Microbiologic Studies of Multiple-Dose Containers of Triamcinolone Acetonide and Lidocaine Hydrochloride

In Brief Purpose: Reports of high endophthalmitis rates following intravitreal triamcinolone acetonide (TA) injection have raised concerns about safety. One possible risk factor is the use of multiple-dose containers. The purpose of this study was to determine whether there is a substantial risk of contamination of multiple-dose containers. Methods: Microbiologic Challenge Study: Suspensions of a known quantity of several microorganisms were placed in samples of TA to determine whether the preservative, benzyl alcohol 0.99%, is rapidly bacteriocidal. Simulated Clinical Use Study: After ten days of simulated clinical use of multiple-dose containers of TA and lidocaine hydrochloride 4%, samples were cultured. Additionally, samples from lidocaine containers in actual clinical use were cultured. Results: Microbiologic Challenge Study: Four of five challenge organisms demonstrated moderate growth, even after 24 hours of exposure to the benzyl alcohol preservative. Simulated Clinical Use Study: Simulated clinical use of multiple-dose containers of TA and lidocaine did not result in contamination, nor did actual clinical use of multiple-dose lidocaine containers. Conclusions: No culture-proven contamination of multiple-dose containers in simulated or actual clinical use was found. However, TA suspension is capable of harboring viable bacterial and fungal pathogens. The use of multiple-dose containers of triamcinolone for intravitreal injections is therefore discouraged. Multiple-dose containers of triamcinolone acetonide are capable of harboring viable bacterial and fungal pathogens, even after 24 hours of exposure to the benzyl alcohol 0.99% preservative. Therefore, the use of multiple-dose containers of triamcinolone for intravitreal injections is discouraged.