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Is there a role for pre- and post-procedural antibiotics for AMD injections?
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Procedure is invasive enough to warrant an antibiotic
 Andrew A. Moshfeghi |
My understanding is that a minority of physicians are doing that. There are two downsides to using post-injection antibiotics. One, you are theoretically increasing the resistance of these infections to antibiotics by using them so frequently. You are putting a lot of cost onto the patients to use these very expensive antibiotics around the time of their injection. Two, I am concerned that these visually debilitated patients can hurt themselves by putting these eye drops in their own eyes.
The pros are that you could be clearing the conjunctival area of any bacteria. It has been well-demonstrated that they do a good job getting rid of the bacteria, but it has not been demonstrated that getting rid of the bacteria therefore leads to a reduced risk of endophthalmitis. It has not been shown not to do that, but it has not been shown to do that, either.
Using post-injection antibiotics was the routine for pretty much every retina specialist in the country after the development of Macugen (pegaptanib sodium injection, Pfizer/Eyetech). After widespread use of Avastin (bevacizumab, Genentech) and Lucentis (ranibizumab, Genentech) injections in the ensuing years, the low rate of endophthalmitis and the high cost of these antibiotics, as well as the theoretical concern about increased resistance, several major groups and organizations suggested that post-injection antibiotics are no longer necessary. There is a fairly large portion of vitreoretinal surgeons who no longer use post-injection antibiotic prophylaxis at all.
I still use them. But I do not use the expensive fourth-generation fluoroquinolones. I will typically use Ciloxan (ciprofloxacin ophthalmic solution, Alcon), Ocuflox (ofloxacin ophthalmic, Allergan) or Polytrim (polymyxin B/trimethoprim sulfate, Allergan). I use it for 3 days after the injection. We are never going to know for sure if it makes a difference, but the procedure itself is invasive enough that if it were my eye, I would want to use an antibiotic afterward.
Andrew A. Moshfeghi, MD, MBA, is medical director at Bascom Palmer Eye Institute. He is a consultant and speaker for Alcon, Allergan, Bausch + Lomb and Genentech and receives research grants from Thrombogenics Inc.
If antibiotics are used, understand that the evidence is not great
 Eric Chen |
My overall strategy for decreasing post-injection endophthalmitis is multifold and includes the use of antibiotics both pre- and post-injection, even though the evidence for their use is not compelling. At the 2010 American Society of Retina Specialists meeting, I presented a study on more than 38,000 intravitreal injections performed over 10 years at our practice. Endophthalmitis developed in 13 cases, for an overall per injection rate of infection of 0.03%. While the risk is low, anything that can possibly further decrease that risk helps, so I use the drops to decrease the bacterial count on the conjunctiva.
I have also switched antibiotics from using the newer fourth-generation fluoroquinolones such as Vigamox (moxifloxacin 0.5%, Alcon) or Zymar (gatifloxacin 0.3%, Allergan) to older drugs such as tobramycin or Polytrim (polymyxin B/trimethoprim sulfate, Allergan). Not only are these older agents cheaper, but recent reports show some common pathogen developing resistance to the fourth-generation fluoroquinolones.
In our 13 cases, we also recognized a higher incidence of viridans streptococci (oral flora) in post-injection cases of endophthalmitis vs. post-cataract endophthalmitis, and all three of these patients had horrendous visual outcomes. Although we cannot definitely prove these organisms are originating from either the patient’s or the physician’s mouth, it seems plausible these organisms are rarely, if ever, found on the conjunctival surface. During injections, now I routinely keep the needle capped as long as possible, avoid talking and even hold my breath.
The subject of preventing post-injection endophthalmitis remains controversial; one problem is that the event itself is so rare, in order to find statistically significant evidence to justify any one intervention or identify any one risk factor, the number of injections needed for evaluation is tremendous. Prospective studies would be difficult given variation in physician practice patterns, and collecting that information would take a long time. For the present time, I continue to take any steps that could decrease the risk of a potentially devastating infection.
Eric Chen, MD, practices at Retina Consultants of Houston. Dr. Chen’s research department receives research grants from Alcon and Allergan, and he attended an advisory board meeting for Allergan regarding Ozurdex in June 2009.