The U.S. Food and Drug Administration recently sent a notice to veterinary clinics and retailers and asked them to post it for the public. The sign said, basically, “People, please don’t take your pets’ ivermectin for Covid-19.”
Worry about humans taking pet medications is not exactly new for veterinarians, as we use controlled drugs and need to be aware of where they are going. But this felt different. And while the poster from the FDA is straightforward (“Hello, don’t take ivermectin”), there are complicated reasons why some people might have thought this home remedy was a good idea.
A few poor quality “trials” are partly to blame. For example, a June 2020 study that circulated widely showed that, in a laboratory setting (not in a human body) and at levels that would be toxic to humans, ivermectin had enough anti-viral activity to warrant further investigation. From there, people apparently moved on to buying, hoarding, and, in enough cases to cause a spike in toxicity cases, ingesting ivermectin.
While ivermectin-believers may point to evidence of the drug’s effectiveness in treating parasites in humans in certain areas of the world, there is no straight line from there to any conclusion about using it to treat Covid.
One interesting thought is that steroids are commonly used in moderate to severe cases of Covid-19, and while their suppression of the immune system and inflammatory cascade can help people survive the viral infection, that effect could theoretically allow a previously hidden lung parasite to replicate. Is this where ivermectin has a role? Maybe, but we don’t know yet.
And I really hope you don’t have a subclinical lung parasite that needs to be treated. My goat might, and that might be normal, but it certainly is not prevalent in human populations here.
Also, do you really want to treat yourself with an unbearable number of those little meat loafs you give your dog each month? I did work with a technician who sampled the beef-flavored taster’s tab without the ivermectin (she reported that it was tasty), but I am not sure anyone could stomach the real deal.
We use a low dose of ivermectin in dogs; an average dog takes one tablet a month. To take the massively high dosage reported in that 2020 study, a human would have to take close to 1,000 tablets. Imagine suffering through that only to be brought to the hospital to have your stomach pumped. Because, again, this stuff is toxic.
If all this is not enough to dissuade you, here’s the kicker: you should not take ivermectin because your dog needs it. There are a lot of gross things in vet med, but heartworm is pretty high on that list. You might want to Google it after you’ve read this article, but I would recommend eating the last bowl of spaghetti you will ever again enjoy before you do so.
Dirofilarious immitus starts its life as an itty-bitty speck that gets through your dog’s skin through the bite of a mosquito. Without monthly medication, it then grows into what I consider a very big parasite, about the size of a spaghetti noodle, which then takes up residence in your dog’s heart or lungs.
Heartworm is potentially fatal to dogs, but it can be prevented with a low dose of ivermectin. So, let us focus on ivermectin’s role in heartworm prevention — there’s plenty to read on the American Heartworm Society website — and ignore the entertaining but not exactly educational Covid memes that so many people believe.
Or just sit down and eat a bowl of spaghetti with your cat and try not to worry about any of these things.
Sadie Hutchings is a veterinarian who lives in Wellfleet.