EyeWorld Asia-Pacific September 2016 Issue

66 EWAP PHARMACEUTICALS September 2016 Eye on endophthalmitis prevention by Maxine Lipner EyeWorld Senior Contributing Writer Opting for intracameral prophylaxis I t’s one of the things that worries practitioners the most: cases of endophthalmitis following cataract surgery. To help keep this at bay, ophthalmologists have long relied on antibiotic drops. However, some are now turning to intracameral antibiotics. Currently, there are no antibiotics approved for intracameral use in the United States, according to Steve Arshinoff, MD , associate professor, Department of ophthalmology and Vision Sciences, University of Toronto. But that hasn’t stopped practitioners from using them off label, he noted. What’s more, the evidence favors intracameral agents for endophthalmitis prevention. “Topical ones have never been shown to be effective,” Dr. Arshinoff said. “Intracameral ones have all been shown to be very effective in studies that cumulatively have involved more than 1.5 million eyes to date.” Francis Mah, MD , director of cornea and external disease, and co-director of refractive surgery, Scripps Clinic, La Jolla, California, likewise thinks that the use of intracameral antibiotics is preferable. “There is one study that was prospective, and it was a head-to-head comparison in cataract surgery comparing intracameral to topical agents,” Dr. Mah said. When intracameral cefuroxime was given, there was a 4 to 5 times better outcome than with topical levofloxacin given perioperativately. 1 Intracameral agents Currently, there are several intracameral agents being used. These include cefuroxime, moxifloxacin, vancomycin, and cefazolin. In Europe, cefuroxime tends to be used the most, Dr. Mah noted, adding that some U.S. practitioners are also using this. “I think moxifloxacin is number 2 in terms of intracameral agents,” he said. “I think about 60 to 70% of the intracameral moxifloxacin used is commercially available Vigamox [Alcon, Fort Worth, Texas]. This is because Vigamox contains no preservatives. “People are diluting it or just using it straight out of the bottle,” he said, adding that when using it straight out of the bottle, there are no problems with dilution. Meanwhile, about 30 to 40% of practitioners rely on compounded moxifloxacin instead of Vigamox, he said. Some are using vancomycin intracamerally. “Historically, vancomycin was the one that kicked off everything,” Dr. Mah said, explaining that now, however, there are reports about a dramatic complication associated with intracameral vancomycin, known as hemorrhagic occlusive retinal vasculitis (HORV), which has been described as a delayed type 3 hypersensitivity reaction. This rare condition shows up anywhere from 1 to 4 weeks after the surgery. The typical cataract protocol in the U.S. calls for doing the second eye 2 weeks after the first, which means that there are bilateral cases. “It’s a devastating vision loss,” Dr. Mah said. “Most of these patients have worse than counting fingers vision.” He views the use of vancomycin in the U.S. as a close third to cefuroxime and moxifloxacin, but thinks that this may dissuade some from injecting it intracamerally. A fourth intracameral option is cefazolin. Reports out of Singapore show it has efficacy similar to cefuroxime, Dr. Mah noted. With all of these intracameral agents, there are reports in the literature that they can be used safely; in terms of efficacy, there is the strongest evidence to support use of cefuroxime and moxifloxacin, he said. However, Dr. Arshinoff noted that there can be issues with cefuroxime, which is an old drug. “Cefuroxime is a drug that has known quite a lot of resistance,” he said. There can be a particular problem in that some who are given intracameral To stave off endophthalmitis following cataract surgery, some practitioners are now administering antibiotics intracamerally during the procedure. Source: Francis Mah, MD