Tobradex®
Tobramycin 0.3% / Dexamethasone 0.1% · ophthalmic suspension
Antibiotic/Steroid
Approved uses
Steroid-responsive ocular inflammation with superficial bacterial infection or a risk of it
One or two drops into the conjunctival sac(s) every 4 to 6 hours, increased to one or two drops every 2 hours during the initial 24 to 48 hours, then tapered; not more than 20 mL initially
Matches loteprednol/tobramycin on signs and symptoms at 14 days but raises IOP about 1 mm Hg.
Chronic anterior uveitis, and corneal injury from chemical, radiation, or thermal burns or foreign body penetration
One or two drops into the conjunctival sac(s) every 4 to 6 hours, increased to one or two drops every 2 hours during the initial 24 to 48 hours, then tapered; not more than 20 mL initially
Contraindications
- Epithelial herpes simplex keratitis (dendritic keratitis), vaccinia, varicella, and many other viral diseases of the cornea and conjunctiva.
- Mycobacterial infection of the eye.
- Fungal diseases of ocular structures.
- Hypersensitivity to a component of the medication.
Available FormsOphthalmic suspension, tobramycin 0.3% (3 mg/mL) and dexamethasone 0.1% (1 mg/mL), 2.5 mL, 5 mL, 10 mL
Mechanism of ActionTobramycin is an aminoglycoside that inhibits bacterial protein synthesis, covering the gram-positive and gram-negative ocular pathogens listed in the label. Dexamethasone is a potent corticoid that suppresses the inflammatory response and probably delays or slows healing, and the antibiotic is paired with it because corticoids may inhibit host defense against infection.
Warnings & Precautions
- Topical ophthalmic use only: Not for injection into the eye.
- Aminoglycoside sensitivity: Reactions range from local effects to erythema, itching, urticaria, skin rash, anaphylaxis, anaphylactoid reactions, or bullous reactions; discontinue if one occurs, and expect possible cross-sensitivity to other aminoglycosides.
- IOP elevation and glaucoma: Prolonged steroid use may produce glaucoma with optic nerve damage and defects in visual acuity and visual fields; monitor IOP routinely, including in pediatric and uncooperative patients where measurement is harder.
- Posterior subcapsular cataract: Prolonged steroid use may produce it.
- Secondary or masked infection: Prolonged use may suppress host response and increase the hazard of secondary ocular infection; in acute purulent conditions and parasitic infections of the eye, steroids may mask infection or enhance existing infection.
- Corneal or scleral perforation: Reported with topical steroids in diseases causing thinning of the cornea or sclera.
- Fungal and nonsusceptible overgrowth: Consider fungal corneal infection after long-term steroid dosing; prolonged antibiotic use may allow overgrowth of nonsusceptible organisms, including fungi.
- Renewal examination: Examine with magnification, such as slit lamp biomicroscopy and where appropriate fluorescein staining, when multiple prescriptions are required or whenever clinical judgment dictates.
- Contact lens wear: Lenses should not be worn during treatment.
Common Side Effects
- Ocular, antibiotic component: Hypersensitivity and localized ocular toxicity, including lid itching, lid swelling, and conjunctival erythema, in under 4%, a figure the label attributes to topical ocular tobramycin 0.3% solution rather than to the combination.
- Ocular, steroid component: Elevation of IOP with possible glaucoma and infrequent optic nerve damage, posterior subcapsular cataract formation, and delayed wound healing; the label gives no incidence figures for the combination.
- Secondary infection: Fungal corneal infection is particularly prone to develop coincidentally with long-term steroid application, and secondary bacterial infection follows suppression of host responses.
- Postmarketing reports: Anaphylactic reaction, erythema multiforme.
- Systemic, steroid component: Cushing's syndrome and adrenal suppression after dexamethasone in excess of the labeled dosing in predisposed patients, including children and patients on CYP3A4 inhibitors.
- Systemic, aminoglycoside class: Neurotoxicity, ototoxicity, and nephrotoxicity have occurred in patients receiving systemic aminoglycoside therapy; aminoglycosides may aggravate muscle weakness in myasthenia gravis or Parkinson's disease.
Pregnancy & LactationPregnancy: Ocular administration of 0.1% dexamethasone produced fetal anomalies in 15.6% and 32.3% of two groups of pregnant rabbits, and chronic dexamethasone therapy produced fetal growth retardation and increased mortality in rats; parenteral tobramycin up to 100 mg/kg/day in rats and rabbits showed no impaired fertility and no fetal harm. No adequate and well-controlled studies in pregnant women; prolonged or repeated corticoid use in pregnancy is associated with increased risk of intrauterine growth retardation, and infants of mothers who received substantial corticosteroid doses should be observed for hypoadrenalism.
Lactation: Systemically administered corticosteroids appear in human milk and could suppress growth or interfere with endogenous corticosteroid production; whether topical ocular dosing produces detectable quantities in human milk is not known.
Pediatric UseSafety and effectiveness below age 2 have not been established.