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iontophoresis lit review....at last:)
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iontophoresis lit review....at last:) - November 26, 2002 5:32:00 PM
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coloradojulie
Posts: 413
Joined: November 10, 2002
From: colorado usa
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Okay, I dug it up! I left one more message in the "supraspinatus" post regarding the australian evidence based web site and the recent medline search.
Anyway, I used 8 articles from the years ranging 1982 to 1997 (the search was done in 2000). I also used the manufacturers "studies" with a very large grain of salt. The studies:
1. Gudeman et al., 1997: Treatment of Plantar Fascitis by Ionto. of .4% Dex.: A RCT, Double Blind, Placebo Controlled Study.
2. Banta, 1994: Iontophoresis treatment of carpal tunnel syndrome (prospective, non-randomized).
3. Petelenz et al., 1992 Iontophoresis of Dex.: Lab Studies. (comparison of negative and positive electrode placement effectiveness at delivering dex)
4. Hasson, 1988: Effects of iontophoretically delivered dex on muscle performance in RA Joints.
5. Braun, 1987: Treatment of Anterior Disc Displacement in the TMJ. (case report)
6. Delacera, 1982: A Comparative Study of three methods of treatment for the shoulder girdle myofascial syndrome.
7. Bertolucci, 1982: Introduction of anti-inflammatory drugs for iontophoresis (double blind)
8. Harris, 1982: Iontophoresis: Clinical Research in Musculoskeletal inflammatory conditions.
I used this information to develop the following treatment information:
Iontophoresis: The introduction of ions into the tissue using continuous galvanic electrical current.
Benefits:
1. Noninvasive.
2. Not effected by GI absorption.
3. Bypasses hepatic filtration metabolism.
4. Reduces overdose risk.
5. Able to use a drug with a shorter biological half-life due to directness of delivery.
6. Simple regimen.
7. Good control of medicine distribution per dosage control.
8. Accelerated symptom reduction in certain inflammatory conditions.
9. Treatment can be repeated with minimal side effects, unlike injection of corticosteroids.
Contraindications:
1. Electrode placement over the temporal region.
2. Electrode placement on or near eyes.
3. Open wounds or skin irritation.
4. Sensitivity to medication or electrode substance.
5. Implanted electrically sensitive devices such as pace makers.
6. Areas of hyposensitivity (require close monitoring.)
Current Clinical Limitations:
1. Physical therapists must rely on a physician for prescribing the medication for clinical use.
2. Relatively expensive due to the high cost of electrodes and treatment units.
3. Limited study data as to the clinical effectiveness of this modality.
4. Limited educational accessibility in most PT programs.
Substances:
1. Dexamethasone 0.4% Sodium Phosphate: anti-inflammatory effect (negative ion)
2. Lidocane: Temporary anesthesia (positive charge)
3. Epinephrine: vaso constrictor (pos.)
4. Hyaluronidase: edema reduction, reduce joint swelling from hemarthrosis, and schleroderma (pos.)
5. Histamine: pain and swelling reduction particularly related to arthritis and muscle spasms
6. Zinc: promote healing reduce infection. (pos)
7. Copper: chronic fungal infections. (pos)
8. Magnesium: inflammation (pos)
9. Lithium: gout. (pos)
10. Acetic acid: myositis ossificans. (neg)
11. Iodide "iodex": reduction of scar tissue (?neg)
12. Insulin. minimal introduction, diabetes
13. Sodium Chloride: scar tissue management. (pos?)
Iontophoresis is currently used in dentistry, dermatology, otorhinolaryngology, opthamology, medicine and allied health.
Application Principles:
1. Polarity: Electrode placement is dependent on the electric charge of the ion which you are trying to deliver into the tissue. A positive ion will be delivered from the positive electrode and a negative ion will be delivered by the negative electrode. Similar premise to like charged magnets repelling each other. Opposite charges attract.
2. Electroosmosis: The passage of a solvent along with its' dissolved substances into the tissue which is sensative to changes in skin pH.
Normally the skin pH is between 3 and 4 (isoelectric). When introducing ions, an increase or decrease in pH can enhance the passage of these ions. Greater than 4 the skin carries a negative charge which can enhance the passage of positive ions (cations) from the anode (positive electrode). With a pH lower than 3 the skin carries a positive charge enhancing migration of negatively charged (anions) from the the cathode (negative electrode).
3. pH: Most electrodes are designed to maintain a stable and optimal pH for the delivery of different medications. Buffers are often added to decrease acidity and prevent tissue irritation.
4. Pore Transport: Due to the nature of the stratum corneum, it is most permeable at the sweat glands and hair follicles.
5.. Semipermiable: The tissue is more permeable to certain types of substances than others, dependant on size, charge, hydrophobic/phillic nature.
6. Penetration/Distribution of Ions: Varying evidence. Some studies have shown penetration and concentration to deeper tissues (with both anti-inflam and anaesthesia)(tendonous and cartilagenous tissues of monkey). Other studies have shown penetration to a depth of 1 cm while others that the subcutaneous circulation will remove all medication and there will be not therapeutic effect. Other more recent evidence suggests that the medication delivered with ionto penetrates slowly into the dermal layer resulting in slow and sustained absorption of meds.
7. Skin injury: Most problematic under the negative electrode. Prevention of burns to skin can be accomplished by:
1. Thoroughly cleaning the area (soap/swab)
2. Using well saturated electrodes (per the required amount)
3. No contact between metal of electrode and skin
4. even skin contact with electrode
5. keeping the current at the cathode at a comfortable level for the patient (ie. not to burning sensation)
6. Keeping the dispersive pad at least 8 cm away and ideally placed over a muscle mass.
8. Dosage: Measured in coulombs. It is the current (in milliamperes) multiplied by the treatment time (minutes) equaling the dose in milliampere-minutes. Literature has demonstrated to date the ideal dose is between 40 and 80 mA-minutes. The intensity of the treatment is inversely proportional to treatment time. Treatment intensity may vary anywhere from 2-4 mA. Three to six treatments is advocated at least one day apart at 10-20 minute duration.
Indications:
1. Plantar fascitis.
2. Shoulder tendonitis.
3. TMJ.
4. Epicondylitis.
5. Carpal Tunnel
6. DeQuervians.
7. ITB friction syndrome.
8. Bursitis.
9. DJD.
10. RA.
11. Muscle spasm.
12. Myofascial pain.
13. Scar tissue.
Iontophoresis was first tested clinically in 1900 by Leduc. Using two rabbits, he placed strychnine on the positive electrode and cyanide on the negative electrode. The first rabbit went into convulsions, the second one died. Reversing polarity of the electrodes demonstrated no effect on subsequent bunnies. (I tell that to my patients just before I hook them up!)
Anyway that is how I decided to use ionto and how we would use it clinically...comments?
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Re: iontophoresis lit review....at last:) - November 26, 2002 5:56:00 PM
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PTupdate.com
Posts: 1490
Joined: October 8, 2001
From: Pittsburgh, PA USA
Status: offline
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Julie,
Great literature review. Too bad there isn't more available on the topic. Didn't see anywhere in your listing about the ice phenomenon?
Here is an abstract I did regarding ionto and venous blood contents:
FAILURE TO DETECT DEXAMETHASONE PHOSPHATE IN THE LOCAL VENOUS BLOOD POSTCATHODIC IONTOPHORESIS IN HUMANS. JOSPT, Vol. 32, No. 9, September 2002
Michael A. Smutok, PT, PhD Michele F. Mayo, MS
Catherine L. Gabaree, PhD Kenneth E. Ferslew, PhD
Peter C. Panus, PT, PhD
ABSTRACT
Previous studies have tested the drug delivery capabilities of iontophoresis using radioactive labeled compounds, elbow synovial fluid of a rhesus monkey, and at the equine tibiotarsal joint. Some have used dosage parameters that are far higher than those that can be used on humans without the risk of tissue injury or burn. These authors wanted to first determine an effective method of extraction and an analysis protocol for dexamethasone in human plasma. The other aim was to determine if accurate delivery could be assessed via body fluids. The last was to determine the concentrations of dexamethasone in venous blood return after delivery of the drug using standard clinical application parameters.
In the first portion of the study, the authors determined that optimal extraction of dexamethasone and dexamethasone phosphate was achieved from plasma rather than blood, due to a higher buffering capacity and lower pH. It was also discovered that to accurately quantify the drug delivery to the body, these two compounds need to be determined in plasma, along with all biologic fluids and body tissues. In the pooled plasma used by these authors, only 5% of the dexamethasone phosphate dephosphorylated into dexamethasone within 2.5 hours, compared to a 50% rate in 5 hours seen by other authors.
For the clinical portion of the trial, 6 volunteers received a standard treatment of iontophoresis while a heparinized catheter was placed in a proximal vein, so that blood could be drawn before, during, and after the treatment. The degree of drug that was to be found was going to be considered a proxy for the amount of drug that was delivered interstitially. No drug was found in the venous return on these subjects. Measurement of in situ drug concentrations after standard clinical delivery is necessary in further studies to determine the clinical usefulness of this modality.
COMMENTS
Treatment with dexamethasone iontophoresis is becoming more common and popular, and even physicians are requesting it by name on prescriptions. To date, we have used evidence which may have some flaws to support the treatment. I think most clinicians would agree that we see improvement with the treatment compared to times we do not. Plantar fasciitis patients seem to improve faster with the treatment compared to those that do not, often due to lack of payment for the treatment by their insurer, or allergy to corticosteroids. When referencing previous studies, they note that reduced blood flow in the region of treatment may result in greater drug concentrations and greater depth of treatment. My clinic has always performed the treatment with ice, in order to reduce blood flow, and our methodology was based on the previous studies that found the drug in the blood stream following treatment. We figured that reducing the amount flushed out of the tissues and into the blood would increase effectiveness. This study may indicate that the drug does not really get into the blood stream anyway, but the ice may increase the depth of treatment and increase the concentration. The optimal test for this modality would be whole tissue biopsy following the treatment to determine concentration and depth with standard protocols, which cannot ethically be done in humans. Perhaps an option would be to perform the test on a person prior to amputation, where the limb is going to be sacrificed anyway.
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Re: iontophoresis lit review....at last:) - November 27, 2002 3:15:00 AM
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Andrew M. Ball PT PhD
Posts: 855
Joined: July 28, 2002
From: Charlotte, NC
Status: offline
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Julie,
You should DEFINATELY try to publish this. This is EXACTLY the systematic literature review that clinical artists struggling to be more evidence-based in a world of limited time are searching for. Don't worry about developing it into a meta-analysis. It's publishable as is as an excellent and clinically applicable literature review.
I'd be happy to work with you in that effort if you'd like.
Drew
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Re: iontophoresis lit review....at last:) - November 28, 2002 4:40:00 PM
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coloradojulie
Posts: 413
Joined: November 10, 2002
From: colorado usa
Status: offline
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Thanks for the feedback...I would be interested in publishing, I guess, but I am sure a more exhaustive search is necessary...what are the steps?
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