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Aminoglycoside Antibiotic — Ophthalmic

Tobramycin Eye Drops 0.3% / Ointment

Brand names: Tobrex

Tobramycin eye preparations are a topical aminoglycoside antibiotic used to treat superficial bacterial infections of the eye such as bacterial conjunctivitis.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

Tobramycin binds to the bacterial 30S ribosomal subunit, inhibiting protein synthesis and producing a bactericidal effect against susceptible Gram-negative and some Gram-positive organisms.

Prescribing in practice

  • It should be reserved for bacterial infection and not used for undiagnosed red eye, as inappropriate use risks masking serious pathology and promoting resistance; sight-threatening keratitis requires urgent specialist management.
  • Local hypersensitivity and ocular surface irritation can develop with use.
  • The ointment formulation may transiently blur vision and is sometimes preferred for overnight use.

Monitoring

No laboratory monitoring is required; review clinical response and reconsider the diagnosis if the infection fails to settle.

Counselling the patient

  • Complete the prescribed course even if the eye improves quickly.
  • Ointment can blur vision temporarily, so it may be best applied before sleep.
  • Avoid contact lens wear while the eye is infected and being treated.

Evidence & guidelines

Topical aminoglycosides are an established treatment for bacterial conjunctivitis, consistent with current prescribing references and antimicrobial stewardship advice.

Reference: RCOphth Microbial Keratitis Guidelines; SPC Tobrex; AAO Preferred Practice Pattern (Bacterial Keratitis); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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