About Stronghold Spot On
Further information about Stronghold Spot On

Stronghold is a colourless to yellow liquid medication that is applied topically to the skin on the back of the neck, once a month. Stronghold contains the active ingredient selamectin which is an insecticide. Stronghold comes in single use, plastic pipettes and is manufactured by Pfizer Ltd. The pipettes come in foil blister packs and each box contains 3 pipettes. Stronghold for cats is also available in boxes of 6 pipettes. Stronghold comes in a variety of sizes so that cats and dogs of various weights can be appropriately dosed.

Stronghold kills the adult fleas and stops any viable eggs being produced. It also kills the larval stages of the flea so it stops reproduction and breaks the flea life cycle. It is recommended to use Stronghold monthly to both treat and prevent fleas, most importantly through the flea season, starting treatment a month before the fleas become active. Stronghold is also used to treat and/or prevent a number of other parasites such as mites, roundworms and lice. The dosage of Stronghold needed to treat these parasites is as follows:

Roundworm: treated with a single dose of Stronghold. Hookworm: treated with a single dose of Stronghold. Lice: treated with a single dose of Stronghold Sarcoptic mange: treated with a single dose of Stronghold for 2 consecutive months Ear mites: treated with a single dose of Stronghold in cats, dogs may need a further dose after 30 days Heartworm: Year round monthly treatment with Stronghold, at least starting a month before and ending a month after exposure to mosquitoes

Although a single dose of Stronghold is sufficient to treat most of these parasites, it is recommended to use Stronghold year round as prevention as well as treatment.

Stronghold for dogs and Stronghold for cats can be used in animals over 6 weeks of age, including pregnant and lactating animals. Collies react badly to other drugs in the same class as selamectin but Stronghold has been shown to be safe in these Collies even at 5x the recommended dose. Occasionally mild and temporary hair loss may be seen at the site of application of Stronghold and if the animal licks off the Stronghold, hyper salivation may occur. Transient neurological signs may occur. You should not apply Stronghold to a wet animal and you should avoid your pet becoming wet for 2 hours after application. Stronghold is flammable to you should keep your pet away from fire for 30 minutes after application or until the hair is dry. Stronghold may leave a white powder on the hair after application but this should go within 24 hours.

Further Information About Dosage and Administration

Stronghold is applied to the skin on the back of the neck, monthly. To open the plastic pipette, hold it upright and push down on the cap as a small spike in the cap will then break the seal on the pipette. Part the hair and squeeze the entire contents of the pipette onto the skin just in front of the shoulder blades in a place that your pet won’t be able to lick it off. Avoid contact between Stronghold and your skin and wash your hands after applying Stronghold to your pet.

Stronghold is available in a range of sizes so that dogs and cats of varying weights can be given an appropriate dose. Each size of Stronghold has different colour packaging for ease of identification. A summary of which size of Stronghold is needed by various sizes of dog and cat is shown in the table below.
Weight (kg)
Stronghold size (mg)
Package Colour
< 2.5
2.6 - 5
5.1 - 10
10.1 - 20
20.1 - 40
> 40
Combination of pipettes
Weight (kg)
Stronghold Size (mg)
Packaging Colour
< 2.5
2.6 - 7.5
> 7.5
Combination of pipettes