Stronghold (Selamectin) Spot-On for Cats & Dogs – Flea, Heartworm, Mites & Worms | 3 Pipettes

What Is Stronghold?

Stronghold is a monthly spot-on (topical) solution containing selamectin as the active ingredient, manufactured by Zoetis. It is applied to the skin at the back of the neck once a month and provides broad-spectrum protection against fleas, heartworm, ear mites, roundworms, lice, hookworms (cats), and sarcoptic mange (dogs) — all from a single application.

Stronghold is the European brand name for the same product sold as Revolution in the United States. Same active ingredient, same manufacturer, same formula. If your vet has recommended Revolution and you’re searching for the equivalent, Stronghold is it.

Each pack contains 3 single-dose pipettes, providing 3 months of continuous monthly parasite protection.

What Makes Stronghold Different from Other Spot-Ons?

Most popular flea spot-ons — Frontline (fipronil), Seresto collar (imidacloprid + flumethrin), Advantage (imidacloprid) — only target external parasites (fleas and/or ticks). Stronghold is one of the very few topical spot-ons that also prevents heartworm disease through systemic absorption, and additionally treats internal parasites including roundworms in both cats and dogs.

This makes Stronghold a true multi-system parasite control product, not just a flea treatment.

What Does Stronghold Treat and Prevent?

In Both Cats and Dogs

• Flea treatment and prevention — kills adult fleas (Ctenocephalides spp.), prevents hatching of flea eggs, and kills flea larvae in the environment; one monthly application provides complete flea lifecycle disruption
• Flea Allergy Dermatitis (FAD) — monthly use as part of a FAD management strategy
• Heartworm prevention — prevents Dirofilaria immitis infection with monthly administration; does NOT kill existing adult heartworms
• Ear mites — treats Otodectes cynotis infestations; a single dose is typically sufficient (a follow-up check at 30 days is recommended in dogs)

In Cats Only

• Roundworms — treats adult Toxocara cati intestinal roundworm infections
• Hookworms — treats adult Ancylostoma tubaeforme intestinal hookworm infections
• Biting lice — treats Felicola subrostratus infestations

In Dogs Only

• Sarcoptic mange — treats Sarcoptes scabiei mange mite infestation; two consecutive monthly treatments are required to eliminate the mites completely
• Roundworms — treats adult Toxocara canis intestinal roundworm infections
• Biting lice — treats Trichodectes canis infestations

How Stronghold Works — The Selamectin Mechanism

Selamectin is a semi-synthetic avermectin-class macrocyclic lactone. After spot-on application, it is absorbed through the skin and distributed systemically throughout the body. It works by binding to glutamate-gated chloride ion channels in invertebrate nerve and muscle cells — channels that exist in insects, mites, and nematode worms but not in mammals.

By locking these channels open, selamectin causes an uncontrolled influx of chloride ions into the parasite nerve or muscle cell, leading to hyperpolarisation and permanent paralysis and death of the parasite. Because mammals lack these specific chloride channels, selamectin is highly selective for invertebrate parasites and has a very wide safety margin in dogs and cats.

Triple-Action Against Fleas

Stronghold is one of the most comprehensive flea products available because it attacks the flea at three life stages simultaneously:

• Adulticidal: Kills adult fleas on the animal
• Ovicidal: Prevents viable flea eggs being laid; ovicidal activity lasts for 3 weeks after application
• Larvicidal: Debris from treated animals (shed skin, hair) kills flea larvae in the pet’s environment

This combination breaks the entire flea life cycle — not just killing what’s on the animal, but also eliminating the environmental reservoir that conventional products leave behind.

Systemic Heartworm Prevention

After skin absorption, selamectin distributes into the blood and tissues. Mosquito larvae (the transmitter of Dirofilaria immitis heartworm) die when they bite a treated animal. Monthly application maintains selamectin at protective levels in the bloodstream throughout the inter-dose interval. The terminal elimination half-life of selamectin is 8–11 days in cats and dogs respectively, meaning protective concentrations persist for the full 30-day period.

Important: Stronghold prevents heartworm infection but does NOT kill existing adult heartworms. All animals over 6 months of age living in heartworm-endemic regions should be tested for existing adult heartworm infection before starting any heartworm prevention programme.

Dosage — Colour-Coded Pipette Guide

The dose is based on body weight, delivering a minimum of 6mg/kg selamectin per application. Select the correct pipette by matching your pet’s weight to the colour code below. Apply the entire contents of one pipette per dose.

Cats

Dogs

Note: Dogs and cats under 2.5 kg use the same rose pipette (15mg). The 6% concentration is used for cats; the 12% concentration is used for most dog sizes for easier volume management.

How to Apply Stronghold — Step by Step

1. Do not apply to wet hair. The animal’s coat must be dry at the time of application
2. Remove the Stronghold pipette from its protective foil packaging
3. Hold the pipette upright; firmly depress the cap downward to puncture the applicator seal, then remove and discard the cap
4. Part the hair at the base of the neck, in front of the shoulder blades, to expose a small area of skin
5. Place the tip of the pipette directly on the skin and squeeze firmly to empty the entire contents in one spot
6. Do not massage the application site — rubbing spreads the product and reduces efficacy
7. Wash hands thoroughly with soap and water after application

⚠️ Critical Safety Rules

Fire Risk — Keep Away from Flames for 30 Minutes

Stronghold is highly flammable. The solvent base (isopropyl alcohol) is flammable until the application site is fully dry. Keep treated animals away from fires, lit candles, gas hobs, fireplaces, and all ignition sources for at least 30 minutes after application or until the hair coat is completely dry. Do not smoke while handling the product.

2-Hour Water Rule

Do not allow the animal to swim, be bathed, or get wet for at least 2 hours after treatment. After 2 hours, efficacy is not reduced by bathing, shampooing, or swimming — the selamectin has been absorbed and the topical carrier has dried. Do not allow treated animals to enter water courses (rivers, ponds) within 2 hours of treatment — selamectin is highly toxic to aquatic invertebrates.

Children and Treated Animals

On the day of treatment, children should not handle treated animals. Treated animals should not sleep with their owners on the day of application. Keep used applicator pipettes out of sight and reach of children.

Ear Mite Treatment — Do Not Apply Directly to the Ear Canal

Despite being used to treat ear mites, Stronghold is applied to the skin at the back of the neck only — never directly into the ear canal. The systemically absorbed selamectin reaches the ear canal via the bloodstream. Applying directly into the ear is incorrect and potentially harmful.

Minimum Age Requirements

• Dogs and puppies: from 6 weeks of age
• Cats and kittens: from 6 weeks of age (some references specify 8 weeks for kittens; use with caution in very young animals)
• Do not use in cats that are debilitated, underweight, or suffering from concurrent serious illness

Safety in Special Populations

• Pregnant and lactating females: Stronghold has been proven safe for use in breeding, pregnant, and lactating cats and dogs. Monthly treatment of pregnant/lactating animals also helps protect litters from flea infestation up to 7 weeks of age.
• Collie and ivermectin-sensitive breeds: Selamectin has been tested at 5× the recommended dose in ivermectin-sensitive Collies with no adverse effects observed. Stronghold does not share the toxicity risk of ivermectin in MDR1/ABCB1 gene-deficient dogs at therapeutic doses.
• Dogs with adult heartworm infection: Stronghold may be safely administered to animals already infected with adult heartworms, but it will not eliminate the adult worms. Test first and implement appropriate adulticidal treatment under veterinary supervision.

Contraindications

• Do not use in animals under 6 weeks of age
• Do not use in cats that are debilitated, underweight, or suffering from significant concurrent disease
• Do not apply to broken, damaged, or inflamed skin
• Do not administer orally or by injection — spot-on use only
• Do not use if the animal is known to be hypersensitive to selamectin

Side Effects

• Temporary hair clumping or white powder at application site (rare) — normal; resolves within 24 hours; does not affect efficacy or safety
• Mild, transient alopecia at application site in cats (rare) — self-resolving; symptomatic treatment occasionally needed
• Brief hypersalivation in cats (rare) — if significant licking occurs; resolves spontaneously
• Focal skin irritation at application site (rare) — normally self-resolving
• Reversible neurological signs including seizures (very rare) — as with other macrocyclic lactones; discontinue and seek veterinary attention immediately if neurological signs occur

Treatment Duration by Parasite

Stronghold vs Frontline vs Advocate — Which Is Right?

When to choose Stronghold: You want flea control AND heartworm prevention AND ear mite treatment in one product. Particularly valuable in heartworm-endemic regions (Southern Europe, USA, Asia, Africa, Australia). Also ideal for Collies and MDR1-sensitive breeds where moxidectin (in Advocate) carries more risk.

When to choose Frontline: Tick prevention is the primary concern, or you need an inexpensive flea-only product.

When to choose Advocate: You also need lungworm (Angiostrongylus) coverage — Stronghold does not cover lungworm; Advocate does.

Storage

• Store below 30°C
• Store in the unopened foil packaging in a dry place — the foil pouch protects against moisture and light
• Do not refrigerate
• Shelf life of the sealed product: 3 years
• Highly flammable — keep away from heat, sparks, and open flames in storage

Frequently Asked Questions

Is Stronghold the same as Revolution?

Yes. Revolution (sold in the USA, Canada, Australia) and Stronghold (sold in Europe and the UK) are the same product — same active ingredient (selamectin), same manufacturer (Zoetis), same formula. The different names are simply regional market branding. If your vet prescribed Revolution and you’re buying from an international pharmacy, Stronghold is the equivalent product.

Can I use Stronghold to treat ear mites if my cat is shaking their head?

Yes — but apply it to the skin at the back of the neck, not into the ear. Stronghold reaches the ear canal systemically via the bloodstream after skin absorption. You should also gently clean visible debris from the external ear canal before treatment. A single dose usually resolves ear mite infestations in cats; dogs may need a follow-up check 30 days later and occasionally a second treatment.

My dog has sarcoptic mange. How many treatments does Stronghold need?

Two consecutive monthly applications are required for sarcoptic mange in dogs. One dose is insufficient to eliminate all mite life stages reliably. Apply on day 1 and then again 30 days later. If signs persist after two treatments, reassess diagnosis and consult your veterinarian.

My cat licked the application site. Is this dangerous?

Brief hypersalivation may occur in cats if significant licking happens — this is related to the isopropyl alcohol solvent carrier rather than the selamectin itself. Apply the product to the correct spot at the base of the neck (where the cat cannot easily reach) and monitor. Hypersalivation is transient and self-resolving. If the cat shows any signs beyond transient hypersalivation, contact your vet.

Can Stronghold and a flea collar be used together?

No significant interactions between Stronghold and routinely used veterinary products were observed in field testing. However, combining products is generally unnecessary when Stronghold already provides full flea lifecycle coverage. Discuss with your veterinarian if additional tick coverage is required (e.g., combining with a tick-specific collar).

Related products: Effipro Duo Spot-On (Fipronil + Permethrin) – tick-focused alternative | Advocate (Imidacloprid + Moxidectin) – includes lungworm coverage