GENTAMICIN (OPHTHALMIC), TOBRAMYCIN (OPHTHALMIC)

Indications/Pharmacology

The aminoglycosides are excellent drugs for gram negative orstaphylococcal corneal infections. With frequent application, clinicians can establish corneal drug levelsfar in excess of MIC for most organisms without exceeding toxic systemic levels. Therefore, MIC reportsmay not be meaningful. Because of the high levels attainable, gentamicin usually exhibits similar efficacyto tobramycin, except in certain resistant gram-negative infections (e.g., Pseudomonas aeruginosa).
For serious gram negative or staphylococcal corneal ulcer infections, some ophthalmologists usecefazolin eye drops (compounded preparation) in combination with gentamicin or tobramycin. Synergismmay result.Precautions/Adverse Effects - Hypersensitivity, and localized ocular toxicity (lid itching, swelling andconjunctival erythema) have been reported rarely. Mydriasis and conjunctival paresthesias may alsooccur.Dosage Forms/Preparations/FDA Approval Status - Veterinary-Approved Products:
Gentamicin Ophthalmic Ointment 3 mg/g in 3.5 gm tubes; Gentocin® (Schering); (Rx). Approved for use in dogs and cats.
Gentamicin Ophthalmic Drops 3 mg/ml in 5 ml btls Gentocin® (Schering); (Rx). Approved for use in dogs and cats.

Human-Approved Products:

Gentamicin Ophthalmic Ointment 3 mg/g in 3.5 gm tubes; Garamycin® (Schering); Genoptic® (Allergan); various; (Rx)
Gentamicin Ophthalmic Drops 3 mg/ml in 5 ml btls Garamycin® (Schering); Genoptic® (Allergan); various; (Rx)
Tobramycin Ophthalmic Ointment 3 mg/g in 3.5 gm tubes; Tobrex® (Alcon); (Rx)
Tobramycin Ophthalmic Drops 3 mg/ml in 5 ml btls Tobrex® (Alcon); (Rx)