Capstar vs Comfortis Flea Treatments: Vet Approved Pros, Cons & Verdict

Vet approved

Reviewed & Fact-Checked By

Dr. Amanda Charles

Veterinarian, BVSc GPCert (Derm) MRCVS

The information is current and up-to-date in accordance with the latest veterinarian research.

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Capstar and Comfortis are two well-known brands of flea treatments for pets. Capstar and Comfortis can be given to cats and dogs, but each uses a different active ingredient to treat the flea infestation. Capstar uses nitenpyram, a systemic insecticide that begins to kill adult fleas after 30 minutes. Comfortis uses Spinosad, an insecticide that overloads a flea’s nervous system, killing it after 30 minutes.

Capstar products are available without a prescription, and the tablets can be given up to once daily, until a flea infestation is controlled. The effects of nitenpyram last for between 24 and 48 hours, so any flea larvae that hatch after this time can jump on and bite your pet. Comfortis products are prescription-only, meaning you’ll need to see a veterinarian to get them prescribed for your pet. They are long-lasting, giving your pet protection against fleas for up to 30 days.

Comfortis is generally better for flea control than Capstar since it lasts longer, helping protect your pet from hatching flea eggs and larvae that could still be in the environment. Regular monthly treatments break the fleas’ life cycle. Using Comfortis means you don’t have to keep re-administering the medication if you have an infestation in your home.

If you’re looking for long-acting flea treatment which prevents and controls flea infestations, choose Comfortis. If you cannot get your pet to the vet for a prescription or only want a short-acting, quick-fix to kill adult fleas, choose Capstar. Another thing to consider is if you have a pregnant or lactating pet: Capstar is safe for use in pregnant or lactating cats and dogs, whereas Comfortis is not.

At a Glance

Rating	Image	Product	Details
		Capstar	Last a month Flavored tablet for ease of administration More cost-effective	Check Price
		Comfortis	Active Ingredient: Spinosad Suitable for cats and dogs Effective for one month	Check Price

Let’s look at the key points of each product.

Overview of Capstar:

Capstar flea tablets are non-flavored and suitable for cats and dogs weighing 2 pounds or more and over and at least 4 weeks old. These tablets kill adult fleas on your pet after 30 minutes, and the active ingredient (nitenpyram) lasts 24–48 hours. They can be re-administered up to once a day if you continue to see fleas on your pet, and ideally should be given with food.

Capstar tablets are available without a prescription, making them suitable for the prompt treatment of adult fleas while a longer-term preventative treatment is found. There are three sizes available based on the species and weight of your pet: two for dogs and one for cats. Capstar is considerably cheaper and easier to buy than Comfortis. Capstar is also safe for pregnant and lactating animals, so it’s ideal to use if your pet is expecting.

Overview of Comfortis:

Comfortis flea tablets are chewable flavored tablets for treating flea infestations on dogs and cats. They are suitable for cats and dogs weighing 5 pounds and over and at least 14 weeks old. They begin to kill adult fleas on your pet after 30 minutes, and the active ingredient (spinosad) lasts 1 month. Comfortis is also effective at reducing flea egg production and so helps to prevent your home from becoming infested. Comfortis is a long-acting preventative that should be given on a full stomach once every month for continuous protection.

They require a veterinary prescription, but each six-tablet pack lasts 6 months. While each pack of Comfortis is more expensive to buy, it’s cheaper in the long run as you get half a year’s worth of treatment in one pack. Your vet will prescribe the appropriate dose but five sizes are available: three for dogs and cats and two for dogs only. Comfortis is more effective as a long-term flea treatment than Capstar, but it is unsuitable for pregnant or lactating animals or animals under 14 weeks of age.

What Are the Differences Between Them?

Performance

Both Comfortis and Capstar flea treatments begin to work after 30 minutes. Both have been proven to kill adult fleas on both and cats; testing of Comfortis showed that it killed 100%  of fleas on dogs and 98% of fleas on cats within 4 hours, and testing of Capstar showed that it killed over 90% of fleas on cats and dogs within 4 hours. However, while both are effective, Comfortis kills a higher percentage of fleas on dogs.

Price

The price is undoubtedly less when buying Capstar flea tablets, likely due to the lack of prescription needed. The cost of one six-tablet pack of the smallest size of Comfortis is more than three times more expensive than Capstar, which can make it inaccessible for some pet owners.

Value for Money

Despite the higher initial outlay, Comfortis works out cheaper in the long run and offers more value for money, as each tablet lasts a month. Capstar tablets may have to be re-administered daily in heavy flea infestations, so a pack of six could last less than a week! On a month-by-month basis, Comfortis is a better option and is more cost-effective (particularly for heavy infestations).

Ease of Obtaining

Capstar is a much easier option for owners looking to quickly treat their animals without a prescription. While Capstar is easier to obtain, prescription medications are usually more effective, so it may be worth the wait to get a packet of Comfortis if you want long-term protection.

Summary

Comfortis is the winner for the most effective flea treatment. While Capstar is an excellent contender in the short-term, Comfortis has the edge for being a once-a-month treatment. This protection makes it not only easier to eradicate a flea infestation on your pet but easier on your wallet, too. Comfortis has a much higher price than Capstar, but each pack gives you 6 months of protection versus the minimum of 6 days from Capstar.

Capstar is great if you’re on a budget, however, as it’s effective and safe and will relieve your pet from fleas. Both products kill most fleas within 4 hours on all pets, and it depends on the length of time you’d prefer your pet to be protected for, and whether or not they’re pregnant or nursing, that’ll sway you towards Comfortis or Capstar.