As some of you know, Tybalt had an outbreak of demodex (common skin disease caused by mites). After 3 days of being on Ivermectin, I noticed Tybalt was seriously lethargic and when he was up, walked about as if he was drunk. He couldn't walk in a straight line, he would take a couple steps, then stumble down and he kept running into things that were clearly in front of him. His back legs just seem to give out on him. His pupils were also fully dilated. His heart was racing, even when he was at rest. And he was drooling everywhere. His appetite was still the same and he was still drinking water normally and nothing unusual was going on with his bathroom trips other then his stools were a bit soft, but that's to be expected on ivermectin. But his stumbling, lethargy, lack of muscle control and dilated pupils happened over a period of just a few hours and even though he was still eating and such, I got really worried. You could tell he didn't feel good or feel like himself.
After looking up side effects of Ivermectin online, I got hold of the vet ASAP. He told me to stop the Ivermectin and that it was a good thing I noticed the change in his behavior and made the call. A quick trip to the vet to be checked out and a very big watery evacuation of his bowels later (sorry to be graphic!), he is back to normal. Ivermectin interferes with parasites neural functions and very, very rarely, in some dogs will a large enough dosage cross over to affect the dogs neural functions. This is what happened with Tybalt. Thankfully, Ivermectin does not metabolise in the body long and the bulk, over 90% of it, is not absorbed and gets excreted through feces.
His skin scrapings still show he has a few active mites, so after a few days rest from the medicine, he is back on for the rest of the course, but this time his dosage has been cut in half. If he doesn't tolerate this course, then I guess we have to look at other options such as seeing if his body builds up the needed immunity to fight them off like other pups. The vet is still sure it's just stress from Tybalt being in a new home and changing puppy hormones that's suppressed his control over the mites, but to be on the safe side we should treat it in case it spreads or gets worse.
Most dogs can tolerate Ivermectin just fine (except for the collie and certain herding breeds who cannot, because they lack a certain gene). I don't want to alarm anyone if you have a dog on it or will have to in the future. But every dog tolerates medicines differently and it's handy to know the side effects of drugs and what to look for, even the smallest of changes. Tybalt had all the classic signs of not tolerating his original dosage which presented themselves clearly and in such a short matter of time one couldn't help but to notice them.