POLYSPORIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for POLYSPORIN (POLYSPORIN).
Polysporin is a combination of polymyxin B and bacitracin. Polymyxin B disrupts bacterial cell membrane by binding to lipopolysaccharides, increasing permeability. Bacitracin inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier in peptidoglycan synthesis.
| Metabolism | Polymyxin B is not significantly metabolized; bacitracin is minimally metabolized. Both are excreted largely unchanged in urine when absorbed systemically, but systemic absorption is minimal with topical use. |
| Excretion | Polysporin (polymyxin B/bacitracin) ophthalmic/otic/topical: Minimal systemic absorption. Renal elimination for absorbed fraction: <1% of dose. |
| Half-life | Polymyxin B: 6–7 hours (impaired renal function: prolonged). Bacitracin: 1.5 hours (topical; not systemically absorbed). |
| Protein binding | Polymyxin B: ~90% bound to plasma proteins (α-1-acid glycoprotein, albumin). Bacitracin: negligible systemic exposure. |
| Volume of Distribution | Polymyxin B: 0.34–0.4 L/kg (limited to extracellular fluid; extensive tissue binding). Bacitracin: not relevant (topical). |
| Bioavailability | Topical/ophthalmic: <0.1% absorbed systemically; local concentration high. |
| Onset of Action | Topical/ophthalmic: Within 12–24 hours for susceptible infections. |
| Duration of Action | Topical/ophthalmic: 6–12 hours after single application; requires q4-6h dosing. |
| Molecular Weight | Bacitracin: 1422.69 Da; Polymyxin B: 1300.5 Da (average) |
Apply a thin layer topically to the affected area 1 to 3 times daily. If using the ointment, cover with a sterile bandage if desired.
| Dosage form | AEROSOL |
| Renal impairment | No dosage adjustment necessary for topical use due to negligible systemic absorption. |
| Liver impairment | No dosage adjustment necessary for topical use due to negligible systemic absorption. |
| Pediatric use | Apply a thin layer topically to the affected area 1 to 3 times daily. Safety and efficacy in infants under 2 months have not been established. |
| Geriatric use | No specific dosage adjustment required; use same as adult dosing. |
| 1st trimester | Topical application of Polysporin (bacitracin/polymyxin B) has minimal systemic absorption and is considered compatible with pregnancy. No known teratogenic effects. Use only if clearly needed. |
| 2nd trimester | Same as T1. Limited data but no reported adverse fetal effects. |
| 3rd trimester | Same as T1. Avoid large areas of broken skin or prolonged use near term. |
Clinical note
Comprehensive clinical and safety monograph for POLYSPORIN (POLYSPORIN).
| Placental transfer | Minimal to no placental transfer due to negligible systemic absorption after topical use. |
| Breastfeeding | Topical Polysporin is poorly absorbed through skin, and systemic levels are negligible. It is considered compatible with breastfeeding. Avoid application to the nipple area to prevent infant ingestion. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to bacitracin, polymyxin B, or any component of the formulation
| Precautions | Avoid contact with eyes or large open wounds, Prolonged use may lead to overgrowth of nonsusceptible organisms including fungi, Do not use in deep puncture wounds or serious burns without medical advice |
| Food/Dietary | No known food interactions with topical Polysporin. |
| Clinical Pearls | Polysporin (bacitracin/polymyxin B) is a topical triple antibiotic ointment without neomycin, reducing risk of allergic contact dermatitis. Avoid use on large areas, deep wounds, or burns due to minimal systemic absorption but potential for toxicity. Used primarily for prophylaxis of infection in minor cuts, scrapes, and burns. Not effective against fungal or viral infections. |
Loading safety data…
| Lactation Rating |
| L1 (Safe) |
| Teratogenic Risk | Polysporin (bacitracin/polymyxin B) is a topical antibiotic with negligible systemic absorption. No adequate and well-controlled studies in pregnant women. Bacitracin and polymyxin B are not known to be teratogenic in animal studies. Risk to fetus is considered minimal when used topically as directed. |
| Fetal Monitoring | No specific monitoring required with topical use. For systemic toxicity signs (extremely rare), monitor renal function and neurological status. No fetal monitoring indicated. |
| Fertility Effects | No known effects on fertility from topical Polysporin. Systemic bacitracin and polymyxin B have not been studied for reproductive effects in humans; animal studies show no impairment of fertility. |
| Patient Advice | Apply a thin layer to affected area 1-3 times daily as directed. · Do not use on deep wounds, puncture wounds, animal bites, or serious burns without medical advice. · Discontinue if rash or irritation develops; seek medical attention if symptoms persist or worsen. · For external use only; avoid contact with eyes and mucous membranes. · Do not use longer than 1 week unless directed by a healthcare provider. |