Translate This Blog

Sunday, April 3, 2011

Scrimping On Heartworm Prevention?

Here's an interesting question I received...

With the economy the way it is I am trying to figure out ways to help our dollar go further.  I currently am trying Trifexis with our 2 1/2 yr old Golden Retriever.  We live on a lake and she swims daily.  The topical treatments were not working.  I heard via the internet that most heart worm medicines can last 45 days but the companies use 30 days for ease of remembering.  If she can go every 45 days,  it would be most helpful.  Thanks for your willingness to help.

First, let's briefly talk about how heartworm prevention works in general.  Most people don't realize that these medications don't stay in the body for a full month (with some exceptions, such as ProHeart).  Heartworm larvae go through several stages of development before reaching adulthood.  When you give an oral heartworm prevention it will kill any of the early larval stages that are in the body.  So basically we assume that a pet has become infected and are killing the larvae when they are young to keep them from developing to the point of causing a problem.  Depending on the ingredients, some preventions can kill larvae up to a couple of months old.  So theoretically, you could go beyond a month with some preventions. 

This is NOT recommended!

First, it's harder to remember odd dates.  Most clients have a hard enough time remembering once monthly preventions (as surveys have shown).  Trying to remember different dates on different months makes it much more likely that doses will be missed.

Second, all heartworm preventions carry a guarantee, promising to pay for treatment if your pet contracts the disease while on the medication.  However, this guarantee requires year-round prevention according to label directions, as well as annual testing.  So if you aren't giving a monthly prevention every month, the warranty is invalidated and doesn't apply.

Let's look at the potential costs and savings, and put it into real-world perspective.  My clinic doesn't carry Trifexis, so I did a quick internet search and a 6-month supply of prevention for a golden retriever is around $120, or about $20 per month.  If you give prevention every 45 days rather than ever 30, you will need eight doses during the year rather than 12.  This is a yearly savings of $80, or about $6.67 per month. If I eat at a fast food restaurant one time I normally spend about $6-7.  If I go to Starbucks it costs me around $5-6.   

Is your dog's health worth $7 per month to you?  Are you willing to gamble with your pet's life for this amount?  Heartworm disease can be deadly if untreated, and can cost $600-1000 to treat a large dog.  Here's an interesting statistic...A golden retriever's life span is around 12 years.  Divide the cost of treatment ($1000 for easy math) over the lifetime and you get a cost of $83 per year.  About the same savings over a lifetime as extending the interval between doses!  So if you look at it this way, there really isn't any significant savings if your dog contracts heartworm disease because of missed doses!!!!

If your personal budget needs an extra $7 per month that bad, I would challenge you to look at how many times you get coffee, eat out, play the lottery, and so on.  Al you have to do is cut out some other non-essential expenses and you can easily afford staying on schedule with the prevention.


  1. Very good advice; nice job doing the math to give some solid financial backing to prove your point!

  2. Can you buy for a larger dog and divide accordingly?

  3. I wouldn't. The pills aren't designed to be divided, so you may not get a completely even distribution of medication throughout the entire pill. Also, if you do this or otherwise don't follow manufacturer's directions you have just voided any guarantee the product may have of effectiveness. It's not worth your pet's health to try and save $20-30 per year.

  4. What would you suggest for an independent rescue with 20 dogs of varying sizes as the most economical method of treatment and prevention? Is there another generic Trifexis? Our rescues are very important and in these financial times, so is our budget, after all, we don't get pledges, etc... to help out with vet care and such.

  5. Great questin, Mej. There isn't a generic version of Trifexis, as the compounds and combination are still under active patent. The most economical would be the ivermectin/pyrantel combinations such as Tri-Heart, Iverheart, Heartgard, and so on. Currently these are the cheapest effective heartworm preventions, and you can typically get six tablets for $30-50.

  6. My dog is a 2yr old great pyr mix that has been on trifexis since she was a puppy and today at her checkup the vet found that she is heartworm positive. She has never been late or missed a dose so of course we are confused as to how this happened. So my question is have you heard of this happening before and do you know if the company Elanco, the makers of trifexis, will cover the cost of her heartworm treatment?

    1. While extremely rare, I have heard of this happening. All manufacturers carry a guarantee, so your vet should call the manufacturer.


Thank you for making a comment on my blog! Please be aware that due to spammers putting links in their comments I moderate every comment. ANY COMMENTS WITH AN EXTERNAL LINK NOT RELATED TO THE TOPIC WILL LIKELY BE DELETED AND MARKED AS SPAM. If you are someone who is posting links to increase the traffic to another website, save me and you the time and hassle and simply don't comment. To everyone else.....comment away! I really do enjoy hearing from readers!