Duration of signs
The endpoint of therapy is resolution of the abnormal clinical findings. We can estimate the duration of signs based on exposure
evidence and metabolism and excretion data extrapolated from human exposure. The plasma half-life in people for inhaled albuterol
is about 3.8 hours (1.7- to 7.1-hour range in a separate study).14 Albuterol is metabolized in the liver to the relatively inactive albuterol 4'-O-sulfate. Excretion of the parent drug and
metabolites occurs rapidly, predominantly through the kidneys,14 but about 10% is excreted in the feces.9 Most dogs with mild signs recover within 12 hours of exposure with appropriate supportive care, but signs can persist for
24 to 48 hours with large overdoses.
The immediate delivery of massive amounts of beta2 agonists from inhalers punctured by dogs warrants prompt veterinary attention. Clinical signs reported in such exposures
are fairly predictable; lethargy, tachypnea, agitation, and trembling are among the most common. Tachycardia is the most consistent
clinical finding. Be aware of the potential for this type of toxicosis and recognize it as a possible cause when signs consistent
with beta2 agonist overdose are encountered. With appropriate monitoring of vital signs and electrolytes, supportive care, and administration
of pharmaceuticals to mitigate the adverse effects, toxicoses due to albuterol and other beta2 agonists can be managed successfully. However, when existing cardiac disease is present or the toxicosis is compounded by
the concurrent use of tricyclic antidepressants, monoamine oxidase inhibitors, or digoxin, complications such as cardiac decompensation
or sudden death may occur.
"Toxicology Brief" was contributed by Donna Mensching, DVM, and Petra A. Volmer, MS, DVM, DABVT, DABT, Department of Veterinary
Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, IL 61802. Dr. Volmer is the editor of "Toxicology
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