Safety profile of bilateral same-day intravitreal injections from a single vial may equal that of unilateral injections

Moreover, a molecular bacterial surveillance system may allow for early detection of drug contamination.

No complications were found in a retrospective review of 135 patients who received 574 bilateral same-day intravitreal injections from a single vial with separate syringes or needles for a host of retinal diseases. Furthermore, of the 278 injections screened for bacterial contamination, there were no detected cases of drug contamination by bacteria.

“As retinal specialists, we frequently meet patients in the clinic who want to receive bilateral injections simultaneously due to limitations in time and distance,” study co-author Kyu Hyung Park, MD, PhD, head of the retina and vitreous division at Seoul National University Bundang Hospital in South Korea said. “In such cases, we always hesitate to perform bilateral injections for fear of serious bilateral complications. Hence, we wanted valid data to assess whether bilateral injection is a viable method in treating patients with bilateral macular diseases.”

The study, which appeared in Retina, employed eubacterial 16S ribosomal DNA real-time polymerase chain reaction (PCR) for molecular bacterial screening.

Molecular bacterial screening

“We found no drug contamination, even if we withdraw bevacizumab from a single vial over 10 times,” Park told OSN Retina.

Kyu Hyung Park

The study authors did not categorically claim that using a single vial is as safe as two separate vials for bilateral injections.

“If the economy permits the use of separate vials for each eye, that would be the safest way to perform bilateral injections,” Park said. “But, in the real world, it is not possible to do so, and we have to find an alternative method while considering risk, benefit and, most importantly, safety.”

Molecular bacterial screening allows for detection of drug contamination early on that may have occurred during drug production, the aliquot procedure or storage.

Although the number of bilateral injections was not large enough to detect cases of endophthalmitis and the eubacterial PCR testing could have missed the low bacterial burden, Park said that the repeated withdrawal of drugs in the same day is relatively safe and might be an alternative to aliquoting by a professional compounding pharmacy.

“[Molecular bacterial screening] helps clinicians decide whether to monitor patients more frequently and may help in making a faster decision whether to treat the patient more vigorously,” he said.

Screening also aids in determining an appropriate antibiotic.

Safety measures

To increase the safety profile of using a single vial, the authors applied a 10% povidone-iodine swab on the rubber cover of the vial and waited until the topical antiseptic dried completely before every withdrawal of the drug.

“We also discard the single vial at the end of injections on the same day,” Park said. “Reuse of the used vial on other days may increase bacterial burden if the vial was accidentally contaminated and may increase the chance of endophthalmitis after intravitreal injections.”

For multiple-aliquot drugs such as bevacizumab, the authors recommended securing products from professional compounding pharmacies that adhere to General Chapter 797 of the U.S. Pharmacopeia.

“If a professional compounding pharmacy is not available for any reason, multiple withdrawals with a single vial on the same day and proper surveillance systems like eubacterial PCR may be an alternative method to detect drug contamination and to provide early adequate intervention to the patient,” Park said.

Since 2008, the authors have performed eubacterial PCR on more than 4,000 patients who received intravitreal injections.

“Because of the low incidence of endophthalmitis and drug contamination, we did not find any positive data from the eubacterial PCR,” Park said. “Therefore, we are going to perform the procedure in approximately 10,000 patients to assess the efficacy of the screening procedure.” – by Bob Kronemyer

Reference:

Woo SJ, Han JM, Ahn J, et al. Bilateral same-day intravitreal injections using a single vial and molecular bacterial screening for safety surveillance. Retina. 2012;32(4):667-671.

For more information:

Kyu Hyung Park, MD, PhD, can be reached at Department of Ophthalmology, Seoul National University Bundang Hospital, No. 300, Gumi-dong, Bundang-gu, Seongnam, Gyeonggi-do, 463-707, South Korea; 82-31-787-7373; email: jiani4@snu.ac.kr.
Disclosure: Park has no relevant financial disclosures.