dexamethasone/tobramycin (Rx)

Frequency Not Defined

Ocular lid itching and swelling

Conjunctival erythema

Elevation of intraocular pressure (IOP) with possible development of glaucoma

Infrequent optic nerve damage

Cataract formation

Posterior subcapsular cataract formation

Delayed wound healing

Secondary infections

Keratitis

Postmarketing Reports

Anaphylactic reaction

Erythema multiforme

Dexamethasone: Cushing’s syndrome and adrenal suppression (after use of dexamethasone in excess of listed dosing instructions in predisposed patients, including children and patients treated with CYP3A4 inhibitors)

Aminoglycosides: Adverse reactions reported with systemic aminoglycosides include neurotoxicity, ototoxicity, and nephrotoxicity have occurred in patients receiving systemic aminoglycoside therapy; aminoglycosides may also aggravate muscle weakness in patients with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson disease, because of their potential effect on neuromuscular function

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

Cautions

Sensitivity to topically administered aminoglycosides may occur; severity may vary from local effects to generalized reactions; discontinue use if sensitivity reactions occur

Bacterial keratitis reported from inadvertent contamination of multiple dose ophthalmic solution

Immunosuppression resulting from prolonged use of steroid use may result in secondary bacterial and fungal infections; steroids may also mask symptoms of infections and enhance existing ocular infections

Ocular hypertension and/or glaucoma reported with prolonged corticosteroid use

Discontinue use if sensitivity reaction to tobramycin develops

Corticosteroid use following cataract surgery may delay healing

Not for injection into eye

Pregnancy

There are no adequate and well-controlled studies in pregnant women; however, prolonged or repeated corticoid use during pregnancy has been associated with an increased risk of intra-uterine growth retardation; treatment should be used during pregnancy only if potential benefit justifies potential risk to fetus; infants born of mothers who have received substantial doses of corticosteroids during pregnancy should be observed carefully for signs of hypoadrenalism

Animal data

• Corticosteroids found to be teratogenic in animal studies; ocular administration of 0.1% dexamethasone resulted in 15.6% and 32.3% incidence of fetal anomalies in two groups of pregnant rabbits; fetal growth retardation and increased mortality rates observed in rats with chronic dexamethasone therapy; reproduction studies have been performed in rats and rabbits with tobramycin at doses up to 100 mg/kg/day parenterally and have revealed no evidence of impaired fertility or harm to the fetus

Lactation

Systemically administered corticosteroids appear in human milk and could suppress growth, interfere with endogenous corticosteroid production, or cause other untoward effects; not known whether topical administration of corticosteroids could result in sufficient systemic absorption to produce detectable quantities in human milk; because many drugs are excreted in human milk, caution should be exercised when therapy is administered to a nursing woman

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Dexamethasone prevents/reduces irritation & swelling by suppressing normal immune response, decreasing inflammatory mediators and reverses capillary permeability

Tobramycin: Alters bacterial cell membrane integrity by binding to 30S and 50S ribosomal subunits, which in turn interferes with bacterial protein synthesis