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What It Is
A PHMB dressing is an antimicrobial wound dressing impregnated with polyhexamethylene biguanide (PHMB, also called polyhexanide), designed to suppress bacterial colonization within the dressing substrate and protect exuding wounds from infection. Its core purpose is to maintain a sustained antimicrobial barrier against strike-through contamination without releasing cytotoxic chemical levels into healing tissue.
Who uses it: Wound care nurses, clinical procurement specialists, surgical staff, and clinical research teams managing acute or chronic wounds requiring bioburden control.
In healthcare supply chains, PHMB dressings serve as an effective alternative to silver-based dressings and topical antibiotics. Unlike ionic silver dressings, PHMB does not stain tissue, does not require light-protective storage, and maintains steady antimicrobial action across diverse exudate levels. Facilities commonly pair PHMB dressings with non-adherent dressing contact layers or use them following wound cleansing governed by antiseptic for wound care protocols.
How It Works or Is Built
A PHMB dressing incorporates polyhexamethylene biguanide into an absorbent carrier—typically woven cotton gauze, non-woven fabric, or open-cell hydrophilic polyurethane foam. PHMB is a synthetic cationic polymer composed of repeating biguanide groups joined by flexible hexamethylene chains.
The antimicrobial mechanism relies on electrostatic binding and cell membrane disruption:
- Electrostatic Attraction: Positively charged biguanide groups bind to negatively charged lipopolysaccharides and phospholipids on bacterial cell envelopes.
- Membrane Disruption: PHMB displaces stabilizing divalent cations (Ca2+ and Mg2+), destabilizing the lipid bilayer and causing cytoplasmic contents (notably potassium ions) to leak out.
- Cell Lysis: Continued disruption leads to irreversible membrane breakdown and cell death across Gram-positive (including MRSA and VRE) and Gram-negative bacteria (such as Pseudomonas aeruginosa), as well as fungi.
- No Target Resistance: Because PHMB acts through physical membrane disruption rather than metabolic pathways, bacteria do not develop plasmid-borne resistance.
In the United States, the Food and Drug Administration (FDA) clears PHMB dressings under 510(k) premarket notifications. Most are classified under Product Code FRO (“Dressing, Wound, Drug”, unclassified / 510(k) review), including clearances K070653 (Kendall Kerlix AMD Super Sponge) and K011941 (Excilon AMD Antimicrobial Sponge). Occlusive gauze variants may reference Product Code NAD under 21 CFR 878.4020 (Class I). The physical structure parallels standard clinical silicone foam wound dressing or traditional gauze pad vs sponge formats.
Types and Variants
PHMB dressings are produced in several physical formats to accommodate different wound depths, exudate amounts, and anatomical locations.
| Dressing Type | Typical Clinical Use | Key Structural Difference |
|---|---|---|
| Gauze Sponges and Flats | Primary packing for cavity wounds, surgical incisions, and exudate absorption. | 100% woven cotton (USP Type VII) with 0.2% PHMB; breathable and non-linting, requires secondary tape or wrap. |
| Conforming Bandage Rolls | Limb wrapping, circumferential retention, and large-area burn coverage. | Crinkle-weave 6-ply cotton with 0.2% PHMB; conforms to joints and provides protective cushioning. |
| Non-Adherent Pads | Skin tears, donor sites, and lightly exuding surgical closures. | Perforated polyester/mylar film covering a 0.2% PHMB absorbent core; prevents trauma during removal. |
| Hydrophilic Foam Dressings | Moderate-to-heavy exuding pressure injuries, venous leg ulcers, and diabetic ulcers. | Open-cell polyurethane foam with 0.5% PHMB and a vapor-permeable polyurethane backing film. |
| Fenestrated Discs and Drain Sponges | Percutaneous lines, tracheostomy sites, surgical drains, and vascular catheters. | Pre-cut radial slit with a central aperture in foam (0.5% PHMB) or gauze (0.2% PHMB) to fit around tubing. |
Sizes or Specifications that Matter
Procurement teams must match product dimensions and substrates to Healthcare Common Procedure Coding System (HCPCS) billing categories. The table below lists sourced specifications, active concentrations, and CMS HCPCS reimbursement codes.
| Product Style and Model | Sourced Dimensions and Specs | Substrate and Concentration | CMS HCPCS Code |
|---|---|---|---|
| Kerlix AMD Super Sponge (Model 6662 / 6665) | 6 in. × 6.75 in. (medium sterile sponge, ~40.5 sq. in.) | 100% cotton gauze, 0.2% PHMB | A6223 (Gauze, impregnated, > 16 to ≤ 48 sq. in.) |
| Kerlix AMD Bandage Roll (Model 3331) | 4.5 in. × 4.1 yd (6-ply crinkle weave, roll) | 100% cotton gauze, 0.2% PHMB | A6266 (Gauze, impregnated roll, per linear yard) |
| Telfa AMD Non-Adherent Pad (Model 7662) | 3 in. × 4 in. (12 sq. in. pad area) | Perforated film/cotton, 0.2% PHMB | A6222 (Gauze, impregnated, ≤ 16 sq. in.) |
| Kendall AMD Foam Dressing (Model 55522) | 2 in. × 2 in. (4 sq. in. pad area) | Hydrophilic foam, 0.5% PHMB | A6209 (Foam dressing, ≤ 16 sq. in., no border) |
| Kendall AMD Foam Dressing (Model 55544) | 4 in. × 4 in. (16 sq. in. pad area) | Hydrophilic foam, 0.5% PHMB | A6209 (Foam dressing, ≤ 16 sq. in., no border) |
| Kendall AMD Foam Dressing (Model 55548) | 4 in. × 8 in. (32 sq. in. pad area) | Hydrophilic foam, 0.5% PHMB | A6210 (Foam dressing, > 16 to ≤ 48 sq. in., no border) |
| Kendall AMD Foam Dressing (Model 55566) | 6 in. × 6 in. (36 sq. in. pad area) | Hydrophilic foam, 0.5% PHMB | A6210 (Foam dressing, > 16 to ≤ 48 sq. in., no border) |
| Kendall AMD Foam Dressing (Model 55588) | 8 in. × 8 in. (64 sq. in. pad area) | Hydrophilic foam, 0.5% PHMB | A6211 (Foam dressing, > 48 sq. in., no border) |
| Kendall AMD Fenestrated Disc (Model 55512AMDX) | 1 in. diameter × 0.276 in. thickness (7 mm center hole) | Hydrophilic foam disc, 0.5% PHMB | A6209 (Foam dressing, ≤ 16 sq. in., no border) |
For limb wraps and compression retention, facilities frequently stock conforming roller gauze alongside flat sponges to maintain multi-layer dressings.
How to Choose
Selecting a PHMB dressing depends on clinical wound presentation evaluated against manufacturer instructions for use (IFU):
- Exudate Level: Use non-adherent pads or thin gauze flats for low-exudate wounds, superficial abrasions, or donor sites to avoid macerating surrounding tissue. For moderate-to-heavy drainage, select hydrophilic polyurethane foam dressings, which absorb high exudate volumes while maintaining an antimicrobial barrier.
- Wound Depth: Deep cavity wounds, sinus tracts, or undermined margins require pliable woven PHMB gauze strips or fluff sponges that conform to irregular crevices. Flat wounds benefit from foam sheets that provide pressure relief over bony prominences.
- Wound Bed Fragility: Friable granulation tissue or fragile geriatric skin demands non-adherent perforated film dressings (such as Telfa AMD) to prevent trauma and pain upon removal. Avoid dry gauze sponges on delicate healing beds unless maintained wet per physician orders.
- Tube and Catheter Exit Sites: Select pre-cut fenestrated foam discs or notched drain sponges for central lines, tracheostomies, and drain tubes. Pre-cut configurations fit snugly around tubing without manual scissors trimming, maintaining sterility and perimeter sealing.
Safe Use and Handling Basics
Safe application and storage must comply with manufacturer IFU and facility infection control guidelines:
- Wound Preparation: Irrigate the wound thoroughly with sterile saline or a compatible wound cleanser per clinical protocol. Pat the intact periwound skin dry before placing the dressing.
- Application: PHMB gauze dressings may be applied wet or dry depending on the treatment plan. Position the dressing with at least a 1 to 2 cm margin over surrounding skin. For fenestrated discs, position the slit snugly around the catheter base.
- Wear Time: PHMB gauze dressings typically remain in place for up to 3 days, whereas PHMB foam dressings may remain up to 7 days, provided exudate does not strike through or reach within 1 cm of the dressing border. Change dressings immediately upon saturation or dislodgement.
- Storage: Store cartons in a clean, dry location at controlled room temperature (15°C to 30°C / 59°F to 86°F), away from direct sunlight and excessive humidity.
- Sterility and Disposal: Supplied sterile for single-patient, single-use only. Do not re-sterilize or reuse. Discard packaging if the sterile barrier is damaged.
Common Mistakes
Clinical practice reviews highlight five common errors to avoid with PHMB dressings:
- Incompatibility with Dakin’s Solution: Combining PHMB dressings with sodium hypochlorite (Dakin’s solution) or other chlorine-releasing oxidizers chemically deactivates the biguanide polymer, neutralizing antimicrobial efficacy and causing yellow discoloration.
- Application to Contraindicated Anatomical Spaces: PHMB dressings must not contact the central nervous system (meninges, spinal cord, brain), inner or middle ear, intraocular spaces, or be used in joint capsule lavages due to neurotoxicity and ototoxicity risks.
- Use with Documented Biguanide Allergy: Contraindicated in patients with known hypersensitivity to polyhexamethylene biguanide. Check allergy records prior to application.
- HCPCS Billing Misclassification: Billing PHMB dressings under non-impregnated gauze codes (A6216/A6219) instead of impregnated codes (A6222/A6223/A6266), or failing to verify pad surface area thresholds, results in claim rejections.
- Over-Packing Deep Cavities: Forcing dry gauze tightly into wound spaces causes pressure-induced tissue ischemia. Cavities should be packed loosely to support drainage without pressure injury.
Frequently Asked Questions
What is a PHMB dressing used for?
A PHMB dressing is used to manage microbial bioburden, absorb exudate, and prevent bacterial strike-through in surgical incisions, pressure injuries, venous ulcers, diabetic foot ulcers, donor sites, and catheter exit sites.
Can a PHMB dressing be used with Dakin’s solution?
No. PHMB dressings should never be combined with Dakin’s solution (sodium hypochlorite) or chlorine-based cleansers, which chemically break down the biguanide molecule and eliminate its antimicrobial activity.
How long can a PHMB dressing stay on a wound?
PHMB gauze dressings typically remain in place for up to 3 days, while PHMB foam dressings can stay in place for up to 7 days, depending on exudate levels and clinical evaluation.
Is PHMB considered an antibiotic?
No. PHMB is a synthetic cationic antiseptic polymer, not an antibiotic. It works by disrupting bacterial cell membranes physically, which prevents bacteria from developing acquired drug resistance.
How are PHMB dressings classified by the US FDA?
The FDA clears PHMB dressings under premarket notification 510(k) reviews, primarily under Product Code FRO (“Dressing, Wound, Drug”, unclassified / 510(k) required) and Product Code NAD (“Dressing, Wound, Occlusive”, 21 CFR 878.4020, Class I).
Sources
- U.S. Food and Drug Administration (FDA). Premarket Notification 510(k) K070653: Kendall Kerlix Antimicrobial Super Sponge Dressing for OTC Use (Model 6662). FDA CDRH Database. URL: https://api.fda.gov/device/510k.json. Checked: 2026-11-09.
- U.S. Food and Drug Administration (FDA). Premarket Notification 510(k) K011941: Excilon AMD Antimicrobial Sponge Model #7088. FDA CDRH Database. URL: https://api.fda.gov/device/510k.json. Checked: 2026-11-09.
- U.S. Food and Drug Administration (FDA). Global Unique Device Identification Database (GUDID): Kendall AMD Antimicrobial Fenestrated Foam Disc (Model 55512AMDX) and Kerlix AMD Sponges. AccessGUDID / openFDA UDI API. URL: https://api.fda.gov/device/udi.json. Checked: 2026-11-09.
- Centers for Medicare and Medicaid Services (CMS). Healthcare Common Procedure Coding System (HCPCS) Level II Coding Directory and DME Wound Care Coverage Policies (Codes A6209, A6210, A6211, A6222, A6223, A6266). URL: https://www.cms.gov/medicare/coding-billing/healthcare-common-procedure-coding-system-hcpcs-level-ii-coding. Checked: 2026-11-09.
- Cardinal Health. Kerlix AMD and Kendall AMD Antimicrobial Dressings: Instructions for Use and Product Specifications. URL: https://www.cardinalhealth.com. Checked: 2026-11-09.
