode
j Alkaline reaction causes sclerolysis of localtissues
j Decreasin current densit b increasin size
8/7/2019 Chap 6- Iontophoresis
http://slidepdf.com/reader/full/chap-6-iontophoresis 41/42
Thermal Treatment Burns
Thermal burns may occur due to highresistance to current flow created by
poor contact of the electrodes with theskinj Electrodes are not moist enoughj Wrinkles in the gauze or paper towels
impregnated with the ionic solutionj Space between the skin and electrode
around the perimeter of the electrode
j Body weight resting on top of electrode
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