Skip to Content
Visit ConferenceInsider to read about the AAO2016 cataract topics. Read more

Tobramycin (Ophthalmic)



(toe bra MYE sin)

Index Terms

  • Tobramycin Sulfate

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Ointment, Ophthalmic:

Tobrex: 0.3% (3.5 g)

Solution, Ophthalmic:

Tobrex: 0.3% (5 mL)

Generic: 0.3% (5 mL)

Brand Names: U.S.

  • Tobrex

Pharmacologic Category

  • Antibiotic, Aminoglycoside
  • Antibiotic, Ophthalmic


Interferes with bacterial protein synthesis by binding to 30S and 50S ribosomal subunits resulting in a defective bacterial cell membrane


Systemic absorption: Undetectable (<0.2 mcg/mL) (Filatov 1994); tear film exposure and time above MIC90 are significantly greater with viscous ophthalmic solution [Canadian product] (Tobrexan Canadian product labeling 2016).

Use: Labeled Indications

Ocular infections: Treatment of external infections of the eye and its adnexa caused by susceptible bacteria.


Hypersensitivity to tobramycin or any component of the formulation

Dosing: Adult

Ocular infections: Ophthalmic:

Ointment: Apply half-inch ribbon into affected eye(s) 2 or 3 times daily for mild to moderate infections; for severe infections, apply every 3 to 4 hours until improvement (then reduce prior to discontinuation).

Solution: Instill 1 to 2 drops into affected eye(s) every 4 hours for mild to moderate infections; for severe infections, instill 2 drops every hour until improvement (then reduce prior to discontinuation).

Viscous solution (Tobrexan [Canadian product]): Instill 1 drop into affected eye(s) 2 times daily for 7 days for mild to moderate infections; for severe infections, instill 1 drop 4 times daily on day 1 and then 2 times daily for duration of treatment period.

Dosing: Pediatric

Ocular infections: Ophthalmic: Infants ≥2 months, Children, and Adolescents: Refer to adult dosing.

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.


For topical ophthalmic use only; not for injection into the eye. Contact lenses should not be worn during treatment of ophthalmic infections. Avoid contaminating the applicator tip with affected eye(s).

Ointment: Apply into conjunctival sac(s) of eye; patient should look downward before closing eye.


Store at 2°C to 25°C (36°F to 77°F).

Drug Interactions

There are no known significant interactions.

Adverse Reactions

<1% (Limited to important or life-threatening): Ocular: Conjunctival erythema, lid itching, lid swelling


Concerns related to adverse effects:

• Hypersensitivity reactions: Sensitivity to topically applied aminoglycosides and cross sensitivity to other aminoglycosides antibiotics may occur; discontinue use if hypersensitivity develops.

• Superinfection: Prolonged use may lead to overgrowth of nonsusceptible organisms, including fungi. If superinfection is suspected, institute appropriate alternative therapy.

Special populations:

• Contact lens wearers: Some products may contain benzalkonium chloride or benzododecinium bromide which may be absorbed by soft contact lenses; contact lenses should not be worn during treatment of ophthalmologic infections.

Other warnings/precautions:

• Appropriate use: For topical application to the eye only; not for injection. To avoid contamination, do not touch tip of container to any surface.

Pregnancy Risk Factor


Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. The amount of tobramycin available systemically following topical application of the ophthalmic drops is undetectable (<0.2 mcg/mL) (Filatov 1994). If ophthalmic agents are needed during pregnancy, the minimum effective dose should be used in combination with punctual occlusion to decrease systemic absorption (Samples 1988).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Have patient report immediately to prescriber vision changes, eye pain, or severe eye irritation (HCAHPS).

• Educate patient about signs of a significant reaction (eg, 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. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.