Gentamicin Ointment
gentamicin 0.3% · ophthalmic ointment
Antibiotic
Approved uses
Ocular bacterial infection: conjunctivitis, keratitis, keratoconjunctivitis, corneal ulcer, blepharitis, blepharoconjunctivitis, acute meibomianitis, dacryocystitis
Approximately 1/2 inch ribbon to the affected eye(s) 2 or 3 times daily
Stays detectable on the ocular surface about 40 minutes versus 10 minutes for the drop.
Contraindications
Known hypersensitivity to any of the components.
Available Forms0.3% (3 mg/g) ointment, 3.5 g tube, box of one
Mechanism of ActionAminoglycoside; actively transported into bacteria, where it binds the 30S ribosomal subunit and blocks protein synthesis, giving concentration-dependent bactericidal killing across Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumoniae, Escherichia coli, Enterobacter aerogenes, Haemophilus influenzae, Neisseria gonorrhoeae, staphylococci, and streptococci. The white petrolatum and mineral oil base prolongs ocular surface contact relative to an aqueous drop.
Warnings & Precautions
- Route restriction: Never inject subconjunctivally or introduce directly into the anterior chamber.
- Delayed corneal healing: Ophthalmic ointments may retard corneal healing, which matters when an epithelial defect or ulcer is being treated.
- Macular infarction: A survey of retinal specialists collected 93 cases attributed to intravitreal or subconjunctival gentamicin sulfate, 23 of them after prophylactic subconjunctival aminoglycoside injection following routine ocular surgery.
- Epithelial toxicity: All four aminoglycosides tested inhibited rabbit corneal epithelial DNA synthesis at every concentration after 30 to 60 minutes of in vitro exposure, which compounds the label's own caution about retarded corneal healing.
- Superinfection: Prolonged use may allow overgrowth of nonsusceptible organisms including fungi, and bacterial resistance may develop.
- Hypersensitivity or worsening infection: Aggravated purulent discharge, inflammation, or pain, or irritation or hypersensitivity to any component, warrants stopping the drug and substituting appropriate therapy.
Common Side Effects
- Ocular, most frequent: Burning and irritation on instillation, non-specific conjunctivitis, conjunctival epithelial defects, conjunctival hyperemia.
- Corneal ulcers: Bacterial and fungal ulcers have developed during treatment with ophthalmic gentamicin preparations.
- Rare reactions: Allergic reactions, thrombocytopenic purpura, hallucinations.
Pregnancy & LactationPregnancy: Pregnancy Category C, with no adequate and well-controlled studies in pregnant women; use only if the potential benefit justifies the potential fetal risk. Systemic dosing of pregnant rats at approximately 500 times the maximum recommended ophthalmic human dose depressed newborn body weights, kidney weights, and median glomerular counts.
Lactation: This label has no nursing mothers section.
Pediatric UseSafety and effectiveness in neonates have not been established.