EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/119916
April 2013 ASCRS issues clinical alert on intracameral alpha agonists O n March 13, 2013, ASCRS issued a clinical alert regarding intracameral alpha agonist formulations for offlabel use during cataract surgery. Since it was first advocated to lessen or prevent intraoperative floppy iris syndrome (IFIS), direct intracameral injection of epinephrine has become a common adjunct for increasing or maintaining pupil dilation during surgery. Because of concerns regarding potential corneal endothelial toxicity from the bisulfite stabilizing agent, many surgeons preferred to use bisulfite-free epinephrine from American Regent (Shirley, N.Y.). During the past year, a nationwide shortage of bisulfite-free epinephrine has raised many questions about the safety of using bisulfite-containing preparations. Now, even bisulfite-containing epinephrine has been unavailable in many parts of the country. To address the many clinical issues caused by these shortages, the ASCRS Cataract Clinical Committee and the ASCRS TASS Task Force collaborated on producing an educational document that summarizes the differences among commercial sources of epinephrine in the U.S. A series of recommendations were provided based on the collective experience and opinions of the Cataract Clinical Committee members. Phenylephrine is commercially available in a number of foreign countries, but is only available through compounding pharmacies within the U.S. The Cataract Clinical Committee therefore also addressed precautions that ophthalmologists should consider when ordering medication for intraocular use from a compounding pharmacy. By issuing this clinical advisory document, the ASCRS Cataract Clinical Committee recognizes and confirms the important but off-label role that intracameral alpha agonists play in managing IFIS and small pupils. The document is intended to provide guidelines and clinical support for the appropriate and proper formulation of epinephrine or phenylephrine by ophthalmologists, operating room personnel, and pharmacists for use during cataract surgery. David F. Chang, MD, chief medical editor I ntracameral epinephrine is commonly used off-label to dilate and stabilize the pupil intraoperatively. Although adding epinephrine to the irrigating solution during cataract surgery has been a common practice for decades, direct intracameral injection of epinephrine has grown in popularity following published reports of its clinical efficacy for IFIS.1-3 In the United States, 1:1000 epinephrine has been commercially available from several different manufacturers. The 30 mL bottle contains the preservative chlorobutanol, and this source should not be used in the eye. Preservative-free 1:1000 epinephrine is packaged in single-use 1 mL vials (1 mg/mL) and comes in two forms—with and without 0.1% bisulfite as a stabilizing agent. Bisulfite improves the stability of the solution by delaying oxidation of the active substance. Studies initially performed in the 1970s by Henry Edelhauser, PhD, found that undiluted epinephrine containing 0.1% bisulfite injected intracamerally caused corneal decompensation due to endothelial toxicity.4 Similarly, undiluted intracardiac epinephrine 1:10,000 (0.1 mg/mL) contains 0.1% bisulfate and has also been shown to be toxic to the corneal endothelium.5 The toxicity is due to the high buffer capacity of the bisulfate rather than to the epinephrine. Based on these findings, many clinicians have only used preservativefree commercial preparations of epinephrine that are also bisulfitefree for direct intracameral injection.6 Another potential problem with undiluted epinephrine taken directly from the vial is a low pH of approximately 3.0, which is well outside the 6.5 to 8.5 pH range thought to be safe for the corneal endothelium.7 For this reason, the 1:1000 epinephrine is usually diluted with BSS, BSS Plus (Alcon, Fort Worth, Texas), or preservative-free 1% lidocaine to raise the pH for direct intracameral injection.1 During the past year in the United States, there has been a nationwide shortage of bisulfite-free epinephrine. This clinical advisory represents the current consensus opinion of the ASCRS Cataract Clinicontinued on page 8 SYMPOSIUM & CONGRESS 2014 APRIL 25–29 BOSTON Additional Programming Cornea Day ASCRS Glaucoma Day ASOA Workshops Technicians & Nurses Program Book Early for the Best Rates Housing is Now Open www.ascrs.org