AVANIANBAN CHAKKARAPANI

LECTURE 11; 5.2.2015; 14.00 TO 15.00

K 401

Iontophoresis

HOW DOES IT WORK

PRINCIPLE

• Current required

• Ionic polarity

• Low-level amplitude

• Electrode size

Current Required

• Direct Current or Galvanic current

• Monophasic pulsed current

• Constant current is preferable to constant

voltage thus, the magnitude of the applied

current will not exceed the present level in

terms of skin resistance.

Ionic Polarity

• The basis of successful ion transfer lies in

basic physics principle i.e LIKE POLES

REPELS each other.

• Ions with same polarity which is the same

as that of stimulating electrode are

repelled into the skin

• The electrode under which the ionic

solution is placed called ACTIVE

ELECTRODE.

Ionic Polarity

• The other electrode placed to complete

the circuit called passive electrode or

inactive electrode or dispersive electrode.

Low level Amplitude

• It is more effective

• The treatment usually applied with

currents up to 5 mA

• With low ionic concentrations up to 5 %

• Treatment time up to 10 – 30 min range

Electrode Size

• The –ve electrode should be larger than

anode ( usually twice)

• Enlarging the negative electrode size

lower the current density on the negative

pad, leading to reduction of irritation.

Physiological Changes

• Ion penetration

• Acid/ alkaline reaction

• Hyperemia

• Dissociation

Ionic Penetration

• Penetration does not exceed 1mm.

• Subsequent deeper absorption through

the capillary circulation.

• The bulk of the deposited ions at the

active electrode are stored, to be depleted

by the sweep of circulating blood.

Acid/Alkaline Reaction

• Will get ACID accumulation under the

positive electrode (HCL).

• This is because the negatively charged

chloride ions (cl- from Nacl) is attracted

towards the anode.

• This is considered sclerotic, which tens to

harden tissues, serving as analgesic agent

due to local release of oxygen.

Acid/Alkaline Reaction

• Alkaline accumulation under the cathode

• Because the positively charged sodium

ions (Na+ from NaCl) will move towards

cathode.

• The Na+ reacts with water to form NaOH.

• Considered sclerolytic, which is softening

agent due to hydrogen release, serving in

management of scars and burns.

Hyperemia

• Both the anode and cathode electrodes

produce hyperemia and heat due to the

vasodilatation.

• The cathodal hyperemia is generally more

pronounced and takes more time to

disappear than anode.

• Generally hyperemia under both the

electrodes does not lasts more than 1 hr.

Complications

• Chemical Burns

• Heat Burns

• Sensitive and allergic reactions to ions

Chemical Burns

Heat Burns

Allergic reactions to Ions

Indications

Selection of Ions

Common Drug Ions Used in

Sports Medicine

• Dexamethasone

– Negative ion

– Reduces inflammation by inhibiting

biosynthesis of prostaglandins and various

other inflammatory substances

• Acetate

– Negative ion

– Assists in dissolving calcium deposits and

scar tissue in soft tissues

Common Drug Ions Used in

Sports Medicine (cont.)• Hydrocortisone

– Positive ion

– Assists in decreasing tissue inflammation by inhibiting biosynthesis of prostaglandins

• Lidocaine– Positive ion

– Assists in decreasing local pain by blocking nerve impulse transmission

Ionto Advantages & Disadvantages

Advantages

Compared to injections:

Virtually painless

Noninvasive, minimizing…

Risk of infection

Risk of tissue necrosis, tendon rupture, etc.

Compared to oral medications:

Localized drug delivery, nonsystemic

Avoid risk of systemic side effects

Disadvantages

1. Eliminates pain or inflammationa. Doesn't deal with the

cause of the

pain/inflammation.

2. Slight risk of electrode burns

3. Some believe transdermal drug delivery is not possible.

Contraindications

Precautions

Current Density

Current Intensity

Treatment Time

Formula for Iontophoresis

Electrodes

• Traditional electrodes.

• Commercial electrodes.

Traditional electrodes

Commercial electrodes

Electrode Prepration

Application

Bibliography