Flea treatment stopped working? Fix it for your Min Pin

A flea treatment that works for two weeks then loses effect is a classic sign of either product resistance or reinfestation from the environment — and it's frustratingly common with certain spot-ons and supermarket treatments. The most effective prevention depends on your dog's size and weight, your local tick risk, and whether you want a spot-on, collar, or oral treatment. Some widely sold products are significantly less effective than others right now due to flea populations building resistance. To point you at the right thing: what breed and size is your dog, are you in an area with high tick activity, and do you have a preference for treatment type — spot-on, tablet, or collar?

That makes a lot of sense. Frontline (fipronil) has well-documented resistance problems in the UK — flea populations in many areas have adapted to it, which is exactly what you're describing: initial knockdown, then a rebound. For a 5kg Min Pin in a tick-active county like Surrey, I'd move to something with a different active ingredient and longer duration. Can I just check — is she on any other medications, and has she had any reactions to spot-ons before?

Good — that makes this straightforward. I'd go with Bravecto Spot-On for Small Dogs (2–4.5kg is the lower range, but there's a 4.5–10kg pack that covers her at 5kg). It uses fluralaner, which works completely differently from fipronil, so resistance isn't an issue. One application covers fleas and ticks for 12 weeks — so three times a year instead of monthly. It kills fleas within 8 hours and has strong efficacy against the tick species common in Surrey, including Ixodes ricinus. It's prescription-strength and available via licensed online vets on Amazon UK or through your vet. The key thing is it breaks the cycle properly: fleas don't get two weeks to lay eggs and reinfest your home. You'll also want to treat your home once with a household flea spray like Indorex to clear any eggs already in carpets — otherwise even a good product can look like it's failing.

Completely understandable concern. Bravecto has a strong safety profile and the dosing is weight-banded, so the 4.5–10kg version is specifically formulated for dogs her size — she won't be getting a dose scaled down from a large-dog product. It's been through extensive EU and UK licensing. Side effects are uncommon and usually mild (occasional digestive upset in a small number of dogs). The much bigger risk with a dog her size is using an underdosed or resistance-prone product and having a flea infestation take hold — that causes far more stress on a small dog than the treatment itself. If she's had no reactions to spot-ons previously, there's no particular reason to expect one here.

Treating the environment is often what makes the difference. Around 95% of a flea infestation lives off the dog — in carpets, sofas, bedding — so treating just the dog leaves a huge reservoir. Indorex contains an insect growth regulator that stops eggs and larvae developing, so it doesn't just kill adults, it breaks the breeding cycle. One can treats a standard home and lasts up to 12 months. Vacuum thoroughly before you spray, wash her bedding at 60°C, and you should see the problem fully clear within a few weeks. Bravecto plus one Indorex treatment is very likely to be the last time this is a problem for a good while.