Neosporin®
Neomycin Sulfate, Polymyxin B Sulfate, Gramicidin · ophthalmic solution
Antibiotic
Approved uses
Superficial bacterial infection of the external eye and adnexa: conjunctivitis, keratitis, keratoconjunctivitis, blepharitis, blepharoconjunctivitis
1 or 2 drops into the affected eye every 4 hours for 7 to 10 days; up to 2 drops every hour in severe infection
Contraindications
Hypersensitivity to any component of the product.
Available FormsOphthalmic solution, 10 mL plastic squeeze bottle with controlled drop tip, neomycin sulfate equivalent to 1.75 mg base per mL, polymyxin B sulfate 10,000 units per mL, gramicidin 0.025 mg per mL
Mechanism of ActionThree bactericidal agents with overlapping spectra: neomycin, an aminoglycoside, binds ribosomal RNA and causes misreading of the bacterial genetic code, halting protein synthesis; polymyxin B interacts with membrane phospholipids to increase permeability in gram-negatives; gramicidin forms channels through the lipid bilayer that make the membrane permeable to inorganic cations in gram-positives. Labeled activity covers Staphylococcus aureus, streptococci including Streptococcus pneumoniae, Escherichia coli, Haemophilus influenzae, Klebsiella-Enterobacter species, Neisseria species, and Pseudomonas aeruginosa, but coverage of Serratia marcescens is stated to be inadequate.
Warnings & Precautions
- Route restriction: Not for injection into the eye, and never to be introduced directly into the anterior chamber or injected subconjunctivally.
- Neomycin sensitization: Topical antibiotics, particularly this aminoglycoside, may cause cutaneous sensitization, usually shown as itching, reddening, and edema of the conjunctiva and eyelid; symptoms subside quickly after withdrawal, and products containing these ingredients should be avoided thereafter.
- Patch test frequency: In the US arm of 28,640 North American Contact Dermatitis Group patch tests from 2005 to 2016, neomycin was the third most frequent allergen at 11.7% positive.
- Failure to heal: A sensitization reaction may manifest simply as failure to heal, so periodic examination for these signs is advisable during long-term use.
- Allergic cross-reactions: Sensitization may preclude later use of kanamycin, paromomycin, streptomycin, and possibly gentamicin.
- Superinfection and resistance: Prolonged use may allow overgrowth of nonsusceptible organisms including fungi, and bacterial resistance may develop.
- Container contamination: Bacterial keratitis has been reported after inadvertent patient contamination of multiple-dose topical ophthalmic containers, most of those patients having concurrent corneal disease or a disrupted ocular epithelial surface.
- Thimerosal preservative: The vehicle contains thimerosal 0.001% and alcohol 0.5%, and thimerosal was among the most relevant allergens (10%) in a German periorbital dermatitis series.
Common Side Effects
- Ocular, most frequent: Allergic reactions including itching, swelling, and conjunctival erythema; the exact incidence is not known.
- Local irritation: Reported on instillation.
- Systemic, rare: More serious hypersensitivity reactions, including anaphylaxis.
Pregnancy & LactationPregnancy: Adequate animal reproduction studies have not been conducted with neomycin, polymyxin B, or gramicidin, and whether the product can cause fetal harm or affect reproductive capacity is unknown, so give only if clearly needed.
Lactation: Excretion in human milk is unknown, so caution is warranted in a nursing woman.
Pediatric UseSafety and effectiveness in pediatric patients have not been established.