What is a Generic Drug?

A generic drug is a copy of the brand-name drug with the same dosage, safety, strength, quality, consumption method, performance, and intended use. Before generics become available on the market, the generic company must prove it has the same active ingredients as the brand-name drug and works in the same way and in the same amount of time in the body.

The only differences between generics and their brand-name counterparts is that generics are less expensive and may look slightly different (eg. different shape or color), as trademarks laws prevent a generic from looking exactly like the brand-name drug.

Generics are less expensive because generic manufacturers don't have to invest large sums of money to develop a drug. When the brand-name patent expires, generic companies can manufacture a copy of the brand-name and sell it at a substantial discount.

Comfortis Chewable Tablets (Spinosad)


Comfortis Chewable Tablets (Spinosad)

Prescription Required

Dog 5-10lbs Cats 4.1-6lbs (140mg)

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  • Product Details


    Comfortis flea pill for dogs

    COMFORTIS (Spinosad) chewable tablets is a veterinary medicine that may be prescribed by or on the order of a licensed veterinarian. COMFORTIS chewable tablets may be used to treat and prevent flea infestations in dogs, puppies, cats, and kittens.

    COMFORTIS (Spinosad) contains the insecticides spinosyn A and spinosyn D. Spinosyn molecules work by activating nicotinic acetylcholine receptors in fleas. By activating these receptors, COMFORTIS causes involuntary muscle contractions in insects which causes paralysis and death.

    DOG: Weight (lbs) DOG: Weight (kg) Indicated on Pack CAT: Weight (lbs) Spinosad (mg) Sourced from UK
    5 - 10lbs 2.3 - 4.5kg 4.1 - 6lbs 140
    10.1 - 20lbs 3.9 - 6kg 6.1 - 12lbs 270 YES
    20.1 - 40lbs 9.1 - 18kg 12.1 - 24lbs 560
    40.1 - 60lbs 18.1 - 27kg 810
    60.1 - 120lbs 23.2 - 36kg 1620 YES

    Dogs: Recommended U.S. Minimum Dosage is 13.5mg/lb per month
    Cats: Recommended U.S. Minimum dosage is 22.5mg/lb per month


    Give COMFORTIS (Spinosad) to your animal orally once per month for as long as directed by your veterinarian. 

    COMFORTIS may be used on cats and kittens 14 weeks of age or older and 4.1 pounds or larger. COMFORTIS flea pill for dogs and puppies should be used on those 14 weeks of age or older and 5.0 pounds or larger. 


    The active ingredient in COMFORTIS is spinosad, which contains the factors spinosyn A and spinosyn D.

    COMFORTIS contains the active ingredients cellulose, croscarmellose, hydroxypropyl cellulose, magnesium stearate, silicon dioxide, and water.


    COMFORTIS (Spinosad) chewable tablets are not for human use.

    The safety of COMFORTIS in animals who are pregnant, breeding, or lactating has not been confirmed. Use COMFORTIS with caution in these animals.

    COMFORTIS can cause seizures in dogs. Use it with caution in puppies and dogs with a prior history of epilepsy.

    Side Effects

    COMFORTIS (Spinosad) may cause different adverse reactions depending on whether it is taken by your dog or your cat.

    Common adverse reactions in cats include:

    • Anorexia
    • Ataxia
    • Decreased appetite
    • Diarrhea
    • Hypersalivation
    • Lethargy
    • Pruritus
    • Vomiting
    • Weight loss

    COMFORTIS for dogs may cause the following adverse effects:

    • Anorexia
    • Ataxia
    • Cough
    • Decreased activity
    • Decreased appetite
    • Diarrhea
    • Excessive salivation
    • Hyperactivity
    • Hypersalivation
    • Incoordination
    • Increased appetite
    • Increased thirst
    • Itching
    • Lethargy
    • Pruritus
    • Redness of the skin
    • Seizures
    • Trembling
    • Vocalization
    • Vomiting
    • Weight loss


    1. Comfortis [package insert]. Greenfield, IN: Elanco; 2018.
    2. Flea Infestations, Healthline, January 26th, 2016. Retrieved May 2020.

    IMPORTANT NOTE: The above information is intended to increase awareness of health information and does not suggest treatment or diagnosis. This information is not a substitute for individual medical attention and should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. See your health care professional for medical advice and treatment.

    Product Code : 10283

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