ProHeart 6 Injection


Heartworm Medicine Linked To Sickness, Death
FDA Recall of Proheart 6
FDA Recall Info on Proheart 6 next to last product on the page


From an email on a rescue list:

13 year old Pork Chop was given the ProHeart 6 injection - a new, 6 month, heart-worm preventative - on May 9, 2002, which almost took his life. He vomited every single morning at 4 AM for three solid months and was down to 8 lbs by November of that year. He would not eat and had to be syringe-fed baby food and 11 crushed medicines (holistic and conventional), along with being injected twice daily with fluids.

Pork Chop initially spent two weeks at Angell Memorial Hospital after the vet who administered the drug to my senior guy was at a loss as to what was going on. Nobody had a clue, even experts from Penn State, who were attempting to help the staff at Angell solve the mystery.

It was on October 13 when Angell Memorial wanted to give up and put him to sleep. After requesting a few minutes to think about it, I went out to the car so as to have a good sob. Suddenly, out of the corner of my eye, I felt someone staring, only to turn and see Golden Retriever, Joshua - who had once again managed to make his way to the passenger seat after slipping over the pet divider - looking squarely atme as if to say, "go get him, ma!". I immediately stormed back in firmly saying, "give me my dog, please!" The vet appearedfurious. In fact, I was made to wait almost three hours before Pork Chop was finally released, along with all of his papers, feeding syringes and some liquid food.

Because it was my feeling that the drug was the culprit, combined with the fact that no concrete diagnosis had been given, I felt compelled not to give up until knowing with absolute certainty that Pork did not stand a chance. Watching this little dog fight was also such inspiration innot quitting. There was another thought - that even if it wasn't the PH6 making him deathly sick, the irreversible properties of this drug were only aiding in the further compromise of his weakened immune system - so my primary objective was to get Pork Chop home, make him comfortable for as long as humanely possible, all the while praying like crazy.

On the week of November 9th (six months to the week after he had been given the PH6 injection), all of the wonderful prayers of my support community were answered when Pork Chop immediately stopped all vomiting and began a total recovery that has lasted to this day. He is now back up to weighing a healthy 17 lbs with no other signs of the illness that nearly killed him.

Fort Dodge, the maker of this new and dangerous drug, has recently settled with me. And although I was fortunate enough to have the physical (time) and emotional energy, along with the financial resources to see Pork Chop through this, there have been others who have lost their dogs as a result of the side effects of ProHeart 6 injections. Just type "Pro-Heart 6 dangers" into your favorite search engine for their sad stories.

Please be careful in allowing your dogs to be given any drug that stays in the body for this long. And avoid all drugs that are under 2 years old, otherwise be prepared to possibly be a guinea pig.

A good way in which to possibly halt or decrease the use of potentially dangerous drugs that are being doled out is to look for a vet that will take a stand against profit over common sense, all the while boycotting those medical professionals who are pushing the stuff without any advance warnings to owners of other known side-effects.


ProHeart 6 (moxidectin) is on our list of NEVER USE drugs. I personally do not use ANY ivermectin based products on my Collies or Sheltie. EVER!!! Heartguard even has a breed specific warning on their packaging that collies have had severe reactions to ivermectin. Numerous studies have been done at Columbia, A&M, Tufts, Washington State and other universities showing that ivermectin is a serious concern in herding dogs and British breeds. Though the studies talk about ivermectin in large doses, there have been serious reacions in herding dogs at very low doses (monthly heartworn preventive). So I choose not to ever use ivermectin on any dog (collie or otherwise).

I have been on the national collie email list for about 6 years and have heard countless stories of collies having anaphylactic reactions, seizures, blindness, coma, brain damage (some resulting in death) from the use of ivermectin. Collies are more sensitive to ivermectin than any other breed.

My only personal experience was with a young collie we pulled from Animal Control who was given Revolution (selamectin) spot-on to remove fleas and ticks. This collie showed the classic signs of ivermectin reaction: drooling, fatigue, confusion, and vomiting.

I know many millions of pet owners use Heartguard and Revolution without incident and I realize that the cases of toxic reaction are few. However, the cases ARE concentrated in Collies, Shelties, other herding breeds and British breeds.

Here's a real stickler though; the only drug that collies with heartworm infection respond to is ultra-high dose ivermectin. So we are taking a very, very serious gamble every time we treat a collie with heartworm. We have nearly lost 2 because of this. All owners of herding breeds and British breeds should do some online research on ivermectin based drugs. Note, if a drug name ends in "ectin", like selamectin in Revolution, it is ivermectin based.

I don't mean to scare anyone .... Heartguard IS a great heartworm preventive, no doubt. But collies are extremely sensitive to many chemicals. This includes most insecticides, chemical fertilizers and lawn treatments. Lysol and Fabreze are also on the list (both can also be toxic to cats). The sensitivity to ivermectin in herding dogs is a because of a gentetic mutation that doesn't allow the drug to clear from the body quickly as it should (ivermectin sensitive phenotype for P-glocoprotein). Ongoing research is directed at determining if other breeds that have been reported to be sensitive to ivermectin (Australian Shepherds, Shelties, Border Collies, and Old English Sheepdogs) have a similar mutation. Other drugs that are substrates for P-glycoprotein include loperamide (Immodium®), digoxin, ondansetron, and many chemotherapeutic drugs including vincristine, vinblastine, and doxorubicin, and other drugs.

Alot of us collie folks use Interceptor for heartworm and intestinal worm prevention and Bio-Spot for flea/tick prevention because they are more gentle. Interceptor is a little more expensive than Heartguard, but Bio-Spot is one fourth of the price of Frontline (and works better in my opinion) so it all works out. (email on RPOArescue list 10-3-03)

Ivermectin Toxicity in Collies

Ivermectin Toxicity


Colby Glass, MLIS