Heartworms Are Treatable Even In Old Dogs

A diagnosis of heartworms is not a death sentence, even in a somewhat older dog.
Precious “Sweetie” came to see us this week, her first doctor’s visit in her 8-year lifespan. Not surprisingly, having never been on a heartworm preventive and living in a swamp-surrounded, mosquito-laden area of a southern state, her test came back positive.
Pre-heartworm treatment radiographs of her chest indicated only moderate damage to the heart and lungs, and complete blood count, chemistry profile and urinalysis show that her body is up to the challenge of a carefully-executed heartworm treatment.
We are beginning the process tomorrow, and anticipate a full and uncomplicated recovery, despite her age.
Best of all, we anticipate extending her lifespan by several years by eliminating heartworms from her body. Within two years, we expect a followup radiograph of her chest to show little or no evidence that heartworms were ever there.
See you tomorrow, Dr. Randolph.


  1. S says:

    I also want to mention that my senior cocker spaniel has since pasted many years ago. I apologize for the delay and thank this community for the support. She made it through heart worm treatment but around 14, it was her time. SJaffe

  2. Judi says:

    I have a bassett hound that is very sick, vomiting clear liquid or white foamey substance. Hasn’t eaten anything since Friday and drinks but immediately throws it back up. Took him to the vet and they have diagnosed him with heart worms in his heart and lungs. He is 10 years old. Is there anything sensible for us to do?

    • Having no data for input, I’m going to leave that decision to you and your local veterinarian. I’m saying a prayer for your basset hound. I have found that many dogs with heartworms also have whipworms, and the ones that don’t show positive on a test, but have gastrointestinal signs, I treat anyway, with a special dewormer that kills whipworms.

  3. Keith says:

    I apoligize for resurrecting such an old thread but I couldn’t send my question through the contact form.
    My wife and I inherited her mother’s dog after she passed. The dog is a 12yo 29 pound Beagle/Lab mix that neither look or acts her age (aside from missing teeth). She looks like a 3 month old yellow lab puppy. We took her to the vet and she was diagnosed with a tapeworm and heartworms but said it was early. She has almost no signs of anything being wrong. She does cough after she drinks, but I think that’s because it’s hot and she may be drinking too fast. She doesn’t cough or sneeze any more than I do and I’m a healthy 32yo. We have already done the 4wks of doxycycline and started her in Iverheart. The Vet called and wants to do the 3 shot imiticide treatment starting with a single shot next week (6wks after diagnosis) and then do 2 more shots 24hrs apart a month after the initial shot.
    I have read horror stories about the treatment (injecting arsenic into an animal you don’t want to kill seems like an oxymoron to me) being almost as bad if not worse than the heartworms, also my wife is worried since she had a 5yo Golden Retriever when she was a kid that was killed by the treatment.
    Given the dog’s age and lack of symptoms, would it be better to treat her with preventative to keep the disease from progressing and let the adult worms die off of “natural causes” (aka Slow Kill method) or would you recommend preventative and the 3 dose Imiticide treatment (aka Fast Kill) I would like to note that she is an outside dog and it is very hot (90F+) and humid (60%+ RH) from End of May to End of October here.
    Thanks in advance

    • I’ve written about slow kill several times. Click here. And, click here. There are plenty of horror stories about heartworm treatment. I could tell you some about slow kill, but I’ve seen only one (myself) using Immiticide. One of the big factors heartworm experts look at is the cardiac silhouette and pulmonary artery profile on a chest radiograph (X-ray). Not everyone who does heartworm treatments radiographs the chest, but we do. Not everyone performs pre-treatment laboratory tests, but we do. I’m confident your pet’s doctor would do those if you asked, or may have done so already. Ultimately, the form of treatment chosen is up to and your veterinarian. I can’t have much input because I haven’t examined your dog, but, age, alone, doesn’t scare me off from heartworm treatment. Online heartworm treatment horror stories don’t scare me off, either.
      As for “injecting arsenic,” it’s a poor analogy to what’s actually done in heartworm treatment. Immiticide and Diroban do contain arsenic, as even their predecessor Sodium Caparsolate did, but the way the arsenic molecule is compounded with other ingredients, the body “sees” the arsenic in a totally different way from just pouring some arsenic down the patient’s throat.
      Every medication has a toxicity level, from aspirin on up. Too much water can kill you. Immiticide and Diroban are administered in a very careful dosing regimen (the three-dose regimen your pet’s doctor is recommending is the only regimen supported by the American Heartworm Society) that is both safe and effective.
      You mentioned you live in a hot-weather area. Activity restriction is crucial during and after heartworm treatment. While some doctors like to delay treatment until cooler weather, I’ve never found that to be a complicating factor, and we live on the Mississippi Gulf Coast. However, the vast majority of our patients live mostly indoors.
      I hope this helps to provide more background information. Now, you and your veterinarian can have another discussion and make an informed decision about treatment. Please write back and let us know what you decided, and, when the treatment is finished, how your inherited baby is doing. Thank you for reading http://www.mypetsdoctor.com.

  4. sjaffe says:

    HI Dr. Randolph, I foster a cocker-spaniel who is 12 yrs old. She is heartworm-positive and it’s just breaking my heart. I would love to do everything I possibly can do help her get through this. She doesn’t really have a cough but she breaths very very deeply (with a wheeze) mostly at night and after getting excited. It seems that her abdomen might be swollen (based on what I’ve read online). She is on her heartworm preventative. Basically, my question in I’m thinking about adopting her. I don’t know how much financially this will hurt me or even if she is suffering right now. Do you have any advice as to alternative treatments/anything?
    Thank you!

    • There is a lot going on here, SJaffe, so let’s go step by step. 1, it’s good that she’s on heartworm preventive (readers need to understand that there is a medical protocol for beginning heartworm preventive for heartworm-positive dogs which must occur under careful medical guidance. Do not attempt this at home.) That will keep her from getting more heartworms. 2, There are many conditions that can cause deep breathing and wheezing. It may or may not be related to her heartworm status. Your veterinarian’s physical examination and chest X-ray will help to determine why this is happening. 3, That said, the swollen abdomen concerns me, and could indicate ascites. In heartworm disease, ascites is most likely to occur when the heartworm burden is great, creating congestion to blood flow from the right side of the heart toward the lungs. Also, ascites may occur in Caudal Vena Cava Syndrome, a complicated process in heartworm disease. In either of these cases a veterinarian’s intervention is needed. 4, Only your local doctor can advise you regarding cost. 5, Beware of “alternative treatments.” Study after study proves that heartworm-infested dogs experience significantly more damage to the lungs and circulation when non-traditional treatments are used. In other words, your veterinarian is going to have to perform an examination and some tests in order to answer your questions. We do hope you will keep us up to date about his findings and her progress. Best wishes, Dr. Randolph.

  5. patrick says:

    Did she make it?

    • Patrick, I’m happy to report that Sweetie came through the heartworm treatment with ZERO complications. In fact, I just saw her in the clinic today and scheduled her for unrelated surgery next week. Thanks for asking, Dr. Randolph.


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