Iontophoresis Medications & Substances: Literature Guide

by Service, Training and Support·November 10, 2025

Iontophoresis

Medications and Substances Delivered by Iontophoresis: Evidence and Polarity Guide

Iontophoresis uses a low-level direct electrical current to increase the movement of ionic or polar substances across the skin. In simplified terms, a positively charged substance is placed beneath the positive electrode, while a negatively charged substance is placed beneath the negative electrode.

The actual process is more complex than “like charges repel.” Drug movement can also be affected by electro-osmosis, changes in skin permeability, molecular size, concentration, competing ions, treatment duration, electrode design, skin resistance, and the chemical form of the substance.

This guide reviews substances that have been reported in clinical, diagnostic, historical, or experimental iontophoresis literature. It is an educational index—not a medication order, treatment protocol, or statement that every substance is appropriate for current clinical use.

Important: The appearance of a substance in published literature does not establish that it is effective, FDA-approved for iontophoretic administration, compatible with a particular electrode or patch, or appropriate for an individual patient. Always follow the prescription, pharmacy instructions, product labeling and device Instructions for Use.

For general information about dose, current, and electrode placement, visit our Iontophoresis Frequently Asked Questions.

Iontophoresis Substances at a Glance

Substance or solutionCommonly reported chargePrincipal literature applicationEvidence summary
Dexamethasone sodium phosphateNegativeSelected inflammatory musculoskeletal conditions and tendinopathiesCondition-specific clinical evidence; outcomes vary
Acetic acid or acetateNegativeCalcific tendinopathy and plantar heel painLimited and mixed clinical evidence
Lidocaine hydrochloridePositiveLocal dermal anesthesiaSupported by multiple controlled studies
PilocarpinePositiveSweat induction for cystic-fibrosis testingEstablished diagnostic application
Tap waterBoth polarities are typically alternatedPalmar and plantar hyperhidrosisEstablished dermatologic application
Glycopyrrolate or glycopyrroniumPositiveHyperhidrosisReported in smaller and older studies
Sodium salicylateNegativePain and inflammatory conditionsLimited older clinical literature
Sodium diclofenacNegativeLateral elbow painLimited small-study evidence
HyaluronidaseFormulation-dependentHistorically investigated for edema and tissue permeabilityLimited or historical reports
Magnesium, calcium, iodide, zinc and other ionsIon-dependentVaried historical physical-medicine and dermatologic purposesPredominantly historical or low-level evidence
Vincristine or vinblastinePositive in older reportsHistorical investigations of severe neuralgiaHazardous cytotoxic drugs; not routine rehabilitation use

The strongest evidence and clearest accepted uses do not necessarily involve the same clinical specialty. Pilocarpine iontophoresis is established in diagnostic sweat testing; lidocaine has controlled evidence for local anesthesia; and tap-water iontophoresis is recognized in hyperhidrosis care. Rehabilitation uses such as dexamethasone or acetic acid tend to have more condition-specific and mixed results. (Cystic Fibrosis Foundation)

How to Interpret the Evidence

This article uses four general evidence categories.

Evidence categoryMeaning
Established applicationSupported by clinical guidance, standardized diagnostic practice or multiple controlled studies
Condition-specific evidenceSupported for a defined condition, but not necessarily generalizable to other diagnoses
Limited evidenceSmall studies, inconsistent findings, case reports or older trials
Historical or experimentalReported in older publications, laboratory research, specialty drug-device development or isolated clinical reports

A study demonstrating that a substance entered the skin or was detected in underlying tissue does not prove that the treatment improved pain, healing, or function. Pharmacokinetic transport and clinical effectiveness are separate research questions.

Why Salt Form and Polarity Matter

Medication names alone are not sufficient for selecting electrode polarity. The full formulation matters.

For example:

  • Dexamethasone sodium phosphate is generally treated as a negatively charged phosphate formulation.
  • Lidocaine hydrochloride is commonly delivered as a positively charged ion.
  • Acetic acid produces negatively charged acetate ions in solution.
  • Pilocarpine salts are commonly delivered from the positive electrode.
  • Potassium iodide contains positively charged potassium and negatively charged iodide ions; the intended therapeutic ion must be identified.

Polarity can be influenced by:

  • The particular salt form
  • Solution pH
  • Concentration
  • Buffering agents
  • Preservatives
  • Competing ions
  • The medication vehicle
  • The product’s specific Instructions for Use

Before connecting an iontophoresis electrode, consult the prescription, dispensing pharmacy, and product labeling. Our Iontophoresis Electrode Directions for Use provides additional guidance on electrode connections and polarity.

Dexamethasone Sodium Phosphate Iontophoresis

Dexamethasone sodium phosphate is one of the most frequently discussed iontophoresis medications in physical therapy, sports medicine, and rehabilitation literature.

Dexamethasone considerationLiterature summary
Common formulation describedApproximately 0.4%, equivalent to 4 mg/mL
Commonly reported polarityNegative
Drug classCorticosteroid
Reported clinical areasAchilles tendinopathy, lateral epicondylitis, plantar heel pain, carpal tunnel syndrome and other inflammatory presentations
EvidenceVaries considerably by diagnosis and study design
Main cautionA reported anti-inflammatory rationale does not establish benefit for every tendinopathy

Human studies have confirmed that treatment conditions such as current magnitude, treatment duration, competing ions, and skin thickness influence dexamethasone-phosphate transport. Clinical results, however, have not been uniformly positive. (PubMed)

Achilles tendinopathy

The 2024 Academy of Orthopaedic Physical Therapy clinical practice guideline retains a grade-B recommendation that clinicians use dexamethasone iontophoresis to decrease pain and improve function in acute midportion Achilles tendinopathy. The recommendation is diagnosis- and stage-specific; it should not be generalized to every Achilles disorder or chronic tendon presentation. (APTA Orthopedics)

Lateral epicondylitis

Clinical studies have reported short-term improvements after dexamethasone iontophoresis for lateral epicondylitis, including earlier improvement in grip strength or return to unrestricted work in some comparisons. These findings do not establish superior long-term outcomes over every other treatment. (Jhandsurg)

Balego also provides a summary of corticosteroid iontophoresis compared with injection for lateral epicondylitis.

Plantar heel pain

A small randomized trial compared 0.4% dexamethasone, 5% acetic acid, and saline placebo iontophoresis when all groups also received low-dye taping and stretching. The study supports describing these substances as investigated treatments, but its size and combined interventions limit broad conclusions. (PMC)

Acetic Acid Iontophoresis

Acetic acid has traditionally been discussed for conditions involving calcium deposits because acetate is a negatively charged ion. Common literature examples include 2% to 5% solutions, although the presence of a published concentration is not a recommendation to compound or administer it.

Acetic-acid considerationLiterature summary
Reported active ionAcetate
Commonly reported polarityNegative
Frequently cited concentration5% in several musculoskeletal studies
Reported usesCalcific tendinopathy and plantar heel pain
Evidence qualityLimited and inconsistent
Appropriate conclusionInvestigated in the literature, not proven to “dissolve” every calcium deposit

Calcific shoulder tendinopathy

A double-blind randomized trial found that adding acetic-acid iontophoresis to physiotherapy did not produce better clinical or radiographic results than physiotherapy alone. Case reports and uncontrolled series have described improvement, but these lower-level reports cannot establish that acetic acid caused deposit resorption. (ScienceDirect)

This distinction is important for SEO and clinical accuracy. The page should not claim that acetic acid iontophoresis reliably “dissolves calcium,” “removes bone spurs," or reverses calcific tendinopathy.

Plantar fasciitis and heel pain

Acetic acid has also appeared in plantar fasciitis and heel pain literature. The available studies are generally small and frequently combine iontophoresis with taping, stretching, orthoses or other interventions. Results should therefore be described as preliminary or condition-specific rather than definitive. (PMC)

Lidocaine Iontophoresis

Lidocaine is a local anesthetic. Lidocaine hydrochloride is commonly described as positively charged for iontophoresis.

Lidocaine considerationLiterature summary
Commonly reported polarityPositive
Studied formulationsFrequently 2% or 4%, sometimes with epinephrine
Principal applicationLocal dermal anesthesia
EvidenceMultiple randomized and controlled studies
Important limitationAnesthesia studies do not validate unrelated musculoskeletal uses

Controlled studies have evaluated iontophoretic delivery of 2% lidocaine with epinephrine before intravenous cannulation and dermatologic procedures. Several reported reduced procedural pain or a reduced need for supplemental anesthetic compared with the placebo. (PubMed)

Other research has compared iontophoretic lidocaine with injection, topical application, and alternative enhanced-delivery methods. The depth, onset, and duration of anesthesia depend on the formulation and delivery conditions. (PubMed)

Lidocaine should not be added to a patch or electrode unless it has been specifically prescribed and the formulation is compatible with the selected drug-delivery system.

Pilocarpine Iontophoresis for Sweat Testing

Quantitative pilocarpine iontophoresis occupies a different category from rehabilitation drug delivery. It is a standardized method of stimulating sweat so that sweat chloride can be measured during evaluation for cystic fibrosis.

The Cystic Fibrosis Foundation states that quantitative pilocarpine iontophoresis remains the standard sweat-testing method for cystic fibrosis diagnosis. Collection, measurement, and interpretation require rigorously controlled laboratory procedures. (Cystic Fibrosis Foundation)

Pilocarpine considerationLiterature summary
Reported polarityPositive
PurposeSweat stimulation
Main applicationQuantitative sweat-chloride testing
StatusEstablished diagnostic application
Appropriate settingQualified laboratory or accredited clinical program
Not equivalent toRoutine rehabilitation iontophoresis

Pilocarpine sweat testing should not be attempted using ordinary physical-therapy electrodes or wearable medication patches.

Tap-Water Iontophoresis for Hyperhidrosis

Tap-water iontophoresis is used to reduce excessive sweating, particularly of the palms and soles. No prescription medication is necessarily added to the water; the treatment involves current passing through the water and the treated area.

Because both sides are treated and polarity may be alternated, tap-water iontophoresis does not fit neatly into a single medication-polarity chart.

Tap-water considerationLiterature summary
Primary applicationPalmar and plantar hyperhidrosis
Added prescription drugNot necessarily
PolarityCommonly alternated
EvidenceRecognized dermatologic application
Axillary useEvidence and practicality are less consistent
MaintenanceFrequently required after initial response

Clinical literature and dermatology reviews identify iontophoresis as an established option for localized hyperhidrosis. Evidence is strongest for palmar and plantar areas, while axillary results and device practicality are more variable. (JAAD)

Anticholinergic additives

Older and smaller studies have examined anticholinergic agents such as the following:

  • Glycopyrrolate or glycopyrronium bromide
  • Atropine sulfate
  • Poldine methylsulfate

Some reports compared glycopyrrolate-enhanced treatment with tap water or combined an anticholinergic with aluminum chloride. These approaches carry medication-specific risks and should not be presented as routine home-water additives. (JAAD)

A recent randomized study also compared aluminum chloride hexahydrate gel iontophoresis with tap-water iontophoresis for palmar hyperhidrosis, illustrating that research in this area continues to evolve. (PubMed)

Salicylate and Diclofenac Iontophoresis

Sodium salicylate and sodium diclofenac have both appeared in musculoskeletal iontophoresis studies.

SubstanceCommonly reported chargeReported applicationEvidence status
Sodium salicylateNegativePainful or inflammatory musculoskeletal conditionsLimited older evidence
Sodium diclofenacNegativeLateral epicondylitisLimited small-study evidence

One randomized study assigned patients with lateral epicondylitis to sodium-diclofenac or sodium-salicylate iontophoresis. This demonstrates that both substances have been clinically investigated, but a small comparative study is not enough to establish either as a standard iontophoresis medication. (PubMed)

Medication-specific contraindications remain relevant even when a drug is administered through the skin.

Historical Substances Reported in Iontophoresis Literature

The following entries appear in older medical, dermatologic, or physical-medicine literature. Many rely on case reports, uncontrolled observations, or outdated formulations or product names that are no longer commonly used.

Substance or historical termCommonly reported ion or polarityHistorical purpose describedCurrent interpretation
Atropine sulfatePositiveHyperhidrosisHistorical anticholinergic use
Calcium chlorideCalcium ion: positiveMuscle spasm or impaired muscle functionPredominantly historical
Sodium chlorideChloride ion: negativeScar tissue or adhesionsWeak historical rationale
Potassium citrateCitrate ion: negativeRheumatic conditionsHistorical and poorly supported
Copper sulfateCopper ion: positiveAstringent or antifungal purposesHistorical
Gentamicin sulfateCommonly treated as positiveLocal antimicrobial deliveryIsolated specialty reports
HyaluronidaseFormulation- and pH-dependentEdema or enhancement of tissue permeabilityHistorical; not a general iontophoresis additive
IdoxuridineFormulation-dependentHerpes-simplex applicationsHistorical antiviral research
Iodide or potassium iodideIodide ion: negativeScar tissue or fibrosisHistorical
Lithium chlorideLithium ion: positiveGouty arthritisHistorical
Magnesium sulfateMagnesium ion: positiveMyalgia, spasm or vasodilationHistorical
Methacholine chloride or MecholylPositiveVasodilationObsolete therapeutic context
Methylprednisolone sodium succinateFormulation-dependentInflammatory or neuralgic conditionsLimited specialty reports
Penicillin saltsDepends on specific salt and pHInfected wounds or burnsHistorical
Silver saltsSilver ion: positiveInfection or osteomyelitisHistorical
Zinc compoundsZinc ion: positiveUlcers, dermatitis or wound healingCase-level and historical reports
Meladinine sodium saltReported as negativeVitiligo with ultraviolet treatmentHistorical terminology and protocol
Vincristine or vinblastinePositive in the cited reportSevere post-herpetic or trigeminal neuralgiaHazardous cytotoxic drugs; not routine use

A 1982 report described iontophoretic administration of vincristine or vinblastine for chronic neuralgia. These are potent cytotoxic chemotherapy drugs, and the old report should be treated as medical history—not as a practical rehabilitation protocol. (PubMed)

Similarly, a 1969 publication reported iontophoresis of the sodium salt of “meladinine” for vitiligo. Modern readers should not assume that the historical name, formulation, or combined ultraviolet protocol corresponds to a currently available product. (PubMed)

Updating Obsolete Names in Older Iontophoresis Charts

Legacy charts often use trade names or terminology that can confuse modern readers.

Older termModern interpretation
MecholylHistorical brand name associated with methacholine chloride
Wyadase or WydaseHistorical hyaluronidase preparation
IodexProprietary topical iodine ointment rather than a standardized generic iontophoresis solution
MeladinineHistorical term associated with a khellin-related photosensitizing preparation used in vitiligo literature
“Iron/titanium oxide”Insufficiently defined in many secondary charts; exact compound and formulation must be identified
“Water, positive or negative."Usually refers to tap-water iontophoresis and electrode reversal, not drug delivery in the usual sense

These names should not be copied into a modern medication order without identifying the exact active ingredient, concentration, charge, vehicle, and source publication.

Newer and Experimental Iontophoresis Research

Modern transdermal research extends beyond traditional rehabilitation medications.

Substance or categoryResearch areaPresent status
DutasterideAndrogenetic alopeciaEmerging small clinical study
Tranexamic acidMelasmaSmall randomized dermatologic study
Botulinum toxinHyperhidrosisPilot and experimental delivery research
Insulin and peptide drugsSystemic transdermal deliveryPrimarily formulation and device research
Opioid analgesicsSpecialized systemic drug-device systemsNot interchangeable with rehabilitation iontophoresis equipment
Diclofenac and other NSAIDsLocal musculoskeletal deliveryHuman and preclinical research; formulation-specific
Nanoparticle-assisted drugsEnhanced transdermal transportExperimental

A 2025 study reported preliminary results for dutasteride delivered with iontophoresis in treatment-resistant androgenetic alopecia, while a randomized study investigated tranexamic-acid essence with iontophoresis for melasma. These specialized dermatologic techniques should not be assumed compatible with physical-therapy electrodes or wearable rehabilitation patches. (PubMed)

Reviews of transdermal iontophoresis also discuss peptides, systemic analgesics, and other larger or less skin-permeable molecules. Much of this work depends on purpose-built formulations and drug-device combinations. (PubMed)

Clinical Evidence: Transport Does Not Equal Treatment Success

When reviewing an iontophoresis paper, ask what the investigators actually measured.

Study outcomeWhat it establishesWhat it does not establish
Drug detected beneath the skinSome transdermal transport occurredSymptoms or function improved
Higher tissue concentrationDelivery differed from a controlThe concentration was clinically effective
Short-term pain reductionSymptoms changed during the measured periodLong-term recovery or tissue healing
Smaller radiographic depositImaging changedPain or function necessarily improved
Case-report successImprovement occurred in one or several patientsThe treatment caused the improvement
Laboratory skin modelTransport is physically possibleSafe or effective human use
Animal modelBiological activity may be plausibleHuman efficacy or appropriate dosing
FDA device clearanceThe delivery device met its cleared indicationEvery drug-device combination is approved

FDA documents describe iontophoresis devices generally as systems that use direct current to introduce ions of soluble salts or other drugs for medical purposes. The amount and distribution delivered can depend on charge, molecular weight, current, electrode composition, treatment duration and other variables. A device’s clearance does not independently validate every medication or formulation placed in it. (FDA Access Data)

Comparing Balego Iontophoresis Delivery Options

Selecting a medication is separate from selecting a delivery system. Dose capacity, polarity labeling, medication volume, and electrode design must all match the prescription and Instructions for Use.

Delivery formatBalego optionMain characteristicsBest workflow fit
Self-contained wearable patchIontoPATCH® STAT, 80 and Extra StrengthBuilt-in power source; 80 or 120 mA-min models; no external controllerMobile, extended-wear treatment when the formulation and polarity are compatible
Self-contained no-saline patchACTIVApatch® IntelliDose, IontoGo 4.0 and IontoGo 12.0No added saline; current models are designed around negatively charged ionic solutionsSimplified preparation and multiple treatment-time options
Controller-based electrode kitIonto4™ Iontophoresis ElectrodesDrug and dispersive electrodes used with a compatible constant-current controllerClinics requiring programmable current and treatment time
Buffered controller-based kitBuffered Iontophoresis Electrode KitsAg/AgCl drug electrode and buffered return electrodeProfessional controller-based treatments
Flexible electrode systemTrivarion™ Iontophoresis Delivery KitForm-fitting construction for curved or uneven areasSites where flat electrode contact is difficult

Medication is not included with these products. Current specifications and polarity limitations should be checked before purchasing or applying any system.

For a detailed wearable-patch comparison, read IontoPatch vs. ACTIVApatch.

Browse our complete selection of iontophoresis patches, controllers, and electrode kits.

Medication and Device Compatibility Checklist

Before iontophoresis, confirm all of the following:

QuestionWhy it matters
What is the exact medication name?Similar names can represent different active compounds
What is the salt form?Salt form can change polarity and transport
What is the prescribed concentration?Literature concentrations are not universal prescriptions
What is the intended active ion?Determines the drug-electrode polarity
Is the solution water-soluble and ionized?Strongly influences iontophoretic transport
Is the formulation compatible with the reservoir?Some patches have specific volume, pH and polarity requirements
Is the selected patch limited to negative medication?Not every wearable patch accepts both polarities
Is the medication included in the device labeling?Device and medication requirements must be checked separately
Does the patient have a medication contraindication or allergy?Transdermal administration does not eliminate drug risk
Is the skin intact and appropriate for treatment?Skin damage can alter current density and absorption
Has the pharmacist confirmed the formulation?Pharmacy review helps prevent polarity and compatibility errors

Documentation Checklist

For each treatment, consider documenting:

  • Exact drug and salt form
  • Concentration and volume
  • Prescriber and order date
  • Reported medication polarity
  • Active-electrode polarity
  • Electrode or patch brand and model
  • Treatment site
  • Programmed or patch dose in mA-min
  • Current and time when a controller is used
  • Skin condition before application
  • Patient response during treatment
  • Skin condition after removal
  • Patient instructions and expected removal time
  • Any adverse reaction or treatment interruption

For coding considerations, see our Iontophoresis Reimbursement Codes and Documentation Guide.

Frequently Asked Questions

What medications are most commonly associated with physical therapy iontophoresis?

Dexamethasone sodium phosphate is the medication most frequently discussed in contemporary physical therapy and sports medicine literature. Acetic acid, lidocaine, salicylates, and selected NSAIDs have also been investigated, but the quality and consistency of evidence vary.

Is dexamethasone positively or negatively charged?

Dexamethasone sodium phosphate is commonly treated as negatively charged and is generally placed beneath the negative drug electrode. Confirm the exact formulation and device instructions.

Is lidocaine positive or negative for iontophoresis?

Lidocaine hydrochloride is commonly treated as positively charged. Other lidocaine formulations should not automatically be assumed to have identical iontophoretic characteristics.

Is acetic acid positive or negative?

The acetate ion is negative and is generally delivered from the negative electrode.

Does acetic-acid iontophoresis dissolve calcium deposits?

That claim is not supported as a reliable general outcome. A randomized trial of calcific shoulder tendinopathy found no better clinical or radiographic results from acetic-acid iontophoresis plus physiotherapy than from physiotherapy alone. (ScienceDirect)

What is the best medication for iontophoresis?

There is no universal best medication. The selection depends on the diagnosis, evidence for that condition, the prescriber’s order, medication risks, polarity, formulation, device labeling, and patient-specific factors.

Can any water-soluble medication be used?

No. Water solubility alone does not establish suitable charge, stability, safety, tissue delivery, effectiveness, or device compatibility.

Can two drugs be mixed in one iontophoresis electrode?

Only when specifically prescribed, compounded, and confirmed compatible by qualified pharmacy and clinical personnel. Combining solutions can change pH, charge, stability, and the amount of each drug transported.

Is tap water iontophoresis drug delivery?

Not in the conventional sense. It is commonly used for hyperhidrosis without an added prescription drug. The electrical treatment and ions naturally present in the water contribute to the effect.

Is pilocarpine iontophoresis a physical-therapy treatment?

No. Quantitative pilocarpine iontophoresis is primarily a controlled diagnostic procedure used to stimulate sweat for cystic fibrosis testing.

Are the historical ions still used today?

Some appear mainly in older textbooks and case reports. Their presence in a historical chart does not mean they remain accepted, available, or appropriate for current practice.

Can chemotherapy drugs be delivered by iontophoresis?

Specialized studies have investigated cytotoxic substances, including an old report involving vincristine and vinblastine. These hazardous drugs should never be treated as ordinary rehabilitation additives or handled outside appropriate oncology, pharmacy, and research controls.

Does FDA clearance of an iontophoresis device approve the medication?

Not by itself. Device clearance and drug approval are distinct regulatory questions. The drug, formulation, device labeling, and intended use all require separate verification.

Where can I compare iontophoresis patches and electrodes?

Visit Balego’s iontophoresis collection or read the IontoPatch vs. ACTIVApatch comparison.

Selected Research References

  1. Transdermal iontophoresis: mechanisms and drug-delivery principles
  2. 2024 Clinical Practice Guideline for Midportion Achilles Tendinopathy
  3. Effects of current magnitude and duration on dexamethasone delivery
  4. Skin thickness, time and dexamethasone-phosphate absorption
  5. Acetic-acid iontophoresis for calcific shoulder tendinopathy: randomized trial
  6. Dexamethasone and acetic-acid iontophoresis for plantar fasciitis
  7. Lidocaine iontophoresis before intravenous cannulation
  8. Lidocaine iontophoresis before pediatric dermatologic procedures
  9. Cystic Fibrosis Foundation Sweat Test Guidelines
  10. Tap-water iontophoresis for palmar and plantar hyperhidrosis
  11. Sodium salicylate and sodium diclofenac iontophoresis for lateral epicondylitis
  12. Historical vincristine and vinblastine iontophoresis report

Medical and Regulatory Notice

This article is intended for healthcare professional education and literature review. It does not recommend or authorize the use of any medication, chemical, or solution with an iontophoresis product.

Use only:

  • A valid medication order
  • The exact prescribed formulation
  • A compatible FDA-cleared device or electrode system
  • The current manufacturer's Instructions for Use
  • Applicable pharmacy and facility policies
  • Appropriate patient screening and monitoring

Do not use this article as a compounding formula, dosing protocol, or substitute for medical, pharmaceutical, or regulatory guidance.

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