Background: Most emergency departments (EDs) have deficiencies in the type and quantity of antidotes readily available to treat severely poisoned patients. Undue emphasis on the purchase price of several expensive antidotes such as anti-digoxin F(ab) fragments and fomepizole may contribute to this problem by creating the perception that comprehensive antidote stocking is too costly for smaller centres. For rarely used medications, however, purchase price alone is an insufficient estimate of cost.
Objective: To model the initial and annual maintenance cost needed for small to medium Canadian EDs to maintain an appropriate stock of essential antidotes.
Methods: A budget impact analysis was performed from the perspective of the ED pharmacy, using the following input variables: essential antidotes and recommended dose/formulation, estimated frequency of administration, price, shelf-life, and supplier replacement policy for expired drug.
Results: Frequency of use, shelf-life, and especially replacement policy for unused expired antidote are major determinants of cost. Remote hospitals that need to stock sufficient antidote to manage a patient for the initial 4 hours after presentation would incur only modestly increased costs compared to hospitals within one hour of a referral centre.
Conclusions: While other factors (antidote efficacy, safety and available alternate therapy) need to be considered, the cost of maintaining antidote availability is not determined primarily by purchase price. A change in supplier policy to free replacement on expiry for fomepizole and cyanide antidotes would have a considerable effect on making these antidotes less costly for smaller Canadian EDs.