BACITRACIN-NEOMYCIN-POLYMYXIN W/ HYDROCORTISONE ACETATE
Clinical safety rating: safe
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
Bacitracin inhibits bacterial cell wall synthesis by interfering with dephosphorylation of the peptidoglycan carrier lipid; neomycin binds to 30S ribosomal subunit causing misreading of mRNA; polymyxin B disrupts bacterial cell membrane permeability via interaction with phospholipids; hydrocortisone acetate suppresses inflammation by inhibiting phospholipase A2, reducing prostaglandin and leukotriene synthesis.
| Metabolism | Bacitracin: not metabolized, excreted renally; neomycin: minimally metabolized, excreted renally; polymyxin B: metabolism unknown, excreted renally; hydrocortisone acetate: hepatic metabolism via CYP3A4, glucuronidation, sulfation. |
| Excretion | Bacitracin: renal (minimal systemic absorption; eliminated unchanged in urine if absorbed). Neomycin: renal (90-95% excreted unchanged in urine after systemic absorption). Polymyxin B: renal (60% excreted unchanged over 24h; prolonged elimination in renal impairment). Hydrocortisone acetate: hepatic metabolism (glucuronidation, sulfation) and renal excretion of metabolites. |
| Half-life | Bacitracin: 1.5 h (systemic) but clinically irrelevant as topical. Neomycin: 2-3 h (systemic). Polymyxin B: 4.5-6 h (systemic). Hydrocortisone acetate: 1.5-2.5 h (plasma); clinical effect outlasts serum half-life due to intracellular activity. |
| Protein binding | Bacitracin: ~10% (albumin). Neomycin: <30% (albumin). Polymyxin B: 55-60% (albumin, alpha-1-acid glycoprotein). Hydrocortisone acetate: 90-95% (corticosteroid-binding globulin, albumin). |
| Volume of Distribution | Bacitracin: 0.3 L/kg (minimal distribution). Neomycin: 0.2-0.4 L/kg (extracellular fluid). Polymyxin B: 0.6-0.8 L/kg (extensively bound to cell membranes). Hydrocortisone acetate: 0.3-0.6 L/kg (total body water). |
| Bioavailability | Topical/otic/ophthalmic: negligible systemic absorption (<1% for bacitracin, neomycin, polymyxin B; <5% for hydrocortisone acetate). Oral: not applicable (not administered systemically). |
| Onset of Action | Topical: Bacitracin/Neomycin/Polymyxin B: 2-4 h (bacterial growth inhibition). Hydrocortisone acetate: 6-12 h (anti-inflammatory effect). Otic: rapid (within 1 h for anti-inflammatory). Ophthalmic: 1-2 h (antibacterial). |
| Duration of Action | Topical: 4-6 h (combination antibacterial effect). Hydrocortisone acetate: 12-24 h (anti-inflammatory effect from single dose). Otic: 6-8 h (sustained release via vehicle). |
| Molecular Weight | Bacitracin: 1422.7 Da; Neomycin: 614.6 Da; Polymyxin B (sulfate): ~1300 Da; Hydrocortisone acetate: 404.5 Da |
Apply a thin layer to the affected area 3-4 times daily. Ophthalmic: Instill 1-2 drops into the affected eye(s) every 3-4 hours, or more frequently if needed. Otic: Instill 4 drops into the affected ear(s) 3-4 times daily.
| Dosage form | OINTMENT |
| Renal impairment | No systemic absorption anticipated with topical, ophthalmic, or otic use; however, for extensive topical application, caution in renal impairment due to neomycin and polymyxin B. GFR <30 mL/min: monitor for nephrotoxicity; reduce frequency if topical use over large areas. |
| Liver impairment | No specific adjustment required for topical, ophthalmic, or otic use. Hydrocortisone acetate is hepatically metabolized; however, systemic exposure is minimal. Child-Pugh Class C: use with caution if applied to large areas or broken skin. |
| Pediatric use | Children: Apply a thin layer to affected area 3-4 times daily. Ophthalmic: Use same as adult dose. Otic: Infants and children: 3 drops into affected ear(s) 3-4 times daily. Safety and efficacy in neonates not established. |
| Geriatric use | No specific dose adjustment required. Use with caution in elderly with impaired renal or hepatic function, especially if applied to large areas. Monitor for skin atrophy and systemic effects of hydrocortisone with prolonged use. |
| 1st trimester | Avoid routine use; systemic absorption may cause fetal ototoxicity or nephrotoxicity. Topical/otic use generally considered low risk if minimal systemic absorption, but use only if clearly needed. |
| 2nd trimester | Avoid use due to potential fetal nephrotoxicity and ototoxicity from neomycin. Topical use with intact skin may be acceptable if benefits outweigh risks. |
| 3rd trimester | Avoid use especially near term; risk of neonatal ototoxicity and nephrotoxicity. Topical use only if not systemically absorbed. |
Clinical note
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
| FDA category | Animal |
| Placental transfer | Neomycin and polymyxin B cross the placenta in measurable amounts. Bacitracin placental transfer is minimal. Hydrocortisone acetate cross placenta, but low dose topical use limited systemic absorption. |
■ FDA Black Box Warning
None.
| Common Effects | topical infections |
| Serious Effects |
Hypersensitivity to any component (bacitracin, neomycin, polymyxin B, or hydrocortisone)Perforated tympanic membrane (for otic use)Systemic use in renal impairment (neomycin nephrotoxicity)Systemic use in myasthenia gravis (polymyxin B neuromuscular blockade)Ophthalmic use in fungal/viral infections
| Precautions | Prolonged use may lead to secondary infections (e.g., fungal) or hypersensitivity; ophthalmic use may cause increased intraocular pressure, cataract formation, and delayed wound healing; avoid use in patients with epithelial herpes simplex keratitis; systemic absorption may cause nephrotoxicity and ototoxicity (especially neomycin); use with caution in hepatic impairment. |
| Food/Dietary |
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| Breastfeeding | Minimal systemic absorption from topical/otic use suggests low risk to infant. However, neomycin may alter infant gut flora. Use caution; avoid application to breast area for infant feeding. Systemic use contraindicated. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Teratogenic risk is minimal due to negligible systemic absorption from topical application. No studies report fetal harm from bacitracin, neomycin, polymyxin B, or hydrocortisone acetate when used topically. Avoid prolonged use of high-dose hydrocortisone during first trimester due to potential corticosteroid effects. |
| Fetal Monitoring | No specific monitoring required for topical use. Monitor for signs of systemic corticosteroid absorption (e.g., adrenal suppression) if applied to large areas or under occlusion. Assess for superinfection with prolonged use. |
| Fertility Effects | No adverse effects on fertility reported with topical use. Systemic effects from corticosteroids are unlikely at topical doses. |
| No significant food interactions. No dietary restrictions required. |
| Clinical Pearls | This combination product is used for otitis externa and certain ophthalmic infections. The hydrocortisone reduces inflammation, but can mask signs of fungal or viral superinfection. Avoid use in patients with tympanic membrane perforation due to risk of ototoxicity from neomycin and polymyxin B. Neomycin carries sensitization risk; prolonged use may cause contact dermatitis. Monitor for overgrowth of non-susceptible organisms when used beyond 10 days. |
| Patient Advice | Use exactly as prescribed; do not exceed recommended duration. · Avoid contact with eyes unless specifically directed for ophthalmic use. · Do not use if you have a perforated eardrum or ear discharge. · Stop use and notify your doctor if symptoms worsen or persist after 10 days. · Inform your doctor if you experience new pain, redness, or swelling. · Keep this medication out of reach of children. |