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Stronghold Flea Treatment
Stronghold Flea Treatment is a prescription-only spot-on solution for cats and dogs, formulated with the active ingredient selamectin. Selamectin targets the parasite’s nervous system at the source, delivering a full month of protection against fleas, ear mites, sarcoptic mange and certain worms from a single application — dispensed only against a valid veterinary prescription.
Applied directly to the skin rather than given orally, Stronghold offers a refined alternative for pets that are difficult to tablet. At Ashcroft 4 Pets, we stock the complete Stronghold range for cats and dogs, across every weight band.
Browse the range below to find the right strength for your pet.
STRONGHOLD
Stronghold Spot-On
Prescription flea and worm treatment for cats and dogs
Stronghold Flea Treatment is a prescription spot-on solution containing selamectin that treats and prevents fleas, treats ear mites and sarcoptic mange, and helps prevent heartworm disease in cats and dogs — all from a single monthly application. Available against a valid UK prescription.
What Stronghold actually treats
| Fleas | Heartworm | Ear mites |
|---|---|---|
| Kills adult fleas and stops eggs developing into pupae. One application lasts the full month | Prevents heartworm disease. Monthly application protects against infection from imported mosquitoes. | Treats Otodectes mites (ear mites) in both cats and dogs |
| Roundworm & hookworm | Biting lice & mange | Ticks |
| Treats adult roundworms & some hookworms. Does not cover tapeworm. | Treats lice, mange mites, and sarcoptic mange in dogs and cats | Removes ticks. Stronghold does not prevent ticks from attaching |
Find your pet's exact dose below, just as your vet would.
Shop by Pet & Weight
Prescription palatable treatment
Stronghold for Cats
| Product | Weight band | Price |
|---|---|---|
| Stronghold 15mg for Puppies & Kittens | Cats & dogs < 2.5 kg | [XX.XX] |
| Stronghold 30mg for Cats | 2.6–7.5 kg | [XX.XX] |
| Stronghold 60mg for Large Cats | 7.6–10 kg | [XX.XX] |
Stronghold for Dogs
| Product | Weight band | Price |
|---|---|---|
| Stronghold 30mg for Tiny Dogs | 2.6–5.0 kg | [XX.XX] |
| Stronghold 60mg for Small Dogs | 5.1–10 kg | [XX.XX] |
| Stronghold 120mg for Medium Dogs | 10.1–25 kg | [XX.XX] |
| Stronghold 240mg for Large Dogs | 20.1–40 kg | [XX.XX] |
| Stronghold 360mg for XL Dogs | 40.1–60 kg | [XX.XX] |
Always weigh your pet before ordering — the correct pipette size depends on accurate weight, not just size estimate.
Stronghold vs Stronghold Plus vs Frontline Plus
The question we get asked most often before a prescription is filled — here's the honest comparison.
| Coverage | Stronghold | Stronghold Plus (cats) | Frontline Plus |
|---|---|---|---|
| Fleas | Yes | Yes | Yes |
| Ticks | No | Yes | Yes |
| Heartworm prevention | Yes | Yes | No |
| Ear mites | Yes | Yes | No |
| Roundworm/ hookworm | Yes | Yes | No |
| Prescription required | POM-V | POM-V | No |
For general guidance only. Your vet's prescription reflects your pet's individual health and risk factors — always follow what's prescribed rather than switching based on a comparison table.
Additional Information
The cap colour key
Every Stronghold (selamectin) pipette is colour-coded to its dose. If your vet has told you which colour to use, you're already most of the way there.
Rose
15mg — up to 2.5kg
Violet
30mg — up to 5kg
Brown
60mg — up to 10kg
Red
120mg — up to 28kg
Green
240mg — up to 48kg
Plum
360mg — up to 68kg
Rose
15mg — up to 7.5kg
Blue
45mg — up to 7.5kg
Taupe
60mg — up to 10kg
*Always confirm the correct pipette colour and weight band for your pet with your vet or our pharmacy team before use.
Can I use any Stronghold pipette colour for my pet?
No. Each pipette size is matched to a specific weight bracket for cats or dogs, with enough selamectin in it to provide at least 6 mg for every kilogram the animal weighs. That's why pipette size and colour aren't interchangeable — each is designed for a specific weight range, not a generic dose that suits every pet.
Safety information
Stronghold is a prescription medicine. Here's what that means in practice and what the datasheet actually says.
POM-V Prescription-only medicine — vet. Every order is checked against a valid prescription before dispensing.
Do not use if
- Your pet is under 6 weeks old
- Your cat is unwell, debilitated, or underweight for its size and age
Reported side effects, by frequency
| Rare | Temporary hair clumping or a little white powder at the application site, usually gone within 24 hours |
| Very rare | Application site irritation; neurological signs including seizures, consistent with this drug class |
Pregnancy & breeding
- Can be used in pregnant and lactating cats and dogs, and in breeding animals, under veterinary guidance.
This is general guidance and does not replace your vet's advice. Always follow the instructions on your pet's specific prescription label.
Questions pet owners actually ask
Can I buy Stronghold without a prescription?
No. Stronghold is a POM-V medicine, so it can only be dispensed against a valid, in-date prescription from your vet. We can help you upload or arrange your prescription during checkout.
Does Stronghold treat ticks?
No, standard Stronghold does not treat or prevent ticks. If tick cover is needed, ask your vet about Stronghold Plus (cats) or an alternative tick treatment.
How long does Stronghold last?
One application protects against fleas for around four weeks. It should be reapplied monthly for ongoing flea, heartworm and mite prevention.
Is Stronghold the same as Revolution?
Stronghold and Revolution contain the same active ingredient, selamectin, and work the same way. Revolution is the name used for this product in the US and some other markets; Stronghold is the UK name.
Can I bathe my pet after applying Stronghold?
Yes, but wait at least 2 hours after application. Bathing before this may reduce how well it's absorbed.
What if I treat one pet in the house but not others?
Fleas can move between pets and around your home, so vets generally recommend treating all cats and dogs in the household together to fully break the flea life cycle.
Does Stronghold treat tapeworms?
No. Stronghold is not effective against tapeworms in dogs.
Does Stronghold treat hookworms?
No, not in dogs. Hookworm treatment with Stronghold is only indicated for cats.
Does Stronghold treat heartworm if my dog already has it?
No. Stronghold prevents heartworm disease but is not effective against an existing adult heartworm infection. If you suspect your dog may already have heartworm, speak to your vet before starting treatment.
"The most common reason Stronghold doesn't seem to work isn't the product — it's the dose. If your pet's weight has changed since their last prescription, tell us before we dispense, so we can check the dose with your vet."
Dr Brian Faulkner BSc(Hons), BVM&S, GPCert(SAP), GPCert(SAM), MBA, MSc(Psych), FRCVS — Ashcroft 4 Pets
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