​Capstar For Dogs VS Comfortis for Dogs Comparison Chart


​Kills Adult Fleas?



​Kills Fleas Eggs?



​Kills Ticks?







​Once a Month

​Single dose is enough/Redosing for pet once a day is safe

​Active Ingredient



​Average time to kill pesticide

​45 minutes – 1hour

​4-6 hours

Comfortis and Capstar Dog Flea Treatments Review

Does your dog suffer from fleas? Fleas are a common problem with dogs. They cause your pet to itch, lose hair, and suffer from raw and scabby skin.

There are many treatments for flea infestation. Comfortis and Capstar are two of the more popular ones. Unlike inconvenient and messy topical treatments for fleas, both Comfortis and Capstar come in tablet form which makes them easy and simple to administer.

​What is Comfortis

​Comfortis is an FDA-approved chewable tablet that effectively eliminates fleas on cats and dogs. It kills fleas half an hour after your dog receives the dosage. Eliminating fleas before they are able to lay eggs, Comfortis prevents the infestation of fleas for an entire month. It is recommended for dogs or cats that are at least 14 weeks old.

What are the Active Ingredients in Comfortis for Dogs?

Comfortis for dogs contains Spinosad, its primary active ingredient. Spinosad is a natural insecticide/antiparasitic which is a derivative of the natural fermentation of soil microbes. Spinosad works by attacking the nervous system of fleas. It swiftly paralyzes fleas and eventually causes them to die.

Its synthetic beef flavor comes from a combination of hydrolyzed soy and pork protein.

What are the Side Effects of Comfortis?

Your pet may experience vomiting. If your dog or cat continues to demonstrate a significant loss of appetite, diarrhea, sluggishness, weight loss, or any similarly unusual behavior, make sure to consult your veterinarian.

The side effects are common particularly for pets that are also taking extra-label ivermectin. Ivermectin is prescribed for demodectic mange or mite infestation.

What are the Pros and Cons of Using Comfortis for Dogs?


  • It works fast. Thirty minutes after administration, Comfortis starts to eliminate fleas. Laboratory studies demonstrate that the product takes only four hours to effectively eliminate between 98% and 100% of fleas.
  • The effects are long-lasting. Comfortis kills fleas so that they cannot lay or hatch eggs. Comfortis continues to work for a full month after administration.
  • It is easy to administer. Comfortis comes in a pet-friendly beef-flavored chewable tablet that pets are likely to enjoy.
  • It is safe to use. If your dog is healthy, he is unlikely to show adverse reactions to the product. Make sure that your dog is at least 14 weeks old and weighs at least 3.3 lbs. Inform your veterinarian if your pet is pregnant, lactating, or breeding.


  • It may cause adverse reaction in some pets. Side effects include vomiting, decrease in appetite, loss of weight, and diarrhea. Get in touch with your veterinarian if your pet shows continued adverse reactions. Pets that are not affected by these side effects go about their normal activities without interference.
  • Comfortis contains pork-based protein which is responsible for its tasty beef flavor. If your pet is allergic to pork, you may have to consider another alternative.
  • It is not available over-the-counter. You have to get a prescription from your veterinarian so you can purchase the product.

When is it best to administer Comfortis to your pet dog?

You can administer Comfortis any time. Veterinarians, however, suggest that you do so a month before flea season. Continue to give your dog his monthly Comfortis dosage until the end of the flea season.

If you live in a place where fleas are active the entire year, make sure that you administer the product every month without break.

Capstar Flea Treatment

Capstar flea treatment is another popular oral solution for fleas. It is used to eliminate fleas in both cats and dogs.


What is ​Capstar for Dogs?

Capstar for dogs is a flea treatment solution in unflavored tablet form. It is recommended for dogs that are at least 4 weeks old and weigh at least 2 lbs.

The tablet comes in packages for dogs weighing between 2 and 25 lbs and for dogs weighing 25.1 to 125 lbs. The normal dosage is a tablet. If your dog weighs more than 125 lbs, you can give a combination of the tablets appropriate to his weight.

It is safe to use even if your dog is pregnant or nursing.

Capstar for dogs begins to work within half an hour after you let your dog take a tablet. It is expected to kill at least 90% of the adult fleas on your dog within 4 hours after application.

Novartis Capstar works fast, providing immediate relief for your pet. However, the effect only lasts for a day. Capstar kills fleas; however, it does not eliminate larvae and flea eggs. Re-infestation is likely to occur. Thus, daily usage is recommended.

What is the active ingredient is Capstar?

The active ingredient in Capstar is nitenpyram, a substance that effectively kills insects. Nitenpyram effectively eliminates adult fleas by interfering with their nerve transmissions. Its effect is quick and immediate. It effectively kills fleas without adversely affecting your dog.

What are the side effects of Capstar?

You may notice your dog scratching because of the dying fleas when the Capstar dosage takes effect. Don’t worry — the condition is temporary. It is a reaction to the excessive motion of the dying fleas; it is not an adverse reaction caused by the medication itself.

Capstar may have adverse side effects. Make sure that the adverse reactions are not cause by inappropriate or wrong dosage. These side effects may include hyperactivity or exhaustion, nervousness, and trembling. Your dog may also demonstrate vomiting, excessive panting, or diarrhea.

What are the Pros and Cons of Using Capstar?



  • It works fast. It kills adult fleas in less than 30 minutes. You can expect your pet to experience quick relief from the discomfort and allergies associated with fleas.
  • It is easy to use. Coming in easy-to-administer tablet form, you can easily make your pet swallow it. There is no need for the inconvenience, odor, and mess usually associated with topical flea solutions.
  • It is available over-the-counter. You do not need to spend money to see a veterinarian for a prescription.
  • It is safe. You can give it to your dog on a daily basis. You can administer the tablet even if your pet is pregnant or nursing.


  • The effect is limited. Capstar works only for 24 hours, so the fleas are expected to come back.
  • Capstar is designed for use only in certain situations. If you take your dog outside — for training, a walk, or a run — it may take on fleas which are likely to be taken into your home. Giving him Capstar during these occasions ensure that you eliminate the fleas. Your dog will not take the fleas with him to your home where they are likely to breed and cause greater problems.
  • Capstar for dogs is not a stand-alone solution for fleas. It is effective as a support program for other flea treatments.


If you would look at Comfortis versus Capstar, it would be hard to tell which one is better, as each offers certain advantages. While Comfortis’ effects are longer-lasting, Capstar is safe to use on pregnant and nursing dogs. From personal experience, Comfortis has been a really great dog flea medicine when it came to combating fleas. Capstar was not very effective, and the fact that I had to give my dog his flea meds everyday didn’t make it any better. I liked the idea of just giving him one medicine once a month and be good for the entire month. The results for me was Comfortis was way better than capstar.


Hope this helps :)

Buy Comfortis Online Cheap Discount Without Prescription

​Kea Kou

About the Author

​Kea here. I started this blog to help pet owners find better prices on flea medicine. I know what it's like paying an arm and a leg for pet products since I've spent hundreds of dollars on my wiener dog (Dachshund) named Mr. Beans. 

I've done all the research (testing, comparing, talking to other pet owners) and I share with you all that I find. I hope my Blog helps you make a better decision on which products are best for your pet and to help you save money at the same time :)

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