Intracameral fluoroquinolone safe for endophtalmitis prevention

A broader spectrum of bactericide and the possibility to administer antibiotic without mixing or dilution advantageous, surgeon says.

ByMichela Cimberle

Off-the-shelf ophthalmic moxifloxacin solution is safe for intracameral use during cataract surgery for the prophylaxis of endophthalmitis, according to a study.

Samuel Masket

“It is easy to administer and, as compared with intracameral cefuroxime, needs no dilution or mixing,” Samuel Masket, MD, said at the meeting of the European Society of Cataract and Refractive Surgeons.

Intracameral cefuroxime was shown by the ESCRS endophthalmitis study to reduce the risk of the complication by a factor of five. However, as Dr. Masket noted, “acceptance of this regimen has not been universal in the U.S.” Concerns are mainly related to the need of diluting this agent and the consequent risks of “kitchen pharmacy.” In addition, cefuroxime does not provide adequate protection against a number of pathogens, including methicillin-resistant Staphylococcus aureus and Pseudomonas.

“Off-the-shelf Vigamox (moxifloxacin 0.5%, Alcon) turns out to be an advantageous agent. It has a broad spectrum bactericidal activity, and its sterile, self-preserved formulation (without benzalkonium chloride) allows for administration without dilution or mixing,” Dr. Masket said.

In addition, the pH (6.8) and osmolarity (290 mOsm/kg) of moxifloxacin 0.5% are compatible with the human anterior chamber fluid (pH 7.4, osmolarity 305 mOsm/kg).

Safety testing

Dr. Masket was involved in a three-site randomized investigation to test the safety of intracameral moxifloxacin solution. The study involved two groups of patients randomly administered at the end of cataract surgery with either intracameral moxifloxacin solution or BSS (Alcon).

“The two groups were similar in all aspects in respect to the demographics and surgical experience, with the exception that half of them (29 patients) received 50 µL of undiluted 0.5% moxifloxacin ophthalmic solution and the other half (30 patients]) received 50 µL of undiluted BSS, both at the conclusion of surgery,” he said.

In both groups, patients had to be 18 years or older, undergoing uncomplicated cataract surgery with no other ocular pathology precluding postoperative visual acuity of 20/30 or better. Patients with prior ocular trauma or allergy to fluoroquinolones were excluded.

Postoperative visits were scheduled on day 1, week 1, month 1 and month 3.

“In order to assess safety, we measured visual acuity, endothelial cell density, corneal pachymetry, corneal clarity and edema, anterior chamber cells and flare. We also measured IOP and evaluated the effects on the macula by fundus examination and optical coherence tomography,” Dr. Masket said.

Results

At 3 months, mean uncorrected visual acuity, endothelial cell count and corneal thickness were identical in the two groups. A small but statistically significant reduction in IOP was observed in the moxifloxacin group.

“This effect has yet to be explained,” Dr. Masket said.

OCT characteristics for macular edema were evaluated by looking at postoperative changes in the fovea and four other macular locations: temporal, superior, nasal and inferior.

“Changes from preoperative to postoperative macular thickness were comparable in the two groups. The number of eyes with 15% or more increase in macular thickness was also comparable between groups,” he said.

One eye showed traces of corneal edema in the moxifloxacin group. Aqueous flare was not observed in either group, and all eyes had either no evidence or trace evidence of aqueous cells.

The percentage of eyes with no aqueous cells was lower in the moxifloxacin group (61% with no cells vs. 39% with trace cells) than in the BSS group (48% with no cells, 52% with trace cells). Dr. Masket said this was a trend, rather than a statistically significant difference.

“In conclusion, we found no safety risk associated with the use of intracameral moxifloxacin solution compared with BSS within 3 months following surgery. This shows that the commercial preparation of Vigamox 0.5% can be safely used during cataract surgery for the prophylaxis of endophthalmitis,” he said. “Only Vigamox, because of its formulation, is safe for this ‘off-label’ indication.”

Association with topical postoperative therapy may further reduce the risk of endophthalmitis after cataract surgery, Dr. Masket added.

“Efficacy studies similar to the ESCRS investigation are now necessary to determine the prophylactic value of intraocular moxifloxacin,” he said.

For more information:

Samuel Masket, MD, can be reached at 2080 Century Park East, Suite 911, Los Angeles, CA 90067, U.S.A.; +1-310-229-1220 ; e-mail: AVCmasket@aol.com. Dr. Masket consults, receives grants/research support and is on the speaker’s bureau for Alcon.

Alcon, the makers of Vigamox and BSS, can be reached at 6201 South Freeway, Fort Worth, TX 76134, U.S.A.; +1-817-293-0450; fax: +1-817-568-6142; Web site: www.alconlabs.com.

Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.