When using Revolution (selamectin) to control fleas, the main issue for concern is whether or not cats will be exposed to an excess of selamectin. Cats are individuals, just like people, and some cats handle medications better than others. You should always monitor your cat after applying any topical medication (Revolution for pets, Advantage Multi (imidacloprid + moxidectin) Topical Solution for Dogs and Cats ) including Revolution for pets.
If at any point you see signs that may indicate exposure of your cat to an excess of the medication (see below), or if you see nothing but drowsiness, you should bathe your cat with mild dishwashing liquid soap using a sponge – do this as soon as possible after noticing that something isn’t quite right.
What happen if cat is exposed to excess selamectin
Signs of exposure to excess selamectin could be central nervous system signs such as tremors or seizures, or signs of skin irritation ( redness, itchiness, rashes, etc.). If your cat shows any sign of a problem after application, bathe it with mild dishwashing liquid soap and rinse thoroughly.
This should help rid your pet of the excess medication on its coat. Revolution flea control is considered safe to use in conjunction with topical spot-on treatments, oral medications, and collars for dogs provided that they are administered at different points of time – however, if you notice any sign that concerns you the following application then you should contact your vet for advice.

How long does Revolution for pets take to work?
It is a common question to ask something like “how long does Revolution for pets take to work?” in regards to killing fleas, treating worms, or preventing heartworm. The truth is that the actual time varies from drug to drug and from animal to animal – for example, some oral medications which kill parasites can take 4-6 weeks before they have any significant effect on adult worms that are present in an animal at the time of treatment.
Other drugs such as Revolution for pets only require a single dose to affect adult fleas for months – this timeframe can last up until 6 months or more! The bottom line is that it’s impossible to predict how long a given medication will be effective without knowing what kind of parasite we’re dealing with, the drug in question, and the dose administered.
When using Revolution for pets on cats it is important to be aware of these things:
Cats can suffer neurological side effects if given an overdose of selamectin, this includes but is not limited to wobbling, drowsiness, or incoordination.
Some studies have found that certain breeds are more sensitive than others. The Maui Island Studies conducted by Pfizer in 2004 concluded that high doses of Selamectin can treat normal doses in cats without issue however when higher than recommended doses were given tremors and convulsions were observed in some animals.
The abstract from this study concludes with the following statement: “Selamectin is safe for topical use on cats at the recommended minimum dosage of 6mgkg (6-12mgkg) monthly starting at 8 weeks of age, with no evidence of adverse effects observed up to a maximum dose of 18mgkg (18-24mgkg).”