IONOPHORESIS

Iontophoresis Therapy Guide

By iontophoresis (iòno-phòresis = transport of ions) we mean the introduction of a drug into the organism through

the epidermis (transcutaneous administration), using a direct current

(galvanic current), produced by a special generator.

The advantages of administering drugs with this modality are essentially:

Avoid administration by systemic route (oral, intramuscular, intravenous);

Apply the drug directly to the body site affected by the pathology;

Allow the introduction of the active ingredient alone, without carriers (excipients);

Allow ions to bind to certain protoplasmic proteins;

Hyperpolarize the nerve endings.

Regarding the route of administration, it is useful to remember that the systemic route presents

several contraindications; in fact, all drugs present the risk, more or less marked,

of side effects to the detriment of various organs and anatomical systems.

This is because, to ensure a valid therapeutic action, the drug must necessarily achieve

a blood concentration (percentage of drug circulating in the blood),

such as to be able to guarantee a valid therapeutic action.

All this determines the presence in the vascular circulation, as well as of the drug,

also of metabolites of the same, produced by the liver, which must be "disposed of"

from the body through various routes, first of all the renal route.

Added to this is the indirect damage caused by the drug to other organs, due to the alteration

the conditions in which this normally operates, as in the case of the digestive system,

in which some drugs alter the acid-base balance, even with serious consequences (e.g. gastritis

and gastroduodenitis caused by taking NSAIDs - Non-Steroidal Anti-Inflammatory Drugs).

The second advantage is that of being able to apply the drug directly to the area to be treated,

thus reducing therapeutic times, with consequent regression of symptoms in less time.

Painful conditions (pain) of the musculoskeletal system, resulting from arthritis, arthrosis, sciatica, low back pain, cervical pain,

muscle strains, etc., are therefore treated by limiting the therapeutic effect only to the affected area.

The third is the possibility of introducing only the active ingredient of the drug, in ionic form,

without the excipients, which often cause more or less adverse reactions.

At the fourth point we must consider that the drug binds in ionic form

to specific protoplasmic proteins, increasing their residence time in the

anatomical sites involved (half-life), thus being able to reduce the quantities

of drug used for the same pathology compared to other routes of administration.

It was possible to measure that this therapeutic system has the ability to make people absorb

to the affected region a quantity of drug up to 100 times greater than that absorbed,

for example, orally.

Lastly, the application of low intensity direct currents has a significant result

to hyperpolarize the nerve endings, causing their elevation

of the excitability threshold, thus obtaining a high analgesic effect (TENS effect).

All this is possible because all drugs have the characteristic of presence

of positive, negative, or both ions (bipolar) - therefore electrically charged - and, exploiting

therefore the physical principle of ion migration from one electric pole to another, we obtain

a transcutaneous administration, which uses the skin as an administration route.

From a strictly electronic point of view, a generator for iontophoresis

it is essentially a low intensity constant current generator (generally

currents between 5 milliamps and 10 milliamps are used),

that is, it supplies a direct current that is stable over time, accompanied by various control systems

and timing, so as to allow the creation of an electric field which

is applied via two electrodes, one positive and the other negative, constituted

by conductive rubber plates covered with an absorbent surface, placed on the skin

of the subject near the area to be treated.

The drug must be placed on the electrode corresponding to its polarity,

for example, if the drug is of positive polarity it will be applied to the positive plaque, if negative

on the negative plate, if bipolar indifferently.

Applying the plaque with the drug on the area to be treated and the other plaque at a distance

of approximately 20/30 cm, the current will convey the ionized drug inside the tissues

because the ions of the drug itself will migrate towards the opposite pole until complete absorption.