Can Heartworm Preventatives be Given Late?

photo 2006 rikkis_refuge | more info (via: Wylio)Last night as I entered dreamland I was startled awake by a revelation: it was already the 5th...

dogedit  |  Apr 6th 2011

London the houndphoto 2006 rikkis_refuge | more info (via: Wylio)
Last night as I entered dreamland I was startled awake by a revelation: it was already the 5th of the month and my pal Buster hadn’t yet received his Heartgard Plus.*

I, like many people, administer flea and heartworm medications on the first day of each month. That date generally makes it easier for me to remember the task. Obviously, however, first-of-month administration is not a guarantee — witness my experience from last night.

It turns out that many people have this experience. People often ask me what they should do if their dog’s Interceptor, Sentinel, or Heartgard Plus is a few days late.

My recommendation, if the medication is late by one week or less, is to do exactly what I did last night. I got up, gave Buster his medicine (which delighted him — he thinks it’s a treat), and went back to sleep without worrying at all. I will administer his next dose on schedule on May 1.

Monthly heartworm medications can be given one week late without causing any increased heartworm risk.

Many experts believe that the medications actually can be given two weeks late without leading to increased risk of infestation, but in my opinion that is pushing things just a bit. If your pet’s heartworm medication is more than one week late, I recommend that you contact your vet.

*Forgive me for sounding like a broken record, but I seriously feel pain every time I write the word Heartgard. A desire to create a brand is not, in my opinion, a valid reason to misspell the word guard.