The Importance of Heartworm Preventatives

[Karen, Jasper and Jackdoodle]

Some of you have been following Krista Sumlin's blogs about her foster (and now forever!) doodle Matthew. Matthew had been left outdoors and neglected, and came into the DRC program infested with heartworms. He is currently undergoing treatment. 

(You can read the latest installment of Krista's blog here: Krista's Blog )

Many people who read about Matthew's treatment were surprised at how complicated, painful, risky, and restrictive the process is. Although I knew that the treatment was painful and dangerous, I had no idea that the cost to treat a standard doodle is approximately $1500. Now that mosquito season is beginning, it's crucial that we all understand how important it is to prevent our dogs from becoming infested with heartworms. A simple chewable "treat" once a month would have spared Matthew all of this.

Here is some information about heartworm treatment from Veterinary Partner:

http://www.veterinarypartner.com/Content.plx?A=610

 

Excerpt from the article:

 

Heartworm Treatment

Related Articles * Heartworm Information Center Diagnosis of Heartworm Disease Feline Heartworm Infection Heartworm in Los Angeles Heartworm Preventive Comparison Heartworm Treatment Heartworm: The Parasite Preventing Heartworm Infection in Dogs (Chemoprophylaxis) What Happens in Heartworm Disease

It has been said that the treatment of heartworm infection is somewhat of an art. There are several strategies that can be used depending on the dog's medical condition including the option of not treating at all. The important concept to realize is that harsh arsenic-based drugs are necessary to kill adult heartworms and that treating for heartworm infection is neither simple nor safe in itself.

 

The only product currently available for the treatment of adult heartworms is melarsomine dihydrochloride (Immiticide® by Merial). If you follow the manufacturer's recommendations,  treatment can be done in two doses or three doses depending on the class of infection. Most universities, however, opt to treat all patients with the three-dose protocol as it creates a more gradual kill of the adult worms, which is safer in terms of embolism and shock.

The patient receives an intramuscular injection deeply in the lower back muscles as shown above. This is a painful injection with a painful substance, and it is common for the patient to be quite sore afterwards at home. Pain medication may be needed. Be careful of the injection site as it may hurt enough to cause a dog to bite. An abscess may form at the site, which requires use of warm compresses. Approximately 30% of dogs experience some sort of reaction at the injection site that resolves in 1 to 4 weeks. Some dogs develop a permanent firm lump at the site of injection.

In the two-dose protocol, the dog receives a second injection the next day on the opposite side of the lower back. In the three-dose protocol, the dog comes back one month later for two doses 24 hours apart (the first dose represents an introductory treatment to kill some of the more sensitive worms.) Keep in mind, too many worms dying at once creates circulatory shock.

After treatment, the patient must be strictly confined for one month following the final treatment. No walks, no running around. The dog must live the indoor life. The reason for this is that embolism to some degree is inevitable and it is important to minimize embolism-related problems. Exercise increases heart rate and oxygen demand and we need the heart to rest during this recovery period.

 

Illustration of treatment injection:

 

I know there are many of us who did not realize how dangerous mosquito bites can be to our dogs, or even how serious heartworm disease is. Many people may think of it more as an annoyance, in the same category as a dog getting fleas.

Please let Matthew's experience help other dogs from having to endure what he is enduring. Please make sure your doodles are protected against heartworm. Thank you from the DRC, Krista, Matthew, Jackdoodle, and me.

 

 

 

[Karen, Jasper and Jackdoodle]

F Parker is right on the money. This is the reason that heartworm meds are Rx and flea & tick preventatives are not. Heartworm disease and everything connected to it is serious business.
Dogs who do not get heartworm meds year round must be tested every year prior to starting a preventative. Even if your dog gets year-round meds, most vets insist on blood tests at least every other year.

[Karen, Jasper and Jackdoodle]

From F Parker's link, above, here are the products that are sold as heartworm preventatives. They belong to a class of drug called macrocylic lactones, and these are the only drugs that have any effectiveness against heartworm. All of them are Rx products which require a vet's prescription:

Ivermectin
Ivermectin (Heartgard® & Heartgard® Plus by Merial, Iverhart® Plus & Iverhart MAX™ by Virbac and Tri-Heart® Plus by Schering-Plough) was the first in this family of drugs to be approved for preventing heartworm infection. An infection with larvae as long as two months prior to the initiation of ivermectin treatment will be blocked from development.

Milbemycin
Milbemycin oxime (Interceptor® & Sentinel® by Novartis) has benefits, which are similar to ivermectin.

Selamectin
Selamectin (Revolution® by Pfizer) is applied topically to prevent heartworm disease.

Moxidectin
Moxidectin (Advantage Multi™ by Bayer) is available in a topical formulation, in combination with a flea control product, imidacloprid. Moxidectin is also available as a six-month injectable product for dogs (ProHeart®6 (moxidectin) Sustained Release Injectable for Dogs, by Fort Dodge Animal Health).

[Stephanie and Ragley]

Sorry to bring up an old discussion, but I need to order more heartworm meds and I am wondering about any difference in effectiveness between Heartgard Plus and the generic, Iverhart Max? I like the idea of the financial savings, but not if it comes with a step-down in effectiveness

[Karen, Jasper and Jackdoodle]

My concern would be the sourcing. The cheaper products, like the ones sold at Walmart, often come from China. 

[Stephanie and Ragley]

Ok- going with Heartgard Plus. I got it off of 1800petmeds.com. I talked to the vet about it this morning and she seemed to think that was an okay place to purchase it (obviously they would rather I buy it at the office). Thanks for the help, as always!

[Karen, Jasper and Jackdoodle]

I just compared the prices on the Foster & Smith website for Heartgard Plus versus Iverheart Plus. The savings come to 1.59 a month. :)

Iverheart Plus is made by Virbac, which is a good company, so the sourcing may not be an issue.

But where would you buy it? 

We've had some discussions here about buying these products from any source other than your vet, and the fact that Merial (makers of Heartgard) claims that they do not sell to any retailers, including F & S, and the possibility that these products may be counterfeits. There have also been cases of vets actually selling to retail outlets. 

To me, the tiny savings each month that you may realize by buying any of these products anywhere other than your vet's office is not worth it. 

[F, Calla & Luca]

BTW, I was wondering if I could get a larger dosage and cut the pill in half using one half for each dog, which would be less expensive. My vet said she thought the pills are less effective that way and to stick with the usual dosage.

[Adrianne Matzkin]

I searched for Interceptor on line. I saw Interceptor and Interceptor Spectrum. Does anyone know what the difference is?

[Cheryl and Finnegan]

My understanding is that Novartis discontinued Interceptor. I spoke with a company rep last week who said they have no plans to reintroduce it.  Curious as to where you're finding it.  If you click to buy, it may not let you.

http://news.vin.com/VINNews.aspx?articleId=27121

We're using Sentinel because my dog can't take Ivermectin.