The antitoxin is provided in a 10 cc vial that provides 5500 to 8500 international units of each type of specific antitoxin. It has to be diluted 1:10 in isotonic sodium chloride solution and must be slowly infused intravenously. Because it is of equine origin, hypersensitivity reactions are possible, and antitoxin administration should be preceded by a small challenge dose. Diphenhydramine and epinephrine should be available during administration of the antitoxin in case of a severe hypersensitivity reaction. Patients who respond to the test dose with a substantial wheal and flare can be desensitized for more than 3 to 4 h [78] .