Contributors: Omowumi Ajao, Dieter Barutzki, Maggie Fisher, Linda Horspool, Rosanna Marsella

 Species: Feline   |   Classification: Miscellaneous


  • Cats in different circumstances have different likelihoods of carrying and or acquiring fleas. For example, an indoor cat or sole cat in a household with no other pets locally, that has no existing flea problem may be considered low risk. In contrast, a cat that lives in a multipet household in an urban area may have substantial risk of having an on-going established flea infestation in the household and a substantial risk of re-infection from the outdoor environment, particularly when the weather is warm.
  • For the first situation, in the absence of fleas, then regular monitoring may be sufficient to ensure that fleas do not establish on the animal. For the second animal it may be necessary to carry out year-round flea control. Likewise, regular flea control may be essential for the FAD (flea allergy dermatitis)-prone cat where even a minor infestation could result in severe discomfort and clinical signs.
  • The distinction between treatment of the animal to control adult stages and treatment of the environment to control immature stages has become increasingly blurred as some treatments applied to the animal, such as lufenuron, are targeted only at immature stages in the environment, whilst others have both adulticidal and immature activity, which can be achieved by insecticidal activity alone or by the combination of insecticide with IGR (insect growth regulator) as is the case with the combination of fipronil with (S)-methoprene. Treatments applied directly into the environment may include insecticides and larval growth inhibitors, aimed at stages in the environment only.
  • Wherever possible, monitoring for the presence of fleas, regular vacuuming and washing pets bedding should be considered alongside treatment as part of flea management.
    Print off the owner factsheet on Flea control  Flea control to give to your client.

Flea control via animal administration

  • Eliminate existing infestations of adult fleas by treatment of all animals in the same household with an approved treatment.
    Note that care should be taken to when treating dogs with synthetic Pyrethroids such as permethrin Permethrin when there are cats in the same household.
  • Where there is an established infestation it will often be controlled most quickly by using an insecticide on the animal, with some form of environmental treatment, particularly when there is substantial challenge from the environment.
  • There are a range of treatments available and factors such as numbers of animals, cost, convenience, speed of kill and duration of activity will help to identify the most appropriate treatment for a particular situation. Older treatments that contained, for example, organophosphates, are increasingly less available.
  • Other parasite control needs should be considered alongside flea control to ensure that a suitable spectrum of activity is chosen and that unsuitable combinations of products are avoided. Many treatments are effective against a range of other ecto or even endoparasites in addition to fleas. Refer to individual data sheets or see for more information on spectrum of activity and also contra-indications.

Topical ectoparasiticides

  • Each of these treatments can be used as part of a strategy to control FAD:
    • Imidacloprid  Imidacloprid (Advantage®): this is a chloronicotinyl nitroguanidine compound. It causes inhibition of cholinergic transmission in insects resulting in paralysis and death. Available as a spot-on preparation. It is adulticidal and also larvicidal, and protects against fleas for up to three to four weeks on cats.
    • Imidacloprid  Imidacloprid +moxidectin Moxidectin (Advocate®): moxidectin, which is combined with imidacloprid in this spot-on preparation, is a second generation macrocyclic lactone of the milbemycin family providing acaricidal and endoparasite activity. Treatment is active against fleas for four weeks.
    • Indoxacarb  Indoxacarb (Activyl®): a pro-insecticide that belongs to the oxadiazine family and kills fleas within 24 -48 hours of exposure. It is available as a spot-on solution. The spot-on solution is effective for 4 weeks against fleas and prevents the development of environmental stages for at least 4 weeks. The product kills adult fleas, flea larvae and flea eggs.
    • Fipronil  Fipronil  (Frontline®): belongs to the phenylpyrazole family and kills fleas within 24 hours of exposure. It is available both as a spot-on solution and spray. The spot on solution is effective for up to five weeks against fleas and the spray is effective for up to two months. The product is also acaricidal.
    • Fipronil  Fipronil (Other brands): generic brands containing fipronil are becoming available in the UK. Whilst these are likely to be essentially similar to the original brand, the datasheet should be consulted for details.
    • Fipronil  Fipronil +(S)-methoprene Methoprene (Frontline Combo®): (S)-methoprene is combined with fipronil to provide insect growth regulator (IGR) juvenile hormone analogue activity to inhibit the development of immature flea stages. There is both ovicidal activity against eggs on the animal and larvicidal activity effective against larvae in the environment. The product is effective against adult flea infestations for 4 weeks and prevents development of environmental stages for 6 weeks. The product is also effective against ticks and biting lice.
    • Metaflumizone (Promeris®): metaflumizone is a pyrazoline sodium channel blocker. There is residual activity for up to six weeks following application.
    • Selamectin Selamectin (Stronghold®): this macrocyclic compound has adulticidal, larvicidal and ovicidal properties. It is indicated for treatment at monthly intervals. It has activity against a range of ectoparasites and some endoparasites in addition to fleas.

Orally administered ectoparasiticides

  • Spinosad  Spinosad (Comfortis®): effect on fleas may be seen as soon as 30 minutes after administration in dogs (but may take longer in cats), with 100% efficacy (dead or moribund fleas) within 24 hours. Efficacy lasts for up to 4 weeks, but may drop below the 95% threshold for efficacy in Europe in the 4th week. Given directly into the mouth or mixed with a small portion of food. Activity against adult fleas only. The treatment interval should not be less than 4 weeks of age.
  • Nitenpyram (Capstar®): given directly into the mouth or mixed with a small portion of food. Effect on fleas may be seen as soon as 15 minutes after administration, with 100% efficacy within 24 hours. No sustained activity.
  • Lufenuron  Lufenuron  (Program"): a benzoylurea derivative which when administered with food is quickly absorbed from the gut. It is an inhibitor of chitin synthesis and deposition known as an Insect Development Inhibitor (IDI). An oral suspension formulation is available for treatment of cats. Prevents viable eggs being laid from 24 hours after administration and is effective for a month. Does not have an effect on adult fleas. It is recommended that treatment begins two months prior to the expected flea season and continues throughout the flea season to prevent flea infestations establishing. It can be used as a treatment to control or prevent FAD. There is a separate formulation available for subcutaneous injection that controls and prevents flea infestation for six months.

Prevention of infestation or re-infection

  • Where necessary control should begin before the flea season and continue throughout the flea season. With the advent of central heating and with climate change, the flea season may be extended and may continue throughout the year.
  • Once control of adult fleas from an existing flea problem has been achieved then control needs to be maintained for a period to ensure that all stages in the environment have been eliminated. This can be achieved by repeated treatment of the animal or of the environment for a suitable period. As a general rule of thumb, for an environment where there is no supplementation of infestation from an external source, the warmer it is the quicker fleas will develop, hence the shorter the period of flea development.