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Genuine pet medicine
Stronghold Flea & Worm Treatment
Stronghold Spot-On by Zoetis is a prescription-only topical spot-on for cats and dogs, formulated with the active ingredient selamectin. It provides a month of protection against fleas, mites, and certain worms for both dogs and cats.
As a Registered Veterinary Retailer, Ashcroft 4 Pets offers the complete authentic UK range across all weight categories.
Browse the range below to find the right strength for your pet.
STRONGHOLD BRAND
Stronghold spot-on
Prescription flea and worm treatment for cats and dogs
Stronghold flea treatment is a prescription spot-on containing selamectin. One monthly application treats and prevents fleas, treats ear mites, biting lice and roundworms, and prevents heartworm disease in cats and dogs. It also treats sarcoptic mange in dogs and hookworms in cats. Available against a valid UK veterinary prescription.
What Stronghold treats
| Fleas | Heartworm | Ear mites |
|---|---|---|
| Kills adult fleas, flea eggs and larvae. One application protects for a month. | Prevents heartworm disease with monthly use. Not effective against adult heartworms. | Treats ear mites (Otodectes cynotis) in cats and dogs. |
| Roundworm & hookworm | Biting lice & mange | Ticks |
| Treats adult roundworms in cats and dogs, and adult hookworms in cats only. Doesn't cover tapeworm. | Treats biting lice in cats and dogs, and sarcoptic mange in dogs only. | Not licensed for ticks. Stronghold doesn't kill, treat or prevent ticks. For cats, Stronghold Plus treats ticks. |
Source: Stronghold spot-on solution for cats & dogs (GB) datasheet, NOAH Compendium
Find your pet's pipette below by weight.
Shop by pet and weight
Prescription spot-on treatment
Stronghold Plus for cats
For cats from 8 weeks old and at least 1.25 kg. Choose the pipette by your cat's weight, up to 10 kg.
| Product | Weight band | Price |
|---|---|---|
| Stronghold Plus 15 mg/2.5 mg for small cats | 1.25 to 2.5 kg | Check live prices |
| Stronghold Plus 30 mg/5 mg for medium cats | Over 2.5 to 5 kg | Check live prices |
| Stronghold Plus 60 mg/10 mg for large cats | Over 5 to 10 kg | Check live prices |
Stronghold for cats
For cats from 6 weeks old. Choose the pipette by your cat's weight, up to 7.5 kg. For cats over 7.5 kg, ask your vet which pipette or combination they need.
| Product | Weight band | Price |
|---|---|---|
| Stronghold 15 mg for kittens and cats (rose cap) | Up to 2.5 kg | See the prices |
| Stronghold 45 mg for cats (blue cap) | 2.6 to 7.5 kg | See the prices |
Stronghold for dogs
For dogs from 6 weeks old. Choose the pipette by your dog's weight, up to 60 kg. Dogs over 60 kg need a combination of pipettes, prescribed by your vet.
| Product | Weight band | Price |
|---|---|---|
| Stronghold 15 mg for puppies (rose cap) | Up to 2.5 kg | Check live prices |
| Stronghold 30 mg for toy dogs (violet cap) | 2.6 to 5.0 kg | Check live prices |
| Stronghold 60 mg for small dogs (brown cap) | 5.1 to 10.0 kg | Check live prices |
| Stronghold 120 mg for medium dogs (red cap) | 10.1 to 20.0 kg | Check live prices |
| Stronghold 240 mg for large dogs (green cap) | 20.1 to 40.0 kg | Check live prices |
| Stronghold 360 mg for extra-large dogs (plum cap) | 40.1 to 60.0 kg | Check live prices |
Always weigh your pet before ordering. The right pipette depends on your pet's current weight, not their size or breed.
Stronghold vs Stronghold Plus vs Frontline Plus
The question we get asked most often before a prescription is filled.
| 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 | Yes | Yes | No |
| Hookworm | Cats only | Yes | No |
| Prescription required | Yes (POM-V) | Yes (POM-V) | No |
For general guidance only. Your vet's prescription reflects your pet's health and risk factors. 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.
Dogs
Rose
15 mg, up to 2.5 kg
Violet
30 mg, 2.6 to 5.0 kg
Brown
60 mg, 5.1 to 10.0 kg
Red
120 mg, 10.1 to 20.0 kg
Green
240 mg, 20.1 to 40.0 kg
Plum
360 mg, 40.1 to 60.0 kg
Cats
Rose
15 mg, up to 2.5 kg
Blue
45 mg, 2.6 to 7.5 kg
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 is matched to a weight band for cats or dogs, with enough selamectin to give at least 6 mg for every kilogram your pet weighs. Pipette sizes and colours aren't interchangeable.
Safety information
POM-V Prescription-only medicine, veterinary. Every order is checked against a valid prescription before dispensing.
Do not use
- On cats or dogs under 6 weeks old
- On cats that are ill, weak or underweight for their size and age
- By mouth or injection. Apply to the skin only, on a dry coat
Reported side effects, by frequency
| Rare | Temporary hair clumping or a little white powder at the application site, usually gone within 24 hours. In cats, mild short-lived hair loss at the spot. |
| Very rare | Nervous signs, including fits, which are reversible. In cats, short-lived skin irritation at the spot. |
Pregnancy and breeding
- Can be used in pregnant, lactating and breeding cats and dogs.
This is general guidance and doesn't replace your vet's advice. Always follow the instructions on your pet's prescription label.
Questions pet owners ask
Can I buy Stronghold without a prescription?
No. Stronghold is a POM-V medicine and can only be supplied against a valid, in-date prescription from your vet. You can upload your prescription during checkout.
Does Stronghold treat ticks?
No. Stronghold isn't licensed to kill, treat or prevent ticks. For cats, your vet may prescribe Stronghold Plus. For dogs, ask about a separate tick treatment.
How long does Stronghold last?
One application treats and prevents fleas for a month. It's applied monthly for fleas and heartworm prevention. Ear mites, biting lice and roundworms need a single dose, and sarcoptic mange in dogs needs one dose a month for two months.
Can I bathe my pet after applying Stronghold?
Yes, from 2 hours after treatment, with no loss of effect. Don't apply it to a wet coat.
Does Stronghold treat ear mites?
Yes, in cats and dogs, with one dose applied to the neck, never into the ear. A vet check 30 days later is recommended, as some pets need a second treatment.
Does Stronghold treat tapeworms?
No. Tapeworms aren't covered in cats or dogs.
Does Stronghold treat hookworms?
In cats only. It treats adult intestinal hookworms in cats, but not in dogs.
Does Stronghold treat heartworm if my dog already has it?
No. Stronghold prevents heartworm disease but isn't effective against adult heartworms. Dogs 6 months or older in areas where heartworm exists should be tested before starting, and your vet will advise on this.
"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, and 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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