What is the role of Moxifloxacin (a fluoroquinolone antibiotic) in ophthalmology?

From the Guidelines

Moxifloxacin ophthalmic solution is a suitable treatment option for bacterial keratitis, particularly for its broad-spectrum coverage of gram-positive and gram-negative pathogens, including its effectiveness against Moraxella keratitis, which requires a more prolonged treatment duration 1.

Key Considerations

• The choice of moxifloxacin should be based on local availability and resistance patterns, as there has been a reported increase in resistance of P. aeruginosa to moxifloxacin in some regions 1.
• Moxifloxacin has been shown to perform at least as well as standard therapy, fortified cefazolin/tobramycin combination therapy, and potentially better than an earlier generation fluoroquinolone, ciprofloxacin, in the treatment of bacterial keratitis 1.
• Patients with recurrent bacterial keratitis may benefit from treatments to decolonize S. aureus, as this pathogen is a common cause of recurrent infection 1.

Treatment Regimen

• The standard dosing regimen for moxifloxacin ophthalmic solution is 1 drop in the affected eye(s) 3 times daily for 7 days, with possible extension to 10-14 days for severe infections based on clinical response.
• Patients should be instructed on proper administration techniques to minimize systemic absorption and prevent contamination.

Monitoring and Follow-up

• The frequency of reevaluation depends on the extent of disease, with severe cases requiring daily follow-up initially, at least until stable or clinical improvement is confirmed 1.
• Systemic antibiotics may be considered in severe cases where the infectious process has extended to adjacent tissues or when there is impending or frank perforation of the cornea 1.

From the FDA Drug Label

Moxifloxacin ophthalmic solution, 0.5% is a topical fluoroquinolone anti- infective indicated for the treatment of bacterial conjunctivitis caused by susceptible strains of the following organisms: Corynebacterium species*, Micrococcus luteus*, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus warneri*, Streptococcus pneumoniae, Streptococcus viridans group, Acinetobacter lwoffii*, Haemophilus influenzae, Haemophilus parainfluenzae*, Chlamydia trachomatis The antibacterial action of moxifloxacin results from inhibition of the topoisomerase II (DNA gyrase) and topoisomerase IV. Moxifloxacin has been shown to be active against most strains of the following microorganisms, both in vitro and in clinical infections as described in the Indications and Usage section: Aerobic Gram-Positive Microorganisms Corynebacterium species* Micrococcus luteus* Staphylococcus aureus Staphylococcus epidermidis Staphylococcus haemolyticus Staphylococcus hominis Staphylococcus warneri* Streptococcus pneumoniae Streptococcus viridans group

Moxifloxacin ophthalmic solution is used to treat bacterial conjunctivitis caused by susceptible strains of certain microorganisms, including:

• Gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae
• Gram-negative bacteria: Haemophilus influenzae, Acinetobacter lwoffii
• Other microorganisms: Chlamydia trachomatis 2 2

From the Research

Moxifloxacin in Ophthalmology

• Moxifloxacin is a fourth-generation 8-methoxyfluoroquinolone used in the treatment of bacterial conjunctivitis and keratitis 3, 4, 5, 6.
• It has been shown to have good activity against various Gram-positive and -negative ocular isolates in vitro, and achieves good penetration into ocular tissues in healthy volunteers and patients undergoing ocular surgery 3.
• The efficacy of moxifloxacin 0.5% ophthalmic solution in the treatment of bacterial conjunctivitis has been demonstrated in several randomized, double-blind, multicentre trials, with clinical success rates significantly higher than placebo or comparable to other treatments such as levofloxacin 0.5% ophthalmic solution 3, 5.

Treatment of Bacterial Keratitis

• Moxifloxacin has been evaluated in the treatment of bacterial keratitis, with studies showing its effectiveness in resolving keratitis and healing ulcers, with no significant difference in healing rate, cure rate, or complications compared to other treatments such as fortified cephazolin and tobramycin or ofloxacin 4, 6.
• A systematic review and meta-analysis of high-quality randomized controlled trials found that topical antibiotics, including moxifloxacin, had comparable treatment success, time to cure, and serious complications of infection, but differed in their safety profiles, with fluoroquinolones reducing the risk of ocular discomfort and chemical conjunctivitis 7.

Safety and Tolerability

• Moxifloxacin 0.5% ophthalmic solution has been well tolerated in patients with bacterial conjunctivitis, with ocular adverse events such as eye pain and eye irritation being the most commonly reported treatment-related adverse events, mostly of mild severity 3.
• The use of topical moxifloxacin has been shown to be cost-effective and may generate total healthcare budget savings by reducing the costs of managing treatment failures and the use of clinicians' time to manage such failures 5.