by Sunitha Nair
Ginger was a happy, healthy, and energetic six-year-old dog. She is half Australian Shepherd and half Golden Retriever. One day we noticed some rashes on her stomach and took her to the vet. The vet gave her a cortizone shot for itching and put her on antibiotics. When the rash didn't get better we took her back to the vet on February 15th and the vet diagnosed the rash as fox mites and gave her an Ivermectin shot and gave us Revolution (like frontline) that we applied on her that night. On the evening of 2/19, we noticed her back legs slipping and dragging when walking. The next morning it got worse and we took her back to the vet. The vet said it looks like Ivermectin toxicity but was not sure, mentioning that usually it happens within 24-48 hours and only to the collie breeds. The vet said Ginger should be okay in a couple of days and we took her back home. Monday morning (2/22/10) she couldn't walk at all. She was drooling a lot, twitching, clingy, and was disoriented loosing directional ability. When called my vet, asked me to bring her right away. They admitted her and gave her fluids because she was dehydrated from drooling. Our vet did not seem to know much about this, so we decided to do some research ourselves.
We looked online and found that Ivermectin could be deadly to any herding breeds not just collies and should not be used to treat them. Our research led us to the Washington State University (WSU) VCPL. When called, WSU asked me to get in touch with Dr. Katrina Mealey. She was god sent, she knew all about this and volunteered to work with our vet and confirmed that this is indeed Ivermectin toxicity. Per her advice, we started giving her activated Charcoal in addition to fluids. On 2/23/10 when I visited her she couldn't stand up at all, could not eat or drink, tired, no movements other than breathing, and continue drooling.
The next couple of days were bad, seeing her like this was hard for us, but Dr. Mealey assured that almost all dogs will come out of this with out any side effects but it could take several weeks. The doctors and staff at the vet worked with Dr. Mealey, gave her fluids three times daily, hand fed prescription food mixed with the charcoal, and gave her the best care possible.
Dr. Mealey at WSU recommended that we do a test to confirm the Gene Mutation that causes this toxicity. Our vet sent Ginger's blood to WSU Veterinary Clinical Pharmacology Lab (VCPL). Drug sensitivities result from a mutation in the Multi-Drug Resistance gene (MDR1). This gene encodes a protein, P-glycoprotein that is responsible for pumping many drugs and other toxins out of the brain. Dogs with this mutant gene cannot pump some drugs out of the brain as a normal dog would, which may result in abnormal neurological signs. The result may be an illness requiring an extended hospital stay - or even death.
On Friday March 5, 2010, we were visiting Ginger and our vet came in and told us our MDR1 test results came in with double mutant. We were surprised because she had only half herding dog in her (Australian Shepherd) and the other half is Golden Retriever. Because of the double mutant gene she got such a severe reaction to Ivermectin.
On Saturday March 6, 2010, we were at the vet, going to take Ginger home for the weekend. The vet informed us that this morning she had started drinking water and started eating on her own. Along with our vet, we thought that it is better for us to take her home.
On Sunday March 7, 2010, we carried her to our porch, after a few minutes she got up and walked a few steps. She still cannot hold her head up and falls down after walking a few steps. She is improving slowly. She is still tired and sleeps most of the time.
We want everyone to be aware of what happened to Ginger, that it takes time to recover from Ivermectin toxicity, and that be aware not to give Ivermectin to herding dogs even if they are mutts. You can check the WSU web site for the breeds affected and other medicine which is toxic to those breeds. Hopefully by the time this article is published she will be running around and chasing deer in our backyard.
We also wanted to express our sincere thanks to Dr. Katrina Mealey at WSU for all her advice and encouragement.