Dexamethasone with netilmicin

How it works

Dexamethasone dampens ocular inflammation by inhibiting inflammatory mediators, while netilmicin binds the bacterial 30S ribosomal subunit to inhibit protein synthesis, giving bactericidal activity against many Gram-negative and some Gram-positive organisms.

Prescribing in practice

• Topical corticosteroids are contraindicated in undiagnosed red eye and suspected herpes simplex (dendritic) keratitis because of the risk of corneal melt and perforation, so a herpetic cause must be excluded.
• Prolonged use carries the risk of steroid-induced glaucoma, cataract and masking of infection, so courses should be short and ophthalmologist-led.
• Aminoglycosides can cause local hypersensitivity and surface toxicity; discontinue if irritation or allergy develops.

Monitoring

With more than brief use, monitor intraocular pressure and review the cornea and treatment response, stopping if infection worsens or hypersensitivity occurs.

Counselling the patient

• Use only for the prescribed short course and do not self-restart for later eye symptoms.
• Seek advice if the eye becomes more painful, red or swollen.
• Remove contact lenses during treatment unless advised otherwise.

Evidence & guidelines

Combined corticosteroid-aminoglycoside eye preparations are well established for inflammatory ocular conditions with a bacterial component, with safe use contingent on excluding viral keratitis and limiting duration.