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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for POLYSPORIN (POLYSPORIN).
| Breastfeeding | Topical Polysporin is minimally absorbed systemically; excretion into breast milk is unlikely. The American Academy of Pediatrics considers topical bacitracin and polymyxin B compatible with breastfeeding. M/P ratio not determined due to minimal systemic levels. |
| 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. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to any component (polymyxin B or bacitracin)","Ophthalmic infections (not for ophthalmic use)"]
| 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"] |
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| 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. |