Here at Greenbrier Emergency Animal Hospital, we’ve had two very interesting cases lately. This first one was a middle-aged dog who was disoriented. On examination, he was suddenly and completely blind! The second case was a 7-week-old puppy who was normal when the owner went to bed — but In the morning, when the owner woke up, the puppy couldn’t walk and was barely responsive. On examination, this puppy was also suddenly blind! What did these two cases have in common? They were both either on or near a horse farm. Ivermectin toxicity was suspected in both cases, and within a few hours (for the puppy) and a few days (for the older dog), they were completely back to normal.
Ivermectin is a drug commonly and safely used in many dogs to treat a variety of parasitic infections. This drug is also commonly used in cattle and horses at much higher doses — which can be toxic to dogs, if they are exposed to the medication. Certain types of dogs, including but not limited to collies and Australian shepherds, are also far more susceptible to the toxic effects of the drug.
Toxicity signs include depression, disorientation, nonresponsiveness, blindness, drooling, tremors, and walking like he/she is “drunk.” More severe signs, especially in the susceptible breeds, include low heart rate, low breathing rate, coma and death.
Treatment often is centered around supportive care, which may include intravenous fluid therapy, nutritional support and appropriate nursing care. Although ivermectin toxicity can be fatal in rare cases, many dogs do well and make full recoveries. Sometimes it just takes time. If your pet is displaying any abnormal neurologic behavior, or you suspect your pet has ingested anything toxic, bring him/her to your local veterinarian (or to Greenbrier after hours) immediately.
© 2010 Greenbrier Emergency Animal Hospital. All rights reserved.