Written By : M Samy

Do flea treatments make cats sleepy? (side effects and safe use)

My cat becomes sleepy after flea treatment

Cats can become sleepy for a few hours or even the rest of the day after some strong topical flea treatments. If your cat’s gums have become pale and her breathing abnormal, you should call an emergency vet or pet poison control.

How long do cats stay drowsy after flea treatment?

Do flea treatments make cats sleepy? (side effects and safe use)

So, how long do flea treatment side effects last? Cats can stay sleepy for a few hours after flea treatment, but a cat that is already sick, weak, or just small may stay drowsy for the rest of the day. The product you used and the amount you applied to the cat can also extend this period, as some topical flea treatments are often too strong for . Fleas can be deadly to cats, but some flea treatments can also be deadly to cats if overdosed or misapplied.

Cats are not supposed to lick these types of pesticides and the more your cat has absorbed this product, the greater the risk of poisoning and the longer he will remain sleepy.

The side effects of flea treatment in cats appear minutes to hours after the application of flea droppings, but if the cat is in excellent health, the side effects may not appear for a day or two and the risk of poisoning from flea products is real if you do not follow the specific label directions for each product.

You also need to be prepared for any unexpected outcomes after the flea treatment and be aware of what to do to ensure the success of the treatment and the safety of your cat.

Does cat flea treatment have side effects?

Unlike some flea cat collars like Seresto which have virtually no side effects on cats over 10 weeks old, oral and topical flea treatments can often have side effects on cats.

After the application of flea treatment, there are “normal” side effects, like if your cat becomes a little drowsy for two to three hours or if he starts to run around and scratch because fleas will start to agitate too and create an uncomfortable situation for your cat.

If you only notice these three symptoms after applying flea treatments to your cat, know that this is a normal reaction and that you don’t need to worry:

  • Itchiness and excessive grooming
  • Hiding and a situation of discomfort and stress
  • Your cat may get a little bit lethargic and won’t eat for the rest of the day.
  • Your cat may become momentarily aggressive or nervous
  • Agitation

Cat oral and chewable flea medications (flea tablets and pills) like Comfortis often have fewer side effects on cats over 15 weeks and 4.2 pounds, but if you follow the doses and directions.

How long do cat flea treatment side effects last?

Most flea control products are pyrethrum-based (active ingredients) and Pyrethrin (don’t worry, it’s safe when appropriately applied) which should not exceed 1% of the flea treatment composition and can become fatal for cats if ingested in high doses.

The brands that contain it are Talstar, Capture, Ortho Home Defense Max, Bifenthrin, Baygon, Scourge, and Anvil.

Organophosphate products included in some flea medicines can also cause toxicity in cats if used incorrectly, so you should follow the dosage instructions on the packaging, taking into account your cat’s age, weight, and general health. If in doubt, it is best to contact a veterinarian before applying this treatment.

Products that contain it are : Alco, Americare, Beaphar, Happy Jack, Hartz, Hopkins, Kill-Ko, Protection, Rabon, Sergeant’s, Unicorn, Vet-Kem, Victory, and Zema. My personal advice is to avoid them.

You can find more information about these products and their ingredients and active ingredients here on Medvet.

But most mild and severe clinical cat’s flea treatment side effects will go away after 4 to 5 hours but can last up to 72 hours (3 days) as this will depend on several things like:

  • What kind of flea treatment you used (oral or topical)
  • What brand of medication you used.
  • Your cat’s age, weight, and health condition
  • Whether the indications and contraindications on the treatment’s packaging have been followed.
  • Whether your cat licked the product after application or not

If your cat keeps having unusual reactions, this usually happens if too much or the wrong flea product is applied; you should absolutely take your cat to the vet, and take with you the flea medicine that you used.

You will always find on the packaging the side effects your cat may have after the treatment, read them and if you notice any complications, call an emergency vet or poison control at these phone numbers:

  • USA: ASPCA /(888) 426-4435)
  • CANADA: ASPCA. Animal Poison Control Center /(888) 426-4435
  • UK: Animal Poison Line (APL)/ 01202 509000
  • AU: Australian Animal Poisons Helpline / 1300 869 738
  • NZ: New Zealand APH 0800 869 738

What if your cat licks flea treatment?

If your cat has just licked a topical flea medicine, start by brushing his teeth and preventing him from swallowing the paste, then give him a few treats before consulting a vet if you suspect that your cat has swallowed too much of the medicine and is beginning to show signs of poisoning such as excessive salivation and foaming, nausea and vomiting, and loss of balance as early symptoms.

Signs of flea treatment poisoning in cats:

You must read the packaging carefully before applying flea preventatives and treatments. These are the common symptoms of flea medicine poisoning in cats that can appear one to 12 hours after application, don’t worry, most cats will regain their good health right after a treatment that usually consists of intravenous (IV) fluids, muscle relaxants, and symptomatic care. :

Signs of poisoning from pyrethrum-based flea products:

  • Hypersalivation (excessive drooling)
  • Tremors ( muscle and/or ear ) twitching and trembling

Signs of poisoning from flea products containing organophosphates: 

(much more dangerous for cats), your cat may need hospitalization:

  • Excessive paw flicking.
  • Drooling
  • Pale gums
  • Difficulty breathing
  • Small pupils
  • Ataxia (Loss of balance) and weakness
  • Vomiting
  • Severe diarrhea

What to do if your cat shows signs of flea control product poisoning?

If you notice any of the above symptoms, you should start by bathing your cat in warm (not cold) water using a dishwashing liquid to remove the product from his fur and to keep it off your cat’s skin.

You should then immediately call your veterinarian and follow his or her instructions, although it is recommended that you take your cat to the nearest vet.

Is cat flea treatment safe?

Yes, cat flea treatment is safe, especially if you carefully follow the product label and instructions. It is always a good idea to ask your vet before using this kind of product to confirm the dose you need to apply to your cat according to its age, weight, general health, and allergies to get rid of fleas and minimize the side effects on your cat. The vet may even recommend a specific product or whether it is better to use an oral or topical flea treatment.

Cat flea treatment instructions

Each cat flea treatment may have its own instructions and contraindications, so it is recommended to read the product label before use or to consult a vet and use a veterinarian-prescribed flea control product.

But there are some common precautions to take when using flea medicine on cats, here are the most important:

  • Read the label instructions, if you have lost the packaging, google the product brand.
  • It is better to treat your cat against fleas early in the morning to be able to take him to a vet in case of complications (do not use this treatment at night).
  • Avoid at all costs that your cat licks the flea medicine.
  • Avoid using the product on your cat’s face, especially around the eyes, nose, and mouth.
  • Never use two different brands of flea treatments on your cat at the same time.
  • Respect the dosage to use and this, according to the characteristics of your cat (age, weight, allergies…).
  • Never use a product intended for adult cats or dogs to treat a kitten
  • Never use a product for dogs on your cat without consulting a vet first.
  • Never use topical flea treatment on areas where the cat’s skin is red, wounded, irritated, or has lesions.
  • Never use flea treatment on a pregnant cat
  • Keep the cat away from its pups after the treatment and until the mama cat has had her bath after the treatment is done.
  • Separate the treated cat from other pets.
  • Prevention is better than cure, so try to prevent your cat from getting fleas by using a flea collar, especially during the spring and summer.

how to safely apply flea treatment to cats?

How to safely put a Spot-On flea treatment for a cat?

1- Read the label on the product packaging to determine the dosage for your cat, remove a tube and make sure you know in advance how much flea medicine to use, it is best to wear gloves to avoid contact with the product.

2- Find a spot on the back of your cat’s head (between their shoulder blades) so that your cat cannot lick the product. This area of the skin should not have any lesions, scratches, or inflammation and your cat should be relaxed.

3- After reassuring your cat to stay still (you can ask someone to hold him so he doesn’t move), you will pierce the tube using its lid (invert it).

4- You will now take care to apply the spot-on flea treatment directly to the cat’s skin and avoid accidentally pouring it on the cat’s fur.

5- You will finally release the cat’s fur to cover the area, do not wet the area where you applied the product for at least 24 hours (this may differ from one brand to another), and avoid your other pet licking this product because this can happen if you have a cat or a dog that will play with your treated cat and chew it for example in the place where you applied the flea med.

6- Wash your hands well and put the rest of the product in a safe place, away from children and pets as it is toxic if ingested.

PS/ In case you use flea tablets, make sure by reading the product label if you can give them with food or not.

Are there any cat flea treatments to avoid?

For a flea treatment to be effective it must contain either organophosphates or pyrethroid. Both are toxic to cats if absorbed in large quantities.

Flea treatments that contain organophosphates are known to be the most dangerous since a cat poisoned with these products usually needs to be hospitalized and will require special care to recover.

All flea meds are dangerous if used improperly and it is best to seek the advice of your vet before treating your cat for fleas.

Many flea treatments for dogs are dangerous for cats and cat flea treatment overdose should be avoided, and this is the kind of mistake you should not make.

What cat flea treatment do vets use?

Veterinarians often use specific treatments for each cat, depending on its characteristics and general health. I’m going to list the best flea treatments that are, if administered correctly, the safest and those that have the least side effects on cats.

As for the brands often recommended for cats and kittens by vets, here they are:

  • Advantage (Advantage 2 for kittens)
  • Frontline (Frontline gold for kittens over 8 weeks and +1.5 lbs)
  • Bravecto
  • Revolution (Revolution Plus for kittens 8 weeks and +2.8 lbs)
  • Vectra 
  • Cheristin
  • Comfortis (Oral preventives flea medicine)

Some cat parents have experienced complications when using Advecta made by HARTZ, so I would tell you to avoid any flea treatment from this brand.

Can cat flea treatment cause hair loss?

Yes, some spot-on topical flea treatments can cause hair loss in cats where you apply the product, as can vaccines. This hair loss is often caused by repeated use of the treatment in the same area or by applying more product than is needed (overdose).

How long to leave flea treatment on my cat?

24 hours is enough time for flea treatments to work but you can find other indications on the packaging of the product and if after this time, there are still live fleas on your cat, the product is either expired or you have not dosed the product properly.

In this case, it is better to ask the advice of a veterinarian instead of doing the treatment yourself, which could poison your cat.

Flea treatment for cats with sensitive skin

If your cat has sensitive skin or any other skin problem, even if it suffers from hair loss, it is better to use an Oral flea treatment such as Comfortis tablets, a chewable that you will give your cat once a month if there is still a risk that it will get fleas.

Cat oral flea treatment  vs topical

Oral flea treatments are somewhat more effective than topical ones but your choice should also depend on your cat and its response to the medication.

It is better to use spot-on flea meds if your cat has digestive or stomach problems for example, whereas it would be better to use oral flea tablets if your cat has sensitive skin or any skin problems.

Are flea powders suitable for cats?

Flea powders are only effective in removing adult fleas whereas the larvae and eggs are usually left alive as the powder hardly reaches the cat’s skin when applied and only remains on the hair until it falls off.

Flea powders are also only to be used for the short term and as soon as the powder disappears from your cat’s fur, fleas can come and infest it again.

Cat flea treatment on pregnant and lactating cats

Although Advantage and Frontline Spot-on flea treatment are licensed for use on lactating and pregnant cats, it is advisable to get rid of the fleas before the kittens are born to avoid exposing them to the product, which can be very harmful to them and their development. Ask your veterinarian for more information and advice, it is safer.

Cat flea treatment vet cost

You will have to pay for the vet visit (about $50), plus the treatment itself (about $50 for 3 months), and finally, you will have to think about getting rid of any fleas that may have jumped out of your cat and hidden in your carpet.

Final Thoughts

It’s best to seek the advice of a veterinarian if this is the first time you’re treating your cat for fleas. You can then continue to apply the treatment yourself by following the instructions given by the vet during the first session.

If your cat becomes a little drowsy after flea treatment, it is normal because cats are sensitive to medication. But if your cat remains in this state for more than 24 hours, you should take your cat to the vet.

If you notice other symptoms such as complete loss of balance and tremors, you should immediately call your local pet Poison Control Center or take your cat to the vet as soon as possible.

M Samy pet blogger and author at famillypet

About Author

Hey! Salim Makhloufi (alias M. Samy) here , Welcome to my Blog I'm an animal lover, especially pets and Really concerned about their well being ; I've been around and caring for all my life and Now ; a full-time Pet blogger at your service . My motto here at Famillypet is: "Pets First" ... Read More