JUN 17, 2013
This prospective study conducted in 224 patients with moderate bacterial corneal ulcers found that treatment with moxifloxacin was comparable to cefazolin/tobramycin.
The success rate was similar between patients randomized to a combination of fortified 5% cefazolin sodium and 1.3% tobramycin sulphate eye drops or monotherapy with 0.5% moxifloxacin hydrochloride eye drops. Approximately 80 percent of patients achieved complete resolution of keratitis and healing of ulcers at three months.
The authors write that arguments for combination fortified antibiotic therapy include better coverage of gram-positive and gram-negative organisms and a lower chance of developing antibiotic resistance. However, fortified antibiotics have the disadvantage of needing to be prepared under sterile conditions at a pharmacy. Concerns have been expressed about their shelf life, appropriate method of storage, and the duration for which they can be used safely before replacement.
Fortified drops also have the theoretical risk of the first drug being washed away if both medicines are applied simultaneously. Furthermore, using two drugs as a combination may enhance ocular toxicity and prevent re-epithelialization. Compliance also is difficult to maintain with more medications and confusing regimens.
An argument against fluoroquinolone monotherapy is that although these agents are considered very effective and safe, resistance is bound to occur if they are used indiscriminately, and a few cases of moxifloxacin and gatifloxacin resistance have already emerged; however, their judicious use in an appropriate setting may be justified. Furthermore, poor patients from rural areas often are uneducated and have poor access to tertiary care hospitals or pharmacies, and therefore may not be able to store the fortified medication at a cool temperature to maintain its shelf life.
The authors note that moxifloxacin 0.5% may be continued during the entire treatment course since it is preservative-free and not significantly epitheliotoxic.