Mirabegron Toxicosis in Dogs: a Retrospective Study.

Mirabegron is a selective beta (B) adrenoreceptor agonist marketed for human treatment of an overactive bladder (OAB). It has a wide margin of safety in humans, but in dogs, severe adverse effects have occurred. We sought to determine the effects and outcome of mirabegron toxicosis in dogs. A retrospective review of all calls within the Pet Poison Helpline (PPH), an international animal poison control center, database was performed for mirabegron exposures between 2013 and 2015. Potential ingested doses ranging from 1.31 to 8.3 mg/kg. Many dogs remained asymptomatic and no fatalities occurred in any dogs. The most commonly reported signs were tachycardia and erythema. While mirabegron was found to have a very narrow margin of safety and high toxicity risk to dogs during preclinical trials, effects appear to differ greatly in the nonclinical field environment and further study is needed.