I have heard of people successfully doing the calculations on splitting up the "large dog" version of Revolution to dose a bunch of cats cheaply. I am thinking another cost-effective but easier approach for two "medium" cats would be to split a "large cat" dose exactly in half.

Can anyone confirm that the concentrations are the same and the volume is precisely double for the medium and large cat formulas?

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    Welcome to Pets.SE! Please take the tour, it only takes a minute. And could you please edit your question to add a link to the manufacturers homepage or a product information page? Googling for "Revolution" returns too many unrelated results.
    – Elmy
    Apr 1, 2021 at 5:42
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    I assume it is this company, because of the additional mentioned "selamectin" from this old question Apr 1, 2021 at 11:30
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    It's one of the most common flea treatments in use for cats or dogs, didn't think that was necessary but sure
    – sinthome
    Apr 1, 2021 at 15:11
  • Only for my interest: is it "the most common" used worldwide or specific for the area you come from? Apr 2, 2021 at 16:00
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    Couldn't tell you, but it is held in high regard in the US by all the vets I've talked to. I've had much better success than with competing flea treatments, so it is now my preference.
    – sinthome
    Apr 2, 2021 at 16:17

2 Answers 2


According to the prescribing information sheet:

The recommended minimum dosage is 2.7 mg selamectin per pound (6 mg/kg) of body weight and 0.45 mg sarolaner per pound (1 mg/kg) of body weight.

Administer the entire contents of a single tube (or two tubes in combination for cats weighing over 22 pounds) of REVOLUTION PLUS topically in accordance with the following table.

Body Weight (lbs) Tube Cap Color Tube Volume (mL) Selamectin (mg/tube) Sarolaner (mg/tube)
2.8 - 5.5 gold 0.25 15 2.5
5.6 - 11 orange 0.5 30 5
11.1 - 22* green 1 60 10

*Cats over 22 lbs should be treated with the appropriate combination of tubes.

That confirms that the dosage for cat X is exactly half s much as for a cat weighting twice as much as cat X.

Example calculation: Cat A = 5 lb, Cat B = 10 lb

If both got a single dose, they would get one gold and one orange one.
Both cats combined (15 lb) should get a green dose split in two.

If both cats combined weight more than 20 lb, you need 2 doses anyways.

The problem is that you're not a robot and probably can't divide the dosage perfectly. I suggest treating the bigger cat first because you'll probably squeeze more of the product out of the tube at the first squeeze.

You should also apply the second dose as quickly as possible. Because of the alcohol content, the solution dries very quickly. If you wait half an hour to apply the second dose, the dilution of the solution changes and the second cat might get less of the active ingredients onto their skin.

  • This is great, thank you. I have two cats that both weigh 10lbs each, so a simple split in half should be ideal. I was thinking about getting a small syringe to help administer it accurately.
    – sinthome
    Apr 2, 2021 at 16:14

I'm not a veterinarian, so I can't give medical advice. However, I can share some information that I've found about splitting Revolution doses for cats.

About the concentration of selamectin in the Revolution products for medium and large cats. If the concentration of the active ingredient is indeed the same in both the medium and large cat formulas, and the only difference is the volume of the medication (0.5 mL in the medium cat formula and 1.0 mL in the large cat formula), then it may be possible to split the dose safely.

However, even in this case, I would still strongly recommend consulting with a veterinarian before attempting to split the dose. Your veterinarian can confirm that this is a safe and appropriate approach for your specific cats, taking into consideration their individual health status and any potential risks or variations that may apply to your pets. Veterinarians have the expertise to ensure that your cats receive the correct treatment and dosage for their needs, even when adjusting medication volumes.

This means that it is possible to split a large cat dose of Revolution exactly in half to dose two medium cats. However, it is important to be precise when splitting the dose, as even a small amount of overdose can be harmful to cats.

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    Hello! Can you offer some sources to help back up your information? This is a well-written answer, which could be a great answer with the appropriate references.
    – Allison C
    Oct 5, 2023 at 13:21

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