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Is Your Dog’s Vet Ready for Rattlesnake Season?

Many vets don't stock antivenin, due to its high cost, but cheaper alternatives recently have come on the market.

Dr. Eric Barchas  |  Apr 19th 2016


As the days grow warmer and longer, the urge to go outside and be active grows stronger. I love hiking with my pal Buster, and he loves it perhaps even more than I. In general, I consider hiking to be a low-risk activity because it is. However, we have reached the time of year when dog owners need to be cognizant of snakes.

Most snakes, of course, are harmless to people and pets. And even the ones that can hurt us still do more good than harm. Venomous snakes feed largely on rodents and other creatures that humans consider to be pests. But if a dog decides to sniff a venomous snake, he can suffer a nasty surprise. In the USA, and especially in the western part of the country, the snake most likely to strike a dog is the rattlesnake.

In many parts of the U.S., one needn’t even go for a hike to encounter a rattlesnake. Rattlesnakes may be found in yards in places such as Arizona and Nevada. They also are common in suburban areas of California that abut open space.

Dr. Eric Barchas and Buster. (Photo courtesy Dr. Eric Barchas)

Dr. Eric Barchas and Buster. (Photo by Liz Acosta)

I remember the first case of rattlesnake envenomation that I treated as a vet. I was working a single shift at a practice in a suburb of San Francisco. The owner witnessed the incident. The dog had made the mistake of investigating a rattlesnake. This is by far the most common way for dogs to be struck by the snakes, although they also sometimes encounter them accidentally or step on them without meaning to. The snake did not rattle — it simply struck. (It is a myth that the snakes always rattle before striking.) The left side of the Labrador Retriever’s muzzle was bitten, and the bite was not dry (meaning the snake released venom) — the muzzle promptly began to swell, and the dog was in intense pain.

My first, naive thought was, “We have rattlesnakes in the Bay Area?” Indeed we do. In fact, rattlesnakes are very common in some local areas, including the area where I was working that day. The practice, unlike many, had antivenin in stock. The price tag for the antivenin shocked me: $2,000 per bottle. The owner, on the other hand, was not surprised. He approved immediate treatment.

In fact, the owner was quite knowledgeable about rattlesnake bites in dogs. He had not made any of the common mistakes, based upon rattlesnake mythology, that people often make. He didn’t try to cut open the skin in order to suck out the venom (all that does is cause more trauma to the area, increase the risk of infection, and cause more pain to the dog). He didn’t attempt to apply a tourniquet to the area (admittedly, it’s not possible on a muzzle, but on a limb it can exacerbate tissue damage by altering blood flow). He didn’t give any medications to the dog (some medications can complicate treatment). He didn’t apply ice to the affected area (ice can exacerbate tissue damage). And he didn’t try to capture the snake (capturing the snake puts the owner at risk of a bite, and the type of rattlesnake that bites a dog does not matter much to treatment since the antivenins are “multivalent” and treat bites from most types of rattlesnakes as well as some related species). Instead, he reacted perfectly: He stayed calm, and he took his dog straight to the vet.

When I saw the dog, I noted classic signs of rattlesnake envenomation. The muzzle was swollen, and two fang marks were visible in the center of the affected area. The pain was intense; the dog could not tolerate any handling or touching of the area whatsoever.

Rattlesnake venom causes severe pain and swelling at the site of the bite. It also can have systemic effects, causing blood clotting problems and heart arrhythmias. Treatment includes intravenous fluids to support blood pressure, pain killers, and especially antivenin. Antibiotics traditionally have been used to prevent infection in the tissues damaged by the venom, but recent evidence suggests they’re not necessary in many cases.

Proteins are significant components of rattlesnake venom, and antivenin contains antibodies that neutralize the proteins and hence the venom. The amount of antivenin required may, paradoxically, be larger for a small dog than a large dog, since the relative dose of venom may be higher in a small dog.

The dog in question wound up receiving two vials of antivenin, and the total bill for the day’s treatment came to over $5,000. The expenses didn’t stop there, however. When the practice where I worked closed for the day, the dog was transferred to an emergency clinic for ongoing care. He ultimately made a complete recovery.

The good news is that the price of antivenin appears set to decline. At the time I treated that dog, only one type of antivenin was readily available. With a cost of well over a thousand dollars to buy wholesale, most vets chose not to stock it (and risk having it expire unused).

In the past few years, a number of new antivenins have hit the market. They have a few advantages over the old antivenin. They are easier to administer (the original antivenin took at least 30 minutes to mix into a liquid form from its original powder and was prone to foaming, which could delay treatment). They may have a lower rate of side effects. Some are more potent. And they’re cheaper. At a recent veterinary convention, I spoke with a number of antivenin manufacturers who bragged that their products cost under $500 to buy wholesale. At these prices, it may be possible to treat a dog for under $3,000.

Although I worry about upward price pressure in the future, the less expensive antivenins may mean that more vets will carry them. However, if your dog is struck by a rattlesnake, you should be aware that there are many vets who don’t stock antivenin and therefore can’t effectively treat rattlesnake bites. The best thing to do is to remain calm, get your dog into the car, and call your vet while you’re driving to ask whether they have antivenin. If they don’t, they should be able to refer you to an emergency or specialty practice that does.

And whatever happens, remember one thing: Don’t try to capture or kill the snake. Just get out of there before it strikes again.