Table of Contents
How do flea treatments work?
Why you shouldn’t reapply too early
What if your flea is not working?
What’s the bottom line?
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Is it OK to reapply flea treatment after 2 weeks?
- By Leigha
-
- June 27, 2025
- 2 MIN READ
Can’t get rid of fleas on your pet? Fighting a flea infestation isn’t easy and requires a lot of patience. It’s understandable that you want to find a quick and easy way out to be flea free, but reapplying flea treatment, quicker than usual, to your pet might not be the answer. Keep reading to find out more and what to do in case you’ve applied twice in one month already.
How do flea treatments work?
Most flea treatments are designed to last for around four weeks. That includes spot-ons like Itch Flea Treatment for cats and dogs. Products like such spread through the oils in your pet’s skin and coat, gradually killing fleas over time. Spot-on treatments with the active ingredient, S-Methoprene, don’t just kill adult fleas, they also disrupt the life cycle, stopping eggs from hatching.
So when your pet still has fleas after a couple of weeks, it might not mean the treatment has failed. It just might not be effective at breaking the flea life cycle.
Why you shouldn’t reapply too early
Reapplying flea treatment too soon can be risky. Manufacturers test their products to make sure they’re effective and safe when used as instructed. Using them more than suggested will lead to problems.
Flea treatments are pesticides, and giving another dose before the recommended time can lead to overdose symptoms like:
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Drooling
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Vomiting
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Tremors or twitching
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Skin irritation
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Lethargy
In severe cases, especially with smaller animals, it could lead to poisoning. Cats, in particular, are sensitive to the ingredients in many flea products, so following the recommended dose for the suggested period of time is much safer for your pet.
What if your flea is not working?
If fleas seem completely unaffected and your pet is still miserable after two weeks, here are a few things to consider before reaching for another flea treatment:
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Check your application method
It’s surprisingly easy to mess up a spot-on treatment. You’re meant to apply it directly to the skin, not just onto the fur. And for longer-haired pets, it can be tricky to part the hair enough.
If the product didn’t reach the skin properly, it might not work as expected.
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Consider resistance
Over time, they can develop resistance to certain treatments. If you’ve been using the same product for years, it might be time to switch to something different.
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Treat the environment
Even the best flea treatments can’t tackle every egg, larvae, or pupae lurking in your carpets, furniture, or pet’s bedding. Fleas can survive in the environment for weeks or even months. That’s why a full-blown flea infestation often requires treating your home as well.
Consider using a household flea spray, like the Itch Flea Home Spray as well as washing everything at 60°C, and vacuuming daily for a few weeks. Otherwise, fleas will keep hatching and hopping on.
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Speak to an expert
If you’re unsure whether to reapply, or your pet seems especially uncomfortable, your best bet is to give an expert a call. They might suggest an alternative treatment or approve reapplication under supervision, especially if your pet is suffering. Our friendly and qualified Vet Team at Itch can support with veterinary medicines advice - Contact us here!
What’s the bottom line?
Reapplying flea treatment after just 2 weeks generally isn’t recommended unless specifically advised by an expert or vet. Most products are designed to last a full month, and overusing them could harm your pet.
If the fleas aren’t going away:
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Check that you applied the treatment correctly.
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Treat your home as well as your pet.
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Make sure your flea treatment kills fleas as well as flea eggs.
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When in doubt, chat to an expert for guidance.
Once you’ve tackled a flea infestation, it’s all about staying on top of prevention. Regular monthly treatment, especially in warmer months, will save you a lot of grief. And don’t forget to treat all pets in the household – even if only one seems itchy.
Because when it comes to fleas, if one pet has them, the others almost certainly do too – or soon will.
Here to help your furball.
Our Vet Team are professionally qualified in veterinary medicines advice and they're here to help. Led by Dr Zoe Costigan, we're no nonsense and knowledgeable experts! Nothing makes us happier than helping you be flea and worm free. We're on the usual socials @itchpet, so slide into our DM's, drop us an email or hop on the phone.
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