Overview
Neomycin is an aminoglycoside antibiotic used topically in combination with polymyxin B and hydrocortisone for treating superficial bacterial ear infections. It works by inhibiting bacterial protein synthesis and is particularly effective against gram-negative organisms. Due to potential ototoxicity, treatment should be limited to 10 consecutive days.
Mechanism of Action
Neomycin inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, causing misreading of mRNA and leading to bacterial cell death. It is bactericidal against susceptible gram-negative and some gram-positive organisms.
Indications
- Superficial bacterial infections of the external auditory canal caused by susceptible organisms
- Infections of mastoidectomy and fenestration cavities caused by susceptible organisms
Common Doses
- Neomycin sulfate 3.5 mg/mL with polymyxin B sulfate 10,000 units/mL and hydrocortisone 10 mg/mL in otic suspension
Dosage
Therapy limited to 10 consecutive days. Adults: 4 drops in affected ear 3-4 times daily. Children: 3 drops 3-4 times daily due to smaller ear canal capacity. Patient should lie with affected ear upward for 5 minutes after instillation. Cotton wick may be used and kept moist with suspension every 4 hours, replaced at least every 24 hours.
Contraindications
- Hypersensitivity to any component
- Herpes simplex infections
- Vaccinia infections
- Varicella infections
Side Effects
- Allergic sensitization (skin rash, itching, redness)
- Ototoxicity (hearing loss)
- Nephrotoxicity
- Local reactions: burning, stinging, irritation, dryness
- Folliculitis, hypertrichosis, acneiform eruptions
- Hypopigmentation, perioral dermatitis
- Contact dermatitis, skin atrophy, striae
Interactions
- No specific drug interactions mentioned in label, but caution advised with other ototoxic or nephrotoxic drugs
Counseling Points
- Shake well before using
- Limit use to 10 consecutive days
- Lie with affected ear upward for 5 minutes after instillation
- Discontinue and contact healthcare provider if irritation or hearing changes occur
- Do not use if eardrum is perforated
- Keep wick moist if used, replace at least every 24 hours