Tobradex ST®
Tobramycin 0.3% / Dexamethasone 0.05% · ophthalmic suspension
Antibiotic/Steroid
Approved uses
Steroid-responsive ocular inflammation with superficial bacterial infection or a risk of it
One drop into the conjunctival sac(s) every 4 to 6 hours, increased to one drop every 2 hours during the initial 24 to 48 hours, then tapered; not more than one bottle initially
Global inflammation score is already lower than azithromycin by day 8.
Chronic anterior uveitis, and corneal injury from chemical, radiation, or thermal burns or foreign body penetration
One drop into the conjunctival sac(s) every 4 to 6 hours, increased to one drop every 2 hours during the initial 24 to 48 hours, then tapered; not more than one bottle initially
Contraindications
- Most viral diseases of the cornea and conjunctiva, including epithelial herpes simplex keratitis (dendritic keratitis), vaccinia, and varicella.
- 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 0.05% (0.5 mg/mL), 2.5 mL, 5 mL
Mechanism of ActionTobramycin is an antibacterial that inhibits the growth of bacteria by inhibiting protein synthesis, providing action against susceptible ocular bacteria. Dexamethasone is a potent corticoid that suppresses the inflammatory response and can delay or slow healing, and an antimicrobial is combined with it because corticoids may inhibit host defense against infection.
Warnings & Precautions
- IOP elevation and glaucoma: Prolonged corticosteroid use may result in glaucoma with optic nerve damage and defects in visual acuity and visual fields; monitor IOP if this product is used 10 days or longer, and evaluate it before the initial prescription and each renewal.
- Aminoglycoside sensitivity: Sensitivity to topically applied aminoglycosides may occur.
- Posterior subcapsular cataract: Corticosteroid use may produce it.
- Delayed healing: Steroids after cataract surgery may delay healing and increase the incidence of bleb formation; in diseases causing thinning of the cornea or sclera, perforation has occurred with topical steroids.
- Secondary or masked infection: Prolonged corticosteroid use may suppress host response and increase the hazard of secondary ocular infection, and in acute purulent conditions steroids may mask infection or enhance existing infection; re-evaluate if signs and symptoms fail to improve after 2 days.
- Viral infection exacerbation: Ocular steroids may prolong the course and exacerbate the severity of many viral eye infections, including herpes simplex; a history of herpes simplex requires great caution.
- Fungal infection: Fungal corneal infection is particularly prone to develop with long-term local steroid application, and fungus invasion must be considered in any persistent corneal ulceration where a steroid has been or is in use.
- Renewal examination: The initial prescription and each renewal should follow examination with magnification, such as slit lamp biomicroscopy and where appropriate fluorescein staining.
- Blurred vision: Vision may be temporarily blurred after dosing, which matters for driving and machinery.
- Contact lens wear: The benzalkonium chloride preservative may be absorbed by soft lenses; lenses should not be worn during treatment.
Common Side Effects
- Ocular, antibiotic component: Hypersensitivity and localized ocular toxicity, including eye pain, eyelid pruritus, eyelid edema, and conjunctival hyperemia, in under 4%, a figure the label attributes to topical ocular tobramycin rather than to the combination.
- Ocular, steroid component: Increased IOP with possible glaucoma and infrequent optic nerve disorder, subcapsular cataract, and impaired healing; the label gives no incidence figures for the combination.
- Non-ocular, clinical trials: Headache and increased blood pressure, among the events occurring at an incidence of 0.5% to 1%.
- 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, twice this product's strength, produced fetal anomalies in 15.6% and 32.3% of 2 groups of pregnant rabbits, and chronic dexamethasone therapy produced fetal growth retardation and increased mortality in rats; tobramycin up to 100 mg/kg/day in rats and rabbits (equivalent to human doses of 16 and 32 mg/kg/day) 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.