Revolution For Dog and Cat Heartworm Preventive

Revolution is a monthly heartworm preventive for cats and dogs that also both controls and prevents fleas.’s Dr. James W. Randolph recommends this Pfizer Animal Health medication for many of his canine and feline patients in his own private practice in Long Beach, MS.

Heartworm infestation can lead to heart failure and death
Heartworm infestation can lead to heart failure and death

Heartworm disease is a life-threatening parasitic infestation for both species. However, it presents as a very different syndrome in dogs compared to cats.

In dogs the disease is fairly gradual, and from the initial time of infestation to death may be a year or more.

In cats, however, sudden death is one of the most commonly observed syndromes associated with heartworm disease.

That’s because Dirofilaria immitis, the scientific name of the heartworm parasite, is a usual parasite in the dog but an aberrant parasite in the cat. So, dogs tolerate the parasite fairly well and damage to the heart, lungs and pulmonary arteries progresses slowly but persistently.

In your kitty, however, violent reactions occur immediately in the pre-adult larval stages of heartworm infestation. By the time as few as 1-3 heartworms become adults, the reactions may progress to acute pulmonary edema (lungs filling with fluid) and death. Other, more tolerant cats, may suffer months or years of asthma-like signs and sub-lethal pulmonary edema, as well as a multitude of other possible problems.

Humans, too, may become infected with D. immitis. As another aberrant host, heartworms may do bizarre things in people, such as infect the eye, brain and abdominal organs. Fortunately, infestation of people is a rarity, and people don’t need to be on heartworm preventives.

I can’t overemphasize: All cats need to be on heartworm preventive! Let’s look at it from a risk/benefit standpoint.

On the risk side you have a disease (1) that will almost assuredly kill your cat, (2) for which there is no approved or effective treatment and, (3) which, even if it isn’t fatal, could easily cost you thousands of dollars and your cat untold suffering treating non-lethal episodes.

On the benefit side, (1) it’s incredibly easy to prevent with monthly medication, (2) the monthly medication is inexpensive, and, (3) Revolution also provides both flea control and flea prevention!

In the modern vernacular, it’s a no-brainer!

What is flea control and what is flea prevention?

Revolution provides flea control by killing adult fleas. Alone, that would be pretty good.

But, flea prevention involves killing the egg and larva stages of the pre-adult flea, so those will never be able to mature and become adult, biting fleas. The more fleas killed in this stage the better, as it’s the bite of the flea that hurts and causes anemia from blood loss.

To summarize, Revolution is a monthly medication from Pfizer Animal Health, approved for use in dogs and cats for prevention of Dirofilaria immitis heartworm infestation, killing adult fleas, flea eggs and flea larvae. It is colorless, odorless easy to use.

Contact your pet’s doctor to find out whether it’s right for your dog or cat.


  1. I’m a from Pretoria, South Africa, and I’m writing to share my experience with Revolution and Revolution Plus on my two cats.

    I used Revolution on my cats for a while, but I wasn’t happy with the results. They were still getting fleas and ticks, even though I was following the directions carefully.

    Then I tried Revolution Plus, and I’m so glad I did! It’s been amazing. My cats are finally flea-free and tick-free, and I’m so relieved.

    I’m not sure if the climate in Pretoria is playing a role in the difference in effectiveness between Revolution and Revolution Plus, but it’s certainly possible. Fleas and ticks can be more prevalent in warmer climates, so Revolution Plus may be a better choice for cats that live in those areas.

    • The difference is the “Plus.” When Zoetis added sarolaner to Revolution it ramped up the flea protection dramatically. Thank you for reading and for sharing your positive experience, Dr. Randolph.

  2. Hi Dr. Randolph, My 12 year old dog is recovering from surgery having a mast cell tumor removed. She was very ill and came out of surgery and recovery like a yummy puppy I haven’t seen in months. Although it’s been only 5 days from near death and surgery, she is much better now. Do you think she is a candidate for Revolution at this time? Is Revolution OK to give to a recovering dog?

    • ONLY your treating veterinarian can answer this question, and here is why. 1, the Revolution package insert clearly states that Revolution is to be used ONLY in healthy dogs and cats. Your pet’s doctor will need to give her his clearance to restart Revolution. 2, only your local doctor knows your heartworm preventive purchase history and the results of your dog’s last heartworm test. Without that information, no one can advise you on whether it is SAFE to restart Revolution or any other heartworm preventive. I will also suggest that you read this article. Thank you for your question and your readership of

  3. Hi Dr. Randolph, My 12 year old dog is recovering from surgery having a mass cell tumor removed. She was very ill and came out of surgery and recovery like a yummy puppy that I haven’t seen in months. Although it’s been only 5 days from near death and surgery, but she is much better now,
    do you think she is a candidate for revolution at this time? Is revolution OK to give to a recovering dog?

  4. My 8 yr old 95% indoor Siamese has had a tiny, tiny cough only in the mornings the past 6 months. I have taken her to the vet twice and x-rays and heart look and sound fine. I am worried that she could have a heartworm. The vet tells me its very unlikely that she has a worm because we live in Calif and becuase she is primarily indoors. They did say i could give her Revolution if i wished (so they gave me a Rx for it as they do not carry it at this time). When trying to get it filled vets are giving me different stories….it could hurt or kill my cat if she DOES have a heartworm. I am confused and are panicing becuase i was also told Revolution could only kill a non-adult worm so if Revolution could kill a worm in the early stages, i need to act fast! PS-In the morning, she just gives out a tiny one-time-cough and it doesn’t bother her at all. Would heartworm produce more coughing throughout the day?

  5. Hi Dr. Randolph, My poor cats have fleas. They don’t go outside, but my building has about a million dogs. One of them is scabby (flea dermatitis prob?) They were on Frontline, I’ve switched them to Revolution. I treated the carpet w/ boric acid & I’ve given them Capstar. Can I also give them program? I loove all animals, but I feel like I’m fighting a losing battle w/all the pets in my building (ironically that was one of the things that appealed to me most, about my building.)
    Thank you for this public service you’re doing!

  6. My cat had blood work done at her last visit and I was told yesterday that she tested positive for heartworm. She did not test positive in November 09 when given the same test so she had to have been bitten within the last year. The veterinarian told me there was nothing I could do besides monitor my cats for breathing problems. I have another cat that is not due for his annual exam until June so he will not be tested for heartworms until then. The veterinarian told me that there was no way for my infected cat to give the heartworms to my other cat but I was wondering if this was true. Should I have him tested to make sure? Also, my veterinarian put both cats on Revolution. I gave them the first dose yesterday. However, as I read more information about heartworms in cats, no information says to use a preventive after the cat has been diagnosed with heartworms. The information on the medicine also states to test the animal before administering. My question is: should I continue using the Revolution of my cat that was diagnosed with heartworms or is it harmful for her?

  7. Hi, I have an 18 year old Persian. I am a HUGE fan of Revolution, however, a few months ago I gave it to her and she appeared to get quite sick afterwards. At the time she was in a bad cycle with her arthritis. I am fearful of giving her Revolution again. Knowing how old she is (and having other health problems), do you think Revolution could cause more stress on her body? We are in the middle of summer here and fleas are everywhere! Deb

  8. Dr. Randolph, Jasmine did have a bone biopsy. The tumor was an osteosarcoma, which my veterinarian said we could remove with amputation. Unfortunately, he believes that she had a stroke either right before the bone biopsy or right after we did the bone biopsy. It just doesn’t make sense how she could go from slightly limping in July to dying in September.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.