Flea tablets for cats: oral flea treatments compared

How flea tablets for cats work

When your cat swallows a flea tablet, the active ingredient is absorbed into the bloodstream. Fleas die when they bite and feed. Because the medicine works from the inside, it is not affected by bathing, rain or swimming, and there is nothing on the coat for children or other pets to touch.

The trade-off is that a flea must bite before it dies, so tablets don't repel fleas. For most cats that is not a problem, but cats with flea allergy dermatitis can react to even a single bite, so your vet may suggest a product that kills extra-fast. For a comparison with spot-ons and collars, see our main guide to flea treatment for cats.

Flea tablets for cats available in the UK

Product	Active ingredient	Starts working	Lasts	Ticks?	Prescription?
Capstar	Nitenpyram	15–30 minutes	About 24 hours	No	No
Credelio CAT	Lotilaner	Within hours	1 month	Yes	Yes
Other prescription chewables	Varies	Varies	Usually 1 month	Some	Yes
Program oral suspension	Lufenuron	Does not kill adult fleas	1 month (stops eggs hatching)	No	Usually from vets

Product ranges change, so your vet may offer a different brand. The active ingredient on the box tells you how it works.

Capstar: fast-acting oral flea treatment for cats

Capstar tablets contain nitenpyram, which kills adult fleas on your cat extremely quickly, often within 30 minutes. It is ideal for:

• Knocking down a heavy infestation straight away.
• Rescue or stray cats brought into your home.
• Giving relief to an itchy cat while a longer-acting treatment starts working.
• Before a cat goes into a cattery or stays with family.

Because nitenpyram leaves the body within about a day, Capstar gives no lasting protection. Use it alongside a monthly flea treatment, not instead of one. You can give it daily for a short time if new fleas keep appearing, as directed on the pack.

Prescription monthly flea tablets for cats

Vets can prescribe chewable flea tablets for cats that kill fleas and ticks for a whole month. Lotilaner (Credelio CAT) belongs to the isoxazoline family, the same group of drugs as the active ingredients in Bravecto and several other prescription products. These drugs:

• Kill fleas quickly, usually before they can lay eggs.
• Kill ticks as well as fleas.
• Are not affected by bathing or swimming.
• Need to be given every month, ideally with food.

Isoxazolines have been linked to neurological side effects such as tremors or seizures in a small number of animals, so tell your vet if your cat has ever had a seizure.

Flea tablets vs spot-ons for cats

	Flea tablets	Spot-ons
Washes off?	No	Can be reduced by bathing in the first 48 hours
Residue on fur	None	Greasy patch for 1–2 days
Needs fleas to bite	Yes	Often kills on contact
Ease of giving	Hard for cats that refuse tablets	Easy for most cats
Possible side effects	Occasional vomiting	Skin irritation, drooling if licked
Also covers worms	Usually not	Some prescription spot-ons do

If your cat is impossible to pill, a spot-on such as Advocate or a collar may be easier. If your cat reacts to spot-ons, a tablet is a good alternative.

How to give a cat a flea tablet

Most flea tablets for cats are small and many are flavoured. Try these methods, from easiest to hardest:

1. Offer it as a treat. Some flavoured chewables are eaten willingly.
2. Hide it in food. Wrap it in a small piece of soft treat, pâté or a pill pocket. Give a "decoy" treat first and another afterwards.
3. Give it directly. Hold your cat's head from above, tilt it back gently, open the lower jaw with a finger and drop the tablet at the back of the tongue. Close the mouth and stroke the throat.
4. Use a pill popper if you're worried about being bitten.

Our step-by-step guide on how to give a cat a pill includes the towel wrap method for wriggly cats. Always follow a dry tablet with a little water or wet food, as tablets that stick in the throat can cause irritation.

Oral flea treatment for kittens

Capstar can be used in kittens from 4 weeks of age that weigh at least 1 kg. Monthly prescription tablets have their own minimum age and weight, usually around 8 weeks and 0.5 kg or more. For tiny kittens, daily combing with a fine flea comb and treating the mother cat is often the safest approach. Our cat worming guide explains how to worm kittens at the same time, since kittens with fleas often have tapeworms too.

Flea injection for cats

An injection of lufenuron (Program injectable) is given by vets every six months. It doesn't kill adult fleas but makes flea eggs unable to hatch, so it is used to prevent a population building up. It is usually combined with a product that kills adult fleas. It can be a good option for cats that are very difficult to treat at home.

Side effects of flea tablets for cats

Most cats have no side effects. Possible reactions include:

• Vomiting or reduced appetite, especially if given on an empty stomach.
• A short burst of scratching or restlessness after Capstar, as fleas die and leave the skin.
• Diarrhoea (uncommon).
• Rarely, tremors, wobbliness or seizures with some drugs.

Contact your vet if your cat vomits repeatedly, seems unwell or shows any neurological signs. If your cat vomits within an hour of a tablet, ask your vet whether the dose should be repeated.

Which cats are best suited to flea tablets?

Oral flea treatments are a particularly good choice for:

• Cats with sensitive skin that have reacted to a spot-on with redness, itching or hair loss.
• Homes with babies or young children who stroke and cuddle the cat, since there is no residue on the coat.
• Cats that are bathed regularly, such as Sphynx and other hairless breeds, which need frequent skin cleaning. See our Sphynx cat guide.
• Multi-cat households where cats groom each other and might lick a spot-on off a companion.
• Cats with long, thick coats where it is hard to reach the skin with a spot-on.

Flea tablets are less suitable for cats that are impossible to pill, cats with a history of vomiting or seizures, and very young kittens. In those cases, ask your vet about the safest alternative.

Do I still need to treat my home?

Yes. Flea tablets kill fleas on your cat, but eggs, larvae and pupae in carpets and soft furnishings keep hatching for weeks. Vacuum daily, wash bedding at 60°C, use a household flea spray containing an insect growth regulator, and treat every pet. Dogs need their own dog-licensed product: our guide to whether dogs get cat fleas explains why.

Cat flea tablets UK: cost

Capstar costs roughly £2 to £4 per tablet, usually sold in packs of 3 or 6. Monthly prescription chewables typically cost £8 to £15 per tablet, plus a consultation or prescription fee. Many practice health plans include monthly flea tablets, which spreads the cost. You can check other routine costs in our guide to cat vaccination costs.