dexamethasone + tobramycin: clinical use

Prescribing considerations

• Confirm the postoperative indication and whether bacterial coverage is appropriate.
• Use is established from age 2 years; safety and efficacy are not established below this age.
• Consider greater steroid-response risk in young children and patients with diabetes.
• Assess corneal or scleral thinning, impaired healing, dry eye and compromised corneal surfaces.
• Consider cross-sensitivity with previous aminoglycoside hypersensitivity.
• Be alert to worsening muscle weakness in myasthenia gravis or Parkinson’s disease.

Contraindications and cautions

• Hypersensitivity to tobramycin, dexamethasone or an excipient
• Herpes simplex keratitis
• Vaccinia, varicella or another viral disease of the cornea or conjunctiva
• Mycobacterial ocular infection
• Fungal ocular disease or untreated parasitic eye infection
• Untreated purulent eye infection

Monitoring

• Monitor intraocular pressure, particularly in children younger than 6 years and others predisposed to steroid-induced ocular hypertension.
• Assess persistent blurred vision or other visual disturbance for glaucoma, cataract or less common steroid-associated pathology.
• Monitor for delayed corneal healing, tissue thinning or perforation risk.
• Review deterioration, recurrence or signs of secondary infection.
• With intensive or prolonged exposure, especially alongside CYP3A4 inhibitors, monitor for systemic corticosteroid effects.

Clinical pharmacology

Dexamethasone suppresses inflammatory mediator and leucocyte activity. Tobramycin is a bactericidal aminoglycoside that inhibits bacterial ribosomal protein synthesis; activity depends on organism susceptibility and local resistance.

Formulation and product differences

• The selected product is a white ophthalmic suspension and must be shaken before use.
• It contains benzalkonium chloride, which may irritate dry or compromised eyes and can discolour soft contact lenses.

Eye drops

Route: Ophthalmic

Strengths: 3 mg + 1 mg/mL