Can I give my Pet a Smaller Size of Heartworm Pill?

Can I give my Pet a Smaller Size of Heartworm Pill?

by Dr. Christa Young, DVM - Bellalago Veterinary Hospital

     The quick and simple answer is a resounding NO! Pet parents want what's best for their beloved fur-friend, but sometimes they are misinformed about how to properly and safely accomplish this task. A pet parent recently demanded I prescribe a flea & heartworm preventative medication for a size smaller than the pet weighs.  The client had been under-dosing her beloved dog for years because someone told her it was OK - the client, understandably, had some concerns due to the pet's epilepsy that prompted this poorly-guided and dangerous practice.

      So, an 11.8 pound dog has been getting Sentinel Spectrum for dogs 2-10 pounds the past several years. Just a tiny difference, what's the big deal, right? For starters, this particular dog has guardian angels as it thankfully has not yet tested positive for heartworms - it's a game of Russian roulette as to when a mosquito carrying heartworm larva bites...especially when this dog lives in mosquito-laden Florida.  

      I consulted Auburn University's College of Veterinary Medicine's world-renowned parasitologist (someone that specializes in parasites and how to control & prevent them), Dr. Byron Blagburn, as I have never heard of reducing doses in parasite preventatives. When I asked him about this idea of giving pets a lower dose of heartworm/flea prevention he replied that it is "absolute rubbish and dangerous" and he can not support that recommendation.

     According to Dr. Blagburn, the parasite specialist, giving a lower dose risks product failure and resistance in mosquito, flea, hookworm, roundworm, whipworm, tapeworm, and tick populations. The idea of super-parasites which do not respond to current preventatives is quite frightening! Additionally, product failure is a fancy way of saying that the drug doesn't do anything!  Owners who give lower doses are, essentially, wasting their money.  Pet parents and veterinary healthcare professionals must work as a team, and that means giving the correct dose of parasite preventative medicine!

     As a veterinarian, I am an advocate for pets AND their owners. I am bound by state and federal laws governing my practice of veterinary medicine, as well an established Standards of Care set forth by the AVMA and AAHA. We cannot and will not risk our patients' safety by compromising their medical care.  There is no reason to ever give a lower does of preventative than recommended by the manufacturer.  Additionally, there are a lot of reasons why we shouldn't do it.  If you're a loving, responsible, pet parent who doesn't have money to waste, then this is a practice that just doesn't make sense.