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.