Comfortis For Cats – Review

Comfortis For Cats - Review

Has Your Vet Prescribed Comfortis For Cat Fleas?

Are You Worried About Potential Side Effects, Dosage Or Just How This Drug Works?

Well, We’re Here To Put Your Mind At Rest.

Let’s Take A Look At Our Indepth Guide To Comfortis For Cats.

Cat fleas are a pain, but they are something almost every owner has to deal with.

These parasites have haunted our homes, pets and selves for as long as anyone can remember.

And they don’t seem to be going anywhere anytime soon.

Fortunately, we have a whole range of choices available when it comes to fighting back.

This is a double edged sword though — with so many products claiming to be the best, an abundance of options can be paralyzing.

To help you make an informed decision, today we’re putting the spotlight on one oral flea treatment: Comfortis.

Specifically Comfortis for Cats, the name given to the range of doses made especially for our furry feline friends.

What is Comfortis for cats?

Comfortis is a brand name for spinosad.

This compound was first found in the bacteria Saccharopolyspora spinosa, hence the name spinosad.

The bacteria was first described in 1990 after it was found in a sugar mill, and since then the compound spinosad has been synthesized and used in a number of pesticidal roles.

Spinosad has found a wide range of uses in dealing with creepy crawlies worldwide, having first been used against insects living on crops.

But our current interest is how this pesticide might help our pets — specifically, as Comfortis for cats.


Fleas have a multi-stage lifecycle.

They spend a few weeks as larvae after hatching from eggs.

After this point they pupate, transforming into a fully formed adult flea.

They then instinctively jump at the first shadow that passes over them, hoping to land on a mammal they can feed off of.

Once latched on, they drink their fill of blood, producing eggs!

These eggs shed off of the flea as your cat walks around the house, spreading everywhere your cat goes.

If the conditions are right and the eggs survive, the cycle starts all over again.

Just reading this is enough to make any cat owner itchy!

That’s where Comfortis for cat fleas comes in.

Comfortis for cat fleas

Numerous studies have shown that taking a dose of Comfortis on a monthly basis can keep fleas at bay.

It does this by entering the blood stream through the stomach, making the compound ingestible by fleas on your cat.

Once the fleas ingest Comfortis through the blood, they die quickly.

Hopefully this means they won’t have the opportunity to shed eggs and continue the infestation.

Comfortis has demonstrated the ability to kill 98% of the fleas on a cat within four hours of administration. Such a quick action is essential when dealing with fleas.

This rapidity is necessary because fleas have a very short life cycle. If an insecticide takes too long to kill them they may have already laid eggs all over the house.

A 2013 study compared this method to a topical flea treatment called selamectin, and found spinosad to be markedly more effective.

So how do we administer comfortis, and what form does it come in? Can we buy comfortis flea tablets for cats?

Comfortis flea pill for cats

Comfortis for cats is available in the form of a chewable pill.

This can be added to food, or given separately before or after dinner.

For those of us with picky cats, you may want to cover the tablet in a special treat, or food you know your cat likes.

This is a great way of ‘tricking’ any pet into taking its medicine.

You need a prescription in order to buy the Comfortis flea pill for cats, so you must talk to a vet to benefit from this treatment.

Your vet will evaluate whether your cat does indeed have fleas.

This is more important than you might think. Other conditions like food allergies can present with similarly itchy symptoms.

Your vet will also likely weigh your cat, to prescribe the correct dose. This is important as Comfortis comes in a range of strengths.

So, what dosage of Comfortis is my cat likely to receive?

Would Comfortis 270 mg for cats be right for my furry friend?

Comfortis dosage for cats

The ideal comfortis dosage for cats differs depending on their size.

The minimum recommended dosage of Comfortis is 50mg for every kg that the cat weighs.

Due to the large variety of cat sizes, it comes in four different sized tablets.

These size brackets manage any cat from 2-24lbs but a larger cat will be prescribed one of the largest tablets along with a smaller one to make up the correct dose.

The makers of Comfortis helpfully color code different dosages to make identification a little easier.

For example, Comfortis orange for cats is for those between 2.8kg and 5.4kg, while Comfortis green for cats is for those between 5.5kg and 11.2kg.

How often should I use Comfortis for cats?

This dose is given once per month for however long fleas remain a factor.

This once a month strategy seems arbitrary, but it makes a lot of sense.

We mentioned earlier that it takes 3-4 weeks, or around a month, for fleas to become adult.

By matching up the dosage to this cycle, we can quell any uprising before it has an opportunity to manifest.

If you’re living in an area where fleas are prevalent in a particular season, your vet might preemptively give you Comfortis to prevent an outbreak starting.

In places unlucky enough to experience flea trouble regardless of the season, Comfortis can be used year-round.

Some flea treatments, like frontline, can’t be used this consistently, so this is a huge help to a lot of owners.

Comfortis chewable tablets for cats can be given from the age of 14 weeks. Before this kittens stomachs are just too immature to handle it.

Taking too much comfortis can cause the known side effectsto become more severe, but what are these side effects?

Comfortis side effects

By far, the most common side effect of Comfortis is vomiting.

This is nothing new, as medicines often upset our cats’ stomachs, with around 14% showing this side effect in a 2013 study of 211 cats.

While this doesn’t sound severe, care should be taken to make sure our cats aren’t dehydrated if vomiting.

Make sure water is readily available at all times, but especially when vomiting is a risk.

Other less common side effects can include lethargy and anorexia.

Although relatively rare (only appearing in about 2% in the same study) anorexia could present a problem if your cat begins to lose too much weight.

If your cat is clearly losing interest in food after a course of Comfortis it might be best to get in touch with your vet.

They will be able to evaluate the likely cause, and if it’s Comfortis, change the medication.

As we’ve said though, most of the side effects are relatively rare.

And since fleas can cause our cats to lose sleep and experience secondary infections it’s important to guard our furry friends against them.

It’s important to contact your vet if your cat has taken too much Comfortis, and these side effects appear to be getting more serious.

So, where can I buy Comfortis for cats?

Where to buy Comfortis for cats?

In the age of the internet, we can find pretty much anything online.

Prescription vet medications are included in this. It can be really tempting, especially if we find Comfortis for cats cheap.

This isn’t a good idea though, and there are a few reasons why.

Buying Comfortis for cats without a vet prescription might not just be illegal, but potentially dangerous.

You’re cat might not have fleas, but it might be itching for another reason. By avoiding a vet and choosing medicine yourself you might be missing a symptom.

At best your cat will be itchy for longer while you figure out what’s actually going on, but at worst you might miss the signs of something serious.

Not all animals will react the same to any medication. Your vet will have a much better idea of what’s appropriate for your cat, and be able to prescribe accordingly.

Always speak to your vet

There’s always a risk of making side effects worse by giving your cat too much Comfortis.

Vets will take care to decide the appropriate dose.

There’s also the danger of giving too little; without enough spinosad in her system your cat may not make much of a dent in the fleas plaguing her.

With Comfortis for cats, best price is less important than the right dose.

Comfortis for dogs and cats aren’t necessarily interchangeable either.

You should never give one animal medicine that is intended for another. This is regardless of how innocuous the treatment seems.

So, it goes without saying, the only place you should get Comfortis from is your vet, or a pharmacy (online or otherwise) they’ve directed you to.

If you have a question about where to buy Comfortis for cats, you should ask it during your appointment.

Generic Comfortis for cats, or spinosad, won’t be available in the chewable form.

So, overall is Comfortis flea medicine for cats the right choice for you?

Comfortis flea treatment for cats

Whether Comfortis flea medication is right for your cat is largely up to your vet.

There are reasons these professionals study for years — so they can make these decisions for us.

With all things being considered, the evidence behind Comfortis is impressive.

A flea treatment that can be applied year round with minimal risk is certainly something that’s in demand.

The uncomplicated once a month administration is another thing this treatment has in its favor.

Side effects are scary, and although Comfortis is fairly minimal in this regard it’s still a concern. Comfortis tablets for cats might make our cats feel unwell, but fleas can be much worse.

Fleas seem like an annoyance, but the tiny wounds they open in the course of feeding present a risk in and of themselves.

Secondary infections can develop into worse and potentially life threatening conditions if left to their own devices.

It can be slightly disheartening that every effective flea treatment seems to come with a catch. But it makes sense, seeing as we’re poisoning these parasites.

It seems unreasonable not to expect our cats to be affected by these pesticides as well.

Fortunately, in the grand scheme of flea treatments, Comfortis seems like an effective and relatively safe option.

But it’s important to go to our vets with an open mind and let them suggest the treatment they think is most effective.

Every cat is different, and they will all respond differently to any treatment. Your own living situation, and the surrounding environment, might also affect your vets decision.

What’s your experience using Comfortis? Let us know in the comments below.


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Lucy Patrick

Hi Furiends! Welcome, and thank you for reading CatFoodStuff! To learn more about our story, come visit us on our about page. I am Lucy Patrick, I have been around with cats for around more than 12 years. I have done the catsitting for alot of clients in and around our area & have been pursuing the Veterinary Course from University. Catfoodstuff is my attempt to answer all the issues that comes around while raising cats at your places & I am highly delighted with the reviews I am getting. We would be happy to hear from you! We participate in the Amazon Services LLC Associates Program, an affiliate advertising program that is what provides a means for CatFoodStuff to earn advertising fees by advertising and linking to The price remains the same for you & we receive a small commission contributing to the website development. Certain content that appears on this site comes from amazon services llc. this content is provided 'as is' and is subject to change or removal at any time.