Visiting Veterinarian : Add salt?
By Michelle Gerhard Jasny V.M.D.
Published: January 29, 2009
"So what should we do about the skating rink outside?" Susan asked, coming in to work. I sighed. My parking lot was a solid block of ice topped with a slick veneer of snow. I had shoveled the deck and steps earlier, sprinkling them with the last of my de-icer, a product with the reassuring trade name "Safe Paw," but the rest of the lot remained a vast frozen tundra.
"Check that our liability insurance is paid and hope for the best," I replied, only half joking. At lunch I went in search of more ice-melter. No one had the Safe Paw brand. One store offered me another cleverly named product, Paws Applause. "What's in it?" I asked, searching the label in vain for ingredients. The clerk assured me it was pet-safe, although she didn't know what was in it. Imagining people catapulting across my icy lot, hanging on to leashes as their dogs made desperate attempts to escape the evil veterinarian, I bought the unidentified grey gravel and headed back to work.
A few freezing hours later, a client called. "Hey, doc, we're using this stuff down here for getting ice off the trucks. It works great. Think it would be safe to use on my driveway and sidewalks at home, you know, with the dog and all?"
"Depends what's in it," I replied. This was obviously my day to research de-icer toxicity. Promising to do my homework and call him back, I retrieved the empty Safe Paw container from my recycling bin, placed it beside the new Paws Applause, and the ingredient list from the afternoon's caller, and got to work. Here's what I learned.
Ice melts are not all created equal. The majority are different kinds of salts including sodium chloride, potassium chloride, magnesium chloride, calcium carbonate, and calcium magnesium acetate. So if your Great Dane, Gretzky, gets exposed to these products, a little salt can't hurt him, right? Wrong. Many of these compounds can be irritating to Gretzky's feet, especially with frequent or prolonged exposure. More worrisome is that he may inadvertently ingest them by licking his paws or eating treated ice and snow. Or he might eat it intentionally, directly off the ground or out of improperly stored containers. In some instances, the consequences can be serious.
Let's start with sodium chloride - table salt. Although it is difficult for a pet to eat enough to be lethal, such cases have been reported. (I have seen animals with sodium chloride toxicity from drinking salt water at the beach.) If Gretzky consumes enough, the excessive sodium in the blood can lead to severe problems, most notably swelling of the brain. Clinical signs may include vomiting, diarrhea, excessive thirst, muscle twitching, rapid heart rate, weakness, disorientation, behavior changes, seizures, coma, and death.
Potassium chloride won't cause the neurological problems that sodium chloride does, but it is much more irritating and may cause gastrointestinal hemorrhage. High levels of potassium in the blood may lead to muscle weakness, vomiting, diarrhea, low blood pressure, and heart problems, especially if Gretzky has preexisting cardiac disease.
Magnesium chloride ingestion can cause vomiting and diarrhea and, at higher doses, weakness, low blood pressure, respiratory depression, heart problems, and rarely cardiac arrest.
Finally, we have the calcium salt de-icers, which come in several forms. Calcium chloride is the most irritating, and can cause gastrointestinal upset or bleeding, and eye and skin irritation. All of the salt de-icers pose a greater risk to animals with underlying kidney disease who are less able to excrete the chemicals efficiently.
Treatment of ice melt exposure varies depending on the specific salt, severity of clinical signs, and amount and timing of exposure. For the more irritating substances like potassium chloride or calcium chloride, inducing vomiting is contraindicated, as this may cause even more severe esophageal damage as the de-icer comes back up. On the other hand, if Gretzky ate magnesium chloride, it's fine to make him barf. Pets that eat excessive sodium chloride often vomit spontaneously. Treatment may include intravenous fluid therapy, symptomatic medications such as anticonvulsants if neurological signs develop, and careful monitoring.
Neither Safe Paw nor Paws Applause identify ingredients on the label but after a bit of detective work I found Material Safety Data Sheets (MSDS) for these two putatively pet-friendly products. Paws Applause contains calcium magnesium carbonate and magnesium chloride hexahydrate - salts that can be moderately irritating if ingested - and urea, a nitrogen-containing chemical that is unlikely to cause serious illness in dogs and cats other than occasional drooling or an upset tummy. The MSDS lists potential eye and skin irritation, gastric irritation, nausea, vomiting, dizziness, and pain, and advises immediately flushing the skin with water when exposed and seeking medical attention for eye contact or ingestion. What about Safe Paw? The ingredients are proprietary and patented, thus listed only as "an amide and a glycol." Amides are nitrogen-containing organic compounds, so this is probably something similar to urea. Glycols are organic compounds containing two hydroxyl groups. Some glycols (like ethylene glycol, a.k.a. antifreeze) are extremely toxic, but others are not. Obviously the one in Safe Paws is considered nontoxic. The MSDS says only that ingestion can cause "stomach irritation." Emergency First Aid is listed as "none except to flush area with water." Their website states the product contains no salts, is non-corrosive, and "100 percent safe for children, pets, surfaces, and the environment."
My verdict? The de-icer my caller uses at work is a bit dicey for home application. Paws Applause sounds relatively safe, if used properly and stored securely, but don't let Gretzky go dancing barefoot in it or eat a bowl for afternoon snack. If your pet is very small, has a propensity for ingesting large quantities of non-food items, or has a pre-existing heart or kidney problem, Safe Paw sounds even safer. That's what I'm going to use. Perhaps a local store will decide to stock it. Otherwise, you can find it at safepaw.com.
In the meantime, watch your step. It's slippery out there.
