Chemicals and Your Pet

OOOhhhh, I don’t want to use chemicals around my pets!

We hear that a lot around here.

We’d like to address this. First, what is a chemical?  Technically, everything you eat, drink, or wear is a chemical.  We tend to see the word “chemical” in a bad light, but water is a chemical.  Salt is a chemical.  Vitamin A is a chemical.  The definition of a chemical is “an element or combination of elements”.  Your body, and your pet’s, is made of nothing BUT chemicals.  Hemoglobin, oxygen, estrogen, insulin—all chemicals. 

So, obviously, chemicals aren’t all bad.  Many are necessary for life. 

However, many people use the term to mean things like Roundup, cleaning products, and drugs.  Yes, these, too, are chemicals.  And yes, some of them can be toxic to varying degrees.    One way of measuring toxicity of a compound is to determine its LD50.  This is the amount of the substance that can kill 50% of animals exposed to it within a certain period of time.  It’s also called the median lethal dose.  The lower the LD50, the more dangerous the substance. Water has an LD50 of 90ml/kg of body weight (6 quarts for a 150 pound person, in case you’re wondering). Salt has an LD50 of 3000 mg/kg.  The theobromine in chocolate has an LD50 of 300 mg/kg.  Aspirin has an LD50 of 200 mg/kg in dogs.  Interestingly, the LD50 of Ivermectin varies from 0.12 mg/kg in dogs with a particular gene that allows it to cross the blood-brain barrier, to 80 mg/kg in dogs without this mutation. 

Why do I bring up ivermectin?  Because it is one of the drugs commonly used to prevent heartworms and intestinal parasites in our pets.  The dose in the largest size of heartworm tablet is only 272 MICROgrams, or 0.272 mg.  So you can see that this is quite safe even in dogs with the particular mutation, as this dose is safe in a 5-pound or larger dog with the mutation,  but is labeled for dogs between 50-100 pounds. 

Many times, we find ourselves discussing the importance of vaccine protection and heartworm prevention in pets with their owners.  We want owners to understand what we call the risk:benefit ratio.  What is the risk to the pet if you do or do not follow our advice? How can our advice benefit your pet?  In the case of heartworms or some diseases like parvo and rabies, your pet could suffer serious organ damage or die if they contract these diseases.  In contrast, the exposure to the “chemicals” in a vaccine or heartworm prevention are quite safe relative to that risk. 

One other thing we point out to clients with these concerns is that many of our clients are already minimizing exposure to potentially toxic chemicals.  Many use natural cleaners in the home, natural shampoos on their pets, and refrain from the use of lawn treatments or other external chemical use.  In that light, a monthly dose of heartworm prevention and vaccines every few years (since we do like to measure titers instead of automatically vaccinating every year) is quite safe since the overall cumulative exposure to the pet is already low.

Certainly, long-term exposure to some chemicals may contribute to cancer or other disease.  It’s always a good idea to avoid chemicals that can potentially add to this risk.  But just as some chemicals perform vital functions in the body, some others can help prevent disease such as vaccinations, antibiotics, and parasite control products.  We want our clients to understand that we will always recommend what we feel is best for your pet. It is our goal to work towards optimizing health in our patients.  In most cases, that does mean judicious use of a few chemicals.  But if giving your dog antibiotics means we will alleviate their misery of a skin condition in days rather than the weeks (to never) it might take if we didn’t use antibiotics, then we’ll be reaching for that pill bottle.  We’ll always try to use the “safer” chemicals of good food, vitamins or supplements, and fresh air and sunshine when we can.  But sometimes, you just have to use the conventional route to ease a pet’s suffering.

NOTE: Dog show season has started.  Dr Leonard frequently attends agility trials on Fridays.  This means we are not able to see patients on those days.  For the next few months, the doctor will only be available about one Friday monthly.  Please take this into consideration when calling for an appointment.  Call early in the week!  Our office is usually open 9-3 on these days in case you need to make a purchase.