Skip to Content
Looking to save on your medications?  Find out how 

Gentamicin (Ophthalmic)

Generic name: gentamicin ophthalmic

Brand names: Gentak, Genoptic, Gentacidin, Gentasol, Garamycin Ophthalmic, Ocu-Mycin

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Ointment, Ophthalmic:

Gentak: 0.3% (3.5 g) [contains methylparaben, propylparaben]

Generic: 0.3% (3.5 g [DSC])

Solution, Ophthalmic:

Generic: 0.3% (5 mL, 15 mL [DSC])


Mechanism of Action

Interferes with bacterial protein synthesis by binding to 30S ribosomal subunit resulting in a defective bacterial cell membrane



Ophthalmic drops: Systemic absorption: Undetected (<0.5 mcg/mL)

Use: Labeled Indications

Ophthalmic infections: Topical treatment of ocular bacterial infections, including conjunctivitis, keratitis, keratoconjunctivitis, corneal ulcers, blepharitis, blepharoconjunctivitis, acute meibomianitis, and dacryocystitis caused by Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Enterobacter aerogenes, Escherichia coli, Haemophilus influenza, Klebsiella pneumonia, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Serratia marcescens.


Hypersensitivity to gentamicin or any component of the formulation

Dosage and Administration

Dosing: Adult

Ophthalmic infections: Ophthalmic:

Ointment: Instill 1/2" (1.25 cm) 2 to 3 times daily

Solution: Instill 1 to 2 drops every 4 hours, up to 2 drops every hour for severe infections

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Ophthalmic infections: Ophthalmic:

Ointment: Instill 1/2 inch (1.25 cm) to affected eye(s) 2 to 3 times/day

Solution: Instill 1 to 2 drops into affected eye(s) every 4 hours; up to 2 drops every hour for severe infections


For topical ophthalmic use only; not for injection into the eye. Avoid contaminating tip of the solution container or ointment tube.


Store at controlled room temperature of 20°C to 25°C (68°F to 77°F).

Drug Interactions

There are no known significant interactions.

Adverse Reactions

>1%: Ophthalmic: Burning sensation of eyes, eye irritation

<1%, postmarketing, and/or case reports: Corneal ulcer, hallucination, hypersensitivity reaction, purpura, thrombocytopenia


Concerns related to adverse effects:

  • Corneal healing: May delay corneal healing.
  • Sensitization: Topical use has been associated with local sensitization (redness, irritation); discontinue if sensitization is noted.
  • Superinfection: Prolonged use may result in fungal or bacterial superinfection; if purulent discharge, inflammation, or pain are increased, therapy should be re-evaluated.

Other warnings/precautions:

  • Appropriate use: Not for injection into the eye.
  • Long-term use: Not intended for long-term therapy.


Pregnancy Risk Factor


Pregnancy Considerations

Adverse events were observed following systemic administration of gentamicin in animal reproduction studies. The amount of gentamicin available systemically following application of the ophthalmic drops is below the limit of detection (<0.5 mcg/mL) (Trope 1979). In general, if ophthalmic agents are needed in pregnant women, the minimum effective dose should be used in combination with punctal occlusion to decrease systemic absorption (Samples 1988).

Patient Education

What is this drug used for?

  • It is used to treat eye infections.

Frequently reported side effects of this drug

  • Burning

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Vision changes
  • Eye pain
  • Severe eye irritation
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated January 28, 2020.