ZINC BACITRACIN,NEOMYCIN SULFATE,POLYMYXIN B SULFATE & HYDROCORTISONE
Clinical safety rating: safe
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
Combination antibiotic and corticosteroid: Neomycin, polymyxin B, and bacitracin are antibiotics that inhibit bacterial protein synthesis, disrupt cell membrane permeability, and inhibit cell wall synthesis, respectively; hydrocortisone is a corticosteroid that suppresses inflammatory responses by inhibiting phospholipase A2, reducing prostaglandin and leukotriene synthesis.
| Metabolism | Minimal systemic absorption after topical application; hydrocortisone undergoes hepatic metabolism via CYP3A4; neomycin, polymyxin B, and bacitracin are not significantly metabolized systemically. |
| Excretion | Renal: Neomycin (<1% absorbed, remainder fecal), Bacitracin (10-40% renal if absorbed, negligible), Polymyxin B (60% renal over 24h if absorbed), Hydrocortisone (metabolized, <1% unchanged renal; fecal for unabsorbed). Topical: negligible systemic absorption; fecal for unabsorbed. |
| Half-life | Neomycin: 2-3h (systemic, IM); Bacitracin: 1.5h (systemic, IM); Polymyxin B: 6h (systemic, IV); Hydrocortisone: 1.5-2h (systemic). Topical: not applicable due to minimal absorption. |
| Protein binding | Neomycin: <30% (albumin); Bacitracin: low (<10% probably, not fully characterized); Polymyxin B: ~90% (tissue, not plasma); Hydrocortisone: 90% (corticosteroid-binding globulin, albumin). For topical, irrelevant. |
| Volume of Distribution | Neomycin: 0.25 L/kg (systemic); Bacitracin: ~0.3 L/kg (systemic); Polymyxin B: 0.3 L/kg (systemic); Hydrocortisone: 0.3 L/kg (systemic). Topical: not applicable. |
| Bioavailability | Topical/otic: negligible systemic (<1% for neomycin, bacitracin, polymyxin; hydrocortisone <10% through intact skin, higher through abraded). Oral: neomycin ~3%, bacitracin negligible, polymyxin negligible, hydrocortisone ~100% (but not intended). |
| Onset of Action | Topical: Anti-inflammatory (hydrocortisone) within hours; antibacterial within 24-48h. Otic: Within 24-48h for infection resolution. |
| Duration of Action | Topical: Apply every 6-8h for infection/inflammation. Otic: Continue 7-10 days; clinical improvement within 48h. |
Apply 3-4 times daily to affected area as a thin layer. Topical route. Frequency: every 6-12 hours.
| Dosage form | OINTMENT |
| Renal impairment | No systemic absorption expected with topical application. No dose adjustment required. |
| Liver impairment | No systemic absorption expected with topical application. No dose adjustment required. |
| Pediatric use | Apply 3-4 times daily to affected area. Use smallest amount for minimal coverage. Not recommended for prolonged use in children <2 years due to potential adrenal suppression from hydrocortisone. |
| Geriatric use | Same as adult dosing. Use with caution in patients with thin/fragile skin. Avoid prolonged use due to increased risk of skin atrophy and systemic effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
| FDA category | Animal |
| Breastfeeding | Topical use minimal systemic absorption; unlikely to appear in breast milk. No M/P ratio available. Hydrocortisone at low doses safe. Use caution on broken skin or large areas. |
| Teratogenic Risk | Topical administration results in negligible systemic absorption; no well-controlled studies in pregnant women. Animal reproduction studies not available. Neomycin and polymyxin B are not known teratogens. Hydrocortisone: systemic corticosteroids in first trimester associated with cleft palate (risk increase: 1.3–3.4 per 1000). |
■ FDA Black Box Warning
None
| Common Effects | topical infections |
| Serious Effects |
Hypersensitivity to any component, neomycin or polymyxin allergy, tuberculosis skin lesions, fungal or viral skin infections (e.g., herpes simplex, vaccinia, varicella), otic use if tympanic membrane is perforated.
| Precautions | Prolonged use may lead to superinfection, masking of infection, or systemic absorption; neomycin may cause ototoxicity and nephrotoxicity if absorbed significantly; avoid use on large areas of damaged skin, under occlusive dressings, or in patients with impaired renal function. |
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| Fetal Monitoring | No specific monitoring required for maternal or fetal effects due to topical route. |
| Fertility Effects | No known effects on fertility from topical administration. |