Etomidate, formulated in propylene glycol, was used as the primary ane
sthetic agent in two dogs (No. 1 and 2) and etomidate, formulated in s
aline, was used as the primary anesthetic agent in an additional 20 do
gs, while developing a canine model for baroreceptor sensitivity testi
ng. Dogs 1 and 2 had signs of acute toxicosis after infusion of etomid
ate in propylene glycol. Dog 1 received less total etomidate than did
dog 2, 5.9 mg/kg vs 15.8 mg/kg, respectively. Average infusion rates w
ere 4.7 and 9 mg/kg/h, respectively. Dog 1 developed clinical signs of
mild hemoglobinuria, whereas dog 2 recovered from anesthesia slowly,
was obtunded, bradycardic, and hypothermic, with marked hemoglobinuria
and intravascular hemolysis. After supportive treatment, dog 2 regain
ed consciousness and hemodynamic variables improved within 12 h. None
of the additional 20 dogs that received infusion of etomidate in salin
e had any clinical adverse effects, suggesting a causal relationship b
etween the etomidate-propylene glycol formulation and the adverse effe
cts in dogs 1 and 2. Although etomidate may be useful in designing car
diovascular models under general anesthesia, such complications may wa
rrant use of a different etomidate formulation in the dog when the age
nt is administered at these infusion rates,