The following article is written by Brian Williamson, PharmD, president & CEO of JCB Laboratories.
Dilating patients' eyes before ophthalmic procedures is quite possibly the most time-consuming part of the eye exam/surgery. Many facilities choose to combine various medications to ensure a more efficient pre-operative process. While this practice creates efficiencies for nursing staff and perhaps is less burdensome for patients, the risk of contamination during mixing of these medications is a major concern.
Current USP <797> standards require that products combined outside of a laminar airflow workbench (hood) be used within one hour of mixing and that only three commercially available products shall be mixed together under these conditions.1 This USP standard is in place to prevent bacterial and particulate contamination of the compounded preparations.
So, what other options are available? Here are three to consider.
1. Some facilities opt to administer the various drugs (tropicamide, cyclopentolate, phenylephrine, ketorolac, moxifloxacin, etc.) separately, according to specific pre-op standing orders. The eye is capable of holding only 7-10 microliters (<1 drop of fluid) at any given time,2 but most drops range from 25-50 microliters. Therefore, the drops may not be administered more frequently than every five minutes to avoid washout. Washout may decrease the efficacy of the drops and may necessitate a second round to accomplish proper dilation.
2. Have the patients dilate themselves before the procedure. The patients would be prescribed the series of medications and instructed on how and when to administer the drops. This might be a viable option but the patient may not be able to properly self-administer these drops and proper dilation may not be achieved upon arrival at the facility.
3. Outsource the mixing or compounding process to a qualified compounding pharmacy that specializes in the preparation of compounded sterile preparations (CSPs). A qualified compounding pharmacy with the proper facilities and equipment would be capable of preparing the desired combinations and strengths of dilation drops. Additionally, qualified sterile compounders would have the ability to assign the CSPs with expiration or beyond use dates that result in a more predictable shelf life. The addition of preservatives to the CSP or the use of commercially available ophthalmic drops, which contain preservatives, allows the CSP to be labeled as a multiple-use container.
Resources
1. USP General Chapter <797> Pharmaceutical Compounding - Sterile Preparations. United States Pharmacoepia. 2008. www.usp.org/USPNF/pf/generalChapter797.html
2. Pharmaceutical Dosage Forms and Drug Delivery Systems. Ansel HC, Allen LV, Popovich NG, Lippincott Williams & Wilkins, 1999.
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