NEOSPORIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NEOSPORIN (NEOSPORIN).
Neosporin is a combination of three antibiotics: neomycin (aminoglycoside) inhibits bacterial protein synthesis by binding to 30S ribosomal subunit; polymyxin B (polymyxin) disrupts bacterial cell membrane integrity; bacitracin (polypeptide) inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the lipid carrier.
| Metabolism | Neomycin is minimally absorbed; absorbed fraction undergoes hepatic metabolism and renal excretion. Polymyxin B and bacitracin are not significantly absorbed through intact skin; systemic absorption minimal. |
| Excretion | Renal excretion accounts for >90% of elimination; primarily glomerular filtration with minimal tubular secretion. Small biliary/fecal elimination (<5%). |
| Half-life | Variable based on severity of renal impairment. Normal renal function: 2-3 hours for neomycin (main component); polymyxin B: 4-6 hours. In anuria: half-life extends to 72-96 hours for neomycin. |
| Protein binding | Neomycin: negligible (<10%), primarily to albumin; polymyxin B: approximately 60% bound to plasma proteins. |
| Volume of Distribution | Neomycin: 0.4 L/kg (confined to extracellular fluid); polymyxin B: 0.6 L/kg (largely extracellular). Vd increases with edema or burns. |
| Bioavailability | Oral: <3% (neomycin), <1% (polymyxin B); topical (intact skin): <1%; ophthalmic/otic: minimal systemic absorption. |
| Onset of Action | Topical application to intact skin: no systemic absorption; onset of antimicrobial effect within 12-24 hours. Ophthalmic/otic: 24-48 hours. |
| Duration of Action | Topical: 8-12 hours for antibacterial effect; requires TID-QID dosing to maintain therapeutic levels. Systemic effects negligible due to poor absorption. |
| Molecular Weight | Neomycin: 614.7 Da; Polymyxin B: 1301.6 Da; Bacitracin: 1422.7 Da |
| Brand Substitutes | Nebazine Ointment, Neosporin Skin Ointment, Nebaspor Ointment, Jisporin Ointment, Nexporin Ointment |
Apply a thin layer topically to the affected area 1-3 times daily. May be covered with a sterile bandage.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dose adjustment required for topical use. Systemic absorption is minimal. |
| Liver impairment | No dose adjustment required for topical use. Systemic absorption is minimal. |
| Pediatric use | Apply a thin layer topically to the affected area 1-3 times daily. Safety and efficacy in children under 2 years have not been established. |
| Geriatric use | No specific dose adjustment required. Use caution in elderly with impaired skin integrity or reduced renal function due to potential for increased systemic absorption. |
| 1st trimester | Topical neomycin, polymyxin B, and bacitracin are generally considered safe during the first trimester due to minimal systemic absorption. However, use only if clearly needed. |
| 2nd trimester | Topical neomycin, polymyxin B, and bacitracin are considered safe during the second trimester with minimal systemic absorption. Avoid prolonged use on large areas. |
| 3rd trimester | Topical neomycin, polymyxin B, and bacitracin are considered safe during the third trimester. No known risk of fetal harm. Use as directed. |
Clinical note
Comprehensive clinical and safety monograph for NEOSPORIN (NEOSPORIN).
| Placental transfer | Placental transfer is negligible due to minimal systemic absorption from topical use. Each component has low molecular weight, but absorption is limited. |
| Breastfeeding | Minimal systemic absorption from topical application suggests negligible amounts in breast milk. Considered compatible with breastfeeding. Avoid application to breast area to prevent infant ingestion. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to any componentKnown hypersensitivity to neomycin (risk of cross-sensitivity to aminoglycosides)Perforated eardrum (otic use)
| Precautions | Potential for allergic contact dermatitis (especially neomycin); prolonged use may lead to overgrowth of non-susceptible organisms; avoid use in large areas of broken skin, deep puncture wounds, or serious burns due to risk of systemic absorption; ototoxicity and nephrotoxicity with prolonged use on damaged skin (rare). |
| Food/Dietary | No known food interactions with topical NEOSPORIN. |
| Clinical Pearls |
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| Lactation Rating | L1 (Safest) |
| Teratogenic Risk | Teratogenic risk is low based on animal studies and limited human data. In the first trimester, no increased risk of major congenital malformations has been reported for topical neomycin/polymyxin B/bacitracin. In the second and third trimesters, caution is advised due to potential ototoxicity and nephrotoxicity from systemic absorption of neomycin, though topical application minimizes risk. Avoid prolonged treatment over large areas or on broken skin. |
| Fetal Monitoring | No specific maternal or fetal monitoring is required for topical use; however, monitor for signs of allergic reactions or skin irritation. Use caution with extensive application or open wounds. |
| Fertility Effects | No known effects on fertility. Topical administration results in minimal systemic exposure and is not associated with reproductive toxicity in animal studies. |
| NEOSPORIN (triple antibiotic ointment: neomycin, polymyxin B, bacitracin) is for superficial skin infections only; avoid use on deep wounds, puncture wounds, or animal bites. Neomycin component carries high risk of contact dermatitis; consider alternative mupirocin for known neomycin allergy. Do not use in eyes or large body surface areas. |
| Patient Advice | Apply a thin layer to clean, dry affected area 1-3 times daily. · Do not use on deep cuts, puncture wounds, or serious burns without medical advice. · Discontinue use if rash, itching, or redness develops; may indicate allergic reaction to neomycin. · For external use only; avoid contact with eyes, nose, or mouth. · Seek medical attention if infection worsens or does not improve within 7 days. |