Context: Antidote shortage is a global problem. In Thailand, the National Antidote Project (NAP) has operated since November 2010 to manage the national antidote stockpile, educate the healthcare providers on appropriate antidote use, and evaluate antidote usage.
Objective: To evaluate the effect of NAP implementation on mortality rate and antidote use in cyanide poisoning cases arising from ingestion of cyanide or cyanogenic glycoside.
Methods: This is a retrospective cohort of poisoning cases involving cyanide or cyanogenic glycoside ingestion reported to Ramathibodi Poison Center from 1 January 2007 to 31 December 2015. Mortality rate, antidote use, and appropriateness of antidote use (defined as correct indication, proper dosing regimen, and administration within 90 min) before and after NAP implementation were compared. Association between parameters and fatal outcomes was analyzed.
Results: A total of 343 cases involving cyanide or cyanogenic glycoside ingestion were reported to Ramathibodi Poison Center. There were 213 cases (62.1%) during NAP (Project group) and 130 cases (37.9%) pre-NAP implementation (Before group). Implementation of NAP led to increased antidote use (39.9% in Project group versus 24.6% in Before group) and a higher rate of appropriate antidote use (74.1% in Project group versus 50.0% in Before group). All 30 deaths were presented with initial severe symptoms. Cyanide chemical source and self-harm intent were associated with death (OR: 12.919, 95% CI: 4.863-39.761 and OR: 10.747, 95% CI: 3.884-28.514, respectively). No difference in overall mortality rate (13 [10.0%] deaths before versus 17 [8.0%] deaths after NAP) was found. In subgroup analysis of 80 cases with initial severe symptoms, NAP and appropriate antidote use reduced mortality (OR: 0.327, 95% CI: 0.106-0.997 and OR: 0.024, 95% CI: 0.004-0.122, respectively). In the multivariate analysis of the cases with initial severe symptoms, presence of the NAP and appropriate antidote use independently reduced the risk of death (OR: 0.122, 95% CI: 0.023-0.633 and OR: 0.034, 95% CI: 0.007-0.167, respectively), adjusted for intent of exposure, cyanide source, age, and sex.
Conclusions: After NAP implementation, both antidote use and appropriate antidote use increased. In cases presenting with severe symptoms, presence of the NAP and appropriate antidote use independently reduced the risk of mortality.
Keywords: Cyanide poisoning; National Antidote Project; antidote; antidote stockpile.