Comfortis Chewable Tablets for Dogs & Cats | EntirelyPets Pharmacy
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Comfortis for Dogs & Cats

Comfortis for Dogs & Cats

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  • Description
  • Ingredients
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  • FAQ
  • Reviews


Comfortis is a chewable medication prescribed by veterinarians for dogs and cats to help treat -- and possibly even prevent -- flea infestations for up to one month. These flavored tablets can be added to your pet's favorite food and only need to be given to your canine companion or feline friend once a month to help combat fleas.

Comfortis Use

Comforits kills fleas and is indicated for the prevention and treatment of flea infestations (Ctenocephalides felis) for one month for:

  • Dogs and puppies 14 weeks of age and older and 5.0 pounds of body weight or greater
  • Cats and kittens 14 weeks of age and older and 4.1 pounds of body weight or greater

Key Benefits

  • Begins to kill fleas as quickly as 30 minutes
  • Up to 100% of fleas on dogs and 98% of fleas on cats killed within 4 hours
  • Protection that lasts for one month
  • Kills new fleas before they can lay eggs
  • Easy to adminster beef-flavored tablet your dog or cat will love

How It Works

Comfortis is adminstered through tablet form to your dog or cat. It is then absorbed into your pet's bloodstream and gives month-long protection.


Not for human use. Keep this and all drugs out of the reach of children.


Do not use on dogs younger than 14 weeks. Use with caution in breeding females and dogs with pre-existing epilepsy. The safe use of Comfortis in breeding males has not been evaluated.


Use cautions with concomitant extra-label use of ivermectin. The safe use of Comfortis in breeding, pregnant, or lactating cats has not been evaluated.

Prescription Required

NADA 141-277


Active Ingredient


Package Color Spinosad Per Tablet
Pink140 mg
Orange270 mg
Green560 mg
Blue810 mg
Brown1,620 mg


View Comfortis Drug Facts Sheet.



Comfortis is given orally once a month, at the recommended minimum dosage of 13.5 mg/lb (30 mg/kg).


Administer Comfortis with food for maximum effectiveness.

Comfortis is a chewable tablet and is readily consumed by dogs when offered by the owner just prior to feeding. Alternatively, Comfortis may be offered in food or admistered like other tablet medications. It should be administered at montlhly intervals.

Dosage Table

Body Weight Tablets Administered
5 to 10 lbs. One (Pink)
10.1 to 20 lbs. One (Orange)
20.1 to 40 lbs. One (Green)
40.1 to 60 lbs. One (Blue)
60.1 to 120* lbs. One (Brown)

*Dogs over 120 lbs should be administered the appropriate combination of tablets.

Possible Side Effects

Vomiting, decreased appetite, lethargy, diarrhea, cough, polydipsia, vocalization, increased appetite, erytherna, hyperactivity, excessive salivation.



Comfortis is given orally once a month, at the minimum dosage of 22.5 mg/lb (50 mg/kg)


Administer Comfortis with food for maximum effectiveness.

Comfortis is a chewable tablet and is readily consumed by cats when offered by the owner just prior to feeding. Alternatively, Comfortis may be offered in food or admistered like other tablet medications. It should be administered at montlhly intervals.

Dosage Table

Body Weight Tablets Administered
4.1 to 6 lbs. One (Pink)
6.1 to 12 lbs. One (Orange)
12.1 to 24* lbs. One (Green)

*Cats over 24 lbs should be administered the appropriate combination of tablets.

Quick Tips

  • If vomiting occurs with an hour of administration, redose with another full dose.
  • If a dose is missed, administer Comfortis with food and resume a monthly dosing schedule.
  • Treatent may begin at any time of the year, preferebly starting one month before fleas become active and continuing monthly through the end of the season.
  • In areas where fleas are common year-round, monthly treatment with Comfortis should continue the entire year without interruption.
  • To minimize the likelihood of flea reinfestation, it is important to treat all animals within a household with an approved flea protection product.

Possible Side Effects

Vomiting, lethargy, anorexia, weight loss, diarrhea.

Storage Directions

Store at 20°-25°C (68°-77°F), excursions permitted between 15°-30°C (59°-86°F). Keep out of reach of children and pets.


There are no known contraindications for the use of Comfortis.


Does seeing fleas on my dog or cat mean the treatment isn't working?

If you see fleas on your dog or cat within a month after your pet receives Comfortis, they are most likely new fleas. Because your pet has been treated with Comfortis, these new fleas will be killed before they can produce eggs that contaminate your home.

My pet has allergies. Can he still take Comfortis?

Comfortis contains beef flavoring made from a pork-based protein. If your pet has an allergy to pork, you may need to consider an alternative for flea treatment and prevention. Please discuss these options with your pet's veterinarian. The use of ivermectin at higher than FDA-approved doses at the same time as Comfortis can result in serious side effects.

What if I give more than the prescribed amount of Comfortis to my pet?

Contact your veterinarian if you believe your pet has ingested more than the recommended dose of Comfortis.

Should I restrict my pet's activity or contact with my pet after the tablet is consumed?

No. You can continue normal activities and interactions with your pet.

Can other medications be given while my pet is taking Comfortis?

Comfortis is not contraindicated for use with any veterinary drug/product when they are administered at labeled doses.

However, while labeled heartworm preventatives are not an issue, you should not use Comfortis concurrently with extra-label doses of ivermectin in dogs and should use caution in cats. Make sure your veterinarian is aware of all products that you intend to administer to your pet.

In well-controlled field studies, Comfortis chewable tablets were administered safely in conjunction with other frequently used labeled products, such as vaccines, anthelmintics, antiparasitics, antibiotics, steroids, tick control products, anesthetics, NSAIDs, antihistamines, alternative/herbal remedies, shampoos, prescription diets, and most generally prescribed medications.


Review Summary
20 Reviews
75% (15)
20% (4)
0% (0)
0% (0)
5% (1)
95% Recommend this product (19 of 20 responses)
By Kristi
The only flea and tick prevention that works!
March 15, 2020
I have tried all the other prevention such as frontline, etc and they were a huge waste of money! comfortis is the only prevention that has worked for all of our cats and dogs.
ProsComfortis is worth the money because it actually works.
By HBGary
Huntington Beach
Two dogs, no fleas
November 17, 2019
We have used Comfortis for many years since our vet recommended it during a time of major flea infestation in the area and our dog was suffering (as we were too), Our current two dogs have always used Comfortis after the good experience we had with our prior dogs.
Merchant Response:Flea-free is the way to be. Comfortis is pricy, but worth it in the long run. Take care Gary.
ProsEasy to administer product to the dogs.
By Irene
Los Angeles, ca
Customer service
March 22, 2019
This review is for entirely pets pharmacy: great customer service! Wouldn't use any other online pet pharmacy
By ronald c.
1425 second ave Chula Vista, CA 91911
February 8, 2019
I received product in a timely manner; so I'm well pleased! Thank you
By karla` s.
Miami, Florida
Works great
October 19, 2018
Always kills fleas within 30 minutes. Service was great and delivery on time.
By Katrina
Oregon Coast
Good Value
October 17, 2018
Easiest way to buy and a great price.
By Lu H.
Recent order
August 29, 2018
First time using - great service - contacted my vet for a prescription right away and product arrived very soon after - will use again.
By spex
fountain valley , Ca.
I got it !
May 18, 2018
it was a little faster receiving the comfortis, and sale price was a bonus. I was pleased all around. It is easier to administer to my pet.
ProsEasier to give to my pet.
San Diego, California
Stomach Upset
March 17, 2018
I provided the ComFortis tablet immediately following our dogâ€â"˘s breakfast. He vomited everything up within the hour. Gastrointestinal issues are not typical with our dog.
ConsStomach upset.
By Ella P.
San Diego, California
Comfortis for Dogs
January 18, 2018
Very pleased with the service received. There were no discrepancies with the product, or with the order. The customer service was excellent and quite comforting. I would suggest that Entirely Pets is used for all of your pet needs.
Merchant Response:Thank you for your kind words Ella! Glad we are able to help!
ProsGood prices, order in a timely manner!
ConsNo complaints!
By Orange m.
Huntington Beach California
Great product
October 5, 2017
The time it took to get the actual product was too long but the product itself and the price was great.
ConsTook too long
By Shelley
St. Louis, MO
Comfortis for dogs
October 4, 2017
good value, best price I could find
By Barcomb L.
Houston, Tx
Great product
April 23, 2017
Product works great. No live fleas found on my dog
No scratching.
Happy dog, ?
By pepperoni
san diego, California
Really effective; if only it weren't chewable
April 17, 2016
Great product but both dogs detest the flavor. So I'm left with huge pills I can't even disguise in food and it's the only medication I have to shove down their throats. Comfortis: PLEASE make a small pill that isn't chewable.
Consdogs hate the taste and it's so strong I can't even disguise it covering it with blue cheese!
By holly
Old Fort, NC
works great!
April 4, 2016
I have used this product on my cats. it works really really well and I like it much better than the topical. I hate that stuff. they sleep in my bed and the thought of that getting wiped everywhere freaks me out. the pills are easy, not messy, and really work!!! although I haven't ordered from entirely pets yet, I am planning on using them for my next order because their prices a MUCH less than at the vet!
Prosworks great, no mess, better prices than the vet
By Vicky
McKinlyville CA
Finally NO FLEAs!
March 5, 2016
yĂ y...this product actually works! I've spent hundreds of dollars trying to get the fleas off our GermĂ n Shepherd. For yearrs he would mĂ ke himself, Ă nd me, crazy and hairless from scratching at them. After 2 months, his hair is growing back now and he looks really nice and shiny and happy!! SSo glad I switched from topicals!
By Gary L.
Surf City, USA
Good price...same product as from my vet
August 26, 2015
Easy transaction. Simple and quick. Only delay was getting prescription from my own vet. Not Entirely Pet's problem. They fax'ed request to my vet. Once received from vet, shipped to me.
ProsGood price Easy transaction
ConsDelay in securing prescription from my vet
By Gary L.
Surf City, USA
Same as what I get at my vet
August 23, 2015
Same product sold by my vet at a higher price that was prescribed for my dog. Easy online transaction.
ProsGood Price Works for my dog
ConsTook awhile for my vet to approve the prescription for my dog. Not Entirely Pets' problem as they fax'ed request to vet right after receiving order. I had to follow up with vet to make sure they responded to Entirely Pets' request.
By Jean
Topeka, Kansas
Most reasonable deal found
July 9, 2015
I did a lot of research and found purchasing Comfortis from Entirely Pets Pharmacy was the best deal. Thanks - I always believe in saving money.
By Karen
Ventura County, Ca
June 21, 2015
Requested Comfortis. Provided my vet's name and fax #. EntirelyPets did the rest.

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