347 Trends in the Use of Hydroxocobalamin or Nitrites as Antidotes, 2000-2016

Abstract

Nitrites and hydroxocobalamin are potential therapies utilized in cyanide poisoning. Hydroxocobalamin was approved for use in the United States in 2006. The objective of this study is to evaluate the change in use patterns of these antidotes as reported to the U.S. poison centers. All human exposure calls within the U.S. National Poison Data System where amyl nitrite, sodium nitrite, or hydroxocobalamin were recommended and/or performed as therapies between 01/01/00 and 12/31/16 were collected. The annual trends in the cases reporting these antidotes were documented, comparing cases where therapy was recommended or performed. Additionally, demographic and clinical characteristics of the patients were examined. Descriptive statistics, including frequencies and trends using simple linear regression, were performed. During the study period, 828 cases were identified where hydroxocobalamin was performed (52.7%), recommended (16.1%), or recommended and performed (31.2%) as therapy. The number of cases increased significantly from 4 in 2006 to 126 in 2016. The number of cases where hydroxocobalamin was recommended, as well as used without recommendations by a poison center increased over this 10-year timeframe (3 to 41, and 1 to 65 cases, respectively). The number of cases reporting amyl nitrite decreased from 16 to 4 cases, while the number of sodium nitrite cases was almost unchanged (38 to 37 cases) from 2006-2016. From 2000-2016, amyl nitrite and sodium nitrite were performed in 55.4% and 60% of the cases, respectively. Amyl nitrite was recommended in 22.3% and recommended as well as performed in 22.3% of cases, while the corresponding proportions for sodium nitrite were 15.5% and 24.5%, respectively. Carbon monoxide (43.1%) was the most frequent exposure when hydroxocobalamin was reported as the therapy, while cyanide (32.6%, and 17.8%), was the most frequent exposure for amyl nitrite, and sodium nitrite, respectively. From 2000 to 2016, the use of these antidotes was higher in males (60%) and patients aged 20-59 years. The majority of cases reporting these therapies were single substance exposures with residence noted as the site of exposure. The proportion of cases citing suicide as the reason for exposure that required antidotal therapy were the lowest for hydroxocobalamin (16.2%) and the highest for sodium nitrite (34.6%). Hydroxocobalamin therapy demonstrated an average increase of 12 reports per year [95% CI: 9.9-14.3; p <0.001], while amyl nitrite reports decreased during the same time frame. After its approval, the recommendations and utilization of hydroxocobalamin as therapy have seen a significant increase, while amyl nitrite as therapy has seen a gradual decrease. Sodium nitrite as therapy has seen no change.