Is Heartguard safe for border collies? I've read conflicting reports.

my dog was diagnosed with class 1 heartworm. he is asymptomatic. he was prescribed heartguard monthly for minimum of 1yr. i gave him his first dose today and he has spent most of the day sleeping. he has exercised for a few minutes but tires easily, within 15 mins and immediately lies down and goes to sleep. is this normal? should i be worried?

Asked by Marty on Aug 1st 2008 in Heartworm Control
Report this question Get this question's RSS feed Send this question to a friend


  • Cast your vote for which answer you think is best!



When it comes to herding breeds and many sighthounds, owners need to be very careful when administering heartworm/fea/tick preventatives or treatments. Many herding and sighthound breeds or mixed dogs with those breeds have a genetic mutation in the MDR-1 gene that renders them very susceptible to Ivermectin (Ivermec), the primary ingredient in Heartgard.

Drugs that cause reaction to MDR-1 mutant dogs include:
- Acepromazine (tranquilizer):
- Butorphanol (pain control);
- Cyclosporin (immunosuppression drug);
- Digoxin (heart drug);
- Doxorubicin (anticancer drug);
- Ivermectin (antiparasitic drug);
- Loperamide (ImodiumĀ®, antidiarrheal drug);
- Moxidectin;
- Vinblastine (anticancer drug);
- Vincristine (anticancer drug)

Symptoms can range from lethargy and poor coordination to coma and death.

Genetic tests are available to determine if your dog has the mutant form of MDR-1.

Gio answered on 8/1/08. Helpful? Yes/Helpful: No 3 Report this answer


I agree with the last poster and can't believe your Dr would give you Heartgard. It is KNOWN not to be safe in shelties, collies, and border collies (among a few other breeds).. It's not to say that every case is going to turn out the same but I wouldn't give him any more to be on the safe side. I might find a different vet...sounds as if you may be playing with fire. You definitely don't want to take any chances!

Lennox answered on 8/1/08. Helpful? Yes/Helpful: No 1 Report this answer