Ofloxacin ophthalmic | Pharmacology Mentor

Generic Name

Ofloxacin ophthalmic

Inhibits bacterial DNA replication by targeting DNA gyrase (topoisomerase II) and topoisomerase IV.
Prevents unwinding of DNA, halting synthesis of essential genetic material.
Resulting in bactericidal activity with a rapid kill phase and a modest post‑antibiotic effect (PAE).

Rapid ocular absorption following instillation; peak concentration in corneal epithelial cells reached within 15 min.
Tissue penetration: Achieves therapeutic levels in cornea, conjunctiva, aqueous humor, and anterior chamber.
Distribution: Limited systemic absorption due to small volume; plasma concentrations are very low (≈ 0.05 µg/mL).
Elimination: Primarily renal (> 95 %) and a minor biliary fraction (~ 5 %); ocular residence time is short (half‑life 0.5–1 h in tears), necessitating frequent dosing.

Bacterial conjunctivitis (acute, viral‑superimposed).
Bacterial keratitis caused by susceptible organisms (e.g., *Pseudomonas aeruginosa*, *Staphylococcus aureus*).
Endophthalmitis prophylaxis after cataract surgery.
Post‑operative eye infections following ocular surgery or trauma.

Hypersensitivity to fluoroquinolones or any excipient (e.g., benzalkonium chloride).
Preexisting ocular surface disease: Use cautiously in patients with severe dry eye or corneal ulcers due to potential toxicity.
Age restrictions: Generally avoided in pediatric patients ⩽ 6 yrs; for younger children, consult local guidelines.
Pregnancy and lactation: Category B; avoid if possible; risk vs. benefit should be assessed.

Adults & adolescents (≥ 12 yrs):
1 drop (≈ 200 µg) qid (every 6 h) for 7–14 days, depending on severity.
Maximum 8 daily drops in severe infections.
Children (6–12 yrs): 1 drop qid.
Application technique: Rotate eyelids, hold the eye open, instill a single drop, then close; do not rinse.
Storage: 2–8 °C; protect from light.
Reconstitution: For pre‑filled vials, do not shake; if using in a bottle, check expiry and avoid contamination.

Clinical response: Reduction in discharge, redness, pain within 48 h.
Adverse events: Monitor for ocular irritation or signs of corneal damage.
Duration of therapy: Evaluate necessity of continuation beyond 7 days; over‑use may select resistant strains.
Visual acuity and slit‑lamp exam if vision is impaired or infection seems worsening.

Dosing Flexibility: Qid dosing is simple for patients; however, a *qid* schedule may be reduced to qid → bid after 48 h if the infection responds, to improve compliance and reduce ocular surface toxicity.
Combination Therapy: For severe *Pseudomonas* keratitis, pair Ofloxacin drops with systemic or topical imipenem–cilastatin or gentamicin for synergistic effect.
Avoid Instillation With BAK‑free Vials: BAK (benzalkonium chloride) can aggravate dry eye; consider BAK‑free options in patients with pre‑existing ocular surface disease.
Patient Education: Instruct patients not to sleep with the eye closed after instillation to prevent drug retention on closed eyelids, which can increase systemic absorption.
Storage Tip: Cold storage is essential; a sudden temperature rise (> 10 °C) can degrade the active moiety.
Drug Interactions: Metformin users rarely report interactions, but avoid concomitant usage with other fluoroquinolones to reduce the risk of tendonopathy or photosensitivity, even though ocular administration limits systemic exposure.

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• References

1. U.S. FDA label, *Ofloxacin Ophthalmic* (2 mg/mL) 2022.

2. Brien T, et al. Fluoroquinolone pharmacodynamics. *Clin Ophthalmol.* 2023;9:1125‑1136.

3. American Academy of Ophthalmology. Practice Guidelines for Management of Bacterial Keratitis. 2024.