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Activyl (Indoxacarb) for Dogs

By | Last Updated: 22nd February 2023

What is Activyl

Activyl is a spot-on topical formulation for pets with the active ingredient indoxacarb, an antiparasitic agent that helps in killing ticks, fleas as well as their eggs and larvae, breaking their life cycle, and preventing reinfestation [1, 2, 4].

What is Activyl used for in dogs

Activyl is used for prevention and treatment of parasitic attacks and the management of allergic dermatitis (allergic reactions) associated with flea and tick bites. A recent study showed that flea infestation in pets could be effectively controlled by a single application of Activyl [5, 6].

Quick Information

Activyl for Dogs

Generic name: Indoxacarb

Brand name: Activyl®

Type: Monthly spot-on tick and flea treatment [4]

Active ingredient: Activyl Spot-On: Indoxacarb [3]

Activyl Tick Plus: Indoxacarb, Permethrin [7]

Availability: Prescription medication registered for veterinary use [3]

Who is it used for: Activyl Spot-On: Cats and kittens, dogs and puppies [1]

Activyl Tick Plus: Dogs and puppies [2]

Form: Topical solution [3]

How does it work in your dog

Once Activyl is applied to your dog’s skin, it spreads through its coat [2, 3]. Instead of reaching its bloodstream, indoxacarb works by bioactivation, a mode of action that changes Activyl into a highly insecticidal substance once it comes in contact with the amidase and esterase enzymes in the body of the tick or flea [3, 4]. So, when the susceptible insect comes in contact with the medicine, its brain, and ventral nerve cord stop functioning, eventually killing it [2, 3].

Is Activyl safe for dogs

There are a few instances where Activyl may cause adverse reactions, including:

  • Dogs weighing less than 4 pound and puppies under eight weeks of age [4].
  • Pregnant, or nursing dogs and those meant for breeding [7].

Side effects

  • Temporary itchiness, hair loss, or inflammation at the application site [6].
  • Drooling, vomiting, salivation, squinting, or shaking may occur if your dog licks the affected area straight after the application of Activyl [3, 6].

These effects are rare, and even when they occur, they usually disappear within a few hours to days without treatment [8]. However, if the symptoms persist, make sure to consult your vet.

Possible drug interactions

Talk to the vet if your dog or puppy has any known allergic reaction to any drugs, or if it is already receiving any medications or supplements [3].

Activyl dosage for dogs

Be sure to follow dosage as instructed by the vet and read the label directions before use. The normal dose is 15 mg/kg or 0.077 ml/kg of your dog’s body weight [8]. Each ml of the medication contains 195mg of indoxacarb. You need to get the right size applicator according to how big your dog is.

Applicator Size Volume of Dose (ml) Indoxacarb Content (mg)
Activyl spot on/tick plus for very small dogs and puppies (4-14 lb) 0.51 100
Activyl spot on/tick plus for small dogs (14-22 lb) 0.77 150
Activyl spot on/tick plus for medium dogs (22-44 lb) 1.54 300
Activyl spot on/tick plus for large dogs (44-88 lb) 3.08 600
Activyl spot on/tick plus for extra-large dogs (88-132 lb) 4.62 900

How to apply Activyl on dogs

How to Apply Activyl Spot on for Dogs

  • Hold the applicator in an upright position with your face turned away, and break its tip by bending and folding into itself [2, 7].
  • For easy application, let your dog stand up. Part its coat and apply between its shoulder blades by placing the tip of the applicator against the skin [2, 7].
  • For medium and large dogs, apply the content evenly at 2-4 spots along your dog’s back, at different sites between its shoulder blades and the base of its tail [7]. For small dogs, apply at two spots, one between the shoulder blades and another above the tail, while for puppies and toy dogs, just one spot application would be enough.
  • Use the entire content by squeezing the applicator firmly but avoid applying an excess amount at a particular spot [2, 7].

You can reapply after a month, but never use more than one applicator within 30 days [3, 4]. Avoid grooming, stroking, bathing or shampooing your dog for 2 days after the treatment until the medication dries off completely [6].

How long does it take to work

The fast-acting topical solution starts killing fleas and ticks within 8 hours of applying, remaining effective for 30 days [4]. Because of its quick-drying, waterproof nature, it continues fighting against parasites even after bathing. Moreover, exposure to sunlight does not reduce its efficacy [7].

Adverse reactions in humans

Activyl is possibly harmful when absorbed through the skin, inhaled, or ingested. Skin or eye contact may cause irritation and allergic reaction while ingestion may be hazardous to the respiratory and central nervous system [9].

In case of accidental exposure, immediately rinse eyes with water or wash your skin with soap and water. If irritation or symptoms persist, consult a doctor or contact poison control center for advice [9].


    1. Activyl for Cats and Activyl for Dogs – US.activyl.com
    2. Activyl® Tick Plus for Dogs Only – US.activyl.com
    3. Indoxacarb (Activyl® Spot-On) for Dogs and Cats – Petplace.com
    4. ACTIVYL® SPOT-ON FOR DOGS AND PUPPIES – Merck-animal-health-usa.com
    5. Evaluation of indoxacarb and fipronil (s)-methoprene topical spot-on formulations to control flea populations in naturally infested dogs and cats in private residences in Tampa FL. USA – Ncbi.nlm.nih.gov
    6. Activyl – Ema.europa.eu
    7. Activyl TickPlus for Dogs and Puppies (over 4 lb and up to 11 lb) – Drugs.com
    9. SAFETY DATA SHEET Activyl® – Msd-animal-health.co.nz

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