# Stronghold (120mg) Spot-On for Medium Dogs 

> Stronghold 120mg is a topical spot-on treatment specifically formulated for medium-sized dogs weighing 10.1kg to 20kg (22–44 lbs) — treating fleas, mites, and worm parasites, and preventing fleas and heartworm. Applied to the skin only; not designed for oral or injectable use.  Kills and prevents...

*Source: https://ashcroft4pets.co.uk/dog-medications/stronghold-120mg-spot-on-for-medium-dogs/*

Supplied exclusively on prescription. Issued only after veterinary verification and approval.

Stronghold 120mg Spot-On Solution, prescribed for medium dogs (10.1–20kg)

Stronghold 120mg is a prescription-only, colourless-to-yellow spot-on solution specifically formulated for medium dogs weighing between 10.1kg and 20kg. Applied directly to the skin at the back of the neck, this medication requires a monthly application to provide ongoing, continuous protection against fleas and heartworm.

For the treatment of roundworms, biting lice, and ear mites, a single dose is typically sufficient to clear the infestation. However, a veterinary re-check is highly recommended approximately 30 days after treating ear mites, as some dogs may need a second application.

Importantly, when treating sarcoptic mange, owners must administer a single dose for two consecutive months to ensure full clearance of the mites — making it the only condition listed that strictly requires a follow-up dose to prevent under-treating the infection.

From the [datasheet](https://www.noahcompendium.co.uk/?id=-485261), for dogs specifically, Stronghold does not treat ticks, tapeworms, or hookworms — and it prevents heartworm rather than treating an existing infection. If your dog already has heartworm, speak to your vet before starting treatment.

**Worth Knowing:** *This particular strength (Stronghold 120mg) is built for one specific weight band: dogs between 10.1kg and 20kg — think Cocker Spaniel, Springer Spaniel, or a smaller Border Collie. You’ll know you’ve got the right pipette because the cap is red and it delivers exactly 1.0ml, containing 120mg of selamectin (a 12% concentration). Get a smaller or bigger dog onto this dose, and you’re either under-protecting them or giving more than they need, so the weight band strictly matters here — not just a label on the box.*

 

**Each 1.0ml pipette contains:**

**Active Substance:** Selamectin 120mg

**Excipients:** Butylated Hydroxytoluene 0.08%

**Legal Category:**

**POM-V** |
 [Stronghold for Medium Dogs](https://www.vmd.defra.gov.uk/ProductInformationDatabase/)

**Please note:** Due to current regulations, we are unable to dispatch veterinary medicines to Northern Ireland.