Evaluation of the safety of 500 mg intravenous push thiamine at a tertiary academic medical center

Background: Thiamine, also known as vitamin B1, is an essential water-soluble micronutrient. Although thiamine has minimal safety concerns, parenteral administration has been associated with rare cases of anaphylactic shock, cardiac arrest, and injection site reaction. The objective of this analysis is to evaluate the incidence of anaphylaxis and injection site reactions associated with the administration of thiamine 500 mg as an intravenous (IV) push in adult patients. Method: This single-center, retrospective analysis was performed at Brigham and Women's Hospital in Boston, Massachusetts. Electronic health records were used to identify all adult patients who were ordered for thiamine 500 mg IV push between July 1, 2020, and December 31, 2020. For the major and minor endpoints, anaphylaxis and injection site reactions were assessed, respectively. Descriptive statistics were used as appropriate. Results: A total of 463 doses of thiamine in 69 patients were evaluated. Thiamine was administered peripherally for 392 (84.7%) doses and centrally for 68 (14.7) doses. No anaphylactic reactions were observed. A total of 4 injection site reactions (0.86%) were noted with 4 unique doses. All reactions were classified as low-grade based on our institutional grading system. All injection site reactions were classified as "possible" (Naranjo score of 1-4). Conclusion: Administration of IV push 500 mg thiamine was not associated with anaphylactic events and was associated with a low rate of injection site reactions.