EyeWorld Asia-Pacific December 2013 Issue

44 EWAP CORNEA December 2013 move and not purely a therapeutic choice. There should be concerns about dosage errors, but also antibiotic toxicity to the cornea, meshwork, and macula, and these targets have not been adequately addressed in the U.S. literature.” Although he’s not a proponent for intracameral use in “routine cases,” Dr. Sheppard said the Shorstein article “clearly indicates advantages in targeting high-risk patients, particularly where their capsule has been broken; these cases would have the best risk-to- reward ratio.” Dr. Shorstein’s group looked at more than 16,000 patients; the most striking revelation was that the people who developed infections were those who were not administered intracameral cefuroxime either because of allergy or because the group was initially afraid to inject it in cases of posterior capsular rupture. “When we added moxifloxacin for those allergic patients and injected in all patients, especially in the complicated cases, we found a truly significant decline in infection,” he said. Preferred route of administration Dr. Prescott said the low rates of endophthalmitis result in a double-edged sword of sorts—“the low rates decrease the incentive for improvement,” she said. “Based on the evidence, intracameral antibiotics should be the standard of care. There is not a clear winner for antibiotics, but I prefer moxifloxacin, since that eliminates the compounding issue and has an excellent safety profile. For topical antibiotics, I prefer Polytrim [trimethoprim/ polymyxin B ophthalmic, Allergan, Irvine, Calif., USA] since it has good broad coverage, especially for the most common bacteria, and is inexpensive.” Dr. Sheppard prescribes a topical fluoroquinolone the day before surgery and for a full two weeks postop (noting some studies have shown delayed onset beyond seven days). “I prefer besifloxacin 0.6% because of its superior MICs and pharmacokinetics, which allow for twice-daily use,” he said. He uses either moxifloxacin or cefuroxime intracamerally, but only in high- risk cases, he said, which account for less than 1% of his overall cases. These include secondary IOLs, transplants with vitrectomies, glaucoma procedures in aphakes, and routine cataract surgery with unexpected capsular rupture or vitreous prolapse. Dr. Barry believes intracameral antibiotics should be offered to all patients, not just those at high risk. Beginning in 2010, Dr. Shorstein’s hospital began using an intracameral antibiotic on every cataract patient, “and the net effect has been a 22-fold reduction from baseline in our endophthalmitis rates,” he said. A Spanish study and a French study both found double- digit declines in endophthalmitis rates once they implemented intracameral regimens. Dr. Prescott said she’d “really love to see a similar study performed with intracameral vs. topical moxifloxacin so that the only variable is route of administration.” Other potential drug choices Cefuroxime remains the drug most studied, in the largest randomized trial to date, 2 and has been shown to work. “When we started using intracameral injections in 2007, cefuroxime was the obvious choice because of the ESCRS results,” Dr. Shorstein said, but added smaller surgical centers might use moxifloxacin because it’s easier to dilute. “Other antibiotics have not really been studied to any large degree,” he said. While vancomycin has potential, the Centers for Disease Control have recommended against its use in routine prophylaxis due to risk of emerging resistance. Likewise, Dr. Sheppard noted cefuroxime is not particularly effective against MRSA or gram- negative bacteria. “Moxifloxacin is the most cost effective, vancomycin is the best against MRSA but is also the most toxic,” he said. “Vancomycin achieves bactericidal activity in the aqueous for less than two hours, and therefore only three full bacterial replicative cycles.” Dr. Prescott is still evaluating which antibiotic to use, but is leaning toward undiluted moxifloxacin because of the safety profile. “There’s no clear winner for which antibiotic is best,” she said. “I hope more options will become available that are preservative-free and have better safety profiles.” “What’s truly needed is an inexpensive, off-the-shelf, single- dose, preservative-free, sterile, reliably diluted commercially available preparation,” Dr. Sheppard said, and wouldn’t care which of the antibiotics was used if all those criteria could actually be met. Compounding the issue Compounding pharmacies have a “very bad name these days,” Dr. Barry said. “People are not willing to expose themselves to the risk by using compounding pharmacies.” The recent crackdown on compounding pharmacies in the U.S. will likely result “in more physicians mixing the intracameral drugs themselves, or having their staff mix it in the OR, where dilution and contamination errors are more likely,” Dr. Sheppard said. Most compounding pharmacies are highly reliable, he said (citing Leiter’s in San Jose, Calif., USA), with national accreditation. “That’s been one of the major problems with adaptation of intracameral antibiotics in the U.S. Until we have a commercially available formulation, I do not think that intracameral treatment will become standard of care,” Dr. Prescott said. Dr. Barry thinks that for financial reasons there is little enthusiasm in the American pharmaceutical industry for an intracameral product. “It’s rather small money in comparison,” he said. “The financial savings across the U.S. would be infinitely cheaper for intracameral administration with topical as an adjunctive use.” Although Europeans have a commercially available cefuroxime formulation, U.S. ophthalmologists “are in a quandary because we want to do the right thing, but until a manufacturer provides a commercially available intracameral product, there are hoops and hurdles to overcome,” Dr. Shorstein said. EWAP Editors’ note: The physicians have no financial interests related to this article. References 1. Shorstein NH, Winthrop KL, Her- rington LJ. Decreased postoperative endophthalmitis rate after institution of intracameral antibiotics in a Northern California eye department. J Cataract Refract Surg . 2013;39:8–14. 2. ESCRS Endophthalmitis Study Group. Prophylaxis of postoperative endophthalmitis following cataract sur- gery: results of the ESCRS multicenter study and identification of risk factors. J Cataract Refract Surg . 2007;33: 978–988. Contact information Barry: +353 1 283 7203, peterbarryfrcs@theeyeclinic.ie Prescott: +1-410-893-0480, cpresco4@jhmi.edu Sheppard: +1-757-622-2200, jsheppard@vec2020.com Shorstein: +1-925-906-2010, neal.shorstein@gmail.com Preventing - from page 43