A supplement to Pharmacy Practice News, a Special Report, titled “Rabies Post-Exposure Prophylaxis: A Patient-Centric Approach to Care,” contained information that needs to be clarified.

Page 4 of the supplement includes the following text: “The 300-IU/mL HyperRab^® can be diluted as needed, if a larger volume is required to appropriately infiltrate multiple wounds. If dilution is required, using dextrose 5% in water (D5W) is recommended by the manufacturer (HyperRab [prescribing information] Grifols Therapeutics LLC; 2018). The 2 lower potency 150-IU/mL HRIG products—KEDRAB^TM (rabies immune globulin [human]) (KEDRION Biopharma) [and] rabies immune globulin (human) USP, heat treated, Imogam^® rabies-HT (Sanofi Pasteur)—also can be diluted with D5W if needed” (Vaccine 2018;36[37]:5500-5505; KEDRAB [prescribing information]. Kedrion Biopharma Inc.; 2017; Imogam [prescribing information]. Sanofi Pasteur; 2014).

Following further review, it was determined that the package inserts for Imogam and KEDRAB contain no instructions for further dilution.

Responding to a request for clarification, Sanofi medical information noted that dilution is not discussed in the Imogam package insert and is not recommended. “Sanofi does not recommend the use of Imogam Rabies-HT in a manner that is inconsistent with the approved product labeling”; however, the company points out that the World Health Organization recommendations state that “rabies immunoglobulins can be diluted if necessary, with physiological buffered saline to ensure the infiltration of large and multiple wounds” (Sanofi Medical Information, personal communication).

Also responding to a request for information, a clinical support representative from Kedrion noted that section 3 of the KEDRAB full prescribing information states that “KEDRAB is supplied in single-use vials containing 2 mL or 10 mL of ready-to-use solution with a nominal potency of 150 IU/mL.”

The representative wrote that “Kedrion Biopharma does not recommend dilution of the KEDRAB ready-to-use solution, as there have been no studies done to determine how KEDRAB would interact with D5W. We also do not know if KEDRAB would remain efficacious if diluted with D5W, and since the consequences of rabies can be dire without adequate treatment, we suggest that all such dilution cases be treated as adverse events” (Lorena Rodriguez, RN, personal communication).

In a revised version of the supplement, now available for download on pharmacypracticenews.com, the text has been updated to read: “Dilution is not recommended for the 2 lower potency 150-IU/mL HRIG products—KEDRAB™ (rabies immune globulin [human]) (Kedrion Biopharma) and rabies immune globulin (human) USP, heat treated, Imogam^® rabies–HT (Sanofi Pasteur).”

Portions of this clarification were written with the help of Jerry Siegel, PharmD, vice president of business development and managing partner, Safe Medication Management, in East Greenwich, RI. Siegel also is a clinical associate professor in The Ohio State University College of Pharmacy, in Columbus, Ohio.